Less SIMD.

Bumps [golang.org/x/crypto](https://github.com/golang/crypto) from 0.38.0 to 0.39.0.
- [Commits](https://github.com/golang/crypto/compare/v0.38.0...v0.39.0)

---
updated-dependencies:
- dependency-name: golang.org/x/crypto
  dependency-version: 0.39.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.github/actions/vmactions/template.yml

@@ -0,0 +1,11 @@
+name: VM Actions matrix
+description: VM Actions matrix template
+
+runs:
+  using: composite
+  steps:
+    - uses: ${VMACTIONS}
+      with:
+        usesh: true
+        copyback: false
+        run: . ./test.sh

.github/dependabot.yml

@@ -9,3 +9,7 @@ updates:
     directory: "/" # Location of package manifests
     schedule:
       interval: "daily"
+  - package-ecosystem: "github-actions" # See documentation for possible values
+    directory: "/" # Location of package manifests
+    schedule:
+      interval: "daily"

.github/workflows/bsd.yml

@@ -1,29 +0,0 @@
-name: BSD
-
-on:
-  workflow_dispatch:
-
-jobs:
-  test:
-    runs-on: macos-12
-
-    steps:
-    - uses: actions/checkout@v4
-      with:
-        lfs: 'true'
-
-    - name: Set up
-      uses: actions/setup-go@v4
-      with:
-        go-version: stable
-
-    - name: Build
-      run: GOOS=freebsd go test -c ./...
-
-    - name: Test
-      uses: cross-platform-actions/action@v0.21.1
-      with:
-        operating_system: freebsd
-        version: '13.2'
-        sync_files: runner-to-vm
-        run: find . -name '*.test' -maxdepth 1 -exec {} -test.v \;

.github/workflows/build-test.sh

@@ -0,0 +1,15 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+echo 'set -eu' > test.sh
+
+for p in $(go list ./...); do
+  dir=".${p#github.com/ncruces/go-sqlite3}"
+  name="$(basename "$p").test"
+  (cd ${dir}; go test -c ${BUILDFLAGS:-})
+  [ -f "${dir}/${name}" ] && echo "(cd ${dir}; ./${name} ${TESTFLAGS:-})" >> test.sh
+done
+
+if [[ -v VMACTIONS ]]; then
+  envsubst < .github/actions/vmactions/template.yml > .github/actions/vmactions/action.yml
+fi

.github/workflows/cross.sh

@@ -1,22 +0,0 @@
-#!/usr/bin/env bash
-
-echo android       ; GOOS=android   GOARCH=amd64 go build .
-echo darwin        ; GOOS=darwin    GOARCH=amd64 go build .
-echo dragonfly     ; GOOS=dragonfly GOARCH=amd64 go build .
-echo freebsd       ; GOOS=freebsd   GOARCH=amd64 go build .
-echo illumos       ; GOOS=illumos   GOARCH=amd64 go build .
-echo ios           ; GOOS=ios       GOARCH=amd64 go build .
-echo linux         ; GOOS=linux     GOARCH=amd64 go build .
-echo netbsd        ; GOOS=netbsd    GOARCH=amd64 go build .
-echo openbsd       ; GOOS=openbsd   GOARCH=amd64 go build .
-echo plan9         ; GOOS=plan9     GOARCH=amd64 go build .
-echo solaris       ; GOOS=solaris   GOARCH=amd64 go build .
-echo windows       ; GOOS=windows   GOARCH=amd64 go build .
-# echo aix         ; GOOS=aix       GOARCH=ppc64 go build .
-echo js            ; GOOS=js        GOARCH=wasm  go build .
-echo wasip1        ; GOOS=wasip1    GOARCH=wasm  go build .
-echo darwin-flock  ; GOOS=darwin    GOARCH=amd64 go build -tags sqlite3_flock .
-echo darwin-nosys  ; GOOS=darwin    GOARCH=amd64 go build -tags sqlite3_nosys .
-echo linux-nosys   ; GOOS=linux     GOARCH=amd64 go build -tags sqlite3_nosys .
-echo windows-nosys ; GOOS=windows   GOARCH=amd64 go build -tags sqlite3_nosys .
-echo freebsd-nosys ; GOOS=freebsd   GOARCH=amd64 go build -tags sqlite3_nosys .

.github/workflows/cross.yml

@@ -1,21 +0,0 @@
-name: Cross compile
-
-on:
-  workflow_dispatch:
-
-jobs:
-  test:
-    runs-on: ubuntu-latest
-
-    steps:
-    - uses: actions/checkout@v4
-      with:
-        lfs: 'true'
-
-    - name: Set up
-      uses: actions/setup-go@v4
-      with:
-        go-version: stable
-
-    - name: Build
-      run: .github/workflows/cross.sh

.github/workflows/go.yml

@@ -1,64 +0,0 @@
-name: Go
-
-on:
-  push:
-    branches: [ "main" ]
-  pull_request:
-    branches: [ "main" ]
-  workflow_dispatch:
-
-jobs:
-  test:
-    strategy:
-      matrix:
-        os: [macos-latest, ubuntu-latest, windows-latest]
-    runs-on: ${{ matrix.os }}
-
-    steps:
-    - uses: actions/checkout@v4
-      with:
-        lfs: 'true'
-
-    - name: Set up
-      uses: actions/setup-go@v4
-      with:
-        go-version: stable
-
-    - name: Format
-      run: gofmt -s -w . && git diff --exit-code
-      if: matrix.os != 'windows-latest'
-
-    - name: Tidy
-      run: go mod tidy && git diff --exit-code
-
-    - name: Download
-      run: go mod download
-
-    - name: Verify
-      run: go mod verify
-
-    - name: Vet
-      run: go vet ./...
-
-    - name: Build
-      run: go build -v ./...
-
-    - name: Test
-      run: go test -v ./...
-
-    - name: Test no locks
-      run: go test -v -tags sqlite3_nosys ./tests -run TestDB_nolock
-
-    - name: Test BSD locks
-      run: go test -v -tags sqlite3_flock ./...
-      if: matrix.os == 'macos-latest'
-
-    - name: Coverage report
-      uses: ncruces/go-coverage-report@v0
-      with:
-        chart: true
-        amend: true
-        reuse-go: true
-      if: |
-        github.event_name == 'push' &&
-        matrix.os == 'ubuntu-latest'

.github/workflows/libc.yml

@@ -0,0 +1,23 @@
+name: Benchmark libc
+
+on:
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+jobs:
+  test:
+    strategy:
+      matrix:
+        os: [ubuntu-24.04, ubuntu-24.04-arm, macos-13, macos-15]
+    runs-on: ${{ matrix.os }}
+
+    steps:
+    - uses: actions/checkout@v4
+    - uses: actions/setup-go@v5
+      with: { go-version: stable }
+
+    - name: Benchmark
+      shell: bash
+      run: sqlite3/libc/benchmark.sh

.github/workflows/repro.sh

@@ -0,0 +1,15 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+# Download and build SQLite
+sqlite3/download.sh
+sqlite3/tools.sh
+embed/build.sh
+embed/bcw2/build.sh
+
+# Download and build sqlite-createtable-parser
+util/sql3util/wasm/download.sh
+util/sql3util/wasm/build.sh
+
+# Check diffs
+git diff --exit-code

.github/workflows/repro.yml

@@ -0,0 +1,32 @@
+name: Reproducible build
+
+on:
+  workflow_dispatch:
+
+permissions:
+  contents: read
+  id-token: write
+  attestations: write
+
+jobs:
+  build:
+    strategy:
+      matrix:
+        os: [macos-latest, ubuntu-latest, windows-latest]
+    runs-on: ${{ matrix.os }}
+
+    steps:
+    - uses: ilammy/msvc-dev-cmd@v1
+    - uses: actions/checkout@v4
+
+    - name: Build
+      shell: bash
+      run: .github/workflows/repro.sh
+
+    - uses: actions/attest-build-provenance@v2
+      if: matrix.os == 'ubuntu-latest'
+      with:
+        subject-path: |
+          embed/sqlite3.wasm
+          embed/bcw2/bcw2.wasm
+          util/sql3util/wasm/sql3parse_table.wasm

.github/workflows/test.yml

@@ -0,0 +1,236 @@
+name: Test
+
+on:
+  push:
+    branches: [ 'main' ]
+    paths:
+      - '**.go'
+      - '**.mod'
+      - '**.wasm'
+      - '**.yml'
+  pull_request:
+    branches: [ 'main' ]
+    paths:
+      - '**.go'
+      - '**.mod'
+      - '**.wasm'
+      - '**.yml'
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+jobs:
+  test:
+    strategy:
+      matrix:
+        os: [macos-latest, ubuntu-latest, windows-latest]
+    runs-on: ${{ matrix.os }}
+    permissions:
+      contents: write
+
+    steps:
+    - uses: actions/checkout@v4
+    - uses: actions/setup-go@v5
+      with: { go-version: stable }
+
+    - name: Format
+      run: gofmt -s -w . && git diff --exit-code
+      if: matrix.os != 'windows-latest'
+
+    - name: Tidy
+      run: go mod tidy && git diff --exit-code
+
+    - name: Download
+      run: go mod download
+
+    - name: Verify
+      run: go mod verify
+
+    - name: Vet
+      run: go vet ./...
+
+    - name: Build
+      run: go build -v ./...
+
+    - name: Test
+      run: go test -v ./... -bench . -benchtime=1x
+
+    - name: Test BSD locks
+      run: go test -v -tags sqlite3_flock ./...
+      if: matrix.os != 'windows-latest'
+
+    - name: Test dot locks
+      run: go test -v -tags sqlite3_dotlk ./...
+      if: matrix.os != 'windows-latest'
+
+    - name: Test modules
+      shell: bash
+      run: |
+        go work init .
+        go work use -r embed gormlite
+        go test -v ./embed/bcw2/...
+
+    - name: Test GORM
+      shell: bash
+      run: gormlite/test.sh
+      if: matrix.os != 'windows-latest'
+
+    - name: Collect coverage
+      run: |
+        go get -tool github.com/dave/courtney@v0.4.4
+        go tool courtney
+      if: |
+        github.event_name == 'push' &&
+        matrix.os == 'ubuntu-latest'
+
+    - uses: ncruces/go-coverage-report@v0
+      with:
+        coverage-file: coverage.out
+        chart: true
+        amend: true
+      if: |
+        github.event_name == 'push' &&
+        matrix.os == 'ubuntu-latest'
+
+  test-bsd:
+    strategy:
+      matrix:
+        os:
+          - name: freebsd
+            version: '14.2'
+            flags: '-test.v'
+          - name: netbsd
+            version: '10.1'
+            flags: '-test.v'
+          - name: freebsd
+            arch: arm64
+            version: '14.2'
+            flags: '-test.v -test.short'
+          - name: netbsd
+            arch: arm64
+            version: '10.1'
+            flags: '-test.v -test.short'
+          - name: openbsd
+            version: '7.7'
+            flags: '-test.v -test.short'
+    runs-on: ubuntu-latest
+    needs: test
+
+    steps:
+    - uses: actions/checkout@v4
+
+    - name: Build
+      env:
+        GOOS: ${{ matrix.os.name }}
+        GOARCH: ${{ matrix.os.arch }}
+        TESTFLAGS: ${{ matrix.os.flags }}
+      run: .github/workflows/build-test.sh
+
+    - name: Test
+      uses: cross-platform-actions/action@v0.28.0
+      with:
+        operating_system: ${{ matrix.os.name }}
+        architecture: ${{ matrix.os.arch }}
+        version: ${{ matrix.os.version }}
+        shell: bash
+        run: . ./test.sh
+        sync_files: runner-to-vm
+
+  test-vm:
+    strategy:
+      matrix:
+        os:
+          - name: dragonfly
+            action: 'vmactions/dragonflybsd-vm@v1'
+            tflags: '-test.v'
+          - name: illumos
+            action: 'vmactions/omnios-vm@v1'
+            tflags: '-test.v'
+          - name: solaris
+            action: 'vmactions/solaris-vm@v1'
+            bflags: '-tags sqlite3_dotlk'
+            tflags: '-test.v'
+    runs-on: ubuntu-latest
+    needs: test
+
+    steps:
+    - uses: actions/checkout@v4
+
+    - name: Build
+      env:
+        GOOS: ${{ matrix.os.name }}
+        BUILDFLAGS: ${{ matrix.os.bflags }}
+        TESTFLAGS:  ${{ matrix.os.tflags }}
+        VMACTIONS:  ${{ matrix.os.action }}
+      run: .github/workflows/build-test.sh
+
+    - name: Test
+      uses: ./.github/actions/vmactions
+
+  test-wasip1:
+    runs-on: ubuntu-latest
+    needs: test
+
+    steps:
+    - uses: bytecodealliance/actions/wasmtime/setup@v1
+    - uses: actions/checkout@v4
+    - uses: actions/setup-go@v5
+      with: { go-version: stable }
+
+    - name: Set path
+      run: echo "$(go env GOROOT)/lib/wasm" >> "$GITHUB_PATH"
+
+    - name: Test wasmtime
+      env:
+        GOOS: wasip1
+        GOARCH: wasm
+        GOWASIRUNTIME: wasmtime
+        GOWASIRUNTIMEARGS: '--env CI=true'
+      run: go test -v -short -tags sqlite3_dotlk -skip Example ./...
+
+  test-qemu:
+    runs-on: ubuntu-latest
+    needs: test
+
+    steps:
+    - uses: docker/setup-qemu-action@v3
+    - uses: actions/checkout@v4
+    - uses: actions/setup-go@v5
+      with: { go-version: stable }
+
+    - name: Test 386 (32-bit)
+      run: GOARCH=386 go test -v -short ./...
+
+    - name: Test riscv64 (interpreter)
+      run: GOARCH=riscv64 go test -v -short ./...
+
+    - name: Test ppc64le (interpreter)
+      run: GOARCH=ppc64le go test -v -short ./...
+
+    - name: Test s390x (big-endian)
+      run: GOARCH=s390x go test -v -short -tags sqlite3_dotlk ./...
+
+  test-linuxarm:
+    runs-on: ubuntu-24.04-arm
+    needs: test
+
+    steps:
+    - uses: actions/checkout@v4
+    - uses: actions/setup-go@v5
+      with: { go-version: stable }
+
+    - name: Test
+      run: go test -v ./...
+
+  test-macintel:
+    runs-on: macos-13
+    needs: test
+
+    steps:
+    - uses: actions/checkout@v4
+    - uses: actions/setup-go@v5
+      with: { go-version: stable }
+
+    - name: Test
+      run: go test -v ./...

.gitignore

@@ -13,4 +13,11 @@
 
 # Dependency directories (remove the comment below to include it)
 # vendor/
-tools
+tools
+
+# Go workspace file
+go.work
+go.work.sum
+
+# env file
+.env

README.md

@@ -1,18 +1,39 @@
-# Go bindings to SQLite using Wazero
+# Go bindings to SQLite using wazero
 
 [![Go Reference](https://pkg.go.dev/badge/image)](https://pkg.go.dev/github.com/ncruces/go-sqlite3)
 [![Go Report](https://goreportcard.com/badge/github.com/ncruces/go-sqlite3)](https://goreportcard.com/report/github.com/ncruces/go-sqlite3)
 [![Go Coverage](https://github.com/ncruces/go-sqlite3/wiki/coverage.svg)](https://github.com/ncruces/go-sqlite3/wiki/Test-coverage-report)
 
-Go module `github.com/ncruces/go-sqlite3` wraps a [WASM](https://webassembly.org/) build of [SQLite](https://sqlite.org/),
-and uses [wazero](https://wazero.io/) to provide `cgo`-free SQLite bindings.
+Go module `github.com/ncruces/go-sqlite3` is a `cgo`-free [SQLite](https://sqlite.org/) wrapper.\
+It provides a [`database/sql`](https://pkg.go.dev/database/sql) compatible driver,
+as well as direct access to most of the [C SQLite API](https://sqlite.org/cintro.html).
+
+It wraps a [Wasm](https://webassembly.org/) [build](embed/) of SQLite,
+and uses [wazero](https://wazero.io/) as the runtime.\
+Go, wazero and [`x/sys`](https://pkg.go.dev/golang.org/x/sys) are the _only_ direct dependencies.
+
+### Getting started
+
+Using the [`database/sql`](https://pkg.go.dev/database/sql) driver:
+```go
+
+import "database/sql"
+import _ "github.com/ncruces/go-sqlite3/driver"
+import _ "github.com/ncruces/go-sqlite3/embed"
+
+var version string
+db, _ := sql.Open("sqlite3", "file:demo.db")
+db.QueryRow(`SELECT sqlite_version()`).Scan(&version)
+```
+
+### Packages
 
 - [`github.com/ncruces/go-sqlite3`](https://pkg.go.dev/github.com/ncruces/go-sqlite3)
   wraps the [C SQLite API](https://sqlite.org/cintro.html)
-  ([example usage](https://pkg.go.dev/github.com/ncruces/go-sqlite3#example-package)).
+  ([example](https://pkg.go.dev/github.com/ncruces/go-sqlite3#example-package)).
 - [`github.com/ncruces/go-sqlite3/driver`](https://pkg.go.dev/github.com/ncruces/go-sqlite3/driver)
   provides a [`database/sql`](https://pkg.go.dev/database/sql) driver
-  ([example usage](https://pkg.go.dev/github.com/ncruces/go-sqlite3/driver#example-package)).
+  ([example](https://pkg.go.dev/github.com/ncruces/go-sqlite3/driver#example-package)).
 - [`github.com/ncruces/go-sqlite3/embed`](https://pkg.go.dev/github.com/ncruces/go-sqlite3/embed)
   embeds a build of SQLite into your application.
 - [`github.com/ncruces/go-sqlite3/vfs`](https://pkg.go.dev/github.com/ncruces/go-sqlite3/vfs)
@@ -20,87 +41,93 @@ and uses [wazero](https://wazero.io/) to provide `cgo`-free SQLite bindings.
 - [`github.com/ncruces/go-sqlite3/gormlite`](https://pkg.go.dev/github.com/ncruces/go-sqlite3/gormlite)
   provides a [GORM](https://gorm.io) driver.
 
-### Loadable extensions
-
-- [`github.com/ncruces/go-sqlite3/ext/array`](https://pkg.go.dev/github.com/ncruces/go-sqlite3/ext/blob)
-  provides the [`array`](https://sqlite.org/carray.html) table-valued function.
-- [`github.com/ncruces/go-sqlite3/ext/blob`](https://pkg.go.dev/github.com/ncruces/go-sqlite3/ext/blob)
-  simplifies [incremental BLOB I/O](https://sqlite.org/c3ref/blob_open.html).
-- [`github.com/ncruces/go-sqlite3/ext/csv`](https://pkg.go.dev/github.com/ncruces/go-sqlite3/ext/csv)
-  reads [comma-separated values](https://sqlite.org/csv.html).
-- [`github.com/ncruces/go-sqlite3/ext/lines`](https://pkg.go.dev/github.com/ncruces/go-sqlite3/ext/lines)
-  reads files [line-by-line](https://github.com/asg017/sqlite-lines).
-- [`github.com/ncruces/go-sqlite3/ext/stats`](https://pkg.go.dev/github.com/ncruces/go-sqlite3/ext/stats)
-  provides [statistics functions](https://www.oreilly.com/library/view/sql-in-a/9780596155322/ch04s02.html).
-- [`github.com/ncruces/go-sqlite3/ext/unicode`](https://pkg.go.dev/github.com/ncruces/go-sqlite3/ext/unicode)
-  provides [Unicode aware](https://sqlite.org/src/dir/ext/icu) functions.
-- [`github.com/ncruces/go-sqlite3/vfs/memdb`](https://pkg.go.dev/github.com/ncruces/go-sqlite3/vfs/memdb)
-  implements an in-memory VFS.
-- [`github.com/ncruces/go-sqlite3/vfs/readervfs`](https://pkg.go.dev/github.com/ncruces/go-sqlite3/vfs/readervfs)
-  implements a VFS for immutable databases.
-
 ### Advanced features
 
-- [x] [incremental BLOB I/O](https://sqlite.org/c3ref/blob_open.html)
-- [x] [nested transactions](https://sqlite.org/lang_savepoint.html)
-- [x] [custom functions](https://sqlite.org/c3ref/create_function.html)
-- [x] [virtual tables](https://sqlite.org/vtab.html)
-- [x] [custom VFSes](https://sqlite.org/vfs.html)
-- [x] [online backup](https://sqlite.org/backup.html)
-- [x] [JSON support](https://www.sqlite.org/json1.html)
-- [x] [Unicode support](https://sqlite.org/src/dir/ext/icu)
+- [incremental BLOB I/O](https://sqlite.org/c3ref/blob_open.html)
+  ([example](https://pkg.go.dev/github.com/ncruces/go-sqlite3/ext/blobio#example-package))
+- [nested transactions](https://sqlite.org/lang_savepoint.html)
+  ([example](https://pkg.go.dev/github.com/ncruces/go-sqlite3/driver#example-Savepoint))
+- [custom functions](https://sqlite.org/c3ref/create_function.html)
+  ([example](https://pkg.go.dev/github.com/ncruces/go-sqlite3#example-Conn.CreateFunction))
+- [virtual tables](https://sqlite.org/vtab.html)
+  ([example](https://pkg.go.dev/github.com/ncruces/go-sqlite3#example-CreateModule))
+- [custom VFSes](https://sqlite.org/vfs.html)
+  ([examples](vfs/README.md#custom-vfses))
+- [online backup](https://sqlite.org/backup.html)
+  ([example](https://pkg.go.dev/github.com/ncruces/go-sqlite3/driver#Conn))
+- [JSON support](https://sqlite.org/json1.html)
+  ([example](https://pkg.go.dev/github.com/ncruces/go-sqlite3/driver#example-package-Json))
+- [math functions](https://sqlite.org/lang_mathfunc.html)
+- [full-text search](https://sqlite.org/fts5.html)
+- [geospatial search](https://sqlite.org/geopoly.html)
+- [Unicode support](https://pkg.go.dev/github.com/ncruces/go-sqlite3/ext/unicode)
+- [statistics functions](https://pkg.go.dev/github.com/ncruces/go-sqlite3/ext/stats)
+- [encryption at rest](vfs/adiantum/README.md)
+- [many extensions](ext/README.md)
+- [and more…](embed/README.md)
 
 ### Caveats
 
 This module replaces the SQLite [OS Interface](https://sqlite.org/vfs.html)
-(aka VFS) with a [pure Go](vfs/) implementation.
-This has benefits, but also comes with some drawbacks.
+(aka VFS) with a [pure Go](vfs/) implementation,
+which has advantages and disadvantages.
+Read more about the Go VFS design [here](vfs/README.md).
 
-#### Write-Ahead Logging
+Because each database connection executes within a Wasm sandboxed environment,
+memory usage will be higher than alternatives.
 
-Because WASM does not support shared memory,
-[WAL](https://sqlite.org/wal.html) support is [limited](https://sqlite.org/wal.html#noshm).
+### Testing
 
-To work around this limitation, SQLite is [patched](sqlite3/locking_mode.patch)
-to always use `EXCLUSIVE` locking mode for WAL databases.
+This project aims for [high test coverage](https://github.com/ncruces/go-sqlite3/wiki/Test-coverage-report).
+It also benefits greatly from [SQLite's](https://sqlite.org/testing.html) and
+[wazero's](https://tetrate.io/blog/introducing-wazero-from-tetrate/#:~:text=Rock%2Dsolid%20test%20approach)
+thorough testing.
 
-Because connection pooling is incompatible with `EXCLUSIVE` locking mode,
-to use the [`database/sql`](https://pkg.go.dev/database/sql) driver
-with WAL mode databases you should disable connection pooling by calling
-[`db.SetMaxOpenConns(1)`](https://pkg.go.dev/database/sql#DB.SetMaxOpenConns).
+Every commit is tested on:
+* Linux: amd64, arm64, 386, riscv64, ppc64le, s390x
+* macOS: amd64, arm64
+* Windows: amd64
+* BSD:
+  * FreeBSD: amd64, arm64
+  * OpenBSD: amd64
+  * NetBSD: amd64, arm64
+  * DragonFly BSD: amd64
+* illumos: amd64
+* Solaris: amd64
 
-#### File Locking
+Certain operating system and CPU combinations have some limitations. See the [support matrix](https://github.com/ncruces/go-sqlite3/wiki/Support-matrix) for a complete overview.
 
-POSIX advisory locks, which SQLite uses on Unix, are
-[broken by design](https://sqlite.org/src/artifact/2e8b12?ln=1073-1161).
+The Go VFS is tested by running SQLite's
+[mptest](https://github.com/sqlite/sqlite/blob/master/mptest/mptest.c).
 
-On Linux, macOS and illumos, this module uses
-[OFD locks](https://www.gnu.org/software/libc/manual/html_node/Open-File-Description-Locks.html)
-to synchronize access to database files.
-OFD locks are fully compatible with POSIX advisory locks.
+### Performance
 
-On BSD Unixes, this module uses
-[BSD locks](https://man.freebsd.org/cgi/man.cgi?query=flock&sektion=2).
-On BSD Unixes, BSD locks are fully compatible with POSIX advisory locks.
+Performance of the [`database/sql`](https://pkg.go.dev/database/sql) driver is
+[competitive](https://github.com/cvilsmeier/go-sqlite-bench) with alternatives.
 
-On Windows, this module uses `LockFile`, `LockFileEx`, and `UnlockFile`,
-like SQLite.
-
-On all other platforms, file locking is not supported, and you must use
-[`nolock=1`](https://sqlite.org/uri.html#urinolock)
-to open database files.
-To use the [`database/sql`](https://pkg.go.dev/database/sql) driver
-with `nolock=1` you must disable connection pooling by calling
-[`db.SetMaxOpenConns(1)`](https://pkg.go.dev/database/sql#DB.SetMaxOpenConns).
-
-#### Testing
-
-The pure Go VFS is tested by running SQLite's
-[mptest](https://github.com/sqlite/sqlite/blob/master/mptest/mptest.c)
-on Linux, macOS, Windows and FreeBSD.
-Performance is tested by running
+The Wasm and VFS layers are also benchmarked by running SQLite's
 [speedtest1](https://github.com/sqlite/sqlite/blob/master/test/speedtest1.c).
 
+### Concurrency
+
+This module behaves similarly to SQLite in [multi-thread](https://sqlite.org/threadsafe.html) mode:
+it is goroutine-safe, provided that no single database connection, or object derived from it,
+is used concurrently by multiple goroutines.
+
+The [`database/sql`](https://pkg.go.dev/database/sql) API is safe to use concurrently,
+according to its documentation.
+
+### FAQ, issues, new features
+
+For questions, please see [Discussions](https://github.com/ncruces/go-sqlite3/discussions/categories/q-a).
+
+Also, post there if you used this driver for something interesting
+([_"Show and tell"_](https://github.com/ncruces/go-sqlite3/discussions/categories/show-and-tell)),
+have an [idea](https://github.com/ncruces/go-sqlite3/discussions/categories/ideas)…
+
+The [Issue](https://github.com/ncruces/go-sqlite3/issues) tracker is for bugs,
+and features we're working on, planning to work on, or asking for help with.
+
 ### Alternatives
 
 - [`modernc.org/sqlite`](https://pkg.go.dev/modernc.org/sqlite)

backup.go

@@ -5,8 +5,8 @@ package sqlite3
 // https://sqlite.org/c3ref/backup.html
 type Backup struct {
 	c      *Conn
-	handle uint32
-	otherc uint32
+	handle ptr_t
+	otherc ptr_t
 }
 
 // Backup backs up srcDB on the src connection to the "main" database in dstURI.
@@ -61,8 +61,8 @@ func (src *Conn) BackupInit(srcDB, dstURI string) (*Backup, error) {
 	return src.backupInit(dst, "main", src.handle, srcDB)
 }
 
-func (c *Conn) backupInit(dst uint32, dstName string, src uint32, srcName string) (*Backup, error) {
-	defer c.arena.reset()
+func (c *Conn) backupInit(dst ptr_t, dstName string, src ptr_t, srcName string) (*Backup, error) {
+	defer c.arena.mark()()
 	dstPtr := c.arena.string(dstName)
 	srcPtr := c.arena.string(srcName)
 
@@ -71,19 +71,19 @@ func (c *Conn) backupInit(dst uint32, dstName string, src uint32, srcName string
 		other = src
 	}
 
-	r := c.call(c.api.backupInit,
-		uint64(dst), uint64(dstPtr),
-		uint64(src), uint64(srcPtr))
-	if r == 0 {
+	ptr := ptr_t(c.call("sqlite3_backup_init",
+		stk_t(dst), stk_t(dstPtr),
+		stk_t(src), stk_t(srcPtr)))
+	if ptr == 0 {
 		defer c.closeDB(other)
-		r = c.call(c.api.errcode, uint64(dst))
-		return nil, c.sqlite.error(r, dst)
+		rc := res_t(c.call("sqlite3_errcode", stk_t(dst)))
+		return nil, c.sqlite.error(rc, dst)
 	}
 
 	return &Backup{
 		c:      c,
 		otherc: other,
-		handle: uint32(r),
+		handle: ptr,
 	}, nil
 }
 
@@ -97,10 +97,10 @@ func (b *Backup) Close() error {
 		return nil
 	}
 
-	r := b.c.call(b.c.api.backupFinish, uint64(b.handle))
+	rc := res_t(b.c.call("sqlite3_backup_finish", stk_t(b.handle)))
 	b.c.closeDB(b.otherc)
 	b.handle = 0
-	return b.c.error(r)
+	return b.c.error(rc)
 }
 
 // Step copies up to nPage pages between the source and destination databases.
@@ -108,11 +108,11 @@ func (b *Backup) Close() error {
 //
 // https://sqlite.org/c3ref/backup_finish.html#sqlite3backupstep
 func (b *Backup) Step(nPage int) (done bool, err error) {
-	r := b.c.call(b.c.api.backupStep, uint64(b.handle), uint64(nPage))
-	if r == _DONE {
+	rc := res_t(b.c.call("sqlite3_backup_step", stk_t(b.handle), stk_t(nPage)))
+	if rc == _DONE {
 		return true, nil
 	}
-	return false, b.c.error(r)
+	return false, b.c.error(rc)
 }
 
 // Remaining returns the number of pages still to be backed up
@@ -120,8 +120,8 @@ func (b *Backup) Step(nPage int) (done bool, err error) {
 //
 // https://sqlite.org/c3ref/backup_finish.html#sqlite3backupremaining
 func (b *Backup) Remaining() int {
-	r := b.c.call(b.c.api.backupRemaining, uint64(b.handle))
-	return int(r)
+	n := int32(b.c.call("sqlite3_backup_remaining", stk_t(b.handle)))
+	return int(n)
 }
 
 // PageCount returns the total number of pages in the source database
@@ -129,6 +129,6 @@ func (b *Backup) Remaining() int {
 //
 // https://sqlite.org/c3ref/backup_finish.html#sqlite3backuppagecount
 func (b *Backup) PageCount() int {
-	r := b.c.call(b.c.api.backupPageCount, uint64(b.handle))
-	return int(r)
+	n := int32(b.c.call("sqlite3_backup_pagecount", stk_t(b.handle)))
+	return int(n)
 }

blob.go

@@ -20,7 +20,9 @@ type Blob struct {
 	c      *Conn
 	bytes  int64
 	offset int64
-	handle uint32
+	handle ptr_t
+	bufptr ptr_t
+	buflen int64
 }
 
 var _ io.ReadWriteSeeker = &Blob{}
@@ -29,29 +31,32 @@ var _ io.ReadWriteSeeker = &Blob{}
 //
 // https://sqlite.org/c3ref/blob_open.html
 func (c *Conn) OpenBlob(db, table, column string, row int64, write bool) (*Blob, error) {
-	c.checkInterrupt()
-	defer c.arena.reset()
+	if c.interrupt.Err() != nil {
+		return nil, INTERRUPT
+	}
+
+	defer c.arena.mark()()
 	blobPtr := c.arena.new(ptrlen)
 	dbPtr := c.arena.string(db)
 	tablePtr := c.arena.string(table)
 	columnPtr := c.arena.string(column)
 
-	var flags uint64
+	var flags int32
 	if write {
 		flags = 1
 	}
 
-	r := c.call(c.api.blobOpen, uint64(c.handle),
-		uint64(dbPtr), uint64(tablePtr), uint64(columnPtr),
-		uint64(row), flags, uint64(blobPtr))
+	rc := res_t(c.call("sqlite3_blob_open", stk_t(c.handle),
+		stk_t(dbPtr), stk_t(tablePtr), stk_t(columnPtr),
+		stk_t(row), stk_t(flags), stk_t(blobPtr)))
 
-	if err := c.error(r); err != nil {
+	if err := c.error(rc); err != nil {
 		return nil, err
 	}
 
 	blob := Blob{c: c}
-	blob.handle = util.ReadUint32(c.mod, blobPtr)
-	blob.bytes = int64(c.call(c.api.blobBytes, uint64(blob.handle)))
+	blob.handle = util.Read32[ptr_t](c.mod, blobPtr)
+	blob.bytes = int64(int32(c.call("sqlite3_blob_bytes", stk_t(blob.handle))))
 	return &blob, nil
 }
 
@@ -65,10 +70,10 @@ func (b *Blob) Close() error {
 		return nil
 	}
 
-	r := b.c.call(b.c.api.blobClose, uint64(b.handle))
-
+	rc := res_t(b.c.call("sqlite3_blob_close", stk_t(b.handle)))
+	b.c.free(b.bufptr)
 	b.handle = 0
-	return b.c.error(r)
+	return b.c.error(rc)
 }
 
 // Size returns the size of the BLOB in bytes.
@@ -86,18 +91,19 @@ func (b *Blob) Read(p []byte) (n int, err error) {
 		return 0, io.EOF
 	}
 
-	avail := b.bytes - b.offset
 	want := int64(len(p))
+	avail := b.bytes - b.offset
 	if want > avail {
 		want = avail
 	}
+	if want > b.buflen {
+		b.bufptr = b.c.realloc(b.bufptr, want)
+		b.buflen = want
+	}
 
-	ptr := b.c.new(uint64(want))
-	defer b.c.free(ptr)
-
-	r := b.c.call(b.c.api.blobRead, uint64(b.handle),
-		uint64(ptr), uint64(want), uint64(b.offset))
-	err = b.c.error(r)
+	rc := res_t(b.c.call("sqlite3_blob_read", stk_t(b.handle),
+		stk_t(b.bufptr), stk_t(want), stk_t(b.offset)))
+	err = b.c.error(rc)
 	if err != nil {
 		return 0, err
 	}
@@ -106,7 +112,7 @@ func (b *Blob) Read(p []byte) (n int, err error) {
 		err = io.EOF
 	}
 
-	copy(p, util.View(b.c.mod, ptr, uint64(want)))
+	copy(p, util.View(b.c.mod, b.bufptr, want))
 	return int(want), err
 }
 
@@ -123,19 +129,20 @@ func (b *Blob) WriteTo(w io.Writer) (n int64, err error) {
 	if want > avail {
 		want = avail
 	}
-
-	ptr := b.c.new(uint64(want))
-	defer b.c.free(ptr)
+	if want > b.buflen {
+		b.bufptr = b.c.realloc(b.bufptr, want)
+		b.buflen = want
+	}
 
 	for want > 0 {
-		r := b.c.call(b.c.api.blobRead, uint64(b.handle),
-			uint64(ptr), uint64(want), uint64(b.offset))
-		err = b.c.error(r)
+		rc := res_t(b.c.call("sqlite3_blob_read", stk_t(b.handle),
+			stk_t(b.bufptr), stk_t(want), stk_t(b.offset)))
+		err = b.c.error(rc)
 		if err != nil {
 			return n, err
 		}
 
-		mem := util.View(b.c.mod, ptr, uint64(want))
+		mem := util.View(b.c.mod, b.bufptr, want)
 		m, err := w.Write(mem[:want])
 		b.offset += int64(m)
 		n += int64(m)
@@ -143,6 +150,7 @@ func (b *Blob) WriteTo(w io.Writer) (n int64, err error) {
 			return n, err
 		}
 		if int64(m) != want {
+			// notest // Write misbehaving
 			return n, io.ErrShortWrite
 		}
 
@@ -158,12 +166,16 @@ func (b *Blob) WriteTo(w io.Writer) (n int64, err error) {
 //
 // https://sqlite.org/c3ref/blob_write.html
 func (b *Blob) Write(p []byte) (n int, err error) {
-	ptr := b.c.newBytes(p)
-	defer b.c.free(ptr)
+	want := int64(len(p))
+	if want > b.buflen {
+		b.bufptr = b.c.realloc(b.bufptr, want)
+		b.buflen = want
+	}
+	util.WriteBytes(b.c.mod, b.bufptr, p)
 
-	r := b.c.call(b.c.api.blobWrite, uint64(b.handle),
-		uint64(ptr), uint64(len(p)), uint64(b.offset))
-	err = b.c.error(r)
+	rc := res_t(b.c.call("sqlite3_blob_write", stk_t(b.handle),
+		stk_t(b.bufptr), stk_t(want), stk_t(b.offset)))
+	err = b.c.error(rc)
 	if err != nil {
 		return 0, err
 	}
@@ -186,17 +198,18 @@ func (b *Blob) ReadFrom(r io.Reader) (n int64, err error) {
 	if want < 1 {
 		want = 1
 	}
-
-	ptr := b.c.new(uint64(want))
-	defer b.c.free(ptr)
+	if want > b.buflen {
+		b.bufptr = b.c.realloc(b.bufptr, want)
+		b.buflen = want
+	}
 
 	for {
-		mem := util.View(b.c.mod, ptr, uint64(want))
+		mem := util.View(b.c.mod, b.bufptr, want)
 		m, err := r.Read(mem[:want])
 		if m > 0 {
-			r := b.c.call(b.c.api.blobWrite, uint64(b.handle),
-				uint64(ptr), uint64(m), uint64(b.offset))
-			err := b.c.error(r)
+			rc := res_t(b.c.call("sqlite3_blob_write", stk_t(b.handle),
+				stk_t(b.bufptr), stk_t(m), stk_t(b.offset)))
+			err := b.c.error(rc)
 			if err != nil {
 				return n, err
 			}
@@ -243,8 +256,11 @@ func (b *Blob) Seek(offset int64, whence int) (int64, error) {
 //
 // https://sqlite.org/c3ref/blob_reopen.html
 func (b *Blob) Reopen(row int64) error {
-	err := b.c.error(b.c.call(b.c.api.blobReopen, uint64(b.handle), uint64(row)))
-	b.bytes = int64(b.c.call(b.c.api.blobBytes, uint64(b.handle)))
+	if b.c.interrupt.Err() != nil {
+		return INTERRUPT
+	}
+	err := b.c.error(res_t(b.c.call("sqlite3_blob_reopen", stk_t(b.handle), stk_t(row))))
+	b.bytes = int64(int32(b.c.call("sqlite3_blob_bytes", stk_t(b.handle))))
 	b.offset = 0
 	return err
 }

config.go

@@ -0,0 +1,397 @@
+package sqlite3
+
+import (
+	"context"
+	"fmt"
+	"strconv"
+	"sync/atomic"
+
+	"github.com/tetratelabs/wazero/api"
+
+	"github.com/ncruces/go-sqlite3/internal/util"
+	"github.com/ncruces/go-sqlite3/vfs"
+)
+
+// Config makes configuration changes to a database connection.
+// Only boolean configuration options are supported.
+// Called with no arg reads the current configuration value,
+// called with one arg sets and returns the new value.
+//
+// https://sqlite.org/c3ref/db_config.html
+func (c *Conn) Config(op DBConfig, arg ...bool) (bool, error) {
+	if op < DBCONFIG_ENABLE_FKEY || op > DBCONFIG_REVERSE_SCANORDER {
+		return false, MISUSE
+	}
+
+	// We need to call sqlite3_db_config, a variadic function.
+	// We only support the `int int*` variants.
+	// The int is a three-valued bool: -1 queries, 0/1 sets false/true.
+	// The int* points to where new state will be written to.
+	// The vararg is a pointer to an array containing these arguments:
+	// an int and an int* pointing to that int.
+
+	defer c.arena.mark()()
+	argsPtr := c.arena.new(intlen + ptrlen)
+
+	var flag int32
+	switch {
+	case len(arg) == 0:
+		flag = -1
+	case arg[0]:
+		flag = 1
+	}
+
+	util.Write32(c.mod, argsPtr+0*ptrlen, flag)
+	util.Write32(c.mod, argsPtr+1*ptrlen, argsPtr)
+
+	rc := res_t(c.call("sqlite3_db_config", stk_t(c.handle),
+		stk_t(op), stk_t(argsPtr)))
+	return util.ReadBool(c.mod, argsPtr), c.error(rc)
+}
+
+var defaultLogger atomic.Pointer[func(code ExtendedErrorCode, msg string)]
+
+// ConfigLog sets up the default error logging callback for new connections.
+//
+// https://sqlite.org/errlog.html
+func ConfigLog(cb func(code ExtendedErrorCode, msg string)) {
+	defaultLogger.Store(&cb)
+}
+
+// ConfigLog sets up the error logging callback for the connection.
+//
+// https://sqlite.org/errlog.html
+func (c *Conn) ConfigLog(cb func(code ExtendedErrorCode, msg string)) error {
+	var enable int32
+	if cb != nil {
+		enable = 1
+	}
+	rc := res_t(c.call("sqlite3_config_log_go", stk_t(enable)))
+	if err := c.error(rc); err != nil {
+		return err
+	}
+	c.log = cb
+	return nil
+}
+
+func logCallback(ctx context.Context, mod api.Module, _ ptr_t, iCode res_t, zMsg ptr_t) {
+	if c, ok := ctx.Value(connKey{}).(*Conn); ok && c.log != nil {
+		msg := util.ReadString(mod, zMsg, _MAX_LENGTH)
+		c.log(xErrorCode(iCode), msg)
+	}
+}
+
+// Log writes a message into the error log established by [Conn.ConfigLog].
+//
+// https://sqlite.org/c3ref/log.html
+func (c *Conn) Log(code ExtendedErrorCode, format string, a ...any) {
+	if c.log != nil {
+		c.log(code, fmt.Sprintf(format, a...))
+	}
+}
+
+// FileControl allows low-level control of database files.
+// Only a subset of opcodes are supported.
+//
+// https://sqlite.org/c3ref/file_control.html
+func (c *Conn) FileControl(schema string, op FcntlOpcode, arg ...any) (any, error) {
+	defer c.arena.mark()()
+	ptr := c.arena.new(max(ptrlen, intlen))
+
+	var schemaPtr ptr_t
+	if schema != "" {
+		schemaPtr = c.arena.string(schema)
+	}
+
+	var rc res_t
+	var ret any
+	switch op {
+	default:
+		return nil, MISUSE
+
+	case FCNTL_RESET_CACHE, FCNTL_NULL_IO:
+		rc = res_t(c.call("sqlite3_file_control",
+			stk_t(c.handle), stk_t(schemaPtr),
+			stk_t(op), 0))
+
+	case FCNTL_PERSIST_WAL, FCNTL_POWERSAFE_OVERWRITE:
+		var flag int32
+		switch {
+		case len(arg) == 0:
+			flag = -1
+		case arg[0]:
+			flag = 1
+		}
+		util.Write32(c.mod, ptr, flag)
+		rc = res_t(c.call("sqlite3_file_control",
+			stk_t(c.handle), stk_t(schemaPtr),
+			stk_t(op), stk_t(ptr)))
+		ret = util.ReadBool(c.mod, ptr)
+
+	case FCNTL_CHUNK_SIZE:
+		util.Write32(c.mod, ptr, int32(arg[0].(int)))
+		rc = res_t(c.call("sqlite3_file_control",
+			stk_t(c.handle), stk_t(schemaPtr),
+			stk_t(op), stk_t(ptr)))
+
+	case FCNTL_RESERVE_BYTES:
+		bytes := -1
+		if len(arg) > 0 {
+			bytes = arg[0].(int)
+		}
+		util.Write32(c.mod, ptr, int32(bytes))
+		rc = res_t(c.call("sqlite3_file_control",
+			stk_t(c.handle), stk_t(schemaPtr),
+			stk_t(op), stk_t(ptr)))
+		ret = int(util.Read32[int32](c.mod, ptr))
+
+	case FCNTL_DATA_VERSION:
+		rc = res_t(c.call("sqlite3_file_control",
+			stk_t(c.handle), stk_t(schemaPtr),
+			stk_t(op), stk_t(ptr)))
+		ret = util.Read32[uint32](c.mod, ptr)
+
+	case FCNTL_LOCKSTATE:
+		rc = res_t(c.call("sqlite3_file_control",
+			stk_t(c.handle), stk_t(schemaPtr),
+			stk_t(op), stk_t(ptr)))
+		ret = util.Read32[vfs.LockLevel](c.mod, ptr)
+
+	case FCNTL_VFS_POINTER:
+		rc = res_t(c.call("sqlite3_file_control",
+			stk_t(c.handle), stk_t(schemaPtr),
+			stk_t(op), stk_t(ptr)))
+		if rc == _OK {
+			const zNameOffset = 16
+			ptr = util.Read32[ptr_t](c.mod, ptr)
+			ptr = util.Read32[ptr_t](c.mod, ptr+zNameOffset)
+			name := util.ReadString(c.mod, ptr, _MAX_NAME)
+			ret = vfs.Find(name)
+		}
+
+	case FCNTL_FILE_POINTER, FCNTL_JOURNAL_POINTER:
+		rc = res_t(c.call("sqlite3_file_control",
+			stk_t(c.handle), stk_t(schemaPtr),
+			stk_t(op), stk_t(ptr)))
+		if rc == _OK {
+			const fileHandleOffset = 4
+			ptr = util.Read32[ptr_t](c.mod, ptr)
+			ptr = util.Read32[ptr_t](c.mod, ptr+fileHandleOffset)
+			ret = util.GetHandle(c.ctx, ptr)
+		}
+	}
+
+	if err := c.error(rc); err != nil {
+		return nil, err
+	}
+	return ret, nil
+}
+
+// Limit allows the size of various constructs to be
+// limited on a connection by connection basis.
+//
+// https://sqlite.org/c3ref/limit.html
+func (c *Conn) Limit(id LimitCategory, value int) int {
+	v := int32(c.call("sqlite3_limit", stk_t(c.handle), stk_t(id), stk_t(value)))
+	return int(v)
+}
+
+// SetAuthorizer registers an authorizer callback with the database connection.
+//
+// https://sqlite.org/c3ref/set_authorizer.html
+func (c *Conn) SetAuthorizer(cb func(action AuthorizerActionCode, name3rd, name4th, schema, inner string) AuthorizerReturnCode) error {
+	var enable int32
+	if cb != nil {
+		enable = 1
+	}
+	rc := res_t(c.call("sqlite3_set_authorizer_go", stk_t(c.handle), stk_t(enable)))
+	if err := c.error(rc); err != nil {
+		return err
+	}
+	c.authorizer = cb
+	return nil
+
+}
+
+func authorizerCallback(ctx context.Context, mod api.Module, pDB ptr_t, action AuthorizerActionCode, zName3rd, zName4th, zSchema, zInner ptr_t) (rc AuthorizerReturnCode) {
+	if c, ok := ctx.Value(connKey{}).(*Conn); ok && c.handle == pDB && c.authorizer != nil {
+		var name3rd, name4th, schema, inner string
+		if zName3rd != 0 {
+			name3rd = util.ReadString(mod, zName3rd, _MAX_NAME)
+		}
+		if zName4th != 0 {
+			name4th = util.ReadString(mod, zName4th, _MAX_NAME)
+		}
+		if zSchema != 0 {
+			schema = util.ReadString(mod, zSchema, _MAX_NAME)
+		}
+		if zInner != 0 {
+			inner = util.ReadString(mod, zInner, _MAX_NAME)
+		}
+		rc = c.authorizer(action, name3rd, name4th, schema, inner)
+	}
+	return rc
+}
+
+// Trace registers a trace callback function against the database connection.
+//
+// https://sqlite.org/c3ref/trace_v2.html
+func (c *Conn) Trace(mask TraceEvent, cb func(evt TraceEvent, arg1 any, arg2 any) error) error {
+	rc := res_t(c.call("sqlite3_trace_go", stk_t(c.handle), stk_t(mask)))
+	if err := c.error(rc); err != nil {
+		return err
+	}
+	c.trace = cb
+	return nil
+}
+
+func traceCallback(ctx context.Context, mod api.Module, evt TraceEvent, pDB, pArg1, pArg2 ptr_t) (rc res_t) {
+	if c, ok := ctx.Value(connKey{}).(*Conn); ok && c.handle == pDB && c.trace != nil {
+		var arg1, arg2 any
+		if evt == TRACE_CLOSE {
+			arg1 = c
+		} else {
+			for _, s := range c.stmts {
+				if pArg1 == s.handle {
+					arg1 = s
+					switch evt {
+					case TRACE_STMT:
+						arg2 = s.SQL()
+					case TRACE_PROFILE:
+						arg2 = util.Read64[int64](mod, pArg2)
+					}
+					break
+				}
+			}
+		}
+		if arg1 != nil {
+			_, rc = errorCode(c.trace(evt, arg1, arg2), ERROR)
+		}
+	}
+	return rc
+}
+
+// WALCheckpoint checkpoints a WAL database.
+//
+// https://sqlite.org/c3ref/wal_checkpoint_v2.html
+func (c *Conn) WALCheckpoint(schema string, mode CheckpointMode) (nLog, nCkpt int, err error) {
+	if c.interrupt.Err() != nil {
+		return 0, 0, INTERRUPT
+	}
+
+	defer c.arena.mark()()
+	nLogPtr := c.arena.new(ptrlen)
+	nCkptPtr := c.arena.new(ptrlen)
+	schemaPtr := c.arena.string(schema)
+	rc := res_t(c.call("sqlite3_wal_checkpoint_v2",
+		stk_t(c.handle), stk_t(schemaPtr), stk_t(mode),
+		stk_t(nLogPtr), stk_t(nCkptPtr)))
+	nLog = int(util.Read32[int32](c.mod, nLogPtr))
+	nCkpt = int(util.Read32[int32](c.mod, nCkptPtr))
+	return nLog, nCkpt, c.error(rc)
+}
+
+// WALAutoCheckpoint configures WAL auto-checkpoints.
+//
+// https://sqlite.org/c3ref/wal_autocheckpoint.html
+func (c *Conn) WALAutoCheckpoint(pages int) error {
+	rc := res_t(c.call("sqlite3_wal_autocheckpoint", stk_t(c.handle), stk_t(pages)))
+	return c.error(rc)
+}
+
+// WALHook registers a callback function to be invoked
+// each time data is committed to a database in WAL mode.
+//
+// https://sqlite.org/c3ref/wal_hook.html
+func (c *Conn) WALHook(cb func(db *Conn, schema string, pages int) error) {
+	var enable int32
+	if cb != nil {
+		enable = 1
+	}
+	c.call("sqlite3_wal_hook_go", stk_t(c.handle), stk_t(enable))
+	c.wal = cb
+}
+
+func walCallback(ctx context.Context, mod api.Module, _, pDB, zSchema ptr_t, pages int32) (rc res_t) {
+	if c, ok := ctx.Value(connKey{}).(*Conn); ok && c.handle == pDB && c.wal != nil {
+		schema := util.ReadString(mod, zSchema, _MAX_NAME)
+		err := c.wal(c, schema, int(pages))
+		_, rc = errorCode(err, ERROR)
+	}
+	return rc
+}
+
+// AutoVacuumPages registers a autovacuum compaction amount callback.
+//
+// https://sqlite.org/c3ref/autovacuum_pages.html
+func (c *Conn) AutoVacuumPages(cb func(schema string, dbPages, freePages, bytesPerPage uint) uint) error {
+	var funcPtr ptr_t
+	if cb != nil {
+		funcPtr = util.AddHandle(c.ctx, cb)
+	}
+	rc := res_t(c.call("sqlite3_autovacuum_pages_go", stk_t(c.handle), stk_t(funcPtr)))
+	return c.error(rc)
+}
+
+func autoVacuumCallback(ctx context.Context, mod api.Module, pApp, zSchema ptr_t, nDbPage, nFreePage, nBytePerPage uint32) uint32 {
+	fn := util.GetHandle(ctx, pApp).(func(schema string, dbPages, freePages, bytesPerPage uint) uint)
+	schema := util.ReadString(mod, zSchema, _MAX_NAME)
+	return uint32(fn(schema, uint(nDbPage), uint(nFreePage), uint(nBytePerPage)))
+}
+
+// SoftHeapLimit imposes a soft limit on heap size.
+//
+// https://sqlite.org/c3ref/hard_heap_limit64.html
+func (c *Conn) SoftHeapLimit(n int64) int64 {
+	return int64(c.call("sqlite3_soft_heap_limit64", stk_t(n)))
+}
+
+// HardHeapLimit imposes a hard limit on heap size.
+//
+// https://sqlite.org/c3ref/hard_heap_limit64.html
+func (c *Conn) HardHeapLimit(n int64) int64 {
+	return int64(c.call("sqlite3_hard_heap_limit64", stk_t(n)))
+}
+
+// EnableChecksums enables checksums on a database.
+//
+// https://sqlite.org/cksumvfs.html
+func (c *Conn) EnableChecksums(schema string) error {
+	r, err := c.FileControl(schema, FCNTL_RESERVE_BYTES)
+	if err != nil {
+		return err
+	}
+	if r == 8 {
+		// Correct value, enabled.
+		return nil
+	}
+	if r == 0 {
+		// Default value, enable.
+		_, err = c.FileControl(schema, FCNTL_RESERVE_BYTES, 8)
+		if err != nil {
+			return err
+		}
+		r, err = c.FileControl(schema, FCNTL_RESERVE_BYTES)
+		if err != nil {
+			return err
+		}
+	}
+	if r != 8 {
+		// Invalid value.
+		return util.ErrorString("sqlite3: reserve bytes must be 8, is: " + strconv.Itoa(r.(int)))
+	}
+
+	// VACUUM the database.
+	if schema != "" {
+		err = c.Exec(`VACUUM ` + QuoteIdentifier(schema))
+	} else {
+		err = c.Exec(`VACUUM`)
+	}
+	if err != nil {
+		return err
+	}
+
+	// Checkpoint the WAL.
+	_, _, err = c.WALCheckpoint(schema, CHECKPOINT_FULL)
+	return err
+}

conn.go

@@ -2,14 +2,19 @@ package sqlite3
 
 import (
 	"context"
-	"errors"
 	"fmt"
+	"iter"
+	"math"
+	"math/rand"
 	"net/url"
 	"runtime"
 	"strings"
+	"time"
+
+	"github.com/tetratelabs/wazero/api"
 
 	"github.com/ncruces/go-sqlite3/internal/util"
-	"github.com/tetratelabs/wazero/api"
+	"github.com/ncruces/go-sqlite3/vfs"
 )
 
 // Conn is a database connection handle.
@@ -19,21 +24,39 @@ import (
 type Conn struct {
 	*sqlite
 
-	interrupt context.Context
-	pending   *Stmt
-	arena     arena
+	interrupt  context.Context
+	stmts      []*Stmt
+	busy       func(context.Context, int) bool
+	log        func(xErrorCode, string)
+	collation  func(*Conn, string)
+	wal        func(*Conn, string, int) error
+	trace      func(TraceEvent, any, any) error
+	authorizer func(AuthorizerActionCode, string, string, string, string) AuthorizerReturnCode
+	update     func(AuthorizerActionCode, string, string, int64)
+	commit     func() bool
+	rollback   func()
 
-	handle uint32
+	busy1st time.Time
+	busylst time.Time
+	arena   arena
+	handle  ptr_t
+	gosched uint8
 }
 
-// Open calls [OpenFlags] with [OPEN_READWRITE], [OPEN_CREATE], [OPEN_URI] and [OPEN_NOFOLLOW].
+// Open calls [OpenFlags] with [OPEN_READWRITE], [OPEN_CREATE] and [OPEN_URI].
 func Open(filename string) (*Conn, error) {
-	return newConn(filename, OPEN_READWRITE|OPEN_CREATE|OPEN_URI|OPEN_NOFOLLOW)
+	return newConn(context.Background(), filename, OPEN_READWRITE|OPEN_CREATE|OPEN_URI)
+}
+
+// OpenContext is like [Open] but includes a context,
+// which is used to interrupt the process of opening the connection.
+func OpenContext(ctx context.Context, filename string) (*Conn, error) {
+	return newConn(ctx, filename, OPEN_READWRITE|OPEN_CREATE|OPEN_URI)
 }
 
 // OpenFlags opens an SQLite database file as specified by the filename argument.
 //
-// If none of the required flags is used, a combination of [OPEN_READWRITE] and [OPEN_CREATE] is used.
+// If none of the required flags are used, a combination of [OPEN_READWRITE] and [OPEN_CREATE] is used.
 // If a URI filename is used, PRAGMA statements to execute can be specified using "_pragma":
 //
 //	sqlite3.Open("file:demo.db?_pragma=busy_timeout(10000)")
@@ -43,48 +66,61 @@ func OpenFlags(filename string, flags OpenFlag) (*Conn, error) {
 	if flags&(OPEN_READONLY|OPEN_READWRITE|OPEN_CREATE) == 0 {
 		flags |= OPEN_READWRITE | OPEN_CREATE
 	}
-	return newConn(filename, flags)
+	return newConn(context.Background(), filename, flags)
 }
 
-type connKey struct{}
+type connKey = util.ConnKey
 
-func newConn(filename string, flags OpenFlag) (conn *Conn, err error) {
-	sqlite, err := instantiateSQLite()
+func newConn(ctx context.Context, filename string, flags OpenFlag) (ret *Conn, _ error) {
+	err := ctx.Err()
+	if err != nil {
+		return nil, err
+	}
+
+	c := &Conn{interrupt: ctx}
+	c.sqlite, err = instantiateSQLite()
 	if err != nil {
 		return nil, err
 	}
 	defer func() {
-		if conn == nil {
-			sqlite.close()
+		if ret == nil {
+			c.Close()
+			c.sqlite.close()
 		} else {
-			runtime.SetFinalizer(conn, util.Finalizer[Conn](3))
+			c.interrupt = context.Background()
 		}
 	}()
 
-	c := &Conn{sqlite: sqlite}
-	c.arena = c.newArena(1024)
 	c.ctx = context.WithValue(c.ctx, connKey{}, c)
+	if logger := defaultLogger.Load(); logger != nil {
+		c.ConfigLog(*logger)
+	}
+	c.arena = c.newArena()
 	c.handle, err = c.openDB(filename, flags)
+	if err == nil {
+		err = initExtensions(c)
+	}
 	if err != nil {
 		return nil, err
 	}
 	return c, nil
 }
 
-func (c *Conn) openDB(filename string, flags OpenFlag) (uint32, error) {
-	defer c.arena.reset()
+func (c *Conn) openDB(filename string, flags OpenFlag) (ptr_t, error) {
+	defer c.arena.mark()()
 	connPtr := c.arena.new(ptrlen)
 	namePtr := c.arena.string(filename)
 
 	flags |= OPEN_EXRESCODE
-	r := c.call(c.api.open, uint64(namePtr), uint64(connPtr), uint64(flags), 0)
+	rc := res_t(c.call("sqlite3_open_v2", stk_t(namePtr), stk_t(connPtr), stk_t(flags), 0))
 
-	handle := util.ReadUint32(c.mod, connPtr)
-	if err := c.sqlite.error(r, handle); err != nil {
+	handle := util.Read32[ptr_t](c.mod, connPtr)
+	if err := c.sqlite.error(rc, handle); err != nil {
 		c.closeDB(handle)
 		return 0, err
 	}
 
+	c.call("sqlite3_progress_handler_go", stk_t(handle), 1000)
 	if flags|OPEN_URI != 0 && strings.HasPrefix(filename, "file:") {
 		var pragmas strings.Builder
 		if _, after, ok := strings.Cut(filename, "?"); ok {
@@ -92,28 +128,25 @@ func (c *Conn) openDB(filename string, flags OpenFlag) (uint32, error) {
 			for _, p := range query["_pragma"] {
 				pragmas.WriteString(`PRAGMA `)
 				pragmas.WriteString(p)
-				pragmas.WriteByte(';')
+				pragmas.WriteString(`;`)
 			}
 		}
-
-		c.arena.reset()
-		pragmaPtr := c.arena.string(pragmas.String())
-		r := c.call(c.api.exec, uint64(handle), uint64(pragmaPtr), 0, 0, 0)
-		if err := c.sqlite.error(r, handle, pragmas.String()); err != nil {
-			if errors.Is(err, ERROR) {
+		if pragmas.Len() != 0 {
+			pragmaPtr := c.arena.string(pragmas.String())
+			rc := res_t(c.call("sqlite3_exec", stk_t(handle), stk_t(pragmaPtr), 0, 0, 0))
+			if err := c.sqlite.error(rc, handle, pragmas.String()); err != nil {
 				err = fmt.Errorf("sqlite3: invalid _pragma: %w", err)
+				c.closeDB(handle)
+				return 0, err
 			}
-			c.closeDB(handle)
-			return 0, err
 		}
 	}
-
 	return handle, nil
 }
 
-func (c *Conn) closeDB(handle uint32) {
-	r := c.call(c.api.closeZombie, uint64(handle))
-	if err := c.sqlite.error(r, handle); err != nil {
+func (c *Conn) closeDB(handle ptr_t) {
+	rc := res_t(c.call("sqlite3_close_v2", stk_t(handle)))
+	if err := c.sqlite.error(rc, handle); err != nil {
 		panic(err)
 	}
 }
@@ -132,16 +165,12 @@ func (c *Conn) Close() error {
 		return nil
 	}
 
-	c.pending.Close()
-	c.pending = nil
-
-	r := c.call(c.api.close, uint64(c.handle))
-	if err := c.error(r); err != nil {
+	rc := res_t(c.call("sqlite3_close", stk_t(c.handle)))
+	if err := c.error(rc); err != nil {
 		return err
 	}
 
 	c.handle = 0
-	runtime.SetFinalizer(c, nil)
 	return c.close()
 }
 
@@ -150,12 +179,17 @@ func (c *Conn) Close() error {
 //
 // https://sqlite.org/c3ref/exec.html
 func (c *Conn) Exec(sql string) error {
-	c.checkInterrupt()
-	defer c.arena.reset()
-	sqlPtr := c.arena.string(sql)
+	if c.interrupt.Err() != nil {
+		return INTERRUPT
+	}
+	return c.exec(sql)
+}
 
-	r := c.call(c.api.exec, uint64(c.handle), uint64(sqlPtr), 0, 0, 0)
-	return c.error(r)
+func (c *Conn) exec(sql string) error {
+	defer c.arena.mark()()
+	textPtr := c.arena.string(sql)
+	rc := res_t(c.call("sqlite3_exec", stk_t(c.handle), stk_t(textPtr), 0, 0, 0))
+	return c.error(rc, sql)
 }
 
 // Prepare calls [Conn.PrepareFlags] with no flags.
@@ -170,42 +204,81 @@ func (c *Conn) Prepare(sql string) (stmt *Stmt, tail string, err error) {
 //
 // https://sqlite.org/c3ref/prepare.html
 func (c *Conn) PrepareFlags(sql string, flags PrepareFlag) (stmt *Stmt, tail string, err error) {
-	if len(sql) > _MAX_LENGTH {
+	if len(sql) > _MAX_SQL_LENGTH {
 		return nil, "", TOOBIG
 	}
-	if emptyStatement(sql) {
-		return nil, "", nil
+	if c.interrupt.Err() != nil {
+		return nil, "", INTERRUPT
 	}
 
-	defer c.arena.reset()
+	defer c.arena.mark()()
 	stmtPtr := c.arena.new(ptrlen)
 	tailPtr := c.arena.new(ptrlen)
-	sqlPtr := c.arena.string(sql)
+	textPtr := c.arena.string(sql)
 
-	r := c.call(c.api.prepare, uint64(c.handle),
-		uint64(sqlPtr), uint64(len(sql)+1), uint64(flags),
-		uint64(stmtPtr), uint64(tailPtr))
+	rc := res_t(c.call("sqlite3_prepare_v3", stk_t(c.handle),
+		stk_t(textPtr), stk_t(len(sql)+1), stk_t(flags),
+		stk_t(stmtPtr), stk_t(tailPtr)))
 
-	stmt = &Stmt{c: c}
-	stmt.handle = util.ReadUint32(c.mod, stmtPtr)
-	i := util.ReadUint32(c.mod, tailPtr)
-	tail = sql[i-sqlPtr:]
+	stmt = &Stmt{c: c, sql: sql}
+	stmt.handle = util.Read32[ptr_t](c.mod, stmtPtr)
+	if sql := sql[util.Read32[ptr_t](c.mod, tailPtr)-textPtr:]; sql != "" {
+		tail = sql
+	}
 
-	if err := c.error(r, sql); err != nil {
+	if err := c.error(rc, sql); err != nil {
 		return nil, "", err
 	}
 	if stmt.handle == 0 {
 		return nil, "", nil
 	}
-	return
+	c.stmts = append(c.stmts, stmt)
+	return stmt, tail, nil
+}
+
+// DBName returns the schema name for n-th database on the database connection.
+//
+// https://sqlite.org/c3ref/db_name.html
+func (c *Conn) DBName(n int) string {
+	ptr := ptr_t(c.call("sqlite3_db_name", stk_t(c.handle), stk_t(n)))
+	if ptr == 0 {
+		return ""
+	}
+	return util.ReadString(c.mod, ptr, _MAX_NAME)
+}
+
+// Filename returns the filename for a database.
+//
+// https://sqlite.org/c3ref/db_filename.html
+func (c *Conn) Filename(schema string) *vfs.Filename {
+	var ptr ptr_t
+	if schema != "" {
+		defer c.arena.mark()()
+		ptr = c.arena.string(schema)
+	}
+	ptr = ptr_t(c.call("sqlite3_db_filename", stk_t(c.handle), stk_t(ptr)))
+	return vfs.GetFilename(c.ctx, c.mod, ptr, vfs.OPEN_MAIN_DB)
+}
+
+// ReadOnly determines if a database is read-only.
+//
+// https://sqlite.org/c3ref/db_readonly.html
+func (c *Conn) ReadOnly(schema string) (ro bool, ok bool) {
+	var ptr ptr_t
+	if schema != "" {
+		defer c.arena.mark()()
+		ptr = c.arena.string(schema)
+	}
+	b := int32(c.call("sqlite3_db_readonly", stk_t(c.handle), stk_t(ptr)))
+	return b > 0, b < 0
 }
 
 // GetAutocommit tests the connection for auto-commit mode.
 //
 // https://sqlite.org/c3ref/get_autocommit.html
 func (c *Conn) GetAutocommit() bool {
-	r := c.call(c.api.autocommit, uint64(c.handle))
-	return r != 0
+	b := int32(c.call("sqlite3_get_autocommit", stk_t(c.handle)))
+	return b != 0
 }
 
 // LastInsertRowID returns the rowid of the most recent successful INSERT
@@ -213,8 +286,15 @@ func (c *Conn) GetAutocommit() bool {
 //
 // https://sqlite.org/c3ref/last_insert_rowid.html
 func (c *Conn) LastInsertRowID() int64 {
-	r := c.call(c.api.lastRowid, uint64(c.handle))
-	return int64(r)
+	return int64(c.call("sqlite3_last_insert_rowid", stk_t(c.handle)))
+}
+
+// SetLastInsertRowID allows the application to set the value returned by
+// [Conn.LastInsertRowID].
+//
+// https://sqlite.org/c3ref/set_last_insert_rowid.html
+func (c *Conn) SetLastInsertRowID(id int64) {
+	c.call("sqlite3_set_last_insert_rowid", stk_t(c.handle), stk_t(id))
 }
 
 // Changes returns the number of rows modified, inserted or deleted
@@ -223,8 +303,29 @@ func (c *Conn) LastInsertRowID() int64 {
 //
 // https://sqlite.org/c3ref/changes.html
 func (c *Conn) Changes() int64 {
-	r := c.call(c.api.changes, uint64(c.handle))
-	return int64(r)
+	return int64(c.call("sqlite3_changes64", stk_t(c.handle)))
+}
+
+// TotalChanges returns the number of rows modified, inserted or deleted
+// by all INSERT, UPDATE or DELETE statements completed
+// since the database connection was opened.
+//
+// https://sqlite.org/c3ref/total_changes.html
+func (c *Conn) TotalChanges() int64 {
+	return int64(c.call("sqlite3_total_changes64", stk_t(c.handle)))
+}
+
+// ReleaseMemory frees memory used by a database connection.
+//
+// https://sqlite.org/c3ref/db_release_memory.html
+func (c *Conn) ReleaseMemory() error {
+	rc := res_t(c.call("sqlite3_db_release_memory", stk_t(c.handle)))
+	return c.error(rc)
+}
+
+// GetInterrupt gets the context set with [Conn.SetInterrupt].
+func (c *Conn) GetInterrupt() context.Context {
+	return c.interrupt
 }
 
 // SetInterrupt interrupts a long-running query when a context is done.
@@ -242,73 +343,154 @@ func (c *Conn) Changes() int64 {
 //
 // https://sqlite.org/c3ref/interrupt.html
 func (c *Conn) SetInterrupt(ctx context.Context) (old context.Context) {
-	// Is it the same context?
-	if ctx == c.interrupt {
-		return ctx
+	if ctx == nil {
+		panic("nil Context")
 	}
-
-	// An uncompleted SQL statement prevents SQLite from ignoring
-	// an interrupt that comes before any other statements are started.
-	if c.pending == nil {
-		c.pending, _, _ = c.Prepare(`SELECT 1 UNION ALL SELECT 2`)
-	} else {
-		c.pending.Reset()
-	}
-
 	old = c.interrupt
 	c.interrupt = ctx
-	// Remove the handler if the context can't be canceled.
-	if ctx == nil || ctx.Done() == nil {
-		c.call(c.api.progressHandler, uint64(c.handle), 0)
-		return old
-	}
-
-	c.pending.Step()
-	c.call(c.api.progressHandler, uint64(c.handle), 100)
 	return old
 }
 
-func progressCallback(ctx context.Context, mod api.Module, _ uint32) uint32 {
+func progressCallback(ctx context.Context, mod api.Module, _ ptr_t) (interrupt int32) {
 	if c, ok := ctx.Value(connKey{}).(*Conn); ok {
-		if c.interrupt != nil && c.interrupt.Err() != nil {
-			return 1
+		if c.gosched++; c.gosched%16 == 0 {
+			runtime.Gosched()
 		}
+		if c.interrupt.Err() != nil {
+			interrupt = 1
+		}
+	}
+	return interrupt
+}
+
+// BusyTimeout sets a busy timeout.
+//
+// https://sqlite.org/c3ref/busy_timeout.html
+func (c *Conn) BusyTimeout(timeout time.Duration) error {
+	ms := min((timeout+time.Millisecond-1)/time.Millisecond, math.MaxInt32)
+	rc := res_t(c.call("sqlite3_busy_timeout", stk_t(c.handle), stk_t(ms)))
+	return c.error(rc)
+}
+
+func timeoutCallback(ctx context.Context, mod api.Module, count, tmout int32) (retry int32) {
+	// https://fractaledmind.github.io/2024/04/15/sqlite-on-rails-the-how-and-why-of-optimal-performance/
+	if c, ok := ctx.Value(connKey{}).(*Conn); ok && c.interrupt.Err() == nil {
+		switch {
+		case count == 0:
+			c.busy1st = time.Now()
+		case time.Since(c.busy1st) >= time.Duration(tmout)*time.Millisecond:
+			return 0
+		}
+		if time.Since(c.busylst) < time.Millisecond {
+			const sleepIncrement = 2*1024*1024 - 1 // power of two, ~2ms
+			time.Sleep(time.Duration(rand.Int63() & sleepIncrement))
+		}
+		c.busylst = time.Now()
+		return 1
 	}
 	return 0
 }
 
-func (c *Conn) checkInterrupt() {
-	if c.interrupt != nil && c.interrupt.Err() != nil {
-		c.call(c.api.interrupt, uint64(c.handle))
-	}
-}
-
-// Pragma executes a PRAGMA statement and returns any results.
+// BusyHandler registers a callback to handle [BUSY] errors.
 //
-// https://sqlite.org/pragma.html
-func (c *Conn) Pragma(str string) ([]string, error) {
-	stmt, _, err := c.Prepare(`PRAGMA ` + str)
-	if err != nil {
-		return nil, err
+// https://sqlite.org/c3ref/busy_handler.html
+func (c *Conn) BusyHandler(cb func(ctx context.Context, count int) (retry bool)) error {
+	var enable int32
+	if cb != nil {
+		enable = 1
 	}
-	defer stmt.Close()
-
-	var pragmas []string
-	for stmt.Step() {
-		pragmas = append(pragmas, stmt.ColumnText(0))
+	rc := res_t(c.call("sqlite3_busy_handler_go", stk_t(c.handle), stk_t(enable)))
+	if err := c.error(rc); err != nil {
+		return err
 	}
-	return pragmas, stmt.Close()
+	c.busy = cb
+	return nil
 }
 
-func (c *Conn) error(rc uint64, sql ...string) error {
+func busyCallback(ctx context.Context, mod api.Module, pDB ptr_t, count int32) (retry int32) {
+	if c, ok := ctx.Value(connKey{}).(*Conn); ok && c.handle == pDB && c.busy != nil {
+		if interrupt := c.interrupt; interrupt.Err() == nil &&
+			c.busy(interrupt, int(count)) {
+			retry = 1
+		}
+	}
+	return retry
+}
+
+// Status retrieves runtime status information about a database connection.
+//
+// https://sqlite.org/c3ref/db_status.html
+func (c *Conn) Status(op DBStatus, reset bool) (current, highwater int, err error) {
+	defer c.arena.mark()()
+	hiPtr := c.arena.new(intlen)
+	curPtr := c.arena.new(intlen)
+
+	var i int32
+	if reset {
+		i = 1
+	}
+
+	rc := res_t(c.call("sqlite3_db_status", stk_t(c.handle),
+		stk_t(op), stk_t(curPtr), stk_t(hiPtr), stk_t(i)))
+	if err = c.error(rc); err == nil {
+		current = int(util.Read32[int32](c.mod, curPtr))
+		highwater = int(util.Read32[int32](c.mod, hiPtr))
+	}
+	return
+}
+
+// TableColumnMetadata extracts metadata about a column of a table.
+//
+// https://sqlite.org/c3ref/table_column_metadata.html
+func (c *Conn) TableColumnMetadata(schema, table, column string) (declType, collSeq string, notNull, primaryKey, autoInc bool, err error) {
+	defer c.arena.mark()()
+
+	var schemaPtr, columnPtr ptr_t
+	declTypePtr := c.arena.new(ptrlen)
+	collSeqPtr := c.arena.new(ptrlen)
+	notNullPtr := c.arena.new(ptrlen)
+	autoIncPtr := c.arena.new(ptrlen)
+	primaryKeyPtr := c.arena.new(ptrlen)
+	if schema != "" {
+		schemaPtr = c.arena.string(schema)
+	}
+	tablePtr := c.arena.string(table)
+	if column != "" {
+		columnPtr = c.arena.string(column)
+	}
+
+	rc := res_t(c.call("sqlite3_table_column_metadata", stk_t(c.handle),
+		stk_t(schemaPtr), stk_t(tablePtr), stk_t(columnPtr),
+		stk_t(declTypePtr), stk_t(collSeqPtr),
+		stk_t(notNullPtr), stk_t(primaryKeyPtr), stk_t(autoIncPtr)))
+	if err = c.error(rc); err == nil && column != "" {
+		if ptr := util.Read32[ptr_t](c.mod, declTypePtr); ptr != 0 {
+			declType = util.ReadString(c.mod, ptr, _MAX_NAME)
+		}
+		if ptr := util.Read32[ptr_t](c.mod, collSeqPtr); ptr != 0 {
+			collSeq = util.ReadString(c.mod, ptr, _MAX_NAME)
+		}
+		notNull = util.ReadBool(c.mod, notNullPtr)
+		autoInc = util.ReadBool(c.mod, autoIncPtr)
+		primaryKey = util.ReadBool(c.mod, primaryKeyPtr)
+	}
+	return
+}
+
+func (c *Conn) error(rc res_t, sql ...string) error {
 	return c.sqlite.error(rc, c.handle, sql...)
 }
 
-// DriverConn is implemented by the SQLite [database/sql] driver connection.
+// Stmts returns an iterator for the prepared statements
+// associated with the database connection.
 //
-// It can be used to access SQLite features like [online backup].
-//
-// [online backup]: https://sqlite.org/backup.html
-type DriverConn interface {
-	Raw() *Conn
+// https://sqlite.org/c3ref/next_stmt.html
+func (c *Conn) Stmts() iter.Seq[*Stmt] {
+	return func(yield func(*Stmt) bool) {
+		for _, s := range c.stmts {
+			if !yield(s) {
+				break
+			}
+		}
+	}
 }

const.go

@@ -1,20 +1,28 @@
 package sqlite3
 
-import "strconv"
+import (
+	"strconv"
+
+	"github.com/ncruces/go-sqlite3/internal/util"
+)
 
 const (
 	_OK   = 0   /* Successful result */
 	_ROW  = 100 /* sqlite3_step() has another row ready */
 	_DONE = 101 /* sqlite3_step() has finished executing */
 
-	_UTF8 = 1
+	_MAX_NAME       = 1e6 // Self-imposed limit for most NUL terminated strings.
+	_MAX_LENGTH     = 1e9
+	_MAX_SQL_LENGTH = 1e9
 
-	_MAX_NAME            = 512 // Used for short strings: names, error messages…
-	_MAX_LENGTH          = 1e9
-	_MAX_SQL_LENGTH      = 1e9
-	_MAX_ALLOCATION_SIZE = 0x7ffffeff
+	ptrlen = util.PtrLen
+	intlen = util.IntLen
+)
 
-	ptrlen = 4
+type (
+	stk_t = util.Stk_t
+	ptr_t = util.Ptr_t
+	res_t = util.Res_t
 )
 
 // ErrorCode is a result code that [Error.Code] might return.
@@ -108,7 +116,7 @@ const (
 	CANTOPEN_ISDIR          ExtendedErrorCode = xErrorCode(CANTOPEN) | (2 << 8)
 	CANTOPEN_FULLPATH       ExtendedErrorCode = xErrorCode(CANTOPEN) | (3 << 8)
 	CANTOPEN_CONVPATH       ExtendedErrorCode = xErrorCode(CANTOPEN) | (4 << 8)
-	CANTOPEN_DIRTYWAL       ExtendedErrorCode = xErrorCode(CANTOPEN) | (5 << 8) /* Not Used */
+	// CANTOPEN_DIRTYWAL    ExtendedErrorCode = xErrorCode(CANTOPEN) | (5 << 8) /* Not Used */
 	CANTOPEN_SYMLINK        ExtendedErrorCode = xErrorCode(CANTOPEN) | (6 << 8)
 	CORRUPT_VTAB            ExtendedErrorCode = xErrorCode(CORRUPT) | (1 << 8)
 	CORRUPT_SEQUENCE        ExtendedErrorCode = xErrorCode(CORRUPT) | (2 << 8)
@@ -167,9 +175,11 @@ const (
 	PREPARE_PERSISTENT PrepareFlag = 0x01
 	PREPARE_NORMALIZE  PrepareFlag = 0x02
 	PREPARE_NO_VTAB    PrepareFlag = 0x04
+	PREPARE_DONT_LOG   PrepareFlag = 0x10
 )
 
-// FunctionFlag is a flag that can be passed to [Conn.PrepareFlags].
+// FunctionFlag is a flag that can be passed to
+// [Conn.CreateFunction] and [Conn.CreateWindowFunction].
 //
 // https://sqlite.org/c3ref/c_deterministic.html
 type FunctionFlag uint32
@@ -177,8 +187,211 @@ type FunctionFlag uint32
 const (
 	DETERMINISTIC FunctionFlag = 0x000000800
 	DIRECTONLY    FunctionFlag = 0x000080000
-	SUBTYPE       FunctionFlag = 0x000100000
 	INNOCUOUS     FunctionFlag = 0x000200000
+	SELFORDER1    FunctionFlag = 0x002000000
+	// SUBTYPE        FunctionFlag = 0x000100000
+	// RESULT_SUBTYPE FunctionFlag = 0x001000000
+)
+
+// StmtStatus name counter values associated with the [Stmt.Status] method.
+//
+// https://sqlite.org/c3ref/c_stmtstatus_counter.html
+type StmtStatus uint32
+
+const (
+	STMTSTATUS_FULLSCAN_STEP StmtStatus = 1
+	STMTSTATUS_SORT          StmtStatus = 2
+	STMTSTATUS_AUTOINDEX     StmtStatus = 3
+	STMTSTATUS_VM_STEP       StmtStatus = 4
+	STMTSTATUS_REPREPARE     StmtStatus = 5
+	STMTSTATUS_RUN           StmtStatus = 6
+	STMTSTATUS_FILTER_MISS   StmtStatus = 7
+	STMTSTATUS_FILTER_HIT    StmtStatus = 8
+	STMTSTATUS_MEMUSED       StmtStatus = 99
+)
+
+// DBStatus are the available "verbs" that can be passed to the [Conn.Status] method.
+//
+// https://sqlite.org/c3ref/c_dbstatus_options.html
+type DBStatus uint32
+
+const (
+	DBSTATUS_LOOKASIDE_USED      DBStatus = 0
+	DBSTATUS_CACHE_USED          DBStatus = 1
+	DBSTATUS_SCHEMA_USED         DBStatus = 2
+	DBSTATUS_STMT_USED           DBStatus = 3
+	DBSTATUS_LOOKASIDE_HIT       DBStatus = 4
+	DBSTATUS_LOOKASIDE_MISS_SIZE DBStatus = 5
+	DBSTATUS_LOOKASIDE_MISS_FULL DBStatus = 6
+	DBSTATUS_CACHE_HIT           DBStatus = 7
+	DBSTATUS_CACHE_MISS          DBStatus = 8
+	DBSTATUS_CACHE_WRITE         DBStatus = 9
+	DBSTATUS_DEFERRED_FKS        DBStatus = 10
+	DBSTATUS_CACHE_USED_SHARED   DBStatus = 11
+	DBSTATUS_CACHE_SPILL         DBStatus = 12
+	// DBSTATUS_MAX              DBStatus = 12
+)
+
+// DBConfig are the available database connection configuration options.
+//
+// https://sqlite.org/c3ref/c_dbconfig_defensive.html
+type DBConfig uint32
+
+const (
+	// DBCONFIG_MAINDBNAME         DBConfig = 1000
+	// DBCONFIG_LOOKASIDE          DBConfig = 1001
+	DBCONFIG_ENABLE_FKEY           DBConfig = 1002
+	DBCONFIG_ENABLE_TRIGGER        DBConfig = 1003
+	DBCONFIG_ENABLE_FTS3_TOKENIZER DBConfig = 1004
+	DBCONFIG_ENABLE_LOAD_EXTENSION DBConfig = 1005
+	DBCONFIG_NO_CKPT_ON_CLOSE      DBConfig = 1006
+	DBCONFIG_ENABLE_QPSG           DBConfig = 1007
+	DBCONFIG_TRIGGER_EQP           DBConfig = 1008
+	DBCONFIG_RESET_DATABASE        DBConfig = 1009
+	DBCONFIG_DEFENSIVE             DBConfig = 1010
+	DBCONFIG_WRITABLE_SCHEMA       DBConfig = 1011
+	DBCONFIG_LEGACY_ALTER_TABLE    DBConfig = 1012
+	DBCONFIG_DQS_DML               DBConfig = 1013
+	DBCONFIG_DQS_DDL               DBConfig = 1014
+	DBCONFIG_ENABLE_VIEW           DBConfig = 1015
+	DBCONFIG_LEGACY_FILE_FORMAT    DBConfig = 1016
+	DBCONFIG_TRUSTED_SCHEMA        DBConfig = 1017
+	DBCONFIG_STMT_SCANSTATUS       DBConfig = 1018
+	DBCONFIG_REVERSE_SCANORDER     DBConfig = 1019
+	DBCONFIG_ENABLE_ATTACH_CREATE  DBConfig = 1020
+	DBCONFIG_ENABLE_ATTACH_WRITE   DBConfig = 1021
+	DBCONFIG_ENABLE_COMMENTS       DBConfig = 1022
+	// DBCONFIG_MAX                DBConfig = 1022
+)
+
+// FcntlOpcode are the available opcodes for [Conn.FileControl].
+//
+// https://sqlite.org/c3ref/c_fcntl_begin_atomic_write.html
+type FcntlOpcode uint32
+
+const (
+	FCNTL_LOCKSTATE           FcntlOpcode = 1
+	FCNTL_CHUNK_SIZE          FcntlOpcode = 6
+	FCNTL_FILE_POINTER        FcntlOpcode = 7
+	FCNTL_PERSIST_WAL         FcntlOpcode = 10
+	FCNTL_POWERSAFE_OVERWRITE FcntlOpcode = 13
+	FCNTL_VFS_POINTER         FcntlOpcode = 27
+	FCNTL_JOURNAL_POINTER     FcntlOpcode = 28
+	FCNTL_DATA_VERSION        FcntlOpcode = 35
+	FCNTL_RESERVE_BYTES       FcntlOpcode = 38
+	FCNTL_RESET_CACHE         FcntlOpcode = 42
+	FCNTL_NULL_IO             FcntlOpcode = 43
+)
+
+// LimitCategory are the available run-time limit categories.
+//
+// https://sqlite.org/c3ref/c_limit_attached.html
+type LimitCategory uint32
+
+const (
+	LIMIT_LENGTH              LimitCategory = 0
+	LIMIT_SQL_LENGTH          LimitCategory = 1
+	LIMIT_COLUMN              LimitCategory = 2
+	LIMIT_EXPR_DEPTH          LimitCategory = 3
+	LIMIT_COMPOUND_SELECT     LimitCategory = 4
+	LIMIT_VDBE_OP             LimitCategory = 5
+	LIMIT_FUNCTION_ARG        LimitCategory = 6
+	LIMIT_ATTACHED            LimitCategory = 7
+	LIMIT_LIKE_PATTERN_LENGTH LimitCategory = 8
+	LIMIT_VARIABLE_NUMBER     LimitCategory = 9
+	LIMIT_TRIGGER_DEPTH       LimitCategory = 10
+	LIMIT_WORKER_THREADS      LimitCategory = 11
+)
+
+// AuthorizerActionCode are the integer action codes
+// that the authorizer callback may be passed.
+//
+// https://sqlite.org/c3ref/c_alter_table.html
+type AuthorizerActionCode uint32
+
+const (
+	/***************************************************** 3rd ************ 4th ***********/
+	AUTH_CREATE_INDEX        AuthorizerActionCode = 1  /* Index Name      Table Name      */
+	AUTH_CREATE_TABLE        AuthorizerActionCode = 2  /* Table Name      NULL            */
+	AUTH_CREATE_TEMP_INDEX   AuthorizerActionCode = 3  /* Index Name      Table Name      */
+	AUTH_CREATE_TEMP_TABLE   AuthorizerActionCode = 4  /* Table Name      NULL            */
+	AUTH_CREATE_TEMP_TRIGGER AuthorizerActionCode = 5  /* Trigger Name    Table Name      */
+	AUTH_CREATE_TEMP_VIEW    AuthorizerActionCode = 6  /* View Name       NULL            */
+	AUTH_CREATE_TRIGGER      AuthorizerActionCode = 7  /* Trigger Name    Table Name      */
+	AUTH_CREATE_VIEW         AuthorizerActionCode = 8  /* View Name       NULL            */
+	AUTH_DELETE              AuthorizerActionCode = 9  /* Table Name      NULL            */
+	AUTH_DROP_INDEX          AuthorizerActionCode = 10 /* Index Name      Table Name      */
+	AUTH_DROP_TABLE          AuthorizerActionCode = 11 /* Table Name      NULL            */
+	AUTH_DROP_TEMP_INDEX     AuthorizerActionCode = 12 /* Index Name      Table Name      */
+	AUTH_DROP_TEMP_TABLE     AuthorizerActionCode = 13 /* Table Name      NULL            */
+	AUTH_DROP_TEMP_TRIGGER   AuthorizerActionCode = 14 /* Trigger Name    Table Name      */
+	AUTH_DROP_TEMP_VIEW      AuthorizerActionCode = 15 /* View Name       NULL            */
+	AUTH_DROP_TRIGGER        AuthorizerActionCode = 16 /* Trigger Name    Table Name      */
+	AUTH_DROP_VIEW           AuthorizerActionCode = 17 /* View Name       NULL            */
+	AUTH_INSERT              AuthorizerActionCode = 18 /* Table Name      NULL            */
+	AUTH_PRAGMA              AuthorizerActionCode = 19 /* Pragma Name     1st arg or NULL */
+	AUTH_READ                AuthorizerActionCode = 20 /* Table Name      Column Name     */
+	AUTH_SELECT              AuthorizerActionCode = 21 /* NULL            NULL            */
+	AUTH_TRANSACTION         AuthorizerActionCode = 22 /* Operation       NULL            */
+	AUTH_UPDATE              AuthorizerActionCode = 23 /* Table Name      Column Name     */
+	AUTH_ATTACH              AuthorizerActionCode = 24 /* Filename        NULL            */
+	AUTH_DETACH              AuthorizerActionCode = 25 /* Database Name   NULL            */
+	AUTH_ALTER_TABLE         AuthorizerActionCode = 26 /* Database Name   Table Name      */
+	AUTH_REINDEX             AuthorizerActionCode = 27 /* Index Name      NULL            */
+	AUTH_ANALYZE             AuthorizerActionCode = 28 /* Table Name      NULL            */
+	AUTH_CREATE_VTABLE       AuthorizerActionCode = 29 /* Table Name      Module Name     */
+	AUTH_DROP_VTABLE         AuthorizerActionCode = 30 /* Table Name      Module Name     */
+	AUTH_FUNCTION            AuthorizerActionCode = 31 /* NULL            Function Name   */
+	AUTH_SAVEPOINT           AuthorizerActionCode = 32 /* Operation       Savepoint Name  */
+	AUTH_RECURSIVE           AuthorizerActionCode = 33 /* NULL            NULL            */
+	// AUTH_COPY             AuthorizerActionCode = 0  /* No longer used */
+)
+
+// AuthorizerReturnCode are the integer codes
+// that the authorizer callback may return.
+//
+// https://sqlite.org/c3ref/c_deny.html
+type AuthorizerReturnCode uint32
+
+const (
+	AUTH_OK     AuthorizerReturnCode = 0
+	AUTH_DENY   AuthorizerReturnCode = 1 /* Abort the SQL statement with an error */
+	AUTH_IGNORE AuthorizerReturnCode = 2 /* Don't allow access, but don't generate an error */
+)
+
+// CheckpointMode are all the checkpoint mode values.
+//
+// https://sqlite.org/c3ref/c_checkpoint_full.html
+type CheckpointMode uint32
+
+const (
+	CHECKPOINT_PASSIVE  CheckpointMode = 0 /* Do as much as possible w/o blocking */
+	CHECKPOINT_FULL     CheckpointMode = 1 /* Wait for writers, then checkpoint */
+	CHECKPOINT_RESTART  CheckpointMode = 2 /* Like FULL but wait for readers */
+	CHECKPOINT_TRUNCATE CheckpointMode = 3 /* Like RESTART but also truncate WAL */
+)
+
+// TxnState are the allowed return values from [Conn.TxnState].
+//
+// https://sqlite.org/c3ref/c_txn_none.html
+type TxnState uint32
+
+const (
+	TXN_NONE  TxnState = 0
+	TXN_READ  TxnState = 1
+	TXN_WRITE TxnState = 2
+)
+
+// TraceEvent identify classes of events that can be monitored with [Conn.Trace].
+//
+// https://sqlite.org/c3ref/c_trace.html
+type TraceEvent uint32
+
+const (
+	TRACE_STMT    TraceEvent = 0x01
+	TRACE_PROFILE TraceEvent = 0x02
+	TRACE_ROW     TraceEvent = 0x04
+	TRACE_CLOSE   TraceEvent = 0x08
 )
 
 // Datatype is a fundamental datatype of SQLite.

context.go

@@ -15,7 +15,7 @@ import (
 // https://sqlite.org/c3ref/context.html
 type Context struct {
 	c      *Conn
-	handle uint32
+	handle ptr_t
 }
 
 // Conn returns the database connection of the
@@ -32,14 +32,14 @@ func (ctx Context) Conn() *Conn {
 // https://sqlite.org/c3ref/get_auxdata.html
 func (ctx Context) SetAuxData(n int, data any) {
 	ptr := util.AddHandle(ctx.c.ctx, data)
-	ctx.c.call(ctx.c.api.setAuxData, uint64(ctx.handle), uint64(n), uint64(ptr))
+	ctx.c.call("sqlite3_set_auxdata_go", stk_t(ctx.handle), stk_t(n), stk_t(ptr))
 }
 
 // GetAuxData returns metadata for argument n of the function.
 //
 // https://sqlite.org/c3ref/get_auxdata.html
 func (ctx Context) GetAuxData(n int) any {
-	ptr := uint32(ctx.c.call(ctx.c.api.getAuxData, uint64(ctx.handle), uint64(n)))
+	ptr := ptr_t(ctx.c.call("sqlite3_get_auxdata", stk_t(ctx.handle), stk_t(n)))
 	return util.GetHandle(ctx.c.ctx, ptr)
 }
 
@@ -67,16 +67,16 @@ func (ctx Context) ResultInt(value int) {
 //
 // https://sqlite.org/c3ref/result_blob.html
 func (ctx Context) ResultInt64(value int64) {
-	ctx.c.call(ctx.c.api.resultInteger,
-		uint64(ctx.handle), uint64(value))
+	ctx.c.call("sqlite3_result_int64",
+		stk_t(ctx.handle), stk_t(value))
 }
 
 // ResultFloat sets the result of the function to a float64.
 //
 // https://sqlite.org/c3ref/result_blob.html
 func (ctx Context) ResultFloat(value float64) {
-	ctx.c.call(ctx.c.api.resultFloat,
-		uint64(ctx.handle), math.Float64bits(value))
+	ctx.c.call("sqlite3_result_double",
+		stk_t(ctx.handle), stk_t(math.Float64bits(value)))
 }
 
 // ResultText sets the result of the function to a string.
@@ -84,53 +84,58 @@ func (ctx Context) ResultFloat(value float64) {
 // https://sqlite.org/c3ref/result_blob.html
 func (ctx Context) ResultText(value string) {
 	ptr := ctx.c.newString(value)
-	ctx.c.call(ctx.c.api.resultText,
-		uint64(ctx.handle), uint64(ptr), uint64(len(value)),
-		uint64(ctx.c.api.destructor), _UTF8)
+	ctx.c.call("sqlite3_result_text_go",
+		stk_t(ctx.handle), stk_t(ptr), stk_t(len(value)))
 }
 
 // ResultRawText sets the text result of the function to a []byte.
 //
 // https://sqlite.org/c3ref/result_blob.html
 func (ctx Context) ResultRawText(value []byte) {
+	if len(value) == 0 {
+		ctx.ResultText("")
+		return
+	}
 	ptr := ctx.c.newBytes(value)
-	ctx.c.call(ctx.c.api.resultText,
-		uint64(ctx.handle), uint64(ptr), uint64(len(value)),
-		uint64(ctx.c.api.destructor), _UTF8)
+	ctx.c.call("sqlite3_result_text_go",
+		stk_t(ctx.handle), stk_t(ptr), stk_t(len(value)))
 }
 
 // ResultBlob sets the result of the function to a []byte.
-// Returning a nil slice is the same as calling [Context.ResultNull].
 //
 // https://sqlite.org/c3ref/result_blob.html
 func (ctx Context) ResultBlob(value []byte) {
+	if len(value) == 0 {
+		ctx.ResultZeroBlob(0)
+		return
+	}
 	ptr := ctx.c.newBytes(value)
-	ctx.c.call(ctx.c.api.resultBlob,
-		uint64(ctx.handle), uint64(ptr), uint64(len(value)),
-		uint64(ctx.c.api.destructor))
+	ctx.c.call("sqlite3_result_blob_go",
+		stk_t(ctx.handle), stk_t(ptr), stk_t(len(value)))
 }
 
 // ResultZeroBlob sets the result of the function to a zero-filled, length n BLOB.
 //
 // https://sqlite.org/c3ref/result_blob.html
 func (ctx Context) ResultZeroBlob(n int64) {
-	ctx.c.call(ctx.c.api.resultZeroBlob,
-		uint64(ctx.handle), uint64(n))
+	ctx.c.call("sqlite3_result_zeroblob64",
+		stk_t(ctx.handle), stk_t(n))
 }
 
 // ResultNull sets the result of the function to NULL.
 //
 // https://sqlite.org/c3ref/result_blob.html
 func (ctx Context) ResultNull() {
-	ctx.c.call(ctx.c.api.resultNull,
-		uint64(ctx.handle))
+	ctx.c.call("sqlite3_result_null",
+		stk_t(ctx.handle))
 }
 
 // ResultTime sets the result of the function to a [time.Time].
 //
 // https://sqlite.org/c3ref/result_blob.html
 func (ctx Context) ResultTime(value time.Time, format TimeFormat) {
-	if format == TimeFormatDefault {
+	switch format {
+	case TimeFormatDefault, TimeFormatAuto, time.RFC3339Nano:
 		ctx.resultRFC3339Nano(value)
 		return
 	}
@@ -147,15 +152,14 @@ func (ctx Context) ResultTime(value time.Time, format TimeFormat) {
 }
 
 func (ctx Context) resultRFC3339Nano(value time.Time) {
-	const maxlen = uint64(len(time.RFC3339Nano)) + 5
+	const maxlen = int64(len(time.RFC3339Nano)) + 5
 
 	ptr := ctx.c.new(maxlen)
 	buf := util.View(ctx.c.mod, ptr, maxlen)
 	buf = value.AppendFormat(buf[:0], time.RFC3339Nano)
 
-	ctx.c.call(ctx.c.api.resultText,
-		uint64(ctx.handle), uint64(ptr), uint64(len(buf)),
-		uint64(ctx.c.api.destructor), _UTF8)
+	ctx.c.call("sqlite3_result_text_go",
+		stk_t(ctx.handle), stk_t(ptr), stk_t(len(buf)))
 }
 
 // ResultPointer sets the result of the function to NULL, just like [Context.ResultNull],
@@ -165,29 +169,35 @@ func (ctx Context) resultRFC3339Nano(value time.Time) {
 // https://sqlite.org/c3ref/result_blob.html
 func (ctx Context) ResultPointer(ptr any) {
 	valPtr := util.AddHandle(ctx.c.ctx, ptr)
-	ctx.c.call(ctx.c.api.resultPointer, uint64(valPtr))
+	ctx.c.call("sqlite3_result_pointer_go",
+		stk_t(ctx.handle), stk_t(valPtr))
 }
 
 // ResultJSON sets the result of the function to the JSON encoding of value.
 //
 // https://sqlite.org/c3ref/result_blob.html
 func (ctx Context) ResultJSON(value any) {
-	data, err := json.Marshal(value)
+	err := json.NewEncoder(callbackWriter(func(p []byte) (int, error) {
+		ctx.ResultRawText(p[:len(p)-1]) // remove the newline
+		return 0, nil
+	})).Encode(value)
+
 	if err != nil {
 		ctx.ResultError(err)
+		return // notest
 	}
-	ctx.ResultRawText(data)
 }
 
 // ResultValue sets the result of the function to a copy of [Value].
 //
 // https://sqlite.org/c3ref/result_blob.html
 func (ctx Context) ResultValue(value Value) {
-	if value.sqlite != ctx.c.sqlite {
+	if value.c != ctx.c {
 		ctx.ResultError(MISUSE)
+		return
 	}
-	ctx.c.call(ctx.c.api.resultValue,
-		uint64(ctx.handle), uint64(value.handle))
+	ctx.c.call("sqlite3_result_value",
+		stk_t(ctx.handle), stk_t(value.handle))
 }
 
 // ResultError sets the result of the function an error.
@@ -195,24 +205,33 @@ func (ctx Context) ResultValue(value Value) {
 // https://sqlite.org/c3ref/result_blob.html
 func (ctx Context) ResultError(err error) {
 	if errors.Is(err, NOMEM) {
-		ctx.c.call(ctx.c.api.resultErrorMem, uint64(ctx.handle))
+		ctx.c.call("sqlite3_result_error_nomem", stk_t(ctx.handle))
 		return
 	}
 
 	if errors.Is(err, TOOBIG) {
-		ctx.c.call(ctx.c.api.resultErrorBig, uint64(ctx.handle))
+		ctx.c.call("sqlite3_result_error_toobig", stk_t(ctx.handle))
 		return
 	}
 
 	msg, code := errorCode(err, _OK)
 	if msg != "" {
-		ptr := ctx.c.newString(msg)
-		ctx.c.call(ctx.c.api.resultError,
-			uint64(ctx.handle), uint64(ptr), uint64(len(msg)))
-		ctx.c.free(ptr)
+		defer ctx.c.arena.mark()()
+		ptr := ctx.c.arena.string(msg)
+		ctx.c.call("sqlite3_result_error",
+			stk_t(ctx.handle), stk_t(ptr), stk_t(len(msg)))
 	}
 	if code != _OK {
-		ctx.c.call(ctx.c.api.resultErrorCode,
-			uint64(ctx.handle), uint64(code))
+		ctx.c.call("sqlite3_result_error_code",
+			stk_t(ctx.handle), stk_t(code))
 	}
 }
+
+// VTabNoChange may return true if a column is being fetched as part
+// of an update during which the column value will not change.
+//
+// https://sqlite.org/c3ref/vtab_nochange.html
+func (ctx Context) VTabNoChange() bool {
+	b := int32(ctx.c.call("sqlite3_vtab_nochange", stk_t(ctx.handle)))
+	return b != 0
+}

driver/driver.go

@@ -8,10 +8,74 @@
 //
 // The data source name for "sqlite3" databases can be a filename or a "file:" [URI].
 //
+// # Default transaction mode
+//
 // The [TRANSACTION] mode can be specified using "_txlock":
 //
 //	sql.Open("sqlite3", "file:demo.db?_txlock=immediate")
 //
+// Possible values are: "deferred" (the default), "immediate", "exclusive".
+// Regardless of "_txlock":
+//   - a [linearizable] transaction is always "exclusive";
+//   - a [serializable] transaction is always "immediate";
+//   - a [read-only] transaction is always "deferred".
+//
+// # Datatypes In SQLite
+//
+// SQLite is dynamically typed.
+// Columns can mostly hold any value regardless of their declared type.
+// SQLite supports most [driver.Value] types out of the box,
+// but bool and [time.Time] require special care.
+//
+// Booleans can be stored on any column type and scanned back to a *bool.
+// However, if scanned to a *any, booleans may either become an
+// int64, string or bool, depending on the declared type of the column.
+// If you use BOOLEAN for your column type,
+// 1 and 0 will always scan as true and false.
+//
+// # Working with time
+//
+// Time values can similarly be stored on any column type.
+// The time encoding/decoding format can be specified using "_timefmt":
+//
+//	sql.Open("sqlite3", "file:demo.db?_timefmt=sqlite")
+//
+// Special values are: "auto" (the default), "sqlite", "rfc3339";
+//   - "auto" encodes as RFC 3339 and decodes any [format] supported by SQLite;
+//   - "sqlite" encodes as SQLite and decodes any [format] supported by SQLite;
+//   - "rfc3339" encodes and decodes RFC 3339 only.
+//
+// You can also set "_timefmt" to an arbitrary [sqlite3.TimeFormat] or [time.Layout].
+//
+// If you encode as RFC 3339 (the default),
+// consider using the TIME [collating sequence] to produce time-ordered sequences.
+//
+// If you encode as RFC 3339 (the default),
+// time values will scan back to a *time.Time unless your column type is TEXT.
+// Otherwise, if scanned to a *any, time values may either become an
+// int64, float64 or string, depending on the time format and declared type of the column.
+// If you use DATE, TIME, DATETIME, or TIMESTAMP for your column type,
+// "_timefmt" will be used to decode values.
+//
+// To scan values in custom formats, [sqlite3.TimeFormat.Scanner] may be helpful.
+// To bind values in custom formats, [sqlite3.TimeFormat.Encode] them before binding.
+//
+// When using a custom time struct, you'll have to implement
+// [database/sql/driver.Valuer] and [database/sql.Scanner].
+//
+// The Value method should ideally encode to a time [format] supported by SQLite.
+// This ensures SQL date and time functions work as they should,
+// and that your schema works with other SQLite tools.
+// [sqlite3.TimeFormat.Encode] may help.
+//
+// The Scan method needs to take into account that the value it receives can be of differing types.
+// It can already be a [time.Time], if the driver decoded the value according to "_timefmt" rules.
+// Or it can be a: string, int64, float64, []byte, or nil,
+// depending on the column type and whoever wrote the value.
+// [sqlite3.TimeFormat.Decode] may help.
+//
+// # Setting PRAGMAs
+//
 // [PRAGMA] statements can be specified using "_pragma":
 //
 //	sql.Open("sqlite3", "file:demo.db?_pragma=busy_timeout(10000)")
@@ -19,11 +83,17 @@
 // If no PRAGMAs are specified, a busy timeout of 1 minute is set.
 //
 // Order matters:
-// busy timeout and locking mode should be the first PRAGMAs set, in that order.
+// encryption keys, busy timeout and locking mode should be the first PRAGMAs set,
+// in that order.
 //
 // [URI]: https://sqlite.org/uri.html
 // [PRAGMA]: https://sqlite.org/pragma.html
 // [TRANSACTION]: https://sqlite.org/lang_transaction.html#deferred_immediate_and_exclusive_transactions
+// [linearizable]: https://pkg.go.dev/database/sql#TxOptions
+// [serializable]: https://pkg.go.dev/database/sql#TxOptions
+// [read-only]: https://pkg.go.dev/database/sql#TxOptions
+// [format]: https://sqlite.org/lang_datefunc.html#time_values
+// [collating sequence]: https://sqlite.org/datatype3.html#collating_sequences
 package driver
 
 import (
@@ -34,8 +104,10 @@ import (
 	"fmt"
 	"io"
 	"net/url"
+	"reflect"
 	"strings"
 	"time"
+	"unsafe"
 
 	"github.com/ncruces/go-sqlite3"
 	"github.com/ncruces/go-sqlite3/internal/util"
@@ -43,93 +115,138 @@ import (
 
 // This variable can be replaced with -ldflags:
 //
-//	go build -ldflags="-X github.com/ncruces/go-sqlite3.driverName=sqlite"
+//	go build -ldflags="-X github.com/ncruces/go-sqlite3/driver.driverName=sqlite"
 var driverName = "sqlite3"
 
 func init() {
 	if driverName != "" {
-		sql.Register(driverName, sqlite{})
+		sql.Register(driverName, &SQLite{})
 	}
 }
 
 // Open opens the SQLite database specified by dataSourceName as a [database/sql.DB].
 //
-// The init function is called by the driver on new connections.
-// The conn can be used to execute queries, register functions, etc.
-// Any error return closes the conn and passes the error to [database/sql].
-func Open(dataSourceName string, init func(*sqlite3.Conn) error) (*sql.DB, error) {
-	c, err := newConnector(dataSourceName, init)
+// Open accepts zero, one, or two callbacks (nil callbacks are ignored).
+// The first callback is called when the driver opens a new connection.
+// The second callback is called before the driver closes a connection.
+// The [sqlite3.Conn] can be used to execute queries, register functions, etc.
+func Open(dataSourceName string, fn ...func(*sqlite3.Conn) error) (*sql.DB, error) {
+	if len(fn) > 2 {
+		return nil, sqlite3.MISUSE
+	}
+	var init, term func(*sqlite3.Conn) error
+	if len(fn) > 1 {
+		term = fn[1]
+	}
+	if len(fn) > 0 {
+		init = fn[0]
+	}
+	c, err := newConnector(dataSourceName, init, term)
 	if err != nil {
 		return nil, err
 	}
 	return sql.OpenDB(c), nil
 }
 
-type sqlite struct{}
+// SQLite implements [database/sql/driver.Driver].
+type SQLite struct{}
 
-func (sqlite) Open(name string) (driver.Conn, error) {
-	c, err := newConnector(name, nil)
+var (
+	// Ensure these interfaces are implemented:
+	_ driver.DriverContext = &SQLite{}
+)
+
+// Open implements [database/sql/driver.Driver].
+func (d *SQLite) Open(name string) (driver.Conn, error) {
+	c, err := newConnector(name, nil, nil)
 	if err != nil {
 		return nil, err
 	}
 	return c.Connect(context.Background())
 }
 
-func (sqlite) OpenConnector(name string) (driver.Connector, error) {
-	return newConnector(name, nil)
+// OpenConnector implements [database/sql/driver.DriverContext].
+func (d *SQLite) OpenConnector(name string) (driver.Connector, error) {
+	return newConnector(name, nil, nil)
 }
 
-func newConnector(name string, init func(*sqlite3.Conn) error) (*connector, error) {
-	c := connector{name: name, init: init}
+func newConnector(name string, init, term func(*sqlite3.Conn) error) (*connector, error) {
+	c := connector{name: name, init: init, term: term}
+
+	var txlock, timefmt string
 	if strings.HasPrefix(name, "file:") {
 		if _, after, ok := strings.Cut(name, "?"); ok {
 			query, err := url.ParseQuery(after)
 			if err != nil {
 				return nil, err
 			}
-			c.txlock = query.Get("_txlock")
-			c.pragmas = len(query["_pragma"]) > 0
+			txlock = query.Get("_txlock")
+			timefmt = query.Get("_timefmt")
+			c.pragmas = query.Has("_pragma")
 		}
 	}
+
+	switch txlock {
+	case "", "deferred", "concurrent", "immediate", "exclusive":
+		c.txLock = txlock
+	default:
+		return nil, fmt.Errorf("sqlite3: invalid _txlock: %s", txlock)
+	}
+
+	switch timefmt {
+	case "":
+		c.tmRead = sqlite3.TimeFormatAuto
+		c.tmWrite = sqlite3.TimeFormatDefault
+	case "sqlite":
+		c.tmRead = sqlite3.TimeFormatAuto
+		c.tmWrite = sqlite3.TimeFormat3
+	case "rfc3339":
+		c.tmRead = sqlite3.TimeFormatDefault
+		c.tmWrite = sqlite3.TimeFormatDefault
+	default:
+		c.tmRead = sqlite3.TimeFormat(timefmt)
+		c.tmWrite = sqlite3.TimeFormat(timefmt)
+	}
 	return &c, nil
 }
 
 type connector struct {
 	init    func(*sqlite3.Conn) error
+	term    func(*sqlite3.Conn) error
 	name    string
-	txlock  string
+	txLock  string
+	tmRead  sqlite3.TimeFormat
+	tmWrite sqlite3.TimeFormat
 	pragmas bool
 }
 
 func (n *connector) Driver() driver.Driver {
-	return sqlite{}
+	return &SQLite{}
 }
 
-func (n *connector) Connect(ctx context.Context) (_ driver.Conn, err error) {
-	var c conn
-	c.Conn, err = sqlite3.Open(n.name)
+func (n *connector) Connect(ctx context.Context) (ret driver.Conn, err error) {
+	c := &conn{
+		txLock:  n.txLock,
+		tmRead:  n.tmRead,
+		tmWrite: n.tmWrite,
+	}
+
+	c.Conn, err = sqlite3.OpenContext(ctx, n.name)
 	if err != nil {
 		return nil, err
 	}
 	defer func() {
-		if err != nil {
+		if ret == nil {
 			c.Close()
 		}
 	}()
 
-	old := c.Conn.SetInterrupt(ctx)
-	defer c.Conn.SetInterrupt(old)
-
-	switch n.txlock {
-	case "":
-		c.txBegin = "BEGIN"
-	case "deferred", "immediate", "exclusive":
-		c.txBegin = "BEGIN " + n.txlock
-	default:
-		return nil, fmt.Errorf("sqlite3: invalid _txlock: %s", n.txlock)
+	if old := c.Conn.SetInterrupt(ctx); old != ctx {
+		defer c.Conn.SetInterrupt(old)
 	}
+
 	if !n.pragmas {
-		err = c.Conn.Exec(`PRAGMA busy_timeout=60000`)
+		err = c.Conn.BusyTimeout(time.Minute)
 		if err != nil {
 			return nil, err
 		}
@@ -145,6 +262,7 @@ func (n *connector) Connect(ctx context.Context) (_ driver.Conn, err error) {
 		if err != nil {
 			return nil, err
 		}
+		defer s.Close()
 		if s.Step() && s.ColumnBool(0) {
 			c.readOnly = '1'
 		} else {
@@ -155,59 +273,99 @@ func (n *connector) Connect(ctx context.Context) (_ driver.Conn, err error) {
 			return nil, err
 		}
 	}
-	return &c, nil
+	if n.term != nil {
+		err = c.Conn.Trace(sqlite3.TRACE_CLOSE, func(sqlite3.TraceEvent, any, any) error {
+			return n.term(c.Conn)
+		})
+		if err != nil {
+			return nil, err
+		}
+	}
+	return c, nil
+}
+
+// Conn is implemented by the SQLite [database/sql] driver connections.
+//
+// It can be used to access SQLite features like [online backup]:
+//
+//	db, err := driver.Open("temp.db")
+//	if err != nil {
+//		log.Fatal(err)
+//	}
+//	defer db.Close()
+//
+//	conn, err := db.Conn(context.TODO())
+//	if err != nil {
+//		log.Fatal(err)
+//	}
+//	defer conn.Close()
+//
+//	err = conn.Raw(func(driverConn any) error {
+//		conn := driverConn.(driver.Conn)
+//		return conn.Raw().Backup("main", "backup.db")
+//	})
+//	if err != nil {
+//		log.Fatal(err)
+//	}
+//
+// [online backup]: https://sqlite.org/backup.html
+type Conn interface {
+	Raw() *sqlite3.Conn
+	driver.Conn
+	driver.ConnBeginTx
+	driver.ConnPrepareContext
 }
 
 type conn struct {
 	*sqlite3.Conn
-	txBegin    string
-	txCommit   string
-	txRollback string
-	readOnly   byte
+	txLock   string
+	txReset  string
+	tmRead   sqlite3.TimeFormat
+	tmWrite  sqlite3.TimeFormat
+	readOnly byte
 }
 
 var (
 	// Ensure these interfaces are implemented:
-	_ driver.ConnPrepareContext = &conn{}
-	_ driver.ExecerContext      = &conn{}
-	_ driver.ConnBeginTx        = &conn{}
-	_ sqlite3.DriverConn        = &conn{}
+	_ Conn                 = &conn{}
+	_ driver.ExecerContext = &conn{}
 )
 
 func (c *conn) Raw() *sqlite3.Conn {
 	return c.Conn
 }
 
+// Deprecated: use BeginTx instead.
 func (c *conn) Begin() (driver.Tx, error) {
+	// notest
 	return c.BeginTx(context.Background(), driver.TxOptions{})
 }
 
 func (c *conn) BeginTx(ctx context.Context, opts driver.TxOptions) (driver.Tx, error) {
-	txBegin := c.txBegin
-	c.txCommit = `COMMIT`
-	c.txRollback = `ROLLBACK`
-
-	if opts.ReadOnly {
-		txBegin = `
-			BEGIN deferred;
-			PRAGMA query_only=on`
-		c.txRollback = `
-			ROLLBACK;
-			PRAGMA query_only=` + string(c.readOnly)
-		c.txCommit = c.txRollback
-	}
-
+	var txLock string
 	switch opts.Isolation {
 	default:
 		return nil, util.IsolationErr
-	case
-		driver.IsolationLevel(sql.LevelDefault),
-		driver.IsolationLevel(sql.LevelSerializable):
-		break
+	case driver.IsolationLevel(sql.LevelLinearizable):
+		txLock = "exclusive"
+	case driver.IsolationLevel(sql.LevelSerializable):
+		txLock = "immediate"
+	case driver.IsolationLevel(sql.LevelDefault):
+		if !opts.ReadOnly {
+			txLock = c.txLock
+		}
 	}
 
-	old := c.Conn.SetInterrupt(ctx)
-	defer c.Conn.SetInterrupt(old)
+	c.txReset = ``
+	txBegin := `BEGIN ` + txLock
+	if opts.ReadOnly {
+		txBegin += ` ; PRAGMA query_only=on`
+		c.txReset = `; PRAGMA query_only=` + string(c.readOnly)
+	}
+
+	if old := c.Conn.SetInterrupt(ctx); old != ctx {
+		defer c.Conn.SetInterrupt(old)
+	}
 
 	err := c.Conn.Exec(txBegin)
 	if err != nil {
@@ -217,7 +375,7 @@ func (c *conn) BeginTx(ctx context.Context, opts driver.TxOptions) (driver.Tx, e
 }
 
 func (c *conn) Commit() error {
-	err := c.Conn.Exec(c.txCommit)
+	err := c.Conn.Exec(`COMMIT` + c.txReset)
 	if err != nil && !c.Conn.GetAutocommit() {
 		c.Rollback()
 	}
@@ -225,41 +383,33 @@ func (c *conn) Commit() error {
 }
 
 func (c *conn) Rollback() error {
-	err := c.Conn.Exec(c.txRollback)
-	if errors.Is(err, sqlite3.INTERRUPT) {
-		old := c.Conn.SetInterrupt(context.Background())
+	// ROLLBACK even if interrupted.
+	ctx := context.Background()
+	if old := c.Conn.SetInterrupt(ctx); old != ctx {
 		defer c.Conn.SetInterrupt(old)
-		err = c.Conn.Exec(c.txRollback)
 	}
-	return err
+	return c.Conn.Exec(`ROLLBACK` + c.txReset)
 }
 
 func (c *conn) Prepare(query string) (driver.Stmt, error) {
+	// notest
 	return c.PrepareContext(context.Background(), query)
 }
 
 func (c *conn) PrepareContext(ctx context.Context, query string) (driver.Stmt, error) {
-	old := c.Conn.SetInterrupt(ctx)
-	defer c.Conn.SetInterrupt(old)
+	if old := c.Conn.SetInterrupt(ctx); old != ctx {
+		defer c.Conn.SetInterrupt(old)
+	}
 
 	s, tail, err := c.Conn.Prepare(query)
 	if err != nil {
 		return nil, err
 	}
-	if tail != "" {
-		// Check if the tail contains any SQL.
-		st, _, err := c.Conn.Prepare(tail)
-		if err != nil {
-			s.Close()
-			return nil, err
-		}
-		if st != nil {
-			s.Close()
-			st.Close()
-			return nil, util.TailErr
-		}
+	if notWhitespace(tail) {
+		s.Close()
+		return nil, util.TailErr
 	}
-	return &stmt{s, c.Conn}, nil
+	return &stmt{Stmt: s, tmRead: c.tmRead, tmWrite: c.tmWrite, inputs: -2}, nil
 }
 
 func (c *conn) ExecContext(ctx context.Context, query string, args []driver.NamedValue) (driver.Result, error) {
@@ -270,12 +420,13 @@ func (c *conn) ExecContext(ctx context.Context, query string, args []driver.Name
 
 	if savept, ok := ctx.(*saveptCtx); ok {
 		// Called from driver.Savepoint.
-		savept.Savepoint = c.Savepoint()
+		savept.Savepoint = c.Conn.Savepoint()
 		return resultRowsAffected(0), nil
 	}
 
-	old := c.Conn.SetInterrupt(ctx)
-	defer c.Conn.SetInterrupt(old)
+	if old := c.Conn.SetInterrupt(ctx); old != ctx {
+		defer c.Conn.SetInterrupt(old)
+	}
 
 	err := c.Conn.Exec(query)
 	if err != nil {
@@ -285,13 +436,17 @@ func (c *conn) ExecContext(ctx context.Context, query string, args []driver.Name
 	return newResult(c.Conn), nil
 }
 
-func (*conn) CheckNamedValue(arg *driver.NamedValue) error {
+func (c *conn) CheckNamedValue(arg *driver.NamedValue) error {
+	// Fast path: short circuit argument verification.
+	// Arguments will be rejected by conn.ExecContext.
 	return nil
 }
 
 type stmt struct {
-	Stmt *sqlite3.Stmt
-	Conn *sqlite3.Conn
+	*sqlite3.Stmt
+	tmWrite sqlite3.TimeFormat
+	tmRead  sqlite3.TimeFormat
+	inputs  int
 }
 
 var (
@@ -301,27 +456,30 @@ var (
 	_ driver.NamedValueChecker = &stmt{}
 )
 
-func (s *stmt) Close() error {
-	return s.Stmt.Close()
-}
-
 func (s *stmt) NumInput() int {
+	if s.inputs >= -1 {
+		return s.inputs
+	}
 	n := s.Stmt.BindCount()
 	for i := 1; i <= n; i++ {
 		if s.Stmt.BindName(i) != "" {
+			s.inputs = -1
 			return -1
 		}
 	}
+	s.inputs = n
 	return n
 }
 
 // Deprecated: use ExecContext instead.
 func (s *stmt) Exec(args []driver.Value) (driver.Result, error) {
+	// notest
 	return s.ExecContext(context.Background(), namedValues(args))
 }
 
 // Deprecated: use QueryContext instead.
 func (s *stmt) Query(args []driver.Value) (driver.Rows, error) {
+	// notest
 	return s.QueryContext(context.Background(), namedValues(args))
 }
 
@@ -331,15 +489,19 @@ func (s *stmt) ExecContext(ctx context.Context, args []driver.NamedValue) (drive
 		return nil, err
 	}
 
-	old := s.Conn.SetInterrupt(ctx)
-	defer s.Conn.SetInterrupt(old)
+	c := s.Stmt.Conn()
+	if old := c.SetInterrupt(ctx); old != ctx {
+		defer c.SetInterrupt(old)
+	}
 
-	err = s.Stmt.Exec()
+	err = errors.Join(
+		s.Stmt.Exec(),
+		s.Stmt.ClearBindings())
 	if err != nil {
 		return nil, err
 	}
 
-	return newResult(s.Conn), nil
+	return newResult(c), nil
 }
 
 func (s *stmt) QueryContext(ctx context.Context, args []driver.NamedValue) (driver.Rows, error) {
@@ -347,22 +509,17 @@ func (s *stmt) QueryContext(ctx context.Context, args []driver.NamedValue) (driv
 	if err != nil {
 		return nil, err
 	}
-	return &rows{ctx, s.Stmt, s.Conn}, nil
+	return &rows{ctx: ctx, stmt: s}, nil
 }
 
-func (s *stmt) setupBindings(args []driver.NamedValue) error {
-	err := s.Stmt.ClearBindings()
-	if err != nil {
-		return err
-	}
-
+func (s *stmt) setupBindings(args []driver.NamedValue) (err error) {
 	var ids [3]int
 	for _, arg := range args {
 		ids := ids[:0]
 		if arg.Name == "" {
 			ids = append(ids, arg.Ordinal)
 		} else {
-			for _, prefix := range []string{":", "@", "$"} {
+			for _, prefix := range [...]string{":", "@", "$"} {
 				if id := s.Stmt.BindIndex(prefix + arg.Name); id != 0 {
 					ids = append(ids, id)
 				}
@@ -386,19 +543,19 @@ func (s *stmt) setupBindings(args []driver.NamedValue) error {
 			case sqlite3.ZeroBlob:
 				err = s.Stmt.BindZeroBlob(id, int64(a))
 			case time.Time:
-				err = s.Stmt.BindTime(id, a, sqlite3.TimeFormatDefault)
-			case interface{ Pointer() any }:
-				err = s.Stmt.BindPointer(id, a.Pointer())
-			case interface{ JSON() any }:
-				err = s.Stmt.BindJSON(id, a.JSON())
+				err = s.Stmt.BindTime(id, a, s.tmWrite)
+			case util.JSON:
+				err = s.Stmt.BindJSON(id, a.Value)
+			case util.PointerUnwrap:
+				err = s.Stmt.BindPointer(id, util.UnwrapPointer(a))
 			case nil:
 				err = s.Stmt.BindNull(id)
 			default:
 				panic(util.AssertErr())
 			}
-		}
-		if err != nil {
-			return err
+			if err != nil {
+				return err
+			}
 		}
 	}
 	return nil
@@ -407,9 +564,8 @@ func (s *stmt) setupBindings(args []driver.NamedValue) error {
 func (s *stmt) CheckNamedValue(arg *driver.NamedValue) error {
 	switch arg.Value.(type) {
 	case bool, int, int64, float64, string, []byte,
-		sqlite3.ZeroBlob, time.Time,
-		interface{ Pointer() any },
-		interface{ JSON() any },
+		time.Time, sqlite3.ZeroBlob,
+		util.JSON, util.PointerUnwrap,
 		nil:
 		return nil
 	default:
@@ -449,27 +605,176 @@ func (r resultRowsAffected) RowsAffected() (int64, error) {
 }
 
 type rows struct {
-	ctx  context.Context
-	Stmt *sqlite3.Stmt
-	Conn *sqlite3.Conn
+	ctx context.Context
+	*stmt
+	names []string
+	types []string
+	nulls []bool
+	scans []scantype
 }
 
+type scantype byte
+
+const (
+	_ANY  scantype = iota
+	_INT  scantype = scantype(sqlite3.INTEGER)
+	_REAL scantype = scantype(sqlite3.FLOAT)
+	_TEXT scantype = scantype(sqlite3.TEXT)
+	_BLOB scantype = scantype(sqlite3.BLOB)
+	_NULL scantype = scantype(sqlite3.NULL)
+	_BOOL scantype = iota
+	_TIME
+)
+
+func scanFromDecl(decl string) scantype {
+	// These types are only used before we have rows,
+	// and otherwise as type hints.
+	// The first few ensure STRICT tables are strictly typed.
+	// The other two are type hints for booleans and time.
+	switch decl {
+	case "INT", "INTEGER":
+		return _INT
+	case "REAL":
+		return _REAL
+	case "TEXT":
+		return _TEXT
+	case "BLOB":
+		return _BLOB
+	case "BOOLEAN":
+		return _BOOL
+	case "DATE", "TIME", "DATETIME", "TIMESTAMP":
+		return _TIME
+	}
+	return _ANY
+}
+
+var (
+	// Ensure these interfaces are implemented:
+	_ driver.RowsColumnTypeDatabaseTypeName = &rows{}
+	_ driver.RowsColumnTypeNullable         = &rows{}
+)
+
 func (r *rows) Close() error {
-	return r.Stmt.Reset()
+	return errors.Join(
+		r.Stmt.Reset(),
+		r.Stmt.ClearBindings())
 }
 
 func (r *rows) Columns() []string {
-	count := r.Stmt.ColumnCount()
-	columns := make([]string, count)
-	for i := range columns {
-		columns[i] = r.Stmt.ColumnName(i)
+	if r.names == nil {
+		count := r.Stmt.ColumnCount()
+		names := make([]string, count)
+		for i := range names {
+			names[i] = r.Stmt.ColumnName(i)
+		}
+		r.names = names
+	}
+	return r.names
+}
+
+func (r *rows) scanType(index int) scantype {
+	if r.scans == nil {
+		count := r.Stmt.ColumnCount()
+		scans := make([]scantype, count)
+		for i := range scans {
+			scans[i] = scanFromDecl(strings.ToUpper(r.Stmt.ColumnDeclType(i)))
+		}
+		r.scans = scans
+	}
+	return r.scans[index]
+}
+
+func (r *rows) loadColumnMetadata() {
+	if r.nulls == nil {
+		c := r.Stmt.Conn()
+		count := r.Stmt.ColumnCount()
+		nulls := make([]bool, count)
+		types := make([]string, count)
+		scans := make([]scantype, count)
+		for i := range nulls {
+			if col := r.Stmt.ColumnOriginName(i); col != "" {
+				types[i], _, nulls[i], _, _, _ = c.TableColumnMetadata(
+					r.Stmt.ColumnDatabaseName(i),
+					r.Stmt.ColumnTableName(i),
+					col)
+				types[i] = strings.ToUpper(types[i])
+				scans[i] = scanFromDecl(types[i])
+			}
+		}
+		r.nulls = nulls
+		r.types = types
+		r.scans = scans
+	}
+}
+
+func (r *rows) ColumnTypeDatabaseTypeName(index int) string {
+	r.loadColumnMetadata()
+	decl := r.types[index]
+	if len := len(decl); len > 0 && decl[len-1] == ')' {
+		if i := strings.LastIndexByte(decl, '('); i >= 0 {
+			decl = decl[:i]
+		}
+	}
+	return strings.TrimSpace(decl)
+}
+
+func (r *rows) ColumnTypeNullable(index int) (nullable, ok bool) {
+	r.loadColumnMetadata()
+	if r.nulls[index] {
+		return false, true
+	}
+	return true, false
+}
+
+func (r *rows) ColumnTypeScanType(index int) (typ reflect.Type) {
+	r.loadColumnMetadata()
+	scan := r.scans[index]
+
+	if r.Stmt.Busy() {
+		// SQLite is dynamically typed and we now have a row.
+		// Always use the type of the value itself,
+		// unless the scan type is more specific
+		// and can scan the actual value.
+		val := scantype(r.Stmt.ColumnType(index))
+		useValType := true
+		switch {
+		case scan == _TIME && val != _BLOB && val != _NULL:
+			t := r.Stmt.ColumnTime(index, r.tmRead)
+			useValType = t == time.Time{}
+		case scan == _BOOL && val == _INT:
+			i := r.Stmt.ColumnInt64(index)
+			useValType = i != 0 && i != 1
+		case scan == _BLOB && val == _NULL:
+			useValType = false
+		}
+		if useValType {
+			scan = val
+		}
+	}
+
+	switch scan {
+	case _INT:
+		return reflect.TypeFor[int64]()
+	case _REAL:
+		return reflect.TypeFor[float64]()
+	case _TEXT:
+		return reflect.TypeFor[string]()
+	case _BLOB:
+		return reflect.TypeFor[[]byte]()
+	case _BOOL:
+		return reflect.TypeFor[bool]()
+	case _TIME:
+		return reflect.TypeFor[time.Time]()
+	default:
+		return reflect.TypeFor[any]()
 	}
-	return columns
 }
 
 func (r *rows) Next(dest []driver.Value) error {
-	old := r.Conn.SetInterrupt(r.ctx)
-	defer r.Conn.SetInterrupt(old)
+	c := r.Stmt.Conn()
+	if old := c.SetInterrupt(r.ctx); old != r.ctx {
+		defer c.SetInterrupt(old)
+	}
 
 	if !r.Stmt.Step() {
 		if err := r.Stmt.Err(); err != nil {
@@ -478,22 +783,50 @@ func (r *rows) Next(dest []driver.Value) error {
 		return io.EOF
 	}
 
+	data := unsafe.Slice((*any)(unsafe.SliceData(dest)), len(dest))
+	if err := r.Stmt.ColumnsRaw(data...); err != nil {
+		return err
+	}
 	for i := range dest {
-		switch r.Stmt.ColumnType(i) {
-		case sqlite3.INTEGER:
-			dest[i] = r.Stmt.ColumnInt64(i)
-		case sqlite3.FLOAT:
-			dest[i] = r.Stmt.ColumnFloat(i)
-		case sqlite3.BLOB:
-			dest[i] = r.Stmt.ColumnRawBlob(i)
-		case sqlite3.TEXT:
-			dest[i] = stringOrTime(r.Stmt.ColumnRawText(i))
-		case sqlite3.NULL:
-			dest[i] = nil
+		scan := r.scanType(i)
+		switch v := dest[i].(type) {
+		case int64:
+			if scan == _BOOL {
+				switch v {
+				case 1:
+					dest[i] = true
+				case 0:
+					dest[i] = false
+				}
+				continue
+			}
+		case []byte:
+			if len(v) == cap(v) { // a BLOB
+				continue
+			}
+			if scan != _TEXT {
+				switch r.tmWrite {
+				case "", time.RFC3339, time.RFC3339Nano:
+					t, ok := maybeTime(v)
+					if ok {
+						dest[i] = t
+						continue
+					}
+				}
+			}
+			dest[i] = string(v)
+		case float64:
+			break
 		default:
-			panic(util.AssertErr())
+			continue
+		}
+		if scan == _TIME {
+			t, err := r.tmRead.Decode(dest[i])
+			if err == nil {
+				dest[i] = t
+				continue
+			}
 		}
 	}
-
-	return r.Stmt.Err()
+	return nil
 }

driver/driver_test.go

@@ -6,15 +6,30 @@ import (
 	"database/sql"
 	"errors"
 	"math"
-	"path/filepath"
+	"net/url"
+	"reflect"
 	"testing"
 	"time"
 
 	"github.com/ncruces/go-sqlite3"
 	_ "github.com/ncruces/go-sqlite3/embed"
+	_ "github.com/ncruces/go-sqlite3/internal/testcfg"
 	"github.com/ncruces/go-sqlite3/internal/util"
+	"github.com/ncruces/go-sqlite3/vfs/memdb"
 )
 
+func Test_Open_error(t *testing.T) {
+	t.Parallel()
+
+	_, err := Open("", nil, nil, nil)
+	if err == nil {
+		t.Error("want error")
+	}
+	if !errors.Is(err, sqlite3.MISUSE) {
+		t.Errorf("got %v, want sqlite3.MISUSE", err)
+	}
+}
+
 func Test_Open_dir(t *testing.T) {
 	t.Parallel()
 
@@ -35,8 +50,11 @@ func Test_Open_dir(t *testing.T) {
 
 func Test_Open_pragma(t *testing.T) {
 	t.Parallel()
+	tmp := memdb.TestDB(t, url.Values{
+		"_pragma": {"busy_timeout(1000)"},
+	})
 
-	db, err := sql.Open("sqlite3", "file::memory:?_pragma=busy_timeout(1000)")
+	db, err := sql.Open("sqlite3", tmp)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -54,8 +72,11 @@ func Test_Open_pragma(t *testing.T) {
 
 func Test_Open_pragma_invalid(t *testing.T) {
 	t.Parallel()
+	tmp := memdb.TestDB(t, url.Values{
+		"_pragma": {"busy_timeout 1000"},
+	})
 
-	db, err := sql.Open("sqlite3", "file::memory:?_pragma=busy_timeout+1000")
+	db, err := sql.Open("sqlite3", tmp)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -79,10 +100,12 @@ func Test_Open_pragma_invalid(t *testing.T) {
 
 func Test_Open_txLock(t *testing.T) {
 	t.Parallel()
+	tmp := memdb.TestDB(t, url.Values{
+		"_txlock": {"exclusive"},
+		"_pragma": {"busy_timeout(1000)"},
+	})
 
-	db, err := sql.Open("sqlite3", "file:"+
-		filepath.ToSlash(filepath.Join(t.TempDir(), "test.db"))+
-		"?_txlock=exclusive&_pragma=busy_timeout(0)")
+	db, err := sql.Open("sqlite3", tmp)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -113,14 +136,11 @@ func Test_Open_txLock(t *testing.T) {
 
 func Test_Open_txLock_invalid(t *testing.T) {
 	t.Parallel()
+	tmp := memdb.TestDB(t, url.Values{
+		"_txlock": {"xclusive"},
+	})
 
-	db, err := sql.Open("sqlite3", "file::memory:?_txlock=xclusive")
-	if err != nil {
-		t.Fatal(err)
-	}
-	defer db.Close()
-
-	_, err = db.Conn(context.TODO())
+	_, err := sql.Open("sqlite3", tmp+"_txlock=xclusive")
 	if err == nil {
 		t.Fatal("want error")
 	}
@@ -131,13 +151,15 @@ func Test_Open_txLock_invalid(t *testing.T) {
 
 func Test_BeginTx(t *testing.T) {
 	t.Parallel()
+	tmp := memdb.TestDB(t, url.Values{
+		"_txlock": {"exclusive"},
+		"_pragma": {"busy_timeout(0)"},
+	})
 
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
 
-	db, err := sql.Open("sqlite3", "file:"+
-		filepath.ToSlash(filepath.Join(t.TempDir(), "test.db"))+
-		"?_txlock=exclusive&_pragma=busy_timeout(0)")
+	db, err := sql.Open("sqlite3", tmp)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -158,7 +180,7 @@ func Test_BeginTx(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	_, err = tx1.Exec(`CREATE TABLE IF NOT EXISTS test (col)`)
+	_, err = tx1.Exec(`CREATE TABLE test (col)`)
 	if err == nil {
 		t.Error("want error")
 	}
@@ -177,20 +199,73 @@ func Test_BeginTx(t *testing.T) {
 	}
 }
 
-func Test_Prepare(t *testing.T) {
+func Test_nested_context(t *testing.T) {
 	t.Parallel()
+	tmp := memdb.TestDB(t)
 
-	db, err := sql.Open("sqlite3", ":memory:")
+	db, err := sql.Open("sqlite3", tmp)
 	if err != nil {
 		t.Fatal(err)
 	}
 	defer db.Close()
 
-	stmt, err := db.Prepare(`SELECT 1; -- HERE`)
+	tx, err := db.Begin()
 	if err != nil {
-		t.Error(err)
+		t.Fatal(err)
 	}
-	defer stmt.Close()
+	defer tx.Rollback()
+
+	outer, err := tx.Query(`SELECT value FROM generate_series(0)`)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer outer.Close()
+
+	want := func(rows *sql.Rows, want int) {
+		t.Helper()
+
+		var got int
+		rows.Next()
+		if err := rows.Scan(&got); err != nil {
+			t.Fatal(err)
+		}
+		if got != want {
+			t.Errorf("got %d, want %d", got, want)
+		}
+	}
+
+	want(outer, 0)
+
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	inner, err := tx.QueryContext(ctx, `SELECT value FROM generate_series(0)`)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer inner.Close()
+
+	want(inner, 0)
+	cancel()
+
+	var terr interface{ Temporary() bool }
+	if inner.Next() || !errors.Is(inner.Err(), context.Canceled) &&
+		(!errors.As(inner.Err(), &terr) || !terr.Temporary()) {
+		t.Fatalf("got %v, want cancellation", inner.Err())
+	}
+
+	want(outer, 1)
+}
+
+func Test_Prepare(t *testing.T) {
+	t.Parallel()
+	tmp := memdb.TestDB(t)
+
+	db, err := sql.Open("sqlite3", tmp)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
 
 	var serr *sqlite3.Error
 	_, err = db.Prepare(`SELECT`)
@@ -207,18 +282,14 @@ func Test_Prepare(t *testing.T) {
 		t.Error("got message:", got)
 	}
 
+	_, err = db.Prepare(`SELECT 1; `)
+	if err != nil {
+		t.Error(err)
+	}
+
 	_, err = db.Prepare(`SELECT 1; SELECT`)
-	if err == nil {
-		t.Error("want error")
-	}
-	if !errors.As(err, &serr) {
-		t.Fatalf("got %T, want sqlite3.Error", err)
-	}
-	if rc := serr.Code(); rc != sqlite3.ERROR {
-		t.Errorf("got %d, want sqlite3.ERROR", rc)
-	}
-	if got := err.Error(); got != `sqlite3: SQL logic error: incomplete input` {
-		t.Error("got message:", got)
+	if err.Error() != string(util.TailErr) {
+		t.Error("want tailErr")
 	}
 
 	_, err = db.Prepare(`SELECT 1; SELECT 2`)
@@ -229,11 +300,12 @@ func Test_Prepare(t *testing.T) {
 
 func Test_QueryRow_named(t *testing.T) {
 	t.Parallel()
+	tmp := memdb.TestDB(t)
 
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
 
-	db, err := sql.Open("sqlite3", ":memory:")
+	db, err := sql.Open("sqlite3", tmp)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -281,8 +353,9 @@ func Test_QueryRow_named(t *testing.T) {
 
 func Test_QueryRow_blob_null(t *testing.T) {
 	t.Parallel()
+	tmp := memdb.TestDB(t)
 
-	db, err := sql.Open("sqlite3", ":memory:")
+	db, err := sql.Open("sqlite3", tmp)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -311,3 +384,170 @@ func Test_QueryRow_blob_null(t *testing.T) {
 		}
 	}
 }
+
+func Test_time(t *testing.T) {
+	t.Parallel()
+
+	for _, fmt := range []string{"auto", "sqlite", "rfc3339", time.ANSIC} {
+		t.Run(fmt, func(t *testing.T) {
+			tmp := memdb.TestDB(t, url.Values{
+				"_timefmt": {fmt},
+			})
+
+			db, err := sql.Open("sqlite3", tmp)
+			if err != nil {
+				t.Fatal(err)
+			}
+			defer db.Close()
+
+			twosday := time.Date(2022, 2, 22, 22, 22, 22, 0, time.UTC)
+
+			_, err = db.Exec(`CREATE TABLE test (at DATETIME)`)
+			if err != nil {
+				t.Fatal(err)
+			}
+
+			_, err = db.Exec(`INSERT INTO test VALUES (?)`, twosday)
+			if err != nil {
+				t.Fatal(err)
+			}
+
+			var got time.Time
+			err = db.QueryRow(`SELECT * FROM test`).Scan(&got)
+			if err != nil {
+				t.Fatal(err)
+			}
+
+			if !got.Equal(twosday) {
+				t.Errorf("got: %v", got)
+			}
+		})
+	}
+}
+
+func Test_ColumnType_ScanType(t *testing.T) {
+	var (
+		INT  = reflect.TypeFor[int64]()
+		REAL = reflect.TypeFor[float64]()
+		TEXT = reflect.TypeFor[string]()
+		BLOB = reflect.TypeFor[[]byte]()
+		BOOL = reflect.TypeFor[bool]()
+		TIME = reflect.TypeFor[time.Time]()
+		ANY  = reflect.TypeFor[any]()
+	)
+
+	t.Parallel()
+	tmp := memdb.TestDB(t)
+
+	db, err := sql.Open("sqlite3", tmp)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+
+	_, err = db.Exec(`
+		CREATE TABLE test (
+			col_int  INTEGER,
+			col_real REAL,
+			col_text TEXT,
+			col_blob BLOB,
+			col_bool BOOLEAN,
+			col_time DATETIME,
+			col_decimal DECIMAL
+		);
+		INSERT INTO test VALUES
+			(1, 1, 1, 1, 1, 1, 1),
+			(2.0, 2.0, 2.0, 2.0, 2.0, 2.0, 2.0),
+			('1', '1', '1', '1', '1', '1', '1'),
+			('x', 'x', 'x', 'x', 'x', 'x', 'x'),
+			(x'', x'', x'', x'', x'', x'', x''),
+			('2006-01-02T15:04:05Z', '2006-01-02T15:04:05Z', '2006-01-02T15:04:05Z', '2006-01-02T15:04:05Z',
+			 '2006-01-02T15:04:05Z', '2006-01-02T15:04:05Z', '2006-01-02T15:04:05Z'),
+			(TRUE, TRUE, TRUE, TRUE, TRUE, TRUE, TRUE),
+			(NULL, NULL, NULL, NULL, NULL, NULL, NULL);
+	`)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	rows, err := db.Query(`SELECT * FROM test`)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer rows.Close()
+
+	cols, err := rows.ColumnTypes()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	want := [][]reflect.Type{
+		{INT, REAL, TEXT, BLOB, BOOL, TIME, ANY},
+		{INT, REAL, TEXT, INT, BOOL, TIME, INT},
+		{INT, REAL, TEXT, REAL, INT, TIME, INT},
+		{INT, REAL, TEXT, TEXT, BOOL, TIME, INT},
+		{TEXT, TEXT, TEXT, TEXT, TEXT, TEXT, TEXT},
+		{BLOB, BLOB, BLOB, BLOB, BLOB, BLOB, BLOB},
+		{TEXT, TEXT, TEXT, TEXT, TEXT, TIME, TEXT},
+		{INT, REAL, TEXT, INT, BOOL, TIME, INT},
+		{ANY, ANY, ANY, BLOB, ANY, ANY, ANY},
+	}
+	for j, c := range cols {
+		got := c.ScanType()
+		if got != want[0][j] {
+			t.Errorf("want %v, got %v, at column %d", want[0][j], got, j)
+		}
+	}
+
+	dest := make([]any, len(cols))
+	for i := 1; rows.Next(); i++ {
+		cols, err := rows.ColumnTypes()
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		for j, c := range cols {
+			got := c.ScanType()
+			if got != want[i][j] {
+				t.Errorf("want %v, got %v, at row %d column %d", want[i][j], got, i, j)
+			}
+			dest[j] = reflect.New(got).Interface()
+		}
+
+		err = rows.Scan(dest...)
+		if err != nil {
+			t.Error(err)
+		}
+	}
+
+	err = rows.Err()
+	if err != nil {
+		t.Fatal(err)
+	}
+}
+
+func Benchmark_loop(b *testing.B) {
+	db, err := Open(":memory:")
+	if err != nil {
+		b.Fatal(err)
+	}
+	defer db.Close()
+
+	var version string
+	err = db.QueryRow(`SELECT sqlite_version();`).Scan(&version)
+	if err != nil {
+		b.Fatal(err)
+	}
+
+	ctx, cancel := context.WithCancel(context.Background())
+	b.Cleanup(cancel)
+
+	b.ResetTimer()
+	for range b.N {
+		_, err := db.ExecContext(ctx,
+			`WITH RECURSIVE c(x) AS (VALUES(1) UNION ALL SELECT x+1 FROM c WHERE x < 1000000) SELECT x FROM c;`)
+		if err != nil {
+			b.Fatal(err)
+		}
+	}
+}

driver/example2_test.go

@@ -0,0 +1,140 @@
+package driver_test
+
+import (
+	"database/sql"
+	"database/sql/driver"
+	"fmt"
+	"log"
+	"time"
+
+	"github.com/ncruces/go-sqlite3"
+	_ "github.com/ncruces/go-sqlite3/driver"
+	_ "github.com/ncruces/go-sqlite3/embed"
+	_ "github.com/ncruces/go-sqlite3/vfs/memdb"
+)
+
+func Example_customTime() {
+	db, err := sql.Open("sqlite3", "file:/time.db?vfs=memdb")
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer db.Close()
+
+	_, err = db.Exec(`
+		CREATE TABLE data (
+			id INTEGER PRIMARY KEY,
+			date_time ANY
+		) STRICT;
+	`)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	// This one will be returned as string to [sql.Scanner] because it doesn't
+	// pass the driver's round-trip test when it tries to figure out if it's
+	// a time. 2009-11-17T20:34:58.650Z goes in, but parsing and formatting
+	// it with [time.RFC3338Nano] results in 2009-11-17T20:34:58.65Z. Though
+	// the times are identical, the trailing zero is lost in the string
+	// representation so the driver considers the conversion unsuccessful.
+	c1 := CustomTime{time.Date(
+		2009, 11, 17, 20, 34, 58, 650000000, time.UTC)}
+
+	// Store our custom time in the database.
+	_, err = db.Exec(`INSERT INTO data (date_time) VALUES(?)`, c1)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	var strc1 string
+	// Retrieve it as a string, the result of Value().
+	err = db.QueryRow(`
+		SELECT date_time
+		FROM data
+		WHERE id = last_insert_rowid()
+	`).Scan(&strc1)
+	if err != nil {
+		log.Fatal(err)
+	}
+	fmt.Println("in db:", strc1)
+
+	var resc1 CustomTime
+	// Retrieve it as our custom time type, going through Scan().
+	err = db.QueryRow(`
+		SELECT date_time
+		FROM data
+		WHERE id = last_insert_rowid()
+	`).Scan(&resc1)
+	if err != nil {
+		log.Fatal(err)
+	}
+	fmt.Println("custom time:", resc1)
+
+	// This one will be returned as [time.Time] to [sql.Scanner] because it does
+	// pass the driver's round-trip test when it tries to figure out if it's
+	// a time. 2009-11-17T20:34:58.651Z goes in, and parsing and formatting
+	// it with [time.RFC3339Nano] results in 2009-11-17T20:34:58.651Z.
+	c2 := CustomTime{time.Date(
+		2009, 11, 17, 20, 34, 58, 651000000, time.UTC)}
+	// Store our custom time in the database.
+	_, err = db.Exec(`INSERT INTO data (date_time) VALUES(?)`, c2)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	var strc2 string
+	// Retrieve it as a string, the result of Value().
+	err = db.QueryRow(`
+		SELECT date_time
+		FROM data
+		WHERE id = last_insert_rowid()
+	`).Scan(&strc2)
+	if err != nil {
+		log.Fatal(err)
+	}
+	fmt.Println("in db:", strc2)
+
+	var resc2 CustomTime
+	// Retrieve it as our custom time type, going through Scan().
+	err = db.QueryRow(`
+		SELECT date_time
+		FROM data
+		WHERE id = last_insert_rowid()
+	`).Scan(&resc2)
+	if err != nil {
+		log.Fatal(err)
+	}
+	fmt.Println("custom time:", resc2)
+	// Output:
+	// in db: 2009-11-17T20:34:58.650Z
+	// scan type string: 2009-11-17T20:34:58.650Z
+	// custom time: 2009-11-17 20:34:58.65 +0000 UTC
+	// in db: 2009-11-17T20:34:58.651Z
+	// scan type time: 2009-11-17 20:34:58.651 +0000 UTC
+	// custom time: 2009-11-17 20:34:58.651 +0000 UTC
+}
+
+type CustomTime struct{ time.Time }
+
+func (c CustomTime) Value() (driver.Value, error) {
+	return sqlite3.TimeFormat7TZ.Encode(c.UTC()), nil
+}
+
+func (c *CustomTime) Scan(value any) error {
+	switch v := value.(type) {
+	case nil:
+		*c = CustomTime{time.Time{}}
+	case time.Time:
+		fmt.Println("scan type time:", v)
+		*c = CustomTime{v}
+	case string:
+		fmt.Println("scan type string:", v)
+		t, err := sqlite3.TimeFormat7TZ.Decode(v)
+		if err != nil {
+			return err
+		}
+		*c = CustomTime{t}
+	default:
+		panic("unsupported value type")
+	}
+	return nil
+}

driver/example_test.go

@@ -1,3 +1,5 @@
+//go:build linux || darwin || windows || freebsd || openbsd || netbsd || dragonfly || illumos || sqlite3_flock || sqlite3_dotlk
+
 package driver_test
 
 // Adapted from: https://go.dev/doc/tutorial/database-access
@@ -10,6 +12,7 @@ import (
 
 	_ "github.com/ncruces/go-sqlite3/driver"
 	_ "github.com/ncruces/go-sqlite3/embed"
+	_ "github.com/ncruces/go-sqlite3/vfs/memdb"
 )
 
 var db *sql.DB

driver/json_test.go

@@ -11,18 +11,18 @@ import (
 )
 
 func Example_json() {
-	db, err := driver.Open("file:/test.db?vfs=memdb", nil)
+	db, err := driver.Open("file:/json.db?vfs=memdb")
 	if err != nil {
 		log.Fatal(err)
 	}
 	defer db.Close()
 
 	_, err = db.Exec(`
-		CREATE TABLE IF NOT EXISTS orders (
+		CREATE TABLE orders (
 			cart_id INTEGER PRIMARY KEY,
 			user_id INTEGER NOT NULL,
-			cart    TEXT
-		);
+			cart    BLOB -- stored as JSONB
+		) STRICT;
 	`)
 	if err != nil {
 		log.Fatal(err)
@@ -39,7 +39,8 @@ func Example_json() {
 		Items []CartItem `json:"items"`
 	}
 
-	_, err = db.Exec(`INSERT INTO orders (user_id, cart) VALUES (?, ?)`, 123, sqlite3.JSON(Cart{
+	// convert to JSONB on insertion
+	_, err = db.Exec(`INSERT INTO orders (user_id, cart) VALUES (?, jsonb(?))`, 123, sqlite3.JSON(Cart{
 		[]CartItem{
 			{ItemID: "111", Name: "T-shirt", Quantity: 1, Price: 250},
 			{ItemID: "222", Name: "Trousers", Quantity: 1, Price: 600},
@@ -60,6 +61,24 @@ func Example_json() {
 	}
 
 	fmt.Println("total:", total)
+
+	var cart Cart
+	err = db.QueryRow(`
+		SELECT json(cart) -- convert to JSON on retrieval
+		FROM orders
+		WHERE cart_id = last_insert_rowid()
+	`).Scan(sqlite3.JSON(&cart))
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	for _, item := range cart.Items {
+		fmt.Printf("id: %s, name: %s, quantity: %d, price: %d\n",
+			item.ItemID, item.Name, item.Quantity, item.Price)
+	}
+
 	// Output:
 	// total: 850
+	// id: 111, name: T-shirt, quantity: 1, price: 250
+	// id: 222, name: Trousers, quantity: 1, price: 600
 }

driver/savepoint.go

@@ -16,12 +16,25 @@ func Savepoint(tx *sql.Tx) sqlite3.Savepoint {
 	return ctx.Savepoint
 }
 
+// A saveptCtx is never canceled, has no values, and has no deadline.
 type saveptCtx struct{ sqlite3.Savepoint }
 
-func (*saveptCtx) Deadline() (deadline time.Time, ok bool) { return }
+func (*saveptCtx) Deadline() (deadline time.Time, ok bool) {
+	// notest
+	return
+}
 
-func (*saveptCtx) Done() <-chan struct{} { return nil }
+func (*saveptCtx) Done() <-chan struct{} {
+	// notest
+	return nil
+}
 
-func (*saveptCtx) Err() error { return nil }
+func (*saveptCtx) Err() error {
+	// notest
+	return nil
+}
 
-func (*saveptCtx) Value(key any) any { return nil }
+func (*saveptCtx) Value(key any) any {
+	// notest
+	return nil
+}

driver/savepoint_test.go

@@ -6,17 +6,18 @@ import (
 
 	"github.com/ncruces/go-sqlite3/driver"
 	_ "github.com/ncruces/go-sqlite3/embed"
+	_ "github.com/ncruces/go-sqlite3/internal/testcfg"
 	_ "github.com/ncruces/go-sqlite3/vfs/memdb"
 )
 
 func ExampleSavepoint() {
-	db, err := driver.Open("file:/test.db?vfs=memdb", nil)
+	db, err := driver.Open("file:/svpt.db?vfs=memdb")
 	if err != nil {
 		log.Fatal(err)
 	}
 	defer db.Close()
 
-	_, err = db.Exec(`CREATE TABLE IF NOT EXISTS users (id INT, name VARCHAR(10))`)
+	_, err = db.Exec(`CREATE TABLE users (id INT, name VARCHAR(10))`)
 	if err != nil {
 		log.Fatal(err)
 	}

driver/time.go

@@ -1,7 +1,7 @@
 package driver
 
 import (
-	"database/sql/driver"
+	"bytes"
 	"time"
 )
 
@@ -9,23 +9,24 @@ import (
 // if it roundtrips back to the same string.
 // This way times can be persisted to, and recovered from, the database,
 // but if a string is needed, [database/sql] will recover the same string.
-func stringOrTime(text []byte) driver.Value {
+func maybeTime(text []byte) (_ time.Time, _ bool) {
 	// Weed out (some) values that can't possibly be
 	// [time.RFC3339Nano] timestamps.
 	if len(text) < len("2006-01-02T15:04:05Z") {
-		return string(text)
+		return
 	}
 	if len(text) > len(time.RFC3339Nano) {
-		return string(text)
+		return
 	}
 	if text[4] != '-' || text[10] != 'T' || text[16] != ':' {
-		return string(text)
+		return
 	}
 
 	// Slow path.
+	var buf [len(time.RFC3339Nano)]byte
 	date, err := time.Parse(time.RFC3339Nano, string(text))
-	if err == nil && date.Format(time.RFC3339Nano) == string(text) {
-		return date
+	if err == nil && bytes.Equal(text, date.AppendFormat(buf[:0], time.RFC3339Nano)) {
+		return date, true
 	}
-	return string(text)
+	return
 }

driver/time_test.go

@@ -22,26 +22,18 @@ func Fuzz_stringOrTime_1(f *testing.F) {
 	f.Add("Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.")
 
 	f.Fuzz(func(t *testing.T, str string) {
-		value := stringOrTime([]byte(str))
-
-		switch v := value.(type) {
-		case time.Time:
+		v, ok := maybeTime([]byte(str))
+		if ok {
 			// Make sure times round-trip to the same string:
 			// https://pkg.go.dev/database/sql#Rows.Scan
 			if v.Format(time.RFC3339Nano) != str {
-				t.Fatalf("did not round-trip: %q", str)
+				t.Errorf("did not round-trip: %q", str)
 			}
-		case string:
-			if v != str {
-				t.Fatalf("did not round-trip: %q", str)
-			}
-
+		} else {
 			date, err := time.Parse(time.RFC3339Nano, str)
 			if err == nil && date.Format(time.RFC3339Nano) == str {
-				t.Fatalf("would round-trip: %q", str)
+				t.Errorf("would round-trip: %q", str)
 			}
-		default:
-			t.Fatalf("invalid type %T: %q", v, str)
 		}
 	})
 }
@@ -49,38 +41,34 @@ func Fuzz_stringOrTime_1(f *testing.F) {
 // This checks that any [time.Time] can be recovered as a [time.Time],
 // with nanosecond accuracy, and preserving any timezone offset.
 func Fuzz_stringOrTime_2(f *testing.F) {
-	f.Add(0, 0)
-	f.Add(0, 1)
-	f.Add(0, -1)
-	f.Add(0, 999_999_999)
-	f.Add(0, 1_000_000_000)
-	f.Add(7956915742, 222_222_222)    // twosday
-	f.Add(639095955742, 222_222_222)  // twosday, year 22222AD
-	f.Add(-763421161058, 222_222_222) // twosday, year 22222BC
+	f.Add(int64(0), int64(0))
+	f.Add(int64(0), int64(1))
+	f.Add(int64(0), int64(-1))
+	f.Add(int64(0), int64(999_999_999))
+	f.Add(int64(0), int64(1_000_000_000))
+	f.Add(int64(7956915742), int64(222_222_222))    // twosday
+	f.Add(int64(639095955742), int64(222_222_222))  // twosday, year 22222AD
+	f.Add(int64(-763421161058), int64(222_222_222)) // twosday, year 22222BC
 
 	checkTime := func(t testing.TB, date time.Time) {
-		value := stringOrTime([]byte(date.Format(time.RFC3339Nano)))
-
-		switch v := value.(type) {
-		case time.Time:
+		v, ok := maybeTime(date.AppendFormat(nil, time.RFC3339Nano))
+		if ok {
 			// Make sure times round-trip to the same time:
 			if !v.Equal(date) {
 				t.Fatalf("did not round-trip: %v", date)
 			}
-			// Make with the same zone offset:
+			// With the same zone offset:
 			_, off1 := v.Zone()
 			_, off2 := date.Zone()
 			if off1 != off2 {
 				t.Fatalf("did not round-trip: %v", date)
 			}
-		case string:
+		} else {
 			t.Fatalf("was not recovered: %v", date)
-		default:
-			t.Fatalf("invalid type %T: %v", v, date)
 		}
 	}
 
-	f.Fuzz(func(t *testing.T, sec, nsec int) {
+	f.Fuzz(func(t *testing.T, sec, nsec int64) {
 		// Reduce the search space.
 		if 1e12 < sec || sec < -1e12 {
 			// Dates before 29000BC and after 33000AD; I think we're safe.
@@ -91,7 +79,7 @@ func Fuzz_stringOrTime_2(f *testing.F) {
 			return
 		}
 
-		unix := time.Unix(int64(sec), int64(nsec))
+		unix := time.Unix(sec, nsec)
 		checkTime(t, unix)
 		checkTime(t, unix.UTC())
 		checkTime(t, unix.In(time.FixedZone("", -8*3600)))

driver/util.go

@@ -12,3 +12,63 @@ func namedValues(args []driver.Value) []driver.NamedValue {
 	}
 	return named
 }
+
+func notWhitespace(sql string) bool {
+	const (
+		code = iota
+		slash
+		minus
+		ccomment
+		sqlcomment
+		endcomment
+	)
+
+	state := code
+	for _, b := range ([]byte)(sql) {
+		if b == 0 {
+			break
+		}
+
+		switch state {
+		case code:
+			switch b {
+			case '/':
+				state = slash
+			case '-':
+				state = minus
+			case ' ', ';', '\t', '\n', '\v', '\f', '\r':
+				continue
+			default:
+				return true
+			}
+		case slash:
+			if b != '*' {
+				return true
+			}
+			state = ccomment
+		case minus:
+			if b != '-' {
+				return true
+			}
+			state = sqlcomment
+		case ccomment:
+			if b == '*' {
+				state = endcomment
+			}
+		case sqlcomment:
+			if b == '\n' {
+				state = code
+			}
+		case endcomment:
+			switch b {
+			case '/':
+				state = code
+			case '*':
+				state = endcomment
+			default:
+				state = ccomment
+			}
+		}
+	}
+	return state == slash || state == minus
+}

driver/util_test.go

@@ -1,9 +1,13 @@
 package driver
 
 import (
+	"context"
 	"database/sql/driver"
-	"reflect"
+	"slices"
 	"testing"
+
+	_ "github.com/ncruces/go-sqlite3/embed"
+	_ "github.com/ncruces/go-sqlite3/internal/testcfg"
 )
 
 func Test_namedValues(t *testing.T) {
@@ -12,7 +16,71 @@ func Test_namedValues(t *testing.T) {
 		{Ordinal: 2, Value: false},
 	}
 	got := namedValues([]driver.Value{true, false})
-	if !reflect.DeepEqual(got, want) {
+	if !slices.Equal(got, want) {
 		t.Errorf("got %v, want %v", got, want)
 	}
 }
+
+func Fuzz_notWhitespace(f *testing.F) {
+	f.Add("")
+	f.Add(" ")
+	f.Add(";")
+	f.Add("0")
+	f.Add("-")
+	f.Add("-0")
+	f.Add("--")
+	f.Add("--0")
+	f.Add("--\n")
+	f.Add("--0\n")
+	f.Add("/0")
+	f.Add("/*")
+	f.Add("/*/")
+	f.Add("/**")
+	f.Add("/*0")
+	f.Add("/**/")
+	f.Add("/***/")
+	f.Add("/**0/")
+	f.Add("\v")
+	f.Add(" \v")
+	f.Add("\xf0")
+	f.Add("\000")
+
+	db, err := Open(":memory:")
+	if err != nil {
+		f.Fatal(err)
+	}
+	defer db.Close()
+
+	f.Fuzz(func(t *testing.T, str string) {
+		if len(str) > 128 {
+			t.SkipNow()
+		}
+
+		c, err := db.Conn(context.Background())
+		if err != nil {
+			t.Fatal(err)
+		}
+		defer c.Close()
+
+		c.Raw(func(driverConn any) error {
+			conn := driverConn.(*conn).Conn
+			stmt, tail, err := conn.Prepare(str)
+			stmt.Close()
+
+			// It's hard to be bug for bug compatible with SQLite.
+			// We settle for somewhat less:
+			//   - if SQLite reports whitespace, we must too
+			//   - if we report whitespace, SQLite must not parse a statement
+			if notWhitespace(str) {
+				if stmt == nil && tail == "" && err == nil {
+					t.Errorf("was whitespace: %q", str)
+				}
+			} else {
+				if stmt != nil {
+					t.Errorf("was not whitespace: %q (%v)", str, err)
+				}
+			}
+			return nil
+		})
+	})
+}

embed/README.md

@@ -1,25 +1,41 @@
-# Embeddable WASM build of SQLite
+# Embeddable Wasm build of SQLite
 
-This folder includes an embeddable WASM build of SQLite 3.44.2 for use with
+This folder includes an embeddable Wasm build of SQLite 3.50.1 for use with
 [`github.com/ncruces/go-sqlite3`](https://pkg.go.dev/github.com/ncruces/go-sqlite3).
 
 The following optional features are compiled in:
 - [math functions](https://sqlite.org/lang_mathfunc.html)
-- [FTS3/4](https://sqlite.org/fts3.html)/[5](https://sqlite.org/fts5.html)
+- [FTS5](https://sqlite.org/fts5.html)
 - [JSON](https://sqlite.org/json1.html)
 - [R*Tree](https://sqlite.org/rtree.html)
 - [GeoPoly](https://sqlite.org/geopoly.html)
+- [Spellfix1](https://sqlite.org/spellfix1.html)
 - [soundex](https://sqlite.org/lang_corefunc.html#soundex)
+- [stat4](https://sqlite.org/compile.html#enable_stat4)
 - [base64](https://github.com/sqlite/sqlite/blob/master/ext/misc/base64.c)
 - [decimal](https://github.com/sqlite/sqlite/blob/master/ext/misc/decimal.c)
+- [ieee754](https://github.com/sqlite/sqlite/blob/master/ext/misc/ieee754.c)
 - [regexp](https://github.com/sqlite/sqlite/blob/master/ext/misc/regexp.c)
 - [series](https://github.com/sqlite/sqlite/blob/master/ext/misc/series.c)
 - [uint](https://github.com/sqlite/sqlite/blob/master/ext/misc/uint.c)
-- [uuid](https://github.com/sqlite/sqlite/blob/master/ext/misc/uuid.c)
 - [time](../sqlite3/time.c)
 
-See the [configuration options](../sqlite3/sqlite_cfg.h),
+See the [configuration options](../sqlite3/sqlite_opt.h),
 and [patches](../sqlite3) applied.
 
 Built using [`wasi-sdk`](https://github.com/WebAssembly/wasi-sdk),
-and [`binaryen`](https://github.com/WebAssembly/binaryen).
+and [`binaryen`](https://github.com/WebAssembly/binaryen).
+
+The build is easily reproducible, and verifiable, using
+[Artifact Attestations](https://github.com/ncruces/go-sqlite3/attestations).
+
+### Customizing the build
+
+You can use your own custom build of SQLite.
+
+Examples of custom builds of SQLite are:
+- [`github.com/ncruces/go-sqlite3/embed/bcw2`](https://github.com/ncruces/go-sqlite3/tree/main/embed/bcw2)
+  built from a branch supporting [`BEGIN CONCURRENT`](https://sqlite.org/src/doc/begin-concurrent/doc/begin_concurrent.md)
+  and [Wal2](https://sqlite.org/cgi/src/doc/wal2/doc/wal2.md).
+- [`github.com/asg017/sqlite-vec-go-bindings/ncruces`](https://github.com/asg017/sqlite-vec-go-bindings)
+  which includes the [`sqlite-vec`](https://github.com/asg017/sqlite-vec) vector search extension.

embed/bcw2/.gitignore

@@ -0,0 +1,2 @@
+build/
+sqlite/

embed/bcw2/README.md

@@ -0,0 +1,22 @@
+# Embeddable Wasm build of SQLite
+
+This folder includes an alternative embeddable Wasm build of SQLite,
+which includes the experimental
+[`BEGIN CONCURRENT`](https://sqlite.org/src/doc/begin-concurrent/doc/begin_concurrent.md) and
+[Wal2](https://sqlite.org/cgi/src/doc/wal2/doc/wal2.md) patches.
+
+It also enables the optional
+[`UPDATE … ORDER BY … LIMIT`](https://sqlite.org/lang_update.html#optional_limit_and_order_by_clauses) and
+[`DELETE … ORDER BY … LIMIT`](https://sqlite.org/lang_delete.html#optional_limit_and_order_by_clauses) clauses,
+and the [`WITHIN GROUP ORDER BY`](https://sqlite.org/compile.html#enable_ordered_set_aggregates) aggregate syntax.
+
+> [!IMPORTANT]  
+> This package is experimental.
+> It is built from the `bedrock` branch of SQLite,
+> since that is _currently_ the most stable, maintained branch to include these features.
+
+> [!CAUTION]
+> The Wal2 journaling mode creates databases that other versions of SQLite cannot access.
+
+The build is easily reproducible, and verifiable, using
+[Artifact Attestations](https://github.com/ncruces/go-sqlite3/attestations).

embed/bcw2/bcw2_test.go

@@ -0,0 +1,59 @@
+package bcw2
+
+import (
+	"path/filepath"
+	"testing"
+
+	"github.com/ncruces/go-sqlite3/driver"
+	"github.com/ncruces/go-sqlite3/ext/stats"
+	"github.com/ncruces/go-sqlite3/vfs"
+)
+
+func Test_bcw2(t *testing.T) {
+	if !vfs.SupportsSharedMemory {
+		t.Skip("skipping without shared memory")
+	}
+
+	tmp := filepath.ToSlash(filepath.Join(t.TempDir(), "test.db"))
+
+	db, err := driver.Open("file:"+tmp+"?_pragma=journal_mode(wal2)&_txlock=concurrent", stats.Register)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+
+	tx, err := db.Begin()
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer tx.Rollback()
+
+	_, err = tx.Exec(`CREATE TABLE test (col)`)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	_, err = tx.Exec(`DELETE FROM test LIMIT 1`)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	_, err = tx.Exec(`SELECT median() WITHIN GROUP (ORDER BY col) FROM test`)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = tx.Commit()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	var version string
+	err = db.QueryRow(`SELECT sqlite_version()`).Scan(&version)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if version != "3.51.0" {
+		t.Error(version)
+	}
+}

embed/bcw2/build.sh

@@ -0,0 +1,66 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+cd -P -- "$(dirname -- "$0")"
+
+ROOT=../../
+BINARYEN="$ROOT/tools/binaryen/bin"
+WASI_SDK="$ROOT/tools/wasi-sdk/bin"
+
+trap 'rm -rf build/ sqlite/ bcw2.tmp' EXIT
+
+mkdir -p build/ext/
+cp "$ROOT"/sqlite3/*.[ch] build/
+cp "$ROOT"/sqlite3/*.patch build/
+
+# https://sqlite.org/src/info/93740658c8c6f531
+curl -# https://sqlite.org/src/tarball/sqlite.tar.gz?r=93740658c8 | tar xz
+
+cd sqlite
+if [[ "$OSTYPE" == "msys" || "$OSTYPE" == "cygwin" ]]; then
+	MSYS_NO_PATHCONV=1 nmake /f makefile.msc sqlite3.c "OPTS=-DSQLITE_ENABLE_UPDATE_DELETE_LIMIT -DSQLITE_ENABLE_ORDERED_SET_AGGREGATES"
+else
+	sh configure --enable-update-limit
+	OPTS=-DSQLITE_ENABLE_ORDERED_SET_AGGREGATES make sqlite3.c
+fi
+cd ~-
+
+mv sqlite/sqlite3.c             build/
+mv sqlite/sqlite3.h             build/
+mv sqlite/sqlite3ext.h          build/
+mv sqlite/ext/misc/anycollseq.c build/ext/
+mv sqlite/ext/misc/base64.c     build/ext/
+mv sqlite/ext/misc/decimal.c    build/ext/
+mv sqlite/ext/misc/ieee754.c    build/ext/
+mv sqlite/ext/misc/regexp.c     build/ext/
+mv sqlite/ext/misc/series.c     build/ext/
+mv sqlite/ext/misc/spellfix.c   build/ext/
+mv sqlite/ext/misc/uint.c       build/ext/
+
+cd build
+cat *.patch | patch -p0 --no-backup-if-mismatch
+cd ~-
+
+"$WASI_SDK/clang" --target=wasm32-wasi -std=c23 -g0 -O2 \
+	-Wall -Wextra -Wno-unused-parameter -Wno-unused-function \
+	-o bcw2.wasm build/main.c \
+	-I"$ROOT/sqlite3/libc" -I"build" \
+	-mexec-model=reactor \
+	-mmutable-globals -mnontrapping-fptoint \
+	-msimd128 -mbulk-memory -msign-ext \
+	-mreference-types -mmultivalue \
+	-fno-stack-protector -fno-stack-clash-protection \
+	-Wl,--stack-first \
+	-Wl,--import-undefined \
+	-Wl,--initial-memory=327680 \
+	-D_HAVE_SQLITE_CONFIG_H \
+	-DSQLITE_ENABLE_UPDATE_DELETE_LIMIT \
+	-DSQLITE_CUSTOM_INCLUDE=sqlite_opt.h \
+	$(awk '{print "-Wl,--export="$0}' ../exports.txt)
+
+"$BINARYEN/wasm-ctor-eval" -g -c _initialize bcw2.wasm -o bcw2.tmp
+"$BINARYEN/wasm-opt" -g --strip --strip-producers -c -O3 \
+	bcw2.tmp -o bcw2.wasm --low-memory-unused \
+	--enable-mutable-globals --enable-nontrapping-float-to-int \
+	--enable-simd --enable-bulk-memory --enable-sign-ext \
+	--enable-reference-types --enable-multivalue

embed/bcw2/go.mod

@@ -0,0 +1,14 @@
+module github.com/ncruces/go-sqlite3/embed/bcw2
+
+go 1.23.0
+
+toolchain go1.24.0
+
+require github.com/ncruces/go-sqlite3 v0.26.0
+
+require (
+	github.com/ncruces/julianday v1.0.0 // indirect
+	github.com/ncruces/sort v0.1.5 // indirect
+	github.com/tetratelabs/wazero v1.9.0 // indirect
+	golang.org/x/sys v0.33.0 // indirect
+)

embed/bcw2/go.sum

@@ -0,0 +1,12 @@
+github.com/ncruces/go-sqlite3 v0.26.0 h1:dY6ASfuhSEbtSge6kJwjyJVC7bXCpgEVOycmdboKJek=
+github.com/ncruces/go-sqlite3 v0.26.0/go.mod h1:46HIzeCQQ+aNleAxCli+vpA2tfh7ttSnw24kQahBc1o=
+github.com/ncruces/julianday v1.0.0 h1:fH0OKwa7NWvniGQtxdJRxAgkBMolni2BjDHaWTxqt7M=
+github.com/ncruces/julianday v1.0.0/go.mod h1:Dusn2KvZrrovOMJuOt0TNXL6tB7U2E8kvza5fFc9G7g=
+github.com/ncruces/sort v0.1.5 h1:fiFWXXAqKI8QckPf/6hu/bGFwcEPrirIOFaJqWujs4k=
+github.com/ncruces/sort v0.1.5/go.mod h1:obJToO4rYr6VWP0Uw5FYymgYGt3Br4RXcs/JdKaXAPk=
+github.com/tetratelabs/wazero v1.9.0 h1:IcZ56OuxrtaEz8UYNRHBrUa9bYeX9oVY93KspZZBf/I=
+github.com/tetratelabs/wazero v1.9.0/go.mod h1:TSbcXCfFP0L2FGkRPxHphadXPjo1T6W+CseNNY7EkjM=
+golang.org/x/sys v0.33.0 h1:q3i8TbbEz+JRD9ywIRlyRAQbM0qF7hu24q3teo2hbuw=
+golang.org/x/sys v0.33.0/go.mod h1:BJP2sWEmIv4KK5OTEluFJCKSidICx8ciO85XgH3Ak8k=
+golang.org/x/text v0.25.0 h1:qVyWApTSYLk/drJRO5mDlNYskwQznZmkpV2c8q9zls4=
+golang.org/x/text v0.25.0/go.mod h1:WEdwpYrmk1qmdHvhkSTNPm3app7v4rsT8F2UD6+VHIA=

embed/bcw2/init.go

@@ -0,0 +1,24 @@
+// Package bcw2 embeds SQLite into your application.
+//
+// Importing package bcw2 initializes the [sqlite3.Binary] variable
+// with a build of SQLite that includes the [BEGIN CONCURRENT] and [Wal2] patches:
+//
+//	import _ "github.com/ncruces/go-sqlite3/embed/bcw2"
+//
+// [BEGIN CONCURRENT]: https://sqlite.org/src/doc/begin-concurrent/doc/begin_concurrent.md
+// [Wal2]: https://sqlite.org/cgi/src/doc/wal2/doc/wal2.md
+package bcw2
+
+import (
+	_ "embed"
+	"unsafe"
+
+	"github.com/ncruces/go-sqlite3"
+)
+
+//go:embed bcw2.wasm
+var binary string
+
+func init() {
+	sqlite3.Binary = unsafe.Slice(unsafe.StringData(binary), len(binary))
+}

embed/build.sh

@@ -4,27 +4,30 @@ set -euo pipefail
 cd -P -- "$(dirname -- "$0")"
 
 ROOT=../
-BINARYEN="$ROOT/tools/binaryen-version_116/bin"
-WASI_SDK="$ROOT/tools/wasi-sdk-20.0/bin"
-
-"$WASI_SDK/clang" --target=wasm32-wasi -flto -g0 -O2 \
-	-o sqlite3.wasm "$ROOT/sqlite3/main.c" \
-	-I"$ROOT/sqlite3" \
-	-mexec-model=reactor \
-	-msimd128 -mmutable-globals \
-	-mbulk-memory -mreference-types \
-	-mnontrapping-fptoint -msign-ext \
-	-fno-stack-protector -fno-stack-clash-protection \
-	-Wl,--initial-memory=327680 \
-	-Wl,--stack-first \
-	-Wl,--import-undefined \
-	-D_HAVE_SQLITE_CONFIG_H \
-	$(awk '{print "-Wl,--export="$0}' exports.txt)
+BINARYEN="$ROOT/tools/binaryen/bin"
+WASI_SDK="$ROOT/tools/wasi-sdk/bin"
 
 trap 'rm -f sqlite3.tmp' EXIT
+
+"$WASI_SDK/clang" --target=wasm32-wasi -std=c23 -g0 -O2 \
+	-Wall -Wextra -Wno-unused-parameter -Wno-unused-function \
+	-o sqlite3.wasm "$ROOT/sqlite3/main.c" \
+	-I"$ROOT/sqlite3/libc" -I"$ROOT/sqlite3" \
+	-mexec-model=reactor \
+	-mmutable-globals -mnontrapping-fptoint \
+	-msimd128 -mbulk-memory -msign-ext \
+	-mreference-types -mmultivalue \
+	-fno-stack-protector -fno-stack-clash-protection \
+	-Wl,--stack-first \
+	-Wl,--import-undefined \
+	-Wl,--initial-memory=327680 \
+	-D_HAVE_SQLITE_CONFIG_H \
+	-DSQLITE_CUSTOM_INCLUDE=sqlite_opt.h \
+	$(awk '{print "-Wl,--export="$0}' exports.txt)
+
 "$BINARYEN/wasm-ctor-eval" -g -c _initialize sqlite3.wasm -o sqlite3.tmp
-"$BINARYEN/wasm-opt" -g --strip -c -O3 \
-	sqlite3.tmp -o sqlite3.wasm \
-	--enable-simd --enable-mutable-globals --enable-multivalue \
-	--enable-bulk-memory --enable-reference-types \
-	--enable-nontrapping-float-to-int --enable-sign-ext
+"$BINARYEN/wasm-opt" -g --strip --strip-producers -c -O3 \
+	sqlite3.tmp -o sqlite3.wasm --low-memory-unused \
+	--enable-mutable-globals --enable-nontrapping-float-to-int \
+	--enable-simd --enable-bulk-memory --enable-sign-ext \
+	--enable-reference-types --enable-multivalue

embed/exports.txt

@@ -1,91 +1,142 @@
-free
-malloc
-malloc_destructor
-sqlite3_errcode
-sqlite3_errstr
-sqlite3_errmsg
-sqlite3_error_offset
-sqlite3_open_v2
-sqlite3_close
-sqlite3_close_v2
-sqlite3_prepare_v3
-sqlite3_finalize
-sqlite3_reset
-sqlite3_step
-sqlite3_exec
-sqlite3_interrupt
-sqlite3_progress_handler_go
-sqlite3_clear_bindings
+aligned_alloc
+sqlite3_anycollseq_init
+sqlite3_autovacuum_pages_go
+sqlite3_backup_finish
+sqlite3_backup_init
+sqlite3_backup_pagecount
+sqlite3_backup_remaining
+sqlite3_backup_step
+sqlite3_bind_blob_go
+sqlite3_bind_double
+sqlite3_bind_int64
+sqlite3_bind_null
 sqlite3_bind_parameter_count
 sqlite3_bind_parameter_index
 sqlite3_bind_parameter_name
-sqlite3_bind_null
-sqlite3_bind_int64
-sqlite3_bind_double
-sqlite3_bind_text64
-sqlite3_bind_blob64
-sqlite3_bind_zeroblob64
 sqlite3_bind_pointer_go
-sqlite3_column_count
-sqlite3_column_name
-sqlite3_column_type
-sqlite3_column_int64
-sqlite3_column_double
-sqlite3_column_text
+sqlite3_bind_text_go
+sqlite3_bind_value
+sqlite3_bind_zeroblob64
+sqlite3_blob_bytes
+sqlite3_blob_close
+sqlite3_blob_open
+sqlite3_blob_read
+sqlite3_blob_reopen
+sqlite3_blob_write
+sqlite3_busy_handler_go
+sqlite3_busy_timeout
+sqlite3_changes64
+sqlite3_clear_bindings
+sqlite3_close
+sqlite3_close_v2
+sqlite3_collation_needed_go
 sqlite3_column_blob
 sqlite3_column_bytes
-sqlite3_blob_open
-sqlite3_blob_close
-sqlite3_blob_reopen
-sqlite3_blob_bytes
-sqlite3_blob_read
-sqlite3_blob_write
-sqlite3_backup_init
-sqlite3_backup_step
-sqlite3_backup_finish
-sqlite3_backup_remaining
-sqlite3_backup_pagecount
-sqlite3_uri_parameter
-sqlite3_uri_key
-sqlite3_changes64
-sqlite3_last_insert_rowid
-sqlite3_get_autocommit
-sqlite3_anycollseq_init
+sqlite3_column_count
+sqlite3_column_database_name
+sqlite3_column_decltype
+sqlite3_column_double
+sqlite3_column_int64
+sqlite3_column_name
+sqlite3_column_origin_name
+sqlite3_column_table_name
+sqlite3_column_text
+sqlite3_column_type
+sqlite3_column_value
+sqlite3_columns_go
+sqlite3_commit_hook_go
+sqlite3_config_log_go
+sqlite3_create_aggregate_function_go
 sqlite3_create_collation_go
 sqlite3_create_function_go
-sqlite3_create_aggregate_function_go
+sqlite3_create_module_go
 sqlite3_create_window_function_go
-sqlite3_aggregate_context
-sqlite3_user_data
-sqlite3_set_auxdata_go
+sqlite3_data_count
+sqlite3_database_file_object
+sqlite3_db_cacheflush
+sqlite3_db_config
+sqlite3_db_filename
+sqlite3_db_name
+sqlite3_db_readonly
+sqlite3_db_release_memory
+sqlite3_db_status
+sqlite3_declare_vtab
+sqlite3_errcode
+sqlite3_errmsg
+sqlite3_error_offset
+sqlite3_errstr
+sqlite3_exec
+sqlite3_exec_go
+sqlite3_expanded_sql
+sqlite3_file_control
+sqlite3_filename_database
+sqlite3_filename_journal
+sqlite3_filename_wal
+sqlite3_finalize
+sqlite3_free
+sqlite3_get_autocommit
 sqlite3_get_auxdata
-sqlite3_value_type
-sqlite3_value_int64
-sqlite3_value_double
-sqlite3_value_text
-sqlite3_value_blob
-sqlite3_value_bytes
-sqlite3_value_pointer_go
-sqlite3_result_null
-sqlite3_result_int64
+sqlite3_hard_heap_limit64
+sqlite3_interrupt
+sqlite3_invoke_busy_handler_go
+sqlite3_last_insert_rowid
+sqlite3_limit
+sqlite3_log_go
+sqlite3_malloc64
+sqlite3_open_v2
+sqlite3_overload_function
+sqlite3_prepare_v3
+sqlite3_progress_handler_go
+sqlite3_realloc64
+sqlite3_reset
+sqlite3_result_blob_go
 sqlite3_result_double
-sqlite3_result_text64
-sqlite3_result_blob64
-sqlite3_result_zeroblob64
-sqlite3_result_pointer_go
-sqlite3_result_value
 sqlite3_result_error
 sqlite3_result_error_code
 sqlite3_result_error_nomem
 sqlite3_result_error_toobig
-sqlite3_create_module_go
-sqlite3_declare_vtab
-sqlite3_vtab_config_go
+sqlite3_result_int64
+sqlite3_result_null
+sqlite3_result_pointer_go
+sqlite3_result_text_go
+sqlite3_result_value
+sqlite3_result_zeroblob64
+sqlite3_rollback_hook_go
+sqlite3_set_authorizer_go
+sqlite3_set_auxdata_go
+sqlite3_set_last_insert_rowid
+sqlite3_soft_heap_limit64
+sqlite3_step
+sqlite3_stmt_busy
+sqlite3_stmt_readonly
+sqlite3_stmt_status
+sqlite3_table_column_metadata
+sqlite3_total_changes64
+sqlite3_trace_go
+sqlite3_txn_state
+sqlite3_update_hook_go
+sqlite3_uri_key
+sqlite3_value_blob
+sqlite3_value_bytes
+sqlite3_value_double
+sqlite3_value_dup
+sqlite3_value_free
+sqlite3_value_frombind
+sqlite3_value_int64
+sqlite3_value_nochange
+sqlite3_value_numeric_type
+sqlite3_value_pointer_go
+sqlite3_value_text
+sqlite3_value_type
 sqlite3_vtab_collation
+sqlite3_vtab_config_go
 sqlite3_vtab_distinct
 sqlite3_vtab_in
 sqlite3_vtab_in_first
 sqlite3_vtab_in_next
-sqlite3_vtab_rhs_value
 sqlite3_vtab_nochange
-sqlite3_vtab_on_conflict
+sqlite3_vtab_on_conflict
+sqlite3_vtab_rhs_value
+sqlite3_wal_autocheckpoint
+sqlite3_wal_checkpoint_v2
+sqlite3_wal_hook_go

embed/init.go

@@ -8,13 +8,14 @@ package embed
 
 import (
 	_ "embed"
+	"unsafe"
 
 	"github.com/ncruces/go-sqlite3"
 )
 
 //go:embed sqlite3.wasm
-var binary []byte
+var binary string
 
 func init() {
-	sqlite3.Binary = binary
+	sqlite3.Binary = unsafe.Slice(unsafe.StringData(binary), len(binary))
 }

embed/init_test.go

@@ -0,0 +1,25 @@
+package embed
+
+import (
+	"testing"
+
+	"github.com/ncruces/go-sqlite3/driver"
+	_ "github.com/ncruces/go-sqlite3/vfs/memdb"
+)
+
+func Test_init(t *testing.T) {
+	db, err := driver.Open("file:/test.db?vfs=memdb")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+
+	var version string
+	err = db.QueryRow(`SELECT sqlite_version()`).Scan(&version)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if version != "3.50.1" {
+		t.Error(version)
+	}
+}

error.go

@@ -2,7 +2,6 @@ package sqlite3
 
 import (
 	"errors"
-	"strconv"
 	"strings"
 
 	"github.com/ncruces/go-sqlite3/internal/util"
@@ -12,10 +11,9 @@ import (
 //
 // https://sqlite.org/c3ref/errcode.html
 type Error struct {
-	str  string
 	msg  string
 	sql  string
-	code uint64
+	code res_t
 }
 
 // Code returns the primary error code for this error.
@@ -29,23 +27,16 @@ func (e *Error) Code() ErrorCode {
 //
 // https://sqlite.org/rescode.html
 func (e *Error) ExtendedCode() ExtendedErrorCode {
-	return ExtendedErrorCode(e.code)
+	return xErrorCode(e.code)
 }
 
 // Error implements the error interface.
 func (e *Error) Error() string {
 	var b strings.Builder
-	b.WriteString("sqlite3: ")
-
-	if e.str != "" {
-		b.WriteString(e.str)
-	} else {
-		b.WriteString(strconv.Itoa(int(e.code)))
-	}
+	b.WriteString(util.ErrorCodeString(uint32(e.code)))
 
 	if e.msg != "" {
-		b.WriteByte(':')
-		b.WriteByte(' ')
+		b.WriteString(": ")
 		b.WriteString(e.msg)
 	}
 
@@ -84,7 +75,7 @@ func (e *Error) As(err any) bool {
 
 // Temporary returns true for [BUSY] errors.
 func (e *Error) Temporary() bool {
-	return e.Code() == BUSY
+	return e.Code() == BUSY || e.Code() == INTERRUPT
 }
 
 // Timeout returns true for [BUSY_TIMEOUT] errors.
@@ -104,7 +95,12 @@ func (e ErrorCode) Error() string {
 
 // Temporary returns true for [BUSY] errors.
 func (e ErrorCode) Temporary() bool {
-	return e == BUSY
+	return e == BUSY || e == INTERRUPT
+}
+
+// ExtendedCode returns the extended error code for this error.
+func (e ErrorCode) ExtendedCode() ExtendedErrorCode {
+	return xErrorCode(e)
 }
 
 // Error implements the error interface.
@@ -129,7 +125,7 @@ func (e ExtendedErrorCode) As(err any) bool {
 
 // Temporary returns true for [BUSY] errors.
 func (e ExtendedErrorCode) Temporary() bool {
-	return ErrorCode(e) == BUSY
+	return ErrorCode(e) == BUSY || ErrorCode(e) == INTERRUPT
 }
 
 // Timeout returns true for [BUSY_TIMEOUT] errors.
@@ -137,25 +133,32 @@ func (e ExtendedErrorCode) Timeout() bool {
 	return e == BUSY_TIMEOUT
 }
 
-func errorCode(err error, def ErrorCode) (msg string, code uint32) {
+// Code returns the primary error code for this error.
+func (e ExtendedErrorCode) Code() ErrorCode {
+	return ErrorCode(e)
+}
+
+func errorCode(err error, def ErrorCode) (msg string, code res_t) {
 	switch code := err.(type) {
-	case ErrorCode:
-		return "", uint32(code)
-	case ExtendedErrorCode:
-		return "", uint32(code)
 	case nil:
 		return "", _OK
+	case ErrorCode:
+		return "", res_t(code)
+	case xErrorCode:
+		return "", res_t(code)
+	case *Error:
+		return code.msg, res_t(code.code)
 	}
 
 	var ecode ErrorCode
 	var xcode xErrorCode
 	switch {
 	case errors.As(err, &xcode):
-		code = uint32(xcode)
+		code = res_t(xcode)
 	case errors.As(err, &ecode):
-		code = uint32(ecode)
+		code = res_t(ecode)
 	default:
-		code = uint32(def)
+		code = res_t(def)
 	}
 	return err.Error(), code
 }

error_test.go

@@ -2,6 +2,7 @@ package sqlite3
 
 import (
 	"errors"
+	"fmt"
 	"strings"
 	"testing"
 
@@ -10,7 +11,7 @@ import (
 
 func Test_assertErr(t *testing.T) {
 	err := util.AssertErr()
-	if s := err.Error(); !strings.HasPrefix(s, "sqlite3: assertion failed") || !strings.HasSuffix(s, "error_test.go:12)") {
+	if s := err.Error(); !strings.HasPrefix(s, "sqlite3: assertion failed") || !strings.HasSuffix(s, "error_test.go:13)") {
 		t.Errorf("got %q", s)
 	}
 }
@@ -42,7 +43,7 @@ func TestError(t *testing.T) {
 	if !errors.Is(err, xErrorCode(0x8080)) {
 		t.Errorf("want true")
 	}
-	if s := err.Error(); s != "sqlite3: 32896" {
+	if s := err.Error(); s != "sqlite3: unknown error" {
 		t.Errorf("got %q", s)
 	}
 	if ok := errors.As(err.ExtendedCode(), &ecode); !ok || ecode != ErrorCode(0x80) {
@@ -58,14 +59,14 @@ func TestError_Temporary(t *testing.T) {
 
 	tests := []struct {
 		name string
-		code uint64
+		code res_t
 		want bool
 	}{
-		{"ERROR", uint64(ERROR), false},
-		{"BUSY", uint64(BUSY), true},
-		{"BUSY_RECOVERY", uint64(BUSY_RECOVERY), true},
-		{"BUSY_SNAPSHOT", uint64(BUSY_SNAPSHOT), true},
-		{"BUSY_TIMEOUT", uint64(BUSY_TIMEOUT), true},
+		{"ERROR", res_t(ERROR), false},
+		{"BUSY", res_t(BUSY), true},
+		{"BUSY_RECOVERY", res_t(BUSY_RECOVERY), true},
+		{"BUSY_SNAPSHOT", res_t(BUSY_SNAPSHOT), true},
+		{"BUSY_TIMEOUT", res_t(BUSY_TIMEOUT), true},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
@@ -82,7 +83,7 @@ func TestError_Temporary(t *testing.T) {
 				}
 			}
 			{
-				err := ExtendedErrorCode(tt.code)
+				err := xErrorCode(tt.code)
 				if got := err.Temporary(); got != tt.want {
 					t.Errorf("ExtendedErrorCode.Temporary(%d) = %v, want %v", tt.code, got, tt.want)
 				}
@@ -96,14 +97,14 @@ func TestError_Timeout(t *testing.T) {
 
 	tests := []struct {
 		name string
-		code uint64
+		code res_t
 		want bool
 	}{
-		{"ERROR", uint64(ERROR), false},
-		{"BUSY", uint64(BUSY), false},
-		{"BUSY_RECOVERY", uint64(BUSY_RECOVERY), false},
-		{"BUSY_SNAPSHOT", uint64(BUSY_SNAPSHOT), false},
-		{"BUSY_TIMEOUT", uint64(BUSY_TIMEOUT), true},
+		{"ERROR", res_t(ERROR), false},
+		{"BUSY", res_t(BUSY), false},
+		{"BUSY_RECOVERY", res_t(BUSY_RECOVERY), false},
+		{"BUSY_SNAPSHOT", res_t(BUSY_SNAPSHOT), false},
+		{"BUSY_TIMEOUT", res_t(BUSY_TIMEOUT), true},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
@@ -114,7 +115,7 @@ func TestError_Timeout(t *testing.T) {
 				}
 			}
 			{
-				err := ExtendedErrorCode(tt.code)
+				err := xErrorCode(tt.code)
 				if got := err.Timeout(); got != tt.want {
 					t.Errorf("Error.Timeout(%d) = %v, want %v", tt.code, got, tt.want)
 				}
@@ -135,8 +136,8 @@ func Test_ErrorCode_Error(t *testing.T) {
 	// Test all error codes.
 	for i := 0; i == int(ErrorCode(i)); i++ {
 		want := "sqlite3: "
-		r := db.call(db.api.errstr, uint64(i))
-		want += util.ReadString(db.mod, uint32(r), _MAX_NAME)
+		ptr := ptr_t(db.call("sqlite3_errstr", stk_t(i)))
+		want += util.ReadString(db.mod, ptr, _MAX_NAME)
 
 		got := ErrorCode(i).Error()
 		if got != want {
@@ -155,14 +156,43 @@ func Test_ExtendedErrorCode_Error(t *testing.T) {
 	defer db.Close()
 
 	// Test all extended error codes.
-	for i := 0; i == int(ExtendedErrorCode(i)); i++ {
+	for i := 0; i == int(xErrorCode(i)); i++ {
 		want := "sqlite3: "
-		r := db.call(db.api.errstr, uint64(i))
-		want += util.ReadString(db.mod, uint32(r), _MAX_NAME)
+		ptr := ptr_t(db.call("sqlite3_errstr", stk_t(i)))
+		want += util.ReadString(db.mod, ptr, _MAX_NAME)
 
-		got := ExtendedErrorCode(i).Error()
+		got := xErrorCode(i).Error()
 		if got != want {
 			t.Fatalf("got %q, want %q, with %d", got, want, i)
 		}
 	}
 }
+
+func Test_errorCode(t *testing.T) {
+	tests := []struct {
+		arg      error
+		wantMsg  string
+		wantCode res_t
+	}{
+		{nil, "", _OK},
+		{ERROR, "", util.ERROR},
+		{IOERR, "", util.IOERR},
+		{IOERR_READ, "", util.IOERR_READ},
+		{&Error{code: util.ERROR}, "", util.ERROR},
+		{fmt.Errorf("%w", ERROR), ERROR.Error(), util.ERROR},
+		{fmt.Errorf("%w", IOERR), IOERR.Error(), util.IOERR},
+		{fmt.Errorf("%w", IOERR_READ), IOERR_READ.Error(), util.IOERR_READ},
+		{fmt.Errorf("error"), "error", util.ERROR},
+	}
+	for _, tt := range tests {
+		t.Run("", func(t *testing.T) {
+			gotMsg, gotCode := errorCode(tt.arg, ERROR)
+			if gotMsg != tt.wantMsg {
+				t.Errorf("errorCode() gotMsg = %q, want %q", gotMsg, tt.wantMsg)
+			}
+			if gotCode != tt.wantCode {
+				t.Errorf("errorCode() gotCode = %d, want %d", gotCode, tt.wantCode)
+			}
+		})
+	}
+}

example_test.go

@@ -16,7 +16,7 @@ func Example() {
 		log.Fatal(err)
 	}
 
-	err = db.Exec(`CREATE TABLE IF NOT EXISTS users (id INT, name VARCHAR(10))`)
+	err = db.Exec(`CREATE TABLE users (id INT, name VARCHAR(10))`)
 	if err != nil {
 		log.Fatal(err)
 	}

ext/README.md

@@ -0,0 +1,48 @@
+# Go SQLite Extensions
+
+This folder collects optional SQLite extensions
+you can load into your database connections.
+
+### Extensions
+
+- [`github.com/ncruces/go-sqlite3/ext/array`](https://pkg.go.dev/github.com/ncruces/go-sqlite3/ext/array)
+  provides the [`array`](https://sqlite.org/carray.html) table-valued function.
+- [`github.com/ncruces/go-sqlite3/ext/blobio`](https://pkg.go.dev/github.com/ncruces/go-sqlite3/ext/blobio)
+  simplifies [incremental BLOB I/O](https://sqlite.org/c3ref/blob_open.html).
+- [`github.com/ncruces/go-sqlite3/ext/bloom`](https://pkg.go.dev/github.com/ncruces/go-sqlite3/ext/bloom)
+  provides a [Bloom filter](https://github.com/nalgeon/sqlean/issues/27#issuecomment-1002267134) virtual table.
+- [`github.com/ncruces/go-sqlite3/ext/closure`](https://pkg.go.dev/github.com/ncruces/go-sqlite3/ext/closure)
+  provides a transitive closure virtual table.
+- [`github.com/ncruces/go-sqlite3/ext/csv`](https://pkg.go.dev/github.com/ncruces/go-sqlite3/ext/csv)
+  reads [comma-separated values](https://sqlite.org/csv.html).
+- [`github.com/ncruces/go-sqlite3/ext/fileio`](https://pkg.go.dev/github.com/ncruces/go-sqlite3/ext/fileio)
+  reads, writes and lists files.
+- [`github.com/ncruces/go-sqlite3/ext/hash`](https://pkg.go.dev/github.com/ncruces/go-sqlite3/ext/hash)
+  provides cryptographic hash functions.
+- [`github.com/ncruces/go-sqlite3/ext/lines`](https://pkg.go.dev/github.com/ncruces/go-sqlite3/ext/lines)
+  reads data [line-by-line](https://github.com/asg017/sqlite-lines).
+- [`github.com/ncruces/go-sqlite3/ext/pivot`](https://pkg.go.dev/github.com/ncruces/go-sqlite3/ext/pivot)
+  creates [pivot tables](https://github.com/jakethaw/pivot_vtab).
+- [`github.com/ncruces/go-sqlite3/ext/regexp`](https://pkg.go.dev/github.com/ncruces/go-sqlite3/ext/regexp)
+  provides regular expression functions.
+- [`github.com/ncruces/go-sqlite3/ext/serdes`](https://pkg.go.dev/github.com/ncruces/go-sqlite3/ext/serdes)
+  (de)serializes databases.
+- [`github.com/ncruces/go-sqlite3/ext/statement`](https://pkg.go.dev/github.com/ncruces/go-sqlite3/ext/statement)
+  creates [parameterized views](https://github.com/0x09/sqlite-statement-vtab).
+- [`github.com/ncruces/go-sqlite3/ext/stats`](https://pkg.go.dev/github.com/ncruces/go-sqlite3/ext/stats)
+  provides [statistics](https://oreilly.com/library/view/sql-in-a/9780596155322/ch04s02.html) functions.
+- [`github.com/ncruces/go-sqlite3/ext/unicode`](https://pkg.go.dev/github.com/ncruces/go-sqlite3/ext/unicode)
+  provides [Unicode aware](https://sqlite.org/src/dir/ext/icu) functions.
+- [`github.com/ncruces/go-sqlite3/ext/uuid`](https://pkg.go.dev/github.com/ncruces/go-sqlite3/ext/uuid)
+  generates [UUIDs](https://en.wikipedia.org/wiki/Universally_unique_identifier).
+- [`github.com/ncruces/go-sqlite3/ext/zorder`](https://pkg.go.dev/github.com/ncruces/go-sqlite3/ext/zorder)
+  maps multidimensional data to one dimension.
+
+### Pakages
+
+These packages may also be useful to work with SQLite:
+
+- [`github.com/ncruces/decimal`](https://pkg.go.dev/github.com/ncruces/decimal)
+  decimal arithmetic.
+- [`github.com/ncruces/julianday`](https://pkg.go.dev/github.com/ncruces/julianday)
+  Julian day math.

ext/array/array.go

@@ -1,4 +1,6 @@
 // Package array provides the array table-valued SQL function.
+//
+// https://sqlite.org/carray.html
 package array
 
 import (
@@ -6,17 +8,17 @@ import (
 	"reflect"
 
 	"github.com/ncruces/go-sqlite3"
+	"github.com/ncruces/go-sqlite3/internal/util"
 )
 
 // Register registers the array single-argument, table-valued SQL function.
-// The argument must be an [sqlite3.Pointer] to a Go slice or array
-// of ints, floats, bools, strings or blobs.
-//
-// https://sqlite.org/carray.html
-func Register(db *sqlite3.Conn) {
-	sqlite3.CreateModule[array](db, "array", nil,
-		func(db *sqlite3.Conn, arg ...string) (array, error) {
-			err := db.DeclareVtab(`CREATE TABLE x(value, array HIDDEN)`)
+// The argument must be bound to a Go slice or array of
+// ints, floats, bools, strings or byte slices,
+// using [sqlite3.BindPointer] or [sqlite3.Pointer].
+func Register(db *sqlite3.Conn) error {
+	return sqlite3.CreateModule(db, "array", nil,
+		func(db *sqlite3.Conn, _, _, _ string, _ ...string) (array, error) {
+			err := db.DeclareVTab(`CREATE TABLE x(value, array HIDDEN)`)
 			return array{}, err
 		})
 }
@@ -60,7 +62,7 @@ func (c *cursor) RowID() (int64, error) {
 	return int64(c.rowID), nil
 }
 
-func (c *cursor) Column(ctx *sqlite3.Context, n int) error {
+func (c *cursor) Column(ctx sqlite3.Context, n int) error {
 	if n != 0 {
 		return nil
 	}
@@ -102,7 +104,7 @@ func (c *cursor) Column(ctx *sqlite3.Context, n int) error {
 		ctx.ResultBlob(v.Bytes())
 
 	default:
-		return fmt.Errorf("array: unsupported element:%.0w %v", sqlite3.MISMATCH, v.Type())
+		return fmt.Errorf("array: unsupported element:%.0w %v", sqlite3.MISMATCH, util.ReflectType(v))
 	}
 	return nil
 }
@@ -119,17 +121,16 @@ func (c *cursor) Filter(idxNum int, idxStr string, arg ...sqlite3.Value) error {
 	return nil
 }
 
-func indexable(v reflect.Value) (_ reflect.Value, err error) {
-	if v.Kind() == reflect.Slice {
+func indexable(v reflect.Value) (reflect.Value, error) {
+	switch v.Kind() {
+	case reflect.Slice:
 		return v, nil
-	}
-	if v.Kind() == reflect.Array {
+	case reflect.Array:
 		return v, nil
-	}
-	if v.Kind() == reflect.Pointer {
+	case reflect.Pointer:
 		if v := v.Elem(); v.Kind() == reflect.Array {
 			return v, nil
 		}
 	}
-	return v, fmt.Errorf("array: unsupported argument:%.0w %v", sqlite3.MISMATCH, v.Type())
+	return v, fmt.Errorf("array: unsupported argument:%.0w %v", sqlite3.MISMATCH, util.ReflectType(v))
 }

ext/array/array_test.go

@@ -11,13 +11,12 @@ import (
 	"github.com/ncruces/go-sqlite3/driver"
 	_ "github.com/ncruces/go-sqlite3/embed"
 	"github.com/ncruces/go-sqlite3/ext/array"
+	_ "github.com/ncruces/go-sqlite3/internal/testcfg"
+	"github.com/ncruces/go-sqlite3/vfs/memdb"
 )
 
-func Example() {
-	db, err := driver.Open(":memory:", func(c *sqlite3.Conn) error {
-		array.Register(c)
-		return nil
-	})
+func Example_driver() {
+	db, err := driver.Open("file:/test.db?vfs=memdb", array.Register)
 	if err != nil {
 		log.Fatal(err)
 	}
@@ -51,11 +50,47 @@ func Example() {
 	// geopoly_within
 }
 
+func Example() {
+	sqlite3.AutoExtension(array.Register)
+
+	db, err := sqlite3.Open(":memory:")
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer db.Close()
+
+	stmt, _, err := db.Prepare(`
+		SELECT name
+		FROM pragma_function_list
+		WHERE name like 'geopoly%' AND narg IN array(?)`)
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer stmt.Close()
+
+	err = stmt.BindPointer(1, [...]int{2, 3, 4})
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	for stmt.Step() {
+		fmt.Printf("%s\n", stmt.ColumnText(0))
+	}
+	if err := stmt.Err(); err != nil {
+		log.Fatal(err)
+	}
+	// Unordered output:
+	// geopoly_regular
+	// geopoly_overlap
+	// geopoly_contains_point
+	// geopoly_within
+}
+
 func Test_cursor_Column(t *testing.T) {
-	db, err := driver.Open(":memory:", func(c *sqlite3.Conn) error {
-		array.Register(c)
-		return nil
-	})
+	t.Parallel()
+	tmp := memdb.TestDB(t)
+
+	db, err := driver.Open(tmp, array.Register)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -87,6 +122,35 @@ func Test_cursor_Column(t *testing.T) {
 		want = want[1:]
 	}
 	if err := rows.Err(); err != nil {
-		log.Fatal(err)
+		t.Fatal(err)
+	}
+}
+
+func Test_array_errors(t *testing.T) {
+	t.Parallel()
+
+	db, err := sqlite3.Open(":memory:")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+
+	err = array.Register(db)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = db.Exec(`SELECT * FROM array()`)
+	if err == nil {
+		t.Fatal("want error")
+	} else {
+		t.Log(err)
+	}
+
+	err = db.Exec(`SELECT * FROM array(?)`)
+	if err == nil {
+		t.Fatal("want error")
+	} else {
+		t.Log(err)
 	}
 }

ext/blob/blob.go

@@ -1,70 +0,0 @@
-// Package blob provides an alternative interface to incremental BLOB I/O.
-package blob
-
-import (
-	"errors"
-
-	"github.com/ncruces/go-sqlite3"
-	"github.com/ncruces/go-sqlite3/internal/util"
-)
-
-// Register registers the blob_open SQL function:
-//
-//	blob_open(schema, table, column, rowid, flags, callback, args...)
-//
-// The callback must be an [sqlite3.Pointer] to an [OpenCallback].
-// Any optional args will be passed to the callback,
-// along with the [sqlite3.Blob] handle.
-//
-// https://sqlite.org/c3ref/blob.html
-func Register(db *sqlite3.Conn) {
-	db.CreateFunction("blob_open", -1,
-		sqlite3.DETERMINISTIC|sqlite3.DIRECTONLY, openBlob)
-}
-
-func openBlob(ctx sqlite3.Context, arg ...sqlite3.Value) {
-	if len(arg) < 6 {
-		ctx.ResultError(util.ErrorString("wrong number of arguments to function blob_open()"))
-		return
-	}
-
-	row := arg[3].Int64()
-
-	var err error
-	blob, ok := ctx.GetAuxData(0).(*sqlite3.Blob)
-	if ok {
-		err = blob.Reopen(row)
-		if errors.Is(err, sqlite3.MISUSE) {
-			// Blob was closed (db, table, column or write changed).
-			ok = false
-		}
-	}
-
-	if !ok {
-		db := arg[0].Text()
-		table := arg[1].Text()
-		column := arg[2].Text()
-		write := arg[4].Bool()
-		blob, err = ctx.Conn().OpenBlob(db, table, column, row, write)
-	}
-	if err != nil {
-		ctx.ResultError(err)
-		return
-	}
-
-	fn := arg[5].Pointer().(OpenCallback)
-	err = fn(blob, arg[6:]...)
-	if err != nil {
-		ctx.ResultError(err)
-		return
-	}
-
-	// This ensures the blob is closed if db, table, column or write change.
-	ctx.SetAuxData(0, blob)
-	ctx.SetAuxData(1, blob)
-	ctx.SetAuxData(2, blob)
-	ctx.SetAuxData(4, blob)
-}
-
-// OpenCallback is the type for the blob_open callback.
-type OpenCallback func(*sqlite3.Blob, ...sqlite3.Value) error

ext/blob/blob_test.go

@@ -1,61 +0,0 @@
-package blob_test
-
-import (
-	"io"
-	"log"
-	"os"
-
-	"github.com/ncruces/go-sqlite3"
-	"github.com/ncruces/go-sqlite3/driver"
-	_ "github.com/ncruces/go-sqlite3/embed"
-	"github.com/ncruces/go-sqlite3/ext/blob"
-	_ "github.com/ncruces/go-sqlite3/vfs/memdb"
-)
-
-func Example() {
-	// Open the database, registering the extension.
-	db, err := driver.Open("file:/test.db?vfs=memdb", func(conn *sqlite3.Conn) error {
-		blob.Register(conn)
-		return nil
-	})
-
-	if err != nil {
-		log.Fatal(err)
-	}
-	defer db.Close()
-
-	_, err = db.Exec(`CREATE TABLE IF NOT EXISTS test (col)`)
-	if err != nil {
-		log.Fatal(err)
-	}
-
-	const message = "Hello BLOB!"
-
-	// Create the BLOB.
-	_, err = db.Exec(`INSERT INTO test VALUES (?)`, sqlite3.ZeroBlob(len(message)))
-	if err != nil {
-		log.Fatal(err)
-	}
-
-	// Write the BLOB.
-	_, err = db.Exec(`SELECT blob_open('main', 'test', 'col', last_insert_rowid(), true, ?)`,
-		sqlite3.Pointer[blob.OpenCallback](func(blob *sqlite3.Blob, _ ...sqlite3.Value) error {
-			_, err = io.WriteString(blob, message)
-			return err
-		}))
-	if err != nil {
-		log.Fatal(err)
-	}
-
-	// Read the BLOB.
-	_, err = db.Exec(`SELECT blob_open('main', 'test', 'col', rowid, false, ?) FROM test`,
-		sqlite3.Pointer[blob.OpenCallback](func(blob *sqlite3.Blob, _ ...sqlite3.Value) error {
-			_, err = io.Copy(os.Stdout, blob)
-			return err
-		}))
-	if err != nil {
-		log.Fatal(err)
-	}
-	// Output:
-	// Hello BLOB!
-}

ext/blobio/blob.go

@@ -0,0 +1,159 @@
+// Package blobio provides an SQL interface to incremental BLOB I/O.
+package blobio
+
+import (
+	"errors"
+	"io"
+
+	"github.com/ncruces/go-sqlite3"
+	"github.com/ncruces/go-sqlite3/internal/util"
+)
+
+// Register registers the SQL functions:
+//
+//	readblob(schema, table, column, rowid, offset, n/writer)
+//
+// Reads n bytes of a blob, starting at offset.
+//
+//	writeblob(schema, table, column, rowid, offset, data/reader)
+//
+// Writes data into a blob, at the given offset.
+//
+//	openblob(schema, table, column, rowid, write, callback, args...)
+//
+// Opens blobs for reading or writing.
+// The callback is invoked for each open blob,
+// and must be bound to an [OpenCallback],
+// using [sqlite3.BindPointer] or [sqlite3.Pointer].
+// The optional args will be passed to the callback,
+// along with the [sqlite3.Blob] handle.
+// The [sqlite3.Blob] handle is only valid during
+// the execution of the callback. Callers cannot
+// read or write to the handle after the callback
+// exits.
+//
+// https://sqlite.org/c3ref/blob.html
+func Register(db *sqlite3.Conn) error {
+	return errors.Join(
+		db.CreateFunction("readblob", 6, 0, readblob),
+		db.CreateFunction("writeblob", 6, 0, writeblob),
+		db.CreateFunction("openblob", -1, 0, openblob))
+}
+
+// OpenCallback is the type for the openblob callback.
+type OpenCallback func(*sqlite3.Blob, ...sqlite3.Value) error
+
+func readblob(ctx sqlite3.Context, arg ...sqlite3.Value) {
+	_ = arg[5] // bounds check
+
+	blob, err := getAuxBlob(ctx, arg, false)
+	if err != nil {
+		ctx.ResultError(err)
+		return // notest
+	}
+
+	_, err = blob.Seek(arg[4].Int64(), io.SeekStart)
+	if err != nil {
+		ctx.ResultError(err)
+		return // notest
+	}
+
+	if p, ok := arg[5].Pointer().(io.Writer); ok {
+		var n int64
+		n, err = blob.WriteTo(p)
+		ctx.ResultInt64(n)
+	} else {
+		n := arg[5].Int64()
+		if n <= 0 {
+			return
+		}
+		buf := make([]byte, n)
+		_, err = io.ReadFull(blob, buf)
+		ctx.ResultBlob(buf)
+	}
+	if err != nil {
+		ctx.ResultError(err)
+		return // notest
+	}
+
+	setAuxBlob(ctx, blob, false)
+}
+
+func writeblob(ctx sqlite3.Context, arg ...sqlite3.Value) {
+	_ = arg[5] // bounds check
+
+	blob, err := getAuxBlob(ctx, arg, true)
+	if err != nil {
+		ctx.ResultError(err)
+		return // notest
+	}
+
+	_, err = blob.Seek(arg[4].Int64(), io.SeekStart)
+	if err != nil {
+		ctx.ResultError(err)
+		return // notest
+	}
+
+	if p, ok := arg[5].Pointer().(io.Reader); ok {
+		var n int64
+		n, err = blob.ReadFrom(p)
+		ctx.ResultInt64(n)
+	} else {
+		_, err = blob.Write(arg[5].RawBlob())
+	}
+	if err != nil {
+		ctx.ResultError(err)
+		return // notest
+	}
+
+	setAuxBlob(ctx, blob, false)
+}
+
+func openblob(ctx sqlite3.Context, arg ...sqlite3.Value) {
+	if len(arg) < 6 {
+		ctx.ResultError(util.ErrorString("openblob: wrong number of arguments"))
+		return
+	}
+
+	blob, err := getAuxBlob(ctx, arg, arg[4].Bool())
+	if err != nil {
+		ctx.ResultError(err)
+		return // notest
+	}
+
+	fn := arg[5].Pointer().(OpenCallback)
+	err = fn(blob, arg[6:]...)
+	if err != nil {
+		ctx.ResultError(err)
+		return // notest
+	}
+
+	setAuxBlob(ctx, blob, true)
+}
+
+func getAuxBlob(ctx sqlite3.Context, arg []sqlite3.Value, write bool) (*sqlite3.Blob, error) {
+	row := arg[3].Int64()
+
+	if blob, ok := ctx.GetAuxData(0).(*sqlite3.Blob); ok {
+		if err := blob.Reopen(row); errors.Is(err, sqlite3.MISUSE) {
+			// Blob was closed (db, table, column or write changed).
+		} else {
+			return blob, err
+		}
+	}
+
+	db := arg[0].Text()
+	table := arg[1].Text()
+	column := arg[2].Text()
+	return ctx.Conn().OpenBlob(db, table, column, row, write)
+}
+
+func setAuxBlob(ctx sqlite3.Context, blob *sqlite3.Blob, open bool) {
+	// This ensures the blob is closed if db, table, column or write change.
+	ctx.SetAuxData(0, blob) // db
+	ctx.SetAuxData(1, blob) // table
+	ctx.SetAuxData(2, blob) // column
+	if open {
+		ctx.SetAuxData(4, blob) // write
+	}
+}

ext/blobio/blob_test.go

@@ -0,0 +1,290 @@
+package blobio_test
+
+import (
+	"database/sql"
+	"io"
+	"log"
+	"os"
+	"slices"
+	"strings"
+	"testing"
+
+	"github.com/ncruces/go-sqlite3"
+	"github.com/ncruces/go-sqlite3/driver"
+	_ "github.com/ncruces/go-sqlite3/embed"
+	"github.com/ncruces/go-sqlite3/ext/array"
+	"github.com/ncruces/go-sqlite3/ext/blobio"
+	_ "github.com/ncruces/go-sqlite3/internal/testcfg"
+	_ "github.com/ncruces/go-sqlite3/vfs/memdb"
+)
+
+func Example() {
+	// Open the database, registering the extension.
+	db, err := driver.Open("file:/test.db?vfs=memdb", blobio.Register)
+
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer db.Close()
+
+	_, err = db.Exec(`CREATE TABLE test (col)`)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	const message = "Hello BLOB!"
+
+	// Create the BLOB.
+	r, err := db.Exec(`INSERT INTO test VALUES (:data)`,
+		sql.Named("data", sqlite3.ZeroBlob(len(message))))
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	id, err := r.LastInsertId()
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	// Write the BLOB.
+	_, err = db.Exec(`SELECT writeblob('main', 'test', 'col', :rowid, :offset, :message)`,
+		sql.Named("rowid", id),
+		sql.Named("offset", 0),
+		sql.Named("message", message))
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	// Read the BLOB.
+	_, err = db.Exec(`SELECT readblob('main', 'test', 'col', :rowid, :offset, :writer)`,
+		sql.Named("rowid", id),
+		sql.Named("offset", 0),
+		sql.Named("writer", sqlite3.Pointer(os.Stdout)))
+	if err != nil {
+		log.Fatal(err)
+	}
+	// Output:
+	// Hello BLOB!
+}
+
+func TestMain(m *testing.M) {
+	sqlite3.AutoExtension(blobio.Register)
+	sqlite3.AutoExtension(array.Register)
+	os.Exit(m.Run())
+}
+
+func Test_readblob(t *testing.T) {
+	t.Parallel()
+
+	db, err := sqlite3.Open(":memory:")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+
+	err = db.Exec(`SELECT readblob()`)
+	if err == nil {
+		t.Fatal("want error")
+	} else {
+		t.Log(err)
+	}
+
+	err = db.Exec(`SELECT readblob('main', 'test1', 'col', 1, 1, 1)`)
+	if err == nil {
+		t.Fatal("want error")
+	} else {
+		t.Log(err)
+	}
+
+	err = db.Exec(`
+		CREATE TABLE test1 (col);
+		CREATE TABLE test2 (col);
+		INSERT INTO test1 VALUES (x'cafe');
+		INSERT INTO test1 VALUES (x'dead');
+		INSERT INTO test2 VALUES (x'babe');
+	`)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = db.Exec(`SELECT readblob('main', 'test1', 'col', 1, -1, 1)`)
+	if err == nil {
+		t.Fatal("want error")
+	} else {
+		t.Log(err)
+	}
+
+	err = db.Exec(`SELECT readblob('main', 'test1', 'col', 1, 1, 0)`)
+	if err != nil {
+		t.Log(err)
+	}
+
+	tests := []struct {
+		name  string
+		sql   string
+		want1 string
+		want2 string
+	}{
+		{"rows", `SELECT readblob('main', 'test1', 'col', rowid, 1, 1) FROM test1`, "\xfe", "\xad"},
+		{"tables", `SELECT readblob('main', value, 'col', 1, 1, 1) FROM array(?)`, "\xfe", "\xbe"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			stmt, _, err := db.Prepare(tt.sql)
+			if err != nil {
+				t.Fatal(err)
+			}
+			defer stmt.Close()
+
+			if stmt.BindCount() == 1 {
+				err = stmt.BindPointer(1, []string{"test1", "test2"})
+				if err != nil {
+					t.Fatal(err)
+				}
+			}
+
+			if stmt.Step() {
+				got := stmt.ColumnText(0)
+				if got != tt.want1 {
+					t.Errorf("got %q", got)
+				}
+			}
+
+			if stmt.Step() {
+				got := stmt.ColumnText(0)
+				if got != tt.want2 {
+					t.Errorf("got %q", got)
+				}
+			}
+
+			err = stmt.Err()
+			if err != nil {
+				t.Fatal(err)
+			}
+		})
+	}
+}
+
+func Test_writeblob(t *testing.T) {
+	t.Parallel()
+
+	db, err := sqlite3.Open(":memory:")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+
+	err = db.Exec(`SELECT writeblob()`)
+	if err == nil {
+		t.Fatal("want error")
+	} else {
+		t.Log(err)
+	}
+
+	err = db.Exec(`SELECT writeblob('main', 'test', 'col', 1, 1, x'')`)
+	if err == nil {
+		t.Fatal("want error")
+	} else {
+		t.Log(err)
+	}
+
+	err = db.Exec(`
+		CREATE TABLE test (col);
+		INSERT INTO test VALUES (x'cafe');
+	`)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = db.Exec(`SELECT writeblob('main', 'test', 'col', 1, -1, x'')`)
+	if err == nil {
+		t.Fatal("want error")
+	} else {
+		t.Log(err)
+	}
+
+	stmt, _, err := db.Prepare(`SELECT writeblob('main', 'test', 'col', 1, 0, ?)`)
+	if err != nil {
+		t.Log(err)
+	}
+	defer stmt.Close()
+
+	err = stmt.BindPointer(1, strings.NewReader("\xba\xbe"))
+	if err != nil {
+		t.Log(err)
+	}
+
+	err = stmt.Exec()
+	if err != nil {
+		t.Log(err)
+	}
+}
+
+func Test_openblob(t *testing.T) {
+	t.Parallel()
+
+	db, err := sqlite3.Open(":memory:")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+
+	err = db.Exec(`SELECT openblob()`)
+	if err == nil {
+		t.Fatal("want error")
+	} else {
+		t.Log(err)
+	}
+
+	err = db.Exec(`SELECT openblob('main', 'test1', 'col', 1, false, NULL)`)
+	if err == nil {
+		t.Fatal("want error")
+	} else {
+		t.Log(err)
+	}
+
+	err = db.Exec(`
+		CREATE TABLE test1 (col);
+		CREATE TABLE test2 (col);
+		INSERT INTO test1 VALUES (x'cafe');
+		INSERT INTO test2 VALUES (x'babe');
+	`)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	stmt, _, err := db.Prepare(`SELECT openblob('main', value, 'col', 1, false, ?) FROM array(?)`)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer stmt.Close()
+
+	var got []string
+	err = stmt.BindPointer(1, blobio.OpenCallback(func(b *sqlite3.Blob, _ ...sqlite3.Value) error {
+		d, err := io.ReadAll(b)
+		if err != nil {
+			return err
+		}
+		got = append(got, string(d))
+		return nil
+	}))
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = stmt.BindPointer(2, []string{"test1", "test2"})
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = stmt.Exec()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	want := []string{"\xca\xfe", "\xba\xbe"}
+	if !slices.Equal(got, want) {
+		t.Errorf("got %v, want %v", got, want)
+	}
+}

ext/bloom/bloom.go

@@ -0,0 +1,346 @@
+// Package bloom provides a Bloom filter virtual table.
+//
+// A Bloom filter is a space-efficient probabilistic data structure
+// used to test whether an element is a member of a set.
+//
+// https://github.com/nalgeon/sqlean/issues/27#issuecomment-1002267134
+package bloom
+
+import (
+	"fmt"
+	"io"
+	"math"
+	"strconv"
+
+	"github.com/dchest/siphash"
+
+	"github.com/ncruces/go-sqlite3"
+	"github.com/ncruces/go-sqlite3/internal/util"
+)
+
+// Register registers the bloom_filter virtual table:
+//
+//	CREATE VIRTUAL TABLE foo USING bloom_filter(nElements, falseProb, kHashes)
+func Register(db *sqlite3.Conn) error {
+	return sqlite3.CreateModule(db, "bloom_filter", create, connect)
+}
+
+type bloom struct {
+	db      *sqlite3.Conn
+	schema  string
+	storage string
+	prob    float64
+	bytes   int64
+	hashes  int
+}
+
+func create(db *sqlite3.Conn, _, schema, table string, arg ...string) (_ *bloom, err error) {
+	b := bloom{
+		db:      db,
+		schema:  schema,
+		storage: table + "_storage",
+	}
+
+	var nelem int64
+	if len(arg) > 0 {
+		nelem, err = strconv.ParseInt(arg[0], 10, 64)
+		if err != nil {
+			return nil, err
+		}
+		if nelem <= 0 {
+			return nil, util.ErrorString("bloom: number of elements in filter must be positive")
+		}
+	} else {
+		nelem = 100
+	}
+
+	if len(arg) > 1 {
+		b.prob, err = strconv.ParseFloat(arg[1], 64)
+		if err != nil {
+			return nil, err
+		}
+		if b.prob <= 0 || b.prob >= 1 {
+			return nil, util.ErrorString("bloom: probability must be in the range (0,1)")
+		}
+	} else {
+		b.prob = 0.01
+	}
+
+	if len(arg) > 2 {
+		b.hashes, err = strconv.Atoi(arg[2])
+		if err != nil {
+			return nil, err
+		}
+		if b.hashes <= 0 {
+			return nil, util.ErrorString("bloom: number of hash functions must be positive")
+		}
+	} else {
+		b.hashes = max(1, numHashes(b.prob))
+	}
+
+	b.bytes = numBytes(nelem, b.prob)
+
+	err = db.DeclareVTab(
+		`CREATE TABLE x(present, word HIDDEN NOT NULL PRIMARY KEY) WITHOUT ROWID`)
+	if err != nil {
+		return nil, err
+	}
+
+	err = db.Exec(fmt.Sprintf(
+		`CREATE TABLE %s.%s (data BLOB, p REAL, n INTEGER, m INTEGER, k INTEGER)`,
+		sqlite3.QuoteIdentifier(b.schema), sqlite3.QuoteIdentifier(b.storage)))
+	if err != nil {
+		return nil, err
+	}
+
+	id := db.LastInsertRowID()
+	defer db.SetLastInsertRowID(id)
+
+	err = db.Exec(fmt.Sprintf(
+		`INSERT INTO %s.%s (rowid, data, p, n, m, k)
+		 VALUES (1, zeroblob(%d), %f, %d, %d, %d)`,
+		sqlite3.QuoteIdentifier(b.schema), sqlite3.QuoteIdentifier(b.storage),
+		b.bytes, b.prob, nelem, 8*b.bytes, b.hashes))
+	if err != nil {
+		b.Destroy()
+		return nil, err
+	}
+	return &b, nil
+}
+
+func connect(db *sqlite3.Conn, _, schema, table string, arg ...string) (_ *bloom, err error) {
+	b := bloom{
+		db:      db,
+		schema:  schema,
+		storage: table + "_storage",
+	}
+
+	err = db.DeclareVTab(
+		`CREATE TABLE x(present, word HIDDEN NOT NULL PRIMARY KEY) WITHOUT ROWID`)
+	if err != nil {
+		return nil, err
+	}
+
+	load, _, err := db.Prepare(fmt.Sprintf(
+		`SELECT m/8, p, k FROM %s.%s WHERE rowid = 1`,
+		sqlite3.QuoteIdentifier(b.schema), sqlite3.QuoteIdentifier(b.storage)))
+	if err != nil {
+		return nil, err
+	}
+	defer load.Close()
+
+	if !load.Step() {
+		if err := load.Err(); err != nil {
+			return nil, err
+		}
+		return nil, sqlite3.CORRUPT_VTAB
+	}
+
+	b.bytes = load.ColumnInt64(0)
+	b.prob = load.ColumnFloat(1)
+	b.hashes = load.ColumnInt(2)
+	return &b, nil
+}
+
+func (b *bloom) Destroy() error {
+	return b.db.Exec(fmt.Sprintf(`DROP TABLE %s.%s`,
+		sqlite3.QuoteIdentifier(b.schema),
+		sqlite3.QuoteIdentifier(b.storage)))
+}
+
+func (b *bloom) Rename(new string) error {
+	new += "_storage"
+	err := b.db.Exec(fmt.Sprintf(`ALTER TABLE %s.%s RENAME TO %s`,
+		sqlite3.QuoteIdentifier(b.schema),
+		sqlite3.QuoteIdentifier(b.storage),
+		sqlite3.QuoteIdentifier(new),
+	))
+	if err == nil {
+		b.storage = new
+	}
+	return err
+}
+
+func (t *bloom) ShadowTables() {
+	// notest // not meant to be called
+}
+
+func (t *bloom) Integrity(schema, table string, flags int) error {
+	load, _, err := t.db.Prepare(fmt.Sprintf(
+		`SELECT typeof(data), length(data), p, n, m, k FROM %s.%s WHERE rowid = 1`,
+		sqlite3.QuoteIdentifier(t.schema), sqlite3.QuoteIdentifier(t.storage)))
+	if err != nil {
+		return fmt.Errorf("bloom: %v", err) // can't wrap!
+	}
+	defer load.Close()
+
+	err = util.ErrorString("bloom: invalid parameters")
+	if !load.Step() {
+		return err
+	}
+	if t := load.ColumnText(0); t != "blob" {
+		return err
+	}
+	if m := load.ColumnInt64(4); m <= 0 || m%8 != 0 {
+		return err
+	} else if load.ColumnInt64(1) != m/8 {
+		return err
+	}
+	if p := load.ColumnFloat(2); p <= 0 || p >= 1 {
+		return err
+	}
+	if n := load.ColumnInt64(3); n <= 0 {
+		return err
+	}
+	if k := load.ColumnInt(5); k <= 0 {
+		return err
+	}
+	return nil
+}
+
+func (b *bloom) BestIndex(idx *sqlite3.IndexInfo) error {
+	for i, cst := range idx.Constraint {
+		if cst.Usable && cst.Column == 1 &&
+			cst.Op == sqlite3.INDEX_CONSTRAINT_EQ {
+			idx.ConstraintUsage[i].ArgvIndex = 1
+			idx.OrderByConsumed = true
+			idx.EstimatedRows = 1
+			idx.EstimatedCost = float64(b.hashes)
+			idx.IdxFlags = sqlite3.INDEX_SCAN_UNIQUE
+			return nil
+		}
+	}
+	return sqlite3.CONSTRAINT
+}
+
+func (b *bloom) Update(arg ...sqlite3.Value) (rowid int64, err error) {
+	if arg[0].Type() != sqlite3.NULL {
+		if len(arg) == 1 {
+			return 0, util.ErrorString("bloom: elements cannot be deleted")
+		}
+		return 0, util.ErrorString("bloom: elements cannot be updated")
+	}
+
+	if arg[2].NoChange() {
+		return 0, nil
+	}
+	blob := arg[2].RawBlob()
+
+	f, err := b.db.OpenBlob(b.schema, b.storage, "data", 1, true)
+	if err != nil {
+		return 0, err
+	}
+	defer f.Close()
+
+	for n := range b.hashes {
+		hash := calcHash(n, blob)
+		hash %= uint64(b.bytes * 8)
+		bitpos := byte(hash % 8)
+		bytepos := int64(hash / 8)
+
+		var buf [1]byte
+		_, err = f.Seek(bytepos, io.SeekStart)
+		if err != nil {
+			return 0, err
+		}
+		_, err = f.Read(buf[:])
+		if err != nil {
+			return 0, err
+		}
+
+		buf[0] |= 1 << bitpos
+
+		_, err = f.Seek(bytepos, io.SeekStart)
+		if err != nil {
+			return 0, err
+		}
+		_, err = f.Write(buf[:])
+		if err != nil {
+			return 0, err
+		}
+	}
+	return 0, nil
+}
+
+func (b *bloom) Open() (sqlite3.VTabCursor, error) {
+	return &cursor{bloom: b}, nil
+}
+
+type cursor struct {
+	*bloom
+	arg sqlite3.Value
+	eof bool
+}
+
+func (c *cursor) Filter(idxNum int, idxStr string, arg ...sqlite3.Value) error {
+	c.eof = false
+	c.arg = arg[0]
+	blob := arg[0].RawBlob()
+
+	f, err := c.db.OpenBlob(c.schema, c.storage, "data", 1, false)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+
+	for n := 0; n < c.hashes && !c.eof; n++ {
+		hash := calcHash(n, blob)
+		hash %= uint64(c.bytes * 8)
+		bitpos := byte(hash % 8)
+		bytepos := int64(hash / 8)
+
+		var buf [1]byte
+		_, err = f.Seek(bytepos, io.SeekStart)
+		if err != nil {
+			return err
+		}
+		_, err = f.Read(buf[:])
+		if err != nil {
+			return err
+		}
+
+		c.eof = buf[0]&(1<<bitpos) == 0
+	}
+	return nil
+}
+
+func (c *cursor) Column(ctx sqlite3.Context, n int) error {
+	if ctx.VTabNoChange() {
+		return nil
+	}
+	switch n {
+	case 0:
+		ctx.ResultBool(true)
+	case 1:
+		ctx.ResultValue(c.arg)
+	}
+	return nil
+}
+
+func (c *cursor) Next() error {
+	c.eof = true
+	return nil
+}
+
+func (c *cursor) EOF() bool {
+	return c.eof
+}
+
+func (c *cursor) RowID() (int64, error) {
+	// notest // WITHOUT ROWID
+	return 0, nil
+}
+
+func calcHash(k int, b []byte) uint64 {
+	return siphash.Hash(^uint64(k), uint64(k), b)
+}
+
+func numHashes(p float64) int {
+	k := math.Round(-math.Log2(p))
+	return max(1, int(k))
+}
+
+func numBytes(n int64, p float64) int64 {
+	m := math.Ceil(float64(n) * math.Log(p) / -(math.Ln2 * math.Ln2))
+	return (int64(m) + 7) / 8
+}

ext/bloom/bloom_test.go

@@ -0,0 +1,195 @@
+package bloom_test
+
+import (
+	_ "embed"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/ncruces/go-sqlite3"
+	_ "github.com/ncruces/go-sqlite3/embed"
+	"github.com/ncruces/go-sqlite3/ext/bloom"
+	_ "github.com/ncruces/go-sqlite3/internal/testcfg"
+)
+
+func TestMain(m *testing.M) {
+	sqlite3.AutoExtension(bloom.Register)
+	os.Exit(m.Run())
+}
+
+func TestRegister(t *testing.T) {
+	t.Parallel()
+
+	db, err := sqlite3.Open(":memory:")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+
+	err = db.Exec(`
+		CREATE VIRTUAL TABLE sports_cars USING bloom_filter();
+		INSERT INTO sports_cars VALUES ('ferrari'), ('lamborghini'), ('alfa romeo')
+	`)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	query, _, err := db.Prepare(`SELECT COUNT(*) FROM sports_cars(?)`)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = query.BindText(1, "ferrari")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !query.Step() {
+		t.Error("no rows")
+	}
+	if !query.ColumnBool(0) {
+		t.Error("want true")
+	}
+	err = query.Reset()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = query.BindText(1, "bmw")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !query.Step() {
+		t.Error("no rows")
+	}
+	if query.ColumnBool(0) {
+		t.Error("want false")
+	}
+	err = query.Close()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = db.Exec(`DELETE FROM sports_cars WHERE word = 'lamborghini'`)
+	if err == nil {
+		t.Error("want error")
+	}
+
+	err = db.Exec(`UPDATE sports_cars SET word = 'ferrari' WHERE word = 'lamborghini'`)
+	if err == nil {
+		t.Error("want error")
+	}
+
+	err = db.Exec(`ALTER TABLE sports_cars RENAME TO fast_cars`)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = db.Exec(`DROP TABLE fast_cars`)
+	if err != nil {
+		t.Fatal(err)
+	}
+}
+
+//go:embed testdata/bloom.db
+var testDB []byte
+
+func Test_compatible(t *testing.T) {
+	t.Parallel()
+
+	tmp := filepath.Join(t.TempDir(), "bloom.db")
+	err := os.WriteFile(tmp, testDB, 0666)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	db, err := sqlite3.Open("file:" + filepath.ToSlash(tmp) + "?nolock=1")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+
+	query, _, err := db.Prepare(`SELECT COUNT(*) FROM plants(?)`)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer query.Close()
+
+	err = query.BindText(1, "apple")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !query.Step() {
+		t.Error("no rows")
+	}
+	if !query.ColumnBool(0) {
+		t.Error("want true")
+	}
+	err = query.Reset()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = query.BindText(1, "lemon")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !query.Step() {
+		t.Error("no rows")
+	}
+	if query.ColumnBool(0) {
+		t.Error("want false")
+	}
+	err = query.Reset()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = db.Exec(`PRAGMA integrity_check`)
+	if err != nil {
+		t.Error(err)
+	}
+
+	err = db.Exec(`PRAGMA quick_check`)
+	if err != nil {
+		t.Error(err)
+	}
+}
+
+func Test_errors(t *testing.T) {
+	t.Parallel()
+
+	db, err := sqlite3.Open(":memory:")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+
+	bloom.Register(db)
+
+	err = db.Exec(`CREATE VIRTUAL TABLE sports_cars USING bloom_filter(0)`)
+	if err == nil {
+		t.Error("want error")
+	}
+	err = db.Exec(`CREATE VIRTUAL TABLE sports_cars USING bloom_filter('a')`)
+	if err == nil {
+		t.Error("want error")
+	}
+
+	err = db.Exec(`CREATE VIRTUAL TABLE sports_cars USING bloom_filter(20, 2)`)
+	if err == nil {
+		t.Error("want error")
+	}
+	err = db.Exec(`CREATE VIRTUAL TABLE sports_cars USING bloom_filter(20, 'a')`)
+	if err == nil {
+		t.Error("want error")
+	}
+
+	err = db.Exec(`CREATE VIRTUAL TABLE sports_cars USING bloom_filter(20, 0.9, 0)`)
+	if err == nil {
+		t.Error("want error")
+	}
+	err = db.Exec(`CREATE VIRTUAL TABLE sports_cars USING bloom_filter(20, 0.9, 'a')`)
+	if err == nil {
+		t.Error("want error")
+	}
+}

ext/closure/closure.go

@@ -0,0 +1,264 @@
+// Package closure provides a transitive closure virtual table.
+//
+// The transitive_closure virtual table finds the transitive closure of
+// a parent/child relationship in a real table.
+//
+// https://sqlite.org/src/doc/tip/ext/misc/closure.c
+package closure
+
+import (
+	"fmt"
+	"math"
+
+	"github.com/ncruces/go-sqlite3"
+	"github.com/ncruces/go-sqlite3/internal/util"
+	"github.com/ncruces/go-sqlite3/util/sql3util"
+)
+
+const (
+	_COL_ID           = 0
+	_COL_DEPTH        = 1
+	_COL_ROOT         = 2
+	_COL_TABLENAME    = 3
+	_COL_IDCOLUMN     = 4
+	_COL_PARENTCOLUMN = 5
+)
+
+// Register registers the transitive_closure virtual table:
+//
+//	CREATE VIRTUAL TABLE temp.closure USING transitive_closure;
+func Register(db *sqlite3.Conn) error {
+	return sqlite3.CreateModule(db, "transitive_closure", nil,
+		func(db *sqlite3.Conn, _, _, _ string, arg ...string) (*closure, error) {
+			var (
+				table  string
+				column string
+				parent string
+
+				done = util.Set[string]{}
+			)
+
+			for _, arg := range arg {
+				key, val := sql3util.NamedArg(arg)
+				if done.Contains(key) {
+					return nil, fmt.Errorf("transitive_closure: more than one %q parameter", key)
+				}
+				switch key {
+				case "tablename":
+					table = sql3util.Unquote(val)
+				case "idcolumn":
+					column = sql3util.Unquote(val)
+				case "parentcolumn":
+					parent = sql3util.Unquote(val)
+				default:
+					return nil, fmt.Errorf("transitive_closure: unknown %q parameter", key)
+				}
+				done.Add(key)
+			}
+
+			err := db.DeclareVTab(`CREATE TABLE x(id,depth,root HIDDEN,tablename HIDDEN,idcolumn HIDDEN,parentcolumn HIDDEN)`)
+			if err != nil {
+				return nil, err
+			}
+			return &closure{
+				db:     db,
+				table:  table,
+				column: column,
+				parent: parent,
+			}, nil
+		})
+}
+
+type closure struct {
+	db     *sqlite3.Conn
+	table  string
+	column string
+	parent string
+}
+
+func (c *closure) Destroy() error { return nil }
+
+func (c *closure) BestIndex(idx *sqlite3.IndexInfo) error {
+	plan := 0
+	posi := 1
+	cost := 1e7
+
+	for i, cst := range idx.Constraint {
+		switch {
+		case !cst.Usable:
+			continue
+
+		case plan&1 == 0 && cst.Column == _COL_ROOT:
+			switch cst.Op {
+			case sqlite3.INDEX_CONSTRAINT_EQ:
+				plan |= 1
+				cost /= 100
+				idx.ConstraintUsage[i] = sqlite3.IndexConstraintUsage{
+					ArgvIndex: 1,
+					Omit:      true,
+				}
+			}
+
+		case plan&0xf0 == 0 && cst.Column == _COL_DEPTH:
+			switch cst.Op {
+			case sqlite3.INDEX_CONSTRAINT_LT, sqlite3.INDEX_CONSTRAINT_LE, sqlite3.INDEX_CONSTRAINT_EQ:
+				plan |= posi << 4
+				cost /= 5
+				posi += 1
+				idx.ConstraintUsage[i].ArgvIndex = posi
+				if cst.Op == sqlite3.INDEX_CONSTRAINT_LT {
+					plan |= 2
+				}
+			}
+
+		case plan&0xf00 == 0 && cst.Column == _COL_TABLENAME:
+			switch cst.Op {
+			case sqlite3.INDEX_CONSTRAINT_EQ:
+				plan |= posi << 8
+				cost /= 5
+				posi += 1
+				idx.ConstraintUsage[i] = sqlite3.IndexConstraintUsage{
+					ArgvIndex: posi,
+					Omit:      true,
+				}
+			}
+
+		case plan&0xf000 == 0 && cst.Column == _COL_IDCOLUMN:
+			switch cst.Op {
+			case sqlite3.INDEX_CONSTRAINT_EQ:
+				plan |= posi << 12
+				posi += 1
+				idx.ConstraintUsage[i] = sqlite3.IndexConstraintUsage{
+					ArgvIndex: posi,
+					Omit:      true,
+				}
+			}
+
+		case plan&0xf0000 == 0 && cst.Column == _COL_PARENTCOLUMN:
+			switch cst.Op {
+			case sqlite3.INDEX_CONSTRAINT_EQ:
+				plan |= posi << 16
+				posi += 1
+				idx.ConstraintUsage[i] = sqlite3.IndexConstraintUsage{
+					ArgvIndex: posi,
+					Omit:      true,
+				}
+			}
+		}
+	}
+
+	if plan&1 == 0 ||
+		c.table == "" && plan&0xf00 == 0 ||
+		c.column == "" && plan&0xf000 == 0 ||
+		c.parent == "" && plan&0xf0000 == 0 {
+		return sqlite3.CONSTRAINT
+	}
+
+	idx.EstimatedCost = cost
+	idx.IdxNum = plan
+	return nil
+}
+
+func (c *closure) Open() (sqlite3.VTabCursor, error) {
+	return &cursor{closure: c}, nil
+}
+
+type cursor struct {
+	*closure
+	nodes []node
+}
+
+type node struct {
+	id    int64
+	depth int
+}
+
+func (c *cursor) Filter(idxNum int, idxStr string, arg ...sqlite3.Value) error {
+	root := arg[0].Int64()
+	maxDepth := math.MaxInt
+	if idxNum&0xf0 != 0 {
+		maxDepth = arg[(idxNum>>4)&0xf].Int()
+		if idxNum&2 != 0 {
+			maxDepth -= 1
+		}
+	}
+	table := c.table
+	if idxNum&0xf00 != 0 {
+		table = arg[(idxNum>>8)&0xf].Text()
+	}
+	column := c.column
+	if idxNum&0xf000 != 0 {
+		column = arg[(idxNum>>12)&0xf].Text()
+	}
+	parent := c.parent
+	if idxNum&0xf0000 != 0 {
+		parent = arg[(idxNum>>16)&0xf].Text()
+	}
+
+	sql := fmt.Sprintf(
+		`SELECT %[1]s.%[2]s FROM %[1]s WHERE %[1]s.%[3]s=?`,
+		sqlite3.QuoteIdentifier(table),
+		sqlite3.QuoteIdentifier(column),
+		sqlite3.QuoteIdentifier(parent),
+	)
+	stmt, _, err := c.db.Prepare(sql)
+	if err != nil {
+		return err
+	}
+	defer stmt.Close()
+
+	c.nodes = []node{{root, 0}}
+	set := util.Set[int64]{}
+	set.Add(root)
+	for i := range c.nodes {
+		curr := c.nodes[i]
+		if curr.depth >= maxDepth {
+			continue
+		}
+		if err := stmt.BindInt64(1, curr.id); err != nil {
+			return err
+		}
+		for stmt.Step() {
+			if stmt.ColumnType(0) == sqlite3.INTEGER {
+				next := stmt.ColumnInt64(0)
+				if !set.Contains(next) {
+					set.Add(next)
+					c.nodes = append(c.nodes, node{next, curr.depth + 1})
+				}
+			}
+		}
+		if err := stmt.Reset(); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func (c *cursor) Column(ctx sqlite3.Context, n int) error {
+	switch n {
+	case _COL_ID:
+		ctx.ResultInt64(c.nodes[0].id)
+	case _COL_DEPTH:
+		ctx.ResultInt(c.nodes[0].depth)
+	case _COL_TABLENAME:
+		ctx.ResultText(c.table)
+	case _COL_IDCOLUMN:
+		ctx.ResultText(c.column)
+	case _COL_PARENTCOLUMN:
+		ctx.ResultText(c.parent)
+	}
+	return nil
+}
+
+func (c *cursor) Next() error {
+	c.nodes = c.nodes[1:]
+	return nil
+}
+
+func (c *cursor) EOF() bool {
+	return len(c.nodes) == 0
+}
+
+func (c *cursor) RowID() (int64, error) {
+	return c.nodes[0].id, nil
+}

ext/closure/closure_test.go

@@ -0,0 +1,185 @@
+package closure_test
+
+import (
+	_ "embed"
+	"fmt"
+	"log"
+	"os"
+	"testing"
+
+	"github.com/ncruces/go-sqlite3"
+	_ "github.com/ncruces/go-sqlite3/embed"
+	"github.com/ncruces/go-sqlite3/ext/closure"
+	_ "github.com/ncruces/go-sqlite3/internal/testcfg"
+)
+
+func TestMain(m *testing.M) {
+	sqlite3.AutoExtension(closure.Register)
+	os.Exit(m.Run())
+}
+
+func Example() {
+	db, err := sqlite3.Open(":memory:")
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer db.Close()
+
+	closure.Register(db)
+
+	err = db.Exec(`
+		CREATE TABLE employees (
+			id INTEGER PRIMARY KEY,
+			parent_id INTEGER,
+			name TEXT
+		);
+		CREATE INDEX employees_parent_idx ON employees(parent_id);
+		INSERT INTO employees (id, parent_id, name) VALUES
+			(11, NULL, 'Diane'),
+			(12, 11, 'Bob'),
+			(21, 11, 'Emma'),
+			(22, 21, 'Grace'),
+			(23, 21, 'Henry'),
+			(24, 21, 'Irene'),
+			(25, 21, 'Frank'),
+			(31, 11, 'Cindy'),
+			(32, 31, 'Dave'),
+			(33, 31, 'Alice');
+		CREATE VIRTUAL TABLE hierarchy USING transitive_closure(
+			tablename = "employees",
+			idcolumn = "id",
+			parentcolumn = "parent_id"
+		);
+	`)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	stmt, _, err := db.Prepare(`
+		SELECT employees.id, name FROM employees, hierarchy
+		WHERE employees.id = hierarchy.id AND hierarchy.root = 31
+	`)
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer stmt.Close()
+
+	for stmt.Step() {
+		fmt.Println(stmt.ColumnInt(0), stmt.ColumnText(1))
+	}
+	if err := stmt.Err(); err != nil {
+		log.Fatal(err)
+	}
+
+	err = stmt.Close()
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	err = db.Close()
+	if err != nil {
+		log.Fatal(err)
+	}
+	// Output:
+	// 31 Cindy
+	// 32 Dave
+	// 33 Alice
+}
+
+func TestRegister(t *testing.T) {
+	t.Parallel()
+
+	db, err := sqlite3.Open(":memory:")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+
+	err = db.Exec(`
+		CREATE TABLE employees (
+			id INTEGER PRIMARY KEY,
+			parent_id INTEGER,
+			name TEXT
+		);
+		CREATE INDEX employees_parent_idx ON employees(parent_id);
+		INSERT INTO employees (id, parent_id, name) VALUES
+			(11, NULL, 'Diane'),
+			(12, 11, 'Bob'),
+			(21, 11, 'Emma'),
+			(22, 21, 'Grace'),
+			(23, 21, 'Henry'),
+			(24, 21, 'Irene'),
+			(25, 21, 'Frank'),
+			(31, 11, 'Cindy'),
+			(32, 31, 'Dave'),
+			(33, 31, 'Alice');
+		CREATE VIRTUAL TABLE temp.closure USING transitive_closure;
+	`)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	stmt, _, err := db.Prepare(`
+		SELECT employees.id, name FROM employees, closure
+		 WHERE employees.id = closure.id
+		   AND closure.root = 31
+		   AND closure.depth < 1
+		   AND closure.tablename='employees'
+		   AND closure.idcolumn='id'
+		   AND closure.parentcolumn='parent_id'
+	`)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer stmt.Close()
+
+	if !stmt.Step() {
+		t.Error("want row")
+	}
+	if stmt.Step() {
+		t.Error("don't want row")
+	}
+	if err := stmt.Err(); err != nil {
+		t.Fatal(err)
+	}
+
+	err = stmt.Close()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = db.Close()
+	if err != nil {
+		t.Fatal(err)
+	}
+}
+
+func Test_errors(t *testing.T) {
+	t.Parallel()
+
+	db, err := sqlite3.Open(":memory:")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+
+	err = db.Exec(`CREATE VIRTUAL TABLE hierarchy USING transitive_closure(table='employees')`)
+	if err == nil {
+		t.Error("want error")
+	}
+
+	err = db.Exec(`CREATE VIRTUAL TABLE hierarchy USING transitive_closure(tablename='employees', tablename="employees")`)
+	if err == nil {
+		t.Error("want error")
+	}
+
+	err = db.Exec("CREATE VIRTUAL TABLE hierarchy USING transitive_closure(tablename=`employees`)")
+	if err != nil {
+		t.Error(err)
+	}
+
+	err = db.Exec(`SELECT * FROM hierarchy`)
+	if err == nil {
+		t.Error("want error")
+	}
+}

ext/csv/arg.go

@@ -0,0 +1,35 @@
+package csv
+
+import (
+	"fmt"
+	"strconv"
+
+	"github.com/ncruces/go-sqlite3/util/sql3util"
+)
+
+func uintArg(key, val string) (int, error) {
+	i, err := strconv.ParseUint(val, 10, 15)
+	if err != nil {
+		return 0, fmt.Errorf("csv: invalid %q parameter: %s", key, val)
+	}
+	return int(i), nil
+}
+
+func boolArg(key, val string) (bool, error) {
+	if val == "" {
+		return true, nil
+	}
+	b, ok := sql3util.ParseBool(val)
+	if ok {
+		return b, nil
+	}
+	return false, fmt.Errorf("csv: invalid %q parameter: %s", key, val)
+}
+
+func runeArg(key, val string) (rune, error) {
+	r, _, tail, err := strconv.UnquoteChar(sql3util.Unquote(val), 0)
+	if tail != "" || err != nil {
+		return 0, fmt.Errorf("csv: invalid %q parameter: %s", key, val)
+	}
+	return r, nil
+}

ext/csv/arg_test.go

@@ -1,8 +1,14 @@
 package csv
 
-import "testing"
+import (
+	"testing"
+
+	"github.com/ncruces/go-sqlite3/util/sql3util"
+)
+
+func Test_uintArg(t *testing.T) {
+	t.Parallel()
 
-func Test_uintParam(t *testing.T) {
 	tests := []struct {
 		arg string
 		key string
@@ -18,22 +24,24 @@ func Test_uintParam(t *testing.T) {
 	}
 	for _, tt := range tests {
 		t.Run(tt.arg, func(t *testing.T) {
-			key, val := getParam(tt.arg)
+			key, val := sql3util.NamedArg(tt.arg)
 			if key != tt.key {
-				t.Errorf("getParam() %v, want err %v", key, tt.key)
+				t.Errorf("NamedArg() %v, want err %v", key, tt.key)
 			}
-			got, err := uintParam(key, val)
+			got, err := uintArg(key, val)
 			if (err != nil) != tt.err {
-				t.Fatalf("uintParam() error = %v, want err %v", err, tt.err)
+				t.Fatalf("uintArg() error = %v, want err %v", err, tt.err)
 			}
 			if got != tt.val {
-				t.Errorf("uintParam() = %v, want %v", got, tt.val)
+				t.Errorf("uintArg() = %v, want %v", got, tt.val)
 			}
 		})
 	}
 }
 
-func Test_boolParam(t *testing.T) {
+func Test_boolArg(t *testing.T) {
+	t.Parallel()
+
 	tests := []struct {
 		arg string
 		key string
@@ -54,22 +62,24 @@ func Test_boolParam(t *testing.T) {
 	}
 	for _, tt := range tests {
 		t.Run(tt.arg, func(t *testing.T) {
-			key, val := getParam(tt.arg)
+			key, val := sql3util.NamedArg(tt.arg)
 			if key != tt.key {
-				t.Errorf("getParam() %v, want err %v", key, tt.key)
+				t.Errorf("NamedArg() %v, want err %v", key, tt.key)
 			}
-			got, err := boolParam(key, val)
+			got, err := boolArg(key, val)
 			if (err != nil) != tt.err {
-				t.Fatalf("boolParam() error = %v, want err %v", err, tt.err)
+				t.Fatalf("boolArg() error = %v, want err %v", err, tt.err)
 			}
 			if got != tt.val {
-				t.Errorf("boolParam() = %v, want %v", got, tt.val)
+				t.Errorf("boolArg() = %v, want %v", got, tt.val)
 			}
 		})
 	}
 }
 
-func Test_runeParam(t *testing.T) {
+func Test_runeArg(t *testing.T) {
+	t.Parallel()
+
 	tests := []struct {
 		arg string
 		key string
@@ -86,16 +96,16 @@ func Test_runeParam(t *testing.T) {
 	}
 	for _, tt := range tests {
 		t.Run(tt.arg, func(t *testing.T) {
-			key, val := getParam(tt.arg)
+			key, val := sql3util.NamedArg(tt.arg)
 			if key != tt.key {
-				t.Errorf("getParam() %v, want err %v", key, tt.key)
+				t.Errorf("NamedArg() %v, want err %v", key, tt.key)
 			}
-			got, err := runeParam(key, val)
+			got, err := runeArg(key, val)
 			if (err != nil) != tt.err {
-				t.Fatalf("runeParam() error = %v, want err %v", err, tt.err)
+				t.Fatalf("runeArg() error = %v, want err %v", err, tt.err)
 			}
 			if got != tt.val {
-				t.Errorf("runeParam() = %v, want %v", got, tt.val)
+				t.Errorf("runeArg() = %v, want %v", got, tt.val)
 			}
 		})
 	}

ext/csv/csv.go

@@ -7,28 +7,30 @@
 package csv
 
 import (
+	"bufio"
 	"encoding/csv"
 	"fmt"
 	"io"
-	"math"
-	"os"
+	"io/fs"
+	"strconv"
 	"strings"
 
 	"github.com/ncruces/go-sqlite3"
+	"github.com/ncruces/go-sqlite3/internal/util"
+	"github.com/ncruces/go-sqlite3/util/osutil"
+	"github.com/ncruces/go-sqlite3/util/sql3util"
 )
 
 // Register registers the CSV virtual table.
-// If a filename is specified, `os.Open` is used to read it from disk.
-func Register(db *sqlite3.Conn) {
-	RegisterOpen(db, func(name string) (io.ReaderAt, error) {
-		return os.Open(name)
-	})
+// If a filename is specified, [os.Open] is used to open the file.
+func Register(db *sqlite3.Conn) error {
+	return RegisterFS(db, osutil.FS{})
 }
 
-// RegisterOpen registers the CSV virtual table.
-// If a filename is specified, open is used to open the file.
-func RegisterOpen(db *sqlite3.Conn, open func(name string) (io.ReaderAt, error)) {
-	declare := func(db *sqlite3.Conn, arg ...string) (_ *table, err error) {
+// RegisterFS registers the CSV virtual table.
+// If a filename is specified, fsys is used to open the file.
+func RegisterFS(db *sqlite3.Conn, fsys fs.FS) error {
+	declare := func(db *sqlite3.Conn, _, _, _ string, arg ...string) (_ *table, err error) {
 		var (
 			filename string
 			data     string
@@ -36,98 +38,95 @@ func RegisterOpen(db *sqlite3.Conn, open func(name string) (io.ReaderAt, error))
 			header   bool
 			columns  int  = -1
 			comma    rune = ','
+			comment  rune
 
-			done = map[string]struct{}{}
+			done = util.Set[string]{}
 		)
 
-		for _, arg := range arg[3:] {
-			key, val := getParam(arg)
-			if _, ok := done[key]; ok {
+		for _, arg := range arg {
+			key, val := sql3util.NamedArg(arg)
+			if done.Contains(key) {
 				return nil, fmt.Errorf("csv: more than one %q parameter", key)
 			}
 			switch key {
 			case "filename":
-				filename = unquoteParam(val)
+				filename = sql3util.Unquote(val)
 			case "data":
-				data = unquoteParam(val)
+				data = sql3util.Unquote(val)
 			case "schema":
-				schema = unquoteParam(val)
+				schema = sql3util.Unquote(val)
 			case "header":
-				header, err = boolParam(key, val)
+				header, err = boolArg(key, val)
 			case "columns":
-				columns, err = uintParam(key, val)
+				columns, err = uintArg(key, val)
 			case "comma":
-				comma, err = runeParam(key, val)
+				comma, err = runeArg(key, val)
+			case "comment":
+				comment, err = runeArg(key, val)
 			default:
 				return nil, fmt.Errorf("csv: unknown %q parameter", key)
 			}
 			if err != nil {
 				return nil, err
 			}
-			done[key] = struct{}{}
+			done.Add(key)
 		}
 
 		if (filename == "") == (data == "") {
-			return nil, fmt.Errorf(`csv: must specify either "filename" or "data" but not both`)
+			return nil, util.ErrorString(`csv: must specify either "filename" or "data" but not both`)
 		}
 
-		var r io.ReaderAt
-		if filename != "" {
-			r, err = open(filename)
-		} else {
-			r = strings.NewReader(data)
-		}
-		if err != nil {
-			return nil, err
+		t := &table{
+			fsys:    fsys,
+			name:    filename,
+			data:    data,
+			comma:   comma,
+			comment: comment,
+			header:  header,
 		}
 
-		table := &table{
-			r:      r,
-			comma:  comma,
-			header: header,
-		}
-		defer func() {
-			if err != nil {
-				table.Close()
+		if schema == "" {
+			var row []string
+			if header || columns < 0 {
+				csv, c, err := t.newReader()
+				defer c.Close()
+				if err != nil {
+					return nil, err
+				}
+				row, err = csv.Read()
+				if err != nil {
+					return nil, err
+				}
 			}
-		}()
-
-		if schema == "" && (header || columns < 0) {
-			csv := table.newReader()
-			row, err := csv.Read()
+			schema = getSchema(header, columns, row)
+		} else {
+			t.typs, err = getColumnAffinities(schema)
 			if err != nil {
 				return nil, err
 			}
-			schema = getSchema(header, columns, row)
 		}
 
-		err = db.DeclareVtab(schema)
+		err = db.DeclareVTab(schema)
+		if err == nil {
+			err = db.VTabConfig(sqlite3.VTAB_DIRECTONLY)
+		}
 		if err != nil {
 			return nil, err
 		}
-		err = db.VtabConfig(sqlite3.VTAB_DIRECTONLY)
-		if err != nil {
-			return nil, err
-		}
-		return table, nil
+		return t, nil
 	}
 
-	sqlite3.CreateModule(db, "csv", declare, declare)
+	return sqlite3.CreateModule(db, "csv", declare, declare)
 }
 
 type table struct {
-	r      io.ReaderAt
-	comma  rune
-	header bool
-}
-
-func (t *table) Close() error {
-	if c, ok := t.r.(io.Closer); ok {
-		err := c.Close()
-		t.r = nil
-		return err
-	}
-	return nil
+	fsys    fs.FS
+	name    string
+	data    string
+	typs    []affinity
+	comma   rune
+	comment rune
+	header  bool
 }
 
 func (t *table) BestIndex(idx *sqlite3.IndexInfo) error {
@@ -143,31 +142,82 @@ func (t *table) Rename(new string) error {
 	return nil
 }
 
-func (t *table) Integrity(schema, table string, flags int) (err error) {
-	if flags&1 == 0 {
-		_, err = t.newReader().ReadAll()
+func (t *table) Integrity(schema, table string, flags int) error {
+	if flags&1 != 0 {
+		return nil
+	}
+	csv, c, err := t.newReader()
+	if err != nil {
+		return err
+	}
+	defer c.Close()
+	_, err = csv.ReadAll()
+	return err
+}
+
+func (t *table) newReader() (*csv.Reader, io.Closer, error) {
+	var r io.Reader
+	var c io.Closer
+	if t.name != "" {
+		f, err := t.fsys.Open(t.name)
+		if err != nil {
+			return nil, f, err
+		}
+
+		buf := bufio.NewReader(f)
+		bom, err := buf.Peek(3)
+		if err != nil {
+			return nil, f, err
+		}
+		if string(bom) == "\xEF\xBB\xBF" {
+			buf.Discard(3)
+		}
+
+		r = buf
+		c = f
+	} else {
+		r = strings.NewReader(t.data)
+		c = io.NopCloser(r)
+	}
+
+	csv := csv.NewReader(r)
+	csv.ReuseRecord = true
+	csv.Comma = t.comma
+	csv.Comment = t.comment
+	return csv, c, nil
+}
+
+type cursor struct {
+	table  *table
+	closer io.Closer
+	csv    *csv.Reader
+	row    []string
+	rowID  int64
+}
+
+func (c *cursor) Close() (err error) {
+	if c.closer != nil {
+		err = c.closer.Close()
+		c.closer = nil
 	}
 	return err
 }
 
-func (t *table) newReader() *csv.Reader {
-	csv := csv.NewReader(io.NewSectionReader(t.r, 0, math.MaxInt64))
-	csv.ReuseRecord = true
-	csv.Comma = t.comma
-	return csv
-}
-
-type cursor struct {
-	table *table
-	rowID int64
-	row   []string
-	csv   *csv.Reader
-}
-
 func (c *cursor) Filter(idxNum int, idxStr string, arg ...sqlite3.Value) error {
-	c.csv = c.table.newReader()
+	err := c.Close()
+	if err != nil {
+		return err
+	}
+
+	c.csv, c.closer, err = c.table.newReader()
+	if err != nil {
+		return err
+	}
 	if c.table.header {
-		c.Next() // skip header
+		err = c.Next() // skip header
+		if err != nil {
+			return err
+		}
 	}
 	c.rowID = 0
 	return c.Next()
@@ -190,9 +240,38 @@ func (c *cursor) RowID() (int64, error) {
 	return c.rowID, nil
 }
 
-func (c *cursor) Column(ctx *sqlite3.Context, col int) error {
+func (c *cursor) Column(ctx sqlite3.Context, col int) error {
 	if col < len(c.row) {
-		ctx.ResultText(c.row[col])
+		typ := text
+		if col < len(c.table.typs) {
+			typ = c.table.typs[col]
+		}
+
+		txt := c.row[col]
+		if txt == "" && typ != text {
+			return nil
+		}
+
+		switch typ {
+		case numeric, integer:
+			if strings.TrimLeft(txt, "+-0123456789") == "" {
+				if i, err := strconv.ParseInt(txt, 10, 64); err == nil {
+					ctx.ResultInt64(i)
+					return nil
+				}
+			}
+			fallthrough
+		case real:
+			if strings.TrimLeft(txt, "+-.0123456789Ee") == "" {
+				if f, err := strconv.ParseFloat(txt, 64); err == nil {
+					ctx.ResultFloat(f)
+					return nil
+				}
+			}
+			fallthrough
+		default:
+		}
+		ctx.ResultText(txt)
 	}
 	return nil
 }

ext/csv/csv_test.go

@@ -3,11 +3,13 @@ package csv_test
 import (
 	"fmt"
 	"log"
+	"os"
 	"testing"
 
 	"github.com/ncruces/go-sqlite3"
 	_ "github.com/ncruces/go-sqlite3/embed"
 	"github.com/ncruces/go-sqlite3/ext/csv"
+	_ "github.com/ncruces/go-sqlite3/internal/testcfg"
 )
 
 func Example() {
@@ -17,10 +19,13 @@ func Example() {
 	}
 	defer db.Close()
 
-	csv.Register(db)
+	err = csv.Register(db)
+	if err != nil {
+		log.Fatal(err)
+	}
 
 	err = db.Exec(`
-		CREATE VIRTUAL TABLE IF NOT EXISTS eurofxref USING csv(
+		CREATE VIRTUAL TABLE eurofxref USING csv(
 			filename = 'testdata/eurofxref.csv',
 			header   = YES,
 			columns  = 42,
@@ -50,24 +55,31 @@ func Example() {
 	// On Twosday, 1€ = $1.1342
 }
 
+func TestMain(m *testing.M) {
+	sqlite3.AutoExtension(csv.Register)
+	os.Exit(m.Run())
+}
+
 func TestRegister(t *testing.T) {
+	t.Parallel()
+
 	db, err := sqlite3.Open(":memory:")
 	if err != nil {
 		t.Fatal(err)
 	}
 	defer db.Close()
 
-	csv.Register(db)
-
 	const data = `
+# Comment
 "Rob"	"Pike"	rob
 "Ken"	Thompson	ken
 Robert	"Griesemer"	"gri"`
 	err = db.Exec(`
 		CREATE VIRTUAL TABLE temp.users USING csv(
-			data   = ` + sqlite3.Quote(data) + `,
-			schema = 'CREATE TABLE x(first_name, last_name, username)',
-			comma  = '\t'
+			data    = ` + sqlite3.Quote(data) + `,
+			schema  = 'CREATE TABLE x(first_name, last_name, username)',
+			comma   = '\t',
+			comment = '#'
 		)`)
 	if err != nil {
 		t.Fatal(err)
@@ -82,8 +94,8 @@ Robert	"Griesemer"	"gri"`
 	if !stmt.Step() {
 		t.Fatal("no rows")
 	}
-	if got := stmt.ColumnText(1); got != "Pike" {
-		t.Errorf("got %q want Pike", got)
+	if got := stmt.ColumnText(0); got != "Rob" {
+		t.Errorf("got %q want Rob", got)
 	}
 	if stmt.Step() {
 		t.Fatal("more rows")
@@ -96,23 +108,70 @@ Robert	"Griesemer"	"gri"`
 
 	err = db.Exec(`PRAGMA integrity_check`)
 	if err != nil {
-		t.Fatal(err)
+		t.Error(err)
+	}
+
+	err = db.Exec(`PRAGMA quick_check`)
+	if err != nil {
+		t.Error(err)
 	}
 
 	err = db.Exec(`DROP TABLE temp.csv`)
 	if err != nil {
-		log.Fatal(err)
+		t.Error(err)
 	}
 }
 
-func TestRegister_errors(t *testing.T) {
+func TestAffinity(t *testing.T) {
+	t.Parallel()
+
 	db, err := sqlite3.Open(":memory:")
 	if err != nil {
 		t.Fatal(err)
 	}
 	defer db.Close()
 
-	csv.Register(db)
+	const data = "01\n0.10\ne"
+	err = db.Exec(`
+		CREATE VIRTUAL TABLE temp.nums USING csv(
+			data   = ` + sqlite3.Quote(data) + `,
+			schema = 'CREATE TABLE x(a numeric)'
+		)`)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	stmt, _, err := db.Prepare(`SELECT * FROM temp.nums`)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer stmt.Close()
+
+	if stmt.Step() {
+		if got := stmt.ColumnText(0); got != "1" {
+			t.Errorf("got %q want 1", got)
+		}
+	}
+	if stmt.Step() {
+		if got := stmt.ColumnText(0); got != "0.1" {
+			t.Errorf("got %q want 0.1", got)
+		}
+	}
+	if stmt.Step() {
+		if got := stmt.ColumnText(0); got != "e" {
+			t.Errorf("got %q want e", got)
+		}
+	}
+}
+
+func TestRegister_errors(t *testing.T) {
+	t.Parallel()
+
+	db, err := sqlite3.Open(":memory:")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
 
 	err = db.Exec(`CREATE VIRTUAL TABLE temp.users USING csv()`)
 	if err == nil {

ext/csv/params.go

@@ -1,65 +0,0 @@
-package csv
-
-import (
-	"fmt"
-	"strconv"
-	"strings"
-)
-
-func getParam(arg string) (key, val string) {
-	key, val, _ = strings.Cut(arg, "=")
-	key = strings.TrimSpace(key)
-	val = strings.TrimSpace(val)
-	return
-}
-
-func uintParam(key, val string) (int, error) {
-	i, err := strconv.ParseUint(val, 10, 15)
-	if err != nil {
-		return 0, fmt.Errorf("csv: invalid %q parameter: %s", key, val)
-	}
-	return int(i), nil
-}
-
-func boolParam(key, val string) (bool, error) {
-	if val == "" || val == "1" ||
-		strings.EqualFold(val, "true") ||
-		strings.EqualFold(val, "yes") ||
-		strings.EqualFold(val, "on") {
-		return true, nil
-	}
-	if val == "0" ||
-		strings.EqualFold(val, "false") ||
-		strings.EqualFold(val, "no") ||
-		strings.EqualFold(val, "off") {
-		return false, nil
-	}
-	return false, fmt.Errorf("csv: invalid %q parameter: %s", key, val)
-}
-
-func runeParam(key, val string) (rune, error) {
-	r, _, tail, err := strconv.UnquoteChar(unquoteParam(val), 0)
-	if tail != "" || err != nil {
-		return 0, fmt.Errorf("csv: invalid %q parameter: %s", key, val)
-	}
-	return r, nil
-}
-
-func unquoteParam(val string) string {
-	if len(val) < 2 {
-		return val
-	}
-	if val[0] != val[len(val)-1] {
-		return val
-	}
-	var old, new string
-	switch val[0] {
-	default:
-		return val
-	case '"':
-		old, new = `""`, `"`
-	case '\'':
-		old, new = `''`, `'`
-	}
-	return strings.ReplaceAll(val[1:len(val)-1], old, new)
-}

ext/csv/schema.go

@@ -8,9 +8,9 @@ import (
 )
 
 func getSchema(header bool, columns int, row []string) string {
-	var sep = ""
+	var sep string
 	var str strings.Builder
-	str.WriteString(`CREATE TABLE x(`)
+	str.WriteString("CREATE TABLE x(")
 
 	if 0 <= columns && columns < len(row) {
 		row = row[:columns]
@@ -20,15 +20,17 @@ func getSchema(header bool, columns int, row []string) string {
 		if header && f != "" {
 			str.WriteString(sqlite3.QuoteIdentifier(f))
 		} else {
-			str.WriteByte('c')
+			str.WriteString("c")
 			str.WriteString(strconv.Itoa(i + 1))
 		}
+		str.WriteString(" TEXT")
 		sep = ","
 	}
 	for i := len(row); i < columns; i++ {
 		str.WriteString(sep)
-		str.WriteByte('c')
+		str.WriteString("c")
 		str.WriteString(strconv.Itoa(i + 1))
+		str.WriteString(" TEXT")
 		sep = ","
 	}
 	str.WriteByte(')')

ext/csv/schema_test.go

@@ -3,16 +3,20 @@ package csv
 import "testing"
 
 func Test_getSchema(t *testing.T) {
+	t.Parallel()
+
 	tests := []struct {
 		header  bool
 		columns int
 		row     []string
 		want    string
 	}{
-		{true, 2, nil, `CREATE TABLE x(c1,c2)`},
-		{false, 2, nil, `CREATE TABLE x(c1,c2)`},
-		{true, 3, []string{"abc", ""}, `CREATE TABLE x("abc",c2,c3)`},
-		{true, 1, []string{"abc", "def"}, `CREATE TABLE x("abc")`},
+		{true, 2, nil, `CREATE TABLE x(c1 TEXT,c2 TEXT)`},
+		{false, 2, nil, `CREATE TABLE x(c1 TEXT,c2 TEXT)`},
+		{false, -1, []string{"abc", ""}, `CREATE TABLE x(c1 TEXT,c2 TEXT)`},
+		{true, 3, []string{"abc", ""}, `CREATE TABLE x("abc" TEXT,c2 TEXT,c3 TEXT)`},
+		{true, -1, []string{"abc", "def"}, `CREATE TABLE x("abc" TEXT,"def" TEXT)`},
+		{true, 1, []string{"abc", "def"}, `CREATE TABLE x("abc" TEXT)`},
 	}
 	for _, tt := range tests {
 		t.Run(tt.want, func(t *testing.T) {

ext/csv/testdata/eurofxref.csv

@@ -1,4 +1,4 @@
-Date,USD,JPY,BGN,CYP,CZK,DKK,EEK,GBP,HUF,LTL,LVL,MTL,PLN,ROL,RON,SEK,SIT,SKK,CHF,ISK,NOK,HRK,RUB,TRL,TRY,AUD,BRL,CAD,CNY,HKD,IDR,ILS,INR,KRW,MXN,MYR,NZD,PHP,SGD,THB,ZAR,
+Date,USD,JPY,BGN,CYP,CZK,DKK,EEK,GBP,HUF,LTL,LVL,MTL,PLN,ROL,RON,SEK,SIT,SKK,CHF,ISK,NOK,HRK,RUB,TRL,TRY,AUD,BRL,CAD,CNY,HKD,IDR,ILS,INR,KRW,MXN,MYR,NZD,PHP,SGD,THB,ZAR,
 2022-12-30,1.0666,140.66,1.9558,N/A,24.116,7.4365,N/A,0.88693,400.87,N/A,N/A,N/A,4.6808,N/A,4.9495,11.1218,N/A,N/A,0.9847,151.5,10.5138,7.5365,N/A,N/A,19.9649,1.5693,5.6386,1.444,7.3582,8.3163,16519.82,3.7554,88.171,1344.09,20.856,4.6984,1.6798,59.32,1.43,36.835,18.0986,
 2022-12-29,1.0649,142.24,1.9558,N/A,24.191,7.4365,N/A,0.88549,399.6,N/A,N/A,N/A,4.6855,N/A,4.9493,11.158,N/A,N/A,0.984,152.5,10.55,7.5365,N/A,N/A,19.934,1.5859,5.5351,1.4475,7.4151,8.2994,16680.38,3.7575,88.2295,1350.18,20.651,4.7106,1.6887,59.367,1.436,36.877,18.1967,
 2022-12-28,1.064,142.21,1.9558,N/A,24.252,7.4365,N/A,0.88058,403.3,N/A,N/A,N/A,4.7008,N/A,4.946,11.1038,N/A,N/A,0.9863,151.9,10.4495,7.5365,N/A,N/A,19.9144,1.566,5.6109,1.4361,7.4224,8.2931,16765.93,3.7526,88.0943,1348.59,20.6856,4.7055,1.6772,59.613,1.4323,36.953,18.289,

ext/csv/types.go

@@ -0,0 +1,52 @@
+package csv
+
+import (
+	"strings"
+
+	"github.com/ncruces/go-sqlite3/util/sql3util"
+)
+
+type affinity byte
+
+const (
+	blob    affinity = 0
+	text    affinity = 1
+	numeric affinity = 2
+	integer affinity = 3
+	real    affinity = 4
+)
+
+func getColumnAffinities(schema string) ([]affinity, error) {
+	tab, err := sql3util.ParseTable(schema)
+	if err != nil {
+		return nil, err
+	}
+
+	columns := tab.Columns
+	types := make([]affinity, len(columns))
+	for i, col := range columns {
+		types[i] = getAffinity(col.Type)
+	}
+	return types, nil
+}
+
+func getAffinity(declType string) affinity {
+	// https://sqlite.org/datatype3.html#determination_of_column_affinity
+	if declType == "" {
+		return blob
+	}
+	name := strings.ToUpper(declType)
+	if strings.Contains(name, "INT") {
+		return integer
+	}
+	if strings.Contains(name, "CHAR") || strings.Contains(name, "CLOB") || strings.Contains(name, "TEXT") {
+		return text
+	}
+	if strings.Contains(name, "BLOB") {
+		return blob
+	}
+	if strings.Contains(name, "REAL") || strings.Contains(name, "FLOA") || strings.Contains(name, "DOUB") {
+		return real
+	}
+	return numeric
+}

ext/csv/types_test.go

@@ -0,0 +1,32 @@
+package csv
+
+import "testing"
+
+func Test_getAffinity(t *testing.T) {
+	tests := []struct {
+		decl string
+		want affinity
+	}{
+		{"", blob},
+		{"INTEGER", integer},
+		{"TINYINT", integer},
+		{"TEXT", text},
+		{"CHAR", text},
+		{"CLOB", text},
+		{"BLOB", blob},
+		{"REAL", real},
+		{"FLOAT", real},
+		{"DOUBLE", real},
+		{"NUMERIC", numeric},
+		{"DECIMAL", numeric},
+		{"BOOLEAN", numeric},
+		{"DATETIME", numeric},
+	}
+	for _, tt := range tests {
+		t.Run(tt.decl, func(t *testing.T) {
+			if got := getAffinity(tt.decl); got != tt.want {
+				t.Errorf("getAffinity() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}

ext/fileio/fileio.go

@@ -0,0 +1,63 @@
+// Package fileio provides SQL functions to read, write and list files.
+//
+// https://sqlite.org/src/doc/tip/ext/misc/fileio.c
+package fileio
+
+import (
+	"errors"
+	"fmt"
+	"io/fs"
+	"os"
+
+	"github.com/ncruces/go-sqlite3"
+)
+
+// Register registers SQL functions readfile, writefile, lsmode,
+// and the table-valued function fsdir.
+func Register(db *sqlite3.Conn) error {
+	return RegisterFS(db, nil)
+}
+
+// Register registers SQL functions readfile, lsmode,
+// and the table-valued function fsdir;
+// fsys will be used to read files and list directories.
+func RegisterFS(db *sqlite3.Conn, fsys fs.FS) error {
+	var err error
+	if fsys == nil {
+		err = db.CreateFunction("writefile", -1, sqlite3.DIRECTONLY, writefile)
+	}
+	return errors.Join(err,
+		db.CreateFunction("readfile", 1, sqlite3.DIRECTONLY, readfile(fsys)),
+		db.CreateFunction("lsmode", 1, sqlite3.DETERMINISTIC, lsmode),
+		sqlite3.CreateModule(db, "fsdir", nil, func(db *sqlite3.Conn, _, _, _ string, _ ...string) (fsdir, error) {
+			err := db.DeclareVTab(`CREATE TABLE x(name,mode,mtime TIMESTAMP,data,path HIDDEN,dir HIDDEN)`)
+			if err == nil {
+				err = db.VTabConfig(sqlite3.VTAB_DIRECTONLY)
+			}
+			return fsdir{fsys}, err
+		}))
+}
+
+func lsmode(ctx sqlite3.Context, arg ...sqlite3.Value) {
+	ctx.ResultText(fs.FileMode(arg[0].Int()).String())
+}
+
+func readfile(fsys fs.FS) sqlite3.ScalarFunction {
+	return func(ctx sqlite3.Context, arg ...sqlite3.Value) {
+		var err error
+		var data []byte
+
+		if fsys != nil {
+			data, err = fs.ReadFile(fsys, arg[0].Text())
+		} else {
+			data, err = os.ReadFile(arg[0].Text())
+		}
+
+		switch {
+		case err == nil:
+			ctx.ResultBlob(data)
+		case !errors.Is(err, fs.ErrNotExist):
+			ctx.ResultError(fmt.Errorf("readfile: %w", err)) // notest
+		}
+	}
+}

ext/fileio/fileio_test.go

@@ -0,0 +1,82 @@
+package fileio_test
+
+import (
+	"bytes"
+	"database/sql"
+	"io/fs"
+	"os"
+	"testing"
+
+	"github.com/ncruces/go-sqlite3"
+	"github.com/ncruces/go-sqlite3/driver"
+	_ "github.com/ncruces/go-sqlite3/embed"
+	"github.com/ncruces/go-sqlite3/ext/fileio"
+	_ "github.com/ncruces/go-sqlite3/internal/testcfg"
+	"github.com/ncruces/go-sqlite3/vfs/memdb"
+)
+
+func Test_lsmode(t *testing.T) {
+	t.Parallel()
+	tmp := memdb.TestDB(t)
+
+	db, err := driver.Open(tmp, fileio.Register)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+
+	d, err := os.Getwd()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	s, err := os.Stat(d)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	var mode string
+	err = db.QueryRow(`SELECT lsmode(?)`, s.Mode()).Scan(&mode)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if len(mode) != 10 || mode[0] != 'd' {
+		t.Errorf("got %s", mode)
+	} else {
+		t.Logf("got %s", mode)
+	}
+}
+
+func Test_readfile(t *testing.T) {
+	t.Parallel()
+
+	for _, fsys := range []fs.FS{nil, os.DirFS(".")} {
+		t.Run("", func(t *testing.T) {
+			tmp := memdb.TestDB(t)
+
+			db, err := driver.Open(tmp, func(c *sqlite3.Conn) error {
+				fileio.RegisterFS(c, fsys)
+				return nil
+			})
+			if err != nil {
+				t.Fatal(err)
+			}
+			defer db.Close()
+
+			rows, err := db.Query(`SELECT readfile('fileio_test.go')`)
+			if err != nil {
+				t.Fatal(err)
+			}
+
+			if rows.Next() {
+				var data sql.RawBytes
+				rows.Scan(&data)
+
+				if !bytes.HasPrefix(data, []byte("package fileio_test")) {
+					t.Errorf("got %s", data[:min(64, len(data))])
+				}
+			}
+		})
+	}
+}

ext/fileio/fsdir.go

@@ -0,0 +1,183 @@
+package fileio
+
+import (
+	"io/fs"
+	"iter"
+	"os"
+	"path"
+	"path/filepath"
+	"strings"
+
+	"github.com/ncruces/go-sqlite3"
+)
+
+const (
+	_COL_NAME = 0
+	_COL_MODE = 1
+	_COL_TIME = 2
+	_COL_DATA = 3
+	_COL_ROOT = 4
+	_COL_BASE = 5
+)
+
+type fsdir struct{ fsys fs.FS }
+
+func (d fsdir) BestIndex(idx *sqlite3.IndexInfo) error {
+	var root, base bool
+	for i, cst := range idx.Constraint {
+		switch cst.Column {
+		case _COL_ROOT:
+			if !cst.Usable || cst.Op != sqlite3.INDEX_CONSTRAINT_EQ {
+				return sqlite3.CONSTRAINT
+			}
+			idx.ConstraintUsage[i] = sqlite3.IndexConstraintUsage{
+				Omit:      true,
+				ArgvIndex: 1,
+			}
+			root = true
+		case _COL_BASE:
+			if !cst.Usable || cst.Op != sqlite3.INDEX_CONSTRAINT_EQ {
+				return sqlite3.CONSTRAINT
+			}
+			idx.ConstraintUsage[i] = sqlite3.IndexConstraintUsage{
+				Omit:      true,
+				ArgvIndex: 2,
+			}
+			base = true
+		}
+	}
+	if !root {
+		return sqlite3.CONSTRAINT
+	}
+	if base {
+		idx.EstimatedCost = 10
+	} else {
+		idx.EstimatedCost = 100
+	}
+	return nil
+}
+
+func (d fsdir) Open() (sqlite3.VTabCursor, error) {
+	return &cursor{fsdir: d}, nil
+}
+
+type cursor struct {
+	fsdir
+	base  string
+	next  func() (entry, bool)
+	stop  func()
+	curr  entry
+	eof   bool
+	rowID int64
+}
+
+type entry struct {
+	fs.DirEntry
+	err  error
+	path string
+}
+
+func (c *cursor) Close() error {
+	if c.stop != nil {
+		c.stop()
+	}
+	return nil
+}
+
+func (c *cursor) Filter(idxNum int, idxStr string, arg ...sqlite3.Value) error {
+	if err := c.Close(); err != nil {
+		return err
+	}
+
+	root := arg[0].Text()
+	if len(arg) > 1 {
+		base := arg[1].Text()
+		if c.fsys != nil {
+			root = path.Join(base, root)
+			base = path.Clean(base) + "/"
+		} else {
+			root = filepath.Join(base, root)
+			base = filepath.Clean(base) + string(filepath.Separator)
+		}
+		c.base = base
+	}
+
+	c.next, c.stop = iter.Pull(func(yield func(entry) bool) {
+		walkDir := func(path string, d fs.DirEntry, err error) error {
+			if yield(entry{d, err, path}) {
+				return nil
+			}
+			return fs.SkipAll
+		}
+		if c.fsys != nil {
+			fs.WalkDir(c.fsys, root, walkDir)
+		} else {
+			filepath.WalkDir(root, walkDir)
+		}
+	})
+	c.eof = false
+	c.rowID = 0
+	return c.Next()
+}
+
+func (c *cursor) Next() error {
+	curr, ok := c.next()
+	c.curr = curr
+	c.eof = !ok
+	c.rowID++
+	return c.curr.err
+}
+
+func (c *cursor) EOF() bool {
+	return c.eof
+}
+
+func (c *cursor) RowID() (int64, error) {
+	return c.rowID, nil
+}
+
+func (c *cursor) Column(ctx sqlite3.Context, n int) error {
+	switch n {
+	case _COL_NAME:
+		name := strings.TrimPrefix(c.curr.path, c.base)
+		ctx.ResultText(name)
+
+	case _COL_MODE:
+		i, err := c.curr.Info()
+		if err != nil {
+			return err
+		}
+		ctx.ResultInt64(int64(i.Mode()))
+
+	case _COL_TIME:
+		i, err := c.curr.Info()
+		if err != nil {
+			return err
+		}
+		ctx.ResultTime(i.ModTime(), sqlite3.TimeFormatUnixFrac)
+
+	case _COL_DATA:
+		switch typ := c.curr.Type(); {
+		case typ.IsRegular():
+			var data []byte
+			var err error
+			if c.fsys != nil {
+				data, err = fs.ReadFile(c.fsys, c.curr.path)
+			} else {
+				data, err = os.ReadFile(c.curr.path)
+			}
+			if err != nil {
+				return err
+			}
+			ctx.ResultBlob(data)
+
+		case typ&fs.ModeSymlink != 0 && c.fsys == nil:
+			t, err := os.Readlink(c.curr.path)
+			if err != nil {
+				return err
+			}
+			ctx.ResultText(t)
+		}
+	}
+	return nil
+}

ext/fileio/fsdir_test.go

@@ -0,0 +1,85 @@
+package fileio_test
+
+import (
+	"bytes"
+	"database/sql"
+	"io/fs"
+	"os"
+	"testing"
+	"time"
+
+	"github.com/ncruces/go-sqlite3"
+	"github.com/ncruces/go-sqlite3/driver"
+	_ "github.com/ncruces/go-sqlite3/embed"
+	"github.com/ncruces/go-sqlite3/ext/fileio"
+	_ "github.com/ncruces/go-sqlite3/internal/testcfg"
+	"github.com/ncruces/go-sqlite3/vfs/memdb"
+)
+
+func Test_fsdir(t *testing.T) {
+	t.Parallel()
+
+	for _, fsys := range []fs.FS{nil, os.DirFS(".")} {
+		t.Run("", func(t *testing.T) {
+			tmp := memdb.TestDB(t)
+
+			db, err := driver.Open(tmp, func(c *sqlite3.Conn) error {
+				fileio.RegisterFS(c, fsys)
+				return nil
+			})
+			if err != nil {
+				t.Fatal(err)
+			}
+			defer db.Close()
+
+			rows, err := db.Query(`SELECT * FROM fsdir('.', '.')`)
+			if err != nil {
+				t.Fatal(err)
+			}
+
+			for rows.Next() {
+				var name string
+				var mode fs.FileMode
+				var mtime time.Time
+				var data sql.RawBytes
+				err := rows.Scan(&name, &mode, sqlite3.TimeFormatUnixFrac.Scanner(&mtime), &data)
+				if err != nil {
+					t.Fatal(err)
+				}
+				if mode.Perm() == 0 {
+					t.Errorf("got: %v", mode)
+				}
+				if mtime.Before(time.Unix(0, 0)) {
+					t.Errorf("got: %v", mtime)
+				}
+				if name == "fsdir_test.go" {
+					if !bytes.HasPrefix(data, []byte("package fileio_test")) {
+						t.Errorf("got: %s", data[:min(64, len(data))])
+					}
+				}
+			}
+		})
+	}
+}
+
+func Test_fsdir_errors(t *testing.T) {
+	t.Parallel()
+
+	db, err := sqlite3.Open(":memory:")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+
+	err = fileio.Register(db)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = db.Exec(`SELECT name FROM fsdir()`)
+	if err == nil {
+		t.Fatal("want error")
+	} else {
+		t.Log(err)
+	}
+}

ext/fileio/write.go

@@ -0,0 +1,97 @@
+package fileio
+
+import (
+	"errors"
+	"fmt"
+	"io/fs"
+	"os"
+	"path/filepath"
+	"time"
+
+	"github.com/ncruces/go-sqlite3"
+	"github.com/ncruces/go-sqlite3/internal/util"
+	"github.com/ncruces/go-sqlite3/util/fsutil"
+)
+
+func writefile(ctx sqlite3.Context, arg ...sqlite3.Value) {
+	if len(arg) < 2 || len(arg) > 4 {
+		ctx.ResultError(util.ErrorString("writefile: wrong number of arguments"))
+		return
+	}
+
+	file := arg[0].Text()
+
+	var mode fs.FileMode
+	if len(arg) > 2 {
+		mode = fsutil.FileModeFromValue(arg[2])
+	}
+
+	n, err := createFileAndDir(file, mode, arg[1])
+	if err != nil {
+		if len(arg) > 2 {
+			ctx.ResultError(fmt.Errorf("writefile: %w", err)) // notest
+		}
+		return
+	}
+
+	if mode&fs.ModeSymlink == 0 {
+		if len(arg) > 2 {
+			err := os.Chmod(file, mode.Perm())
+			if err != nil {
+				ctx.ResultError(fmt.Errorf("writefile: %w", err))
+				return // notest
+			}
+		}
+
+		if len(arg) > 3 {
+			mtime := arg[3].Time(sqlite3.TimeFormatUnixFrac)
+			err := os.Chtimes(file, time.Time{}, mtime)
+			if err != nil {
+				ctx.ResultError(fmt.Errorf("writefile: %w", err))
+				return // notest
+			}
+		}
+	}
+
+	if mode.IsRegular() {
+		ctx.ResultInt(n)
+	}
+}
+
+func createFileAndDir(path string, mode fs.FileMode, data sqlite3.Value) (int, error) {
+	n, err := createFile(path, mode, data)
+	if errors.Is(err, fs.ErrNotExist) {
+		if err := os.MkdirAll(filepath.Dir(path), 0777); err == nil {
+			return createFile(path, mode, data)
+		}
+	}
+	return n, err
+}
+
+func createFile(path string, mode fs.FileMode, data sqlite3.Value) (int, error) {
+	if mode.IsRegular() {
+		blob := data.RawBlob()
+		return len(blob), os.WriteFile(path, blob, fixPerm(mode, 0666))
+	}
+	if mode.IsDir() {
+		err := os.Mkdir(path, fixPerm(mode, 0777))
+		if errors.Is(err, fs.ErrExist) {
+			s, err := os.Lstat(path)
+			if err == nil && s.IsDir() {
+				return 0, nil
+			}
+		}
+		return 0, err
+	}
+	if mode&fs.ModeSymlink != 0 {
+		return 0, os.Symlink(data.Text(), path)
+	}
+	return 0, fmt.Errorf("invalid mode: %v", mode)
+}
+
+func fixPerm(mode fs.FileMode, def fs.FileMode) fs.FileMode {
+	if mode.Perm() == 0 {
+		return def
+	}
+	return mode.Perm()
+}

ext/fileio/write_test.go

@@ -0,0 +1,91 @@
+package fileio
+
+import (
+	"database/sql"
+	"io/fs"
+	"path/filepath"
+	"testing"
+	"time"
+
+	"github.com/ncruces/go-sqlite3/driver"
+	_ "github.com/ncruces/go-sqlite3/embed"
+	_ "github.com/ncruces/go-sqlite3/internal/testcfg"
+	"github.com/ncruces/go-sqlite3/vfs/memdb"
+)
+
+func Test_writefile(t *testing.T) {
+	t.Parallel()
+	tmp := memdb.TestDB(t)
+
+	db, err := driver.Open(tmp, Register)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+
+	dir := t.TempDir()
+	link := filepath.Join(dir, "link")
+	file := filepath.Join(dir, "test.txt")
+	nest := filepath.Join(dir, "tmp", "test.txt")
+	sock := filepath.Join(dir, "sock")
+	twosday := time.Date(2022, 2, 22, 22, 22, 22, 0, time.UTC)
+
+	_, err = db.Exec(`SELECT writefile(?, 'Hello world!')`, file)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	_, err = db.Exec(`SELECT writefile(?, ?, ?)`, link, "test.txt", fs.ModeSymlink)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	_, err = db.Exec(`SELECT writefile(?, ?, ?, ?)`, dir, nil, 0040700, twosday.Unix())
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	rows, err := db.Query(`SELECT * FROM fsdir('.', ?)`, dir)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	for rows.Next() {
+		var name string
+		var mode fs.FileMode
+		var mtime time.Time
+		var data sql.NullString
+		err := rows.Scan(&name, &mode, &mtime, &data)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if mode.IsDir() && !mtime.Equal(twosday) {
+			t.Errorf("got: %v", mtime)
+		}
+		if mode.IsRegular() && data.String != "Hello world!" {
+			t.Errorf("got: %v", data)
+		}
+		if mode&fs.ModeSymlink != 0 && data.String != "test.txt" {
+			t.Errorf("got: %v", data)
+		}
+	}
+
+	_, err = db.Exec(`SELECT writefile(?, 'Hello world!')`, nest)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	_, err = db.Exec(`SELECT writefile(?, ?, ?)`, sock, nil, fs.ModeSocket)
+	if err == nil {
+		t.Fatal("want error")
+	} else {
+		t.Log(err)
+	}
+
+	_, err = db.Exec(`SELECT writefile()`)
+	if err == nil {
+		t.Fatal("want error")
+	} else {
+		t.Log(err)
+	}
+}

ext/hash/blake2.go

@@ -0,0 +1,30 @@
+package hash
+
+import (
+	"crypto"
+
+	"github.com/ncruces/go-sqlite3"
+	"github.com/ncruces/go-sqlite3/internal/util"
+)
+
+func blake2sFunc(ctx sqlite3.Context, arg ...sqlite3.Value) {
+	hashFunc(ctx, arg[0], crypto.BLAKE2s_256)
+}
+
+func blake2bFunc(ctx sqlite3.Context, arg ...sqlite3.Value) {
+	size := 512
+	if len(arg) > 1 {
+		size = arg[1].Int()
+	}
+
+	switch size {
+	case 256:
+		hashFunc(ctx, arg[0], crypto.BLAKE2b_256)
+	case 384:
+		hashFunc(ctx, arg[0], crypto.BLAKE2b_384)
+	case 512:
+		hashFunc(ctx, arg[0], crypto.BLAKE2b_512)
+	default:
+		ctx.ResultError(util.ErrorString("blake2b: size must be 256, 384, 512"))
+	}
+}

ext/hash/hash.go

@@ -0,0 +1,110 @@
+// Package hash provides cryptographic hash functions.
+//
+// Provided functions:
+//   - md4(data)
+//   - md5(data)
+//   - sha1(data)
+//   - sha3(data, size) (default size 256)
+//   - sha224(data)
+//   - sha256(data, size) (default size 256)
+//   - sha384(data)
+//   - sha512(data, size) (default size 512)
+//   - blake2s(data)
+//   - blake2b(data, size) (default size 512)
+//   - ripemd160(data)
+//
+// Each SQL function will only be registered if the corresponding
+// [crypto.Hash] function is available.
+// To ensure a specific hash function is available,
+// import the implementing package.
+package hash
+
+import (
+	"crypto"
+	"errors"
+
+	"github.com/ncruces/go-sqlite3"
+	"github.com/ncruces/go-sqlite3/internal/util"
+)
+
+// Register registers cryptographic hash functions for a database connection.
+func Register(db *sqlite3.Conn) error {
+	const flags = sqlite3.DETERMINISTIC | sqlite3.INNOCUOUS
+
+	var errs util.ErrorJoiner
+	if crypto.MD4.Available() {
+		errs.Join(
+			db.CreateFunction("md4", 1, flags, md4Func))
+	}
+	if crypto.MD5.Available() {
+		errs.Join(
+			db.CreateFunction("md5", 1, flags, md5Func))
+	}
+	if crypto.SHA1.Available() {
+		errs.Join(
+			db.CreateFunction("sha1", 1, flags, sha1Func))
+	}
+	if crypto.SHA3_512.Available() {
+		errs.Join(
+			db.CreateFunction("sha3", 1, flags, sha3Func),
+			db.CreateFunction("sha3", 2, flags, sha3Func))
+	}
+	if crypto.SHA256.Available() {
+		errs.Join(
+			db.CreateFunction("sha224", 1, flags, sha224Func),
+			db.CreateFunction("sha256", 1, flags, sha256Func),
+			db.CreateFunction("sha256", 2, flags, sha256Func))
+	}
+	if crypto.SHA512.Available() {
+		errs.Join(
+			db.CreateFunction("sha384", 1, flags, sha384Func),
+			db.CreateFunction("sha512", 1, flags, sha512Func),
+			db.CreateFunction("sha512", 2, flags, sha512Func))
+	}
+	if crypto.BLAKE2s_256.Available() {
+		errs.Join(
+			db.CreateFunction("blake2s", 1, flags, blake2sFunc))
+	}
+	if crypto.BLAKE2b_512.Available() {
+		errs.Join(
+			db.CreateFunction("blake2b", 1, flags, blake2bFunc),
+			db.CreateFunction("blake2b", 2, flags, blake2bFunc))
+	}
+	if crypto.RIPEMD160.Available() {
+		errs.Join(
+			db.CreateFunction("ripemd160", 1, flags, ripemd160Func))
+	}
+	return errors.Join(errs...)
+}
+
+func md4Func(ctx sqlite3.Context, arg ...sqlite3.Value) {
+	hashFunc(ctx, arg[0], crypto.MD4)
+}
+
+func md5Func(ctx sqlite3.Context, arg ...sqlite3.Value) {
+	hashFunc(ctx, arg[0], crypto.MD5)
+}
+
+func sha1Func(ctx sqlite3.Context, arg ...sqlite3.Value) {
+	hashFunc(ctx, arg[0], crypto.SHA1)
+}
+
+func ripemd160Func(ctx sqlite3.Context, arg ...sqlite3.Value) {
+	hashFunc(ctx, arg[0], crypto.RIPEMD160)
+}
+
+func hashFunc(ctx sqlite3.Context, arg sqlite3.Value, fn crypto.Hash) {
+	var data []byte
+	switch arg.Type() {
+	case sqlite3.NULL:
+		return
+	case sqlite3.BLOB:
+		data = arg.RawBlob()
+	default:
+		data = arg.RawText()
+	}
+
+	h := fn.New()
+	h.Write(data)
+	ctx.ResultBlob(h.Sum(nil))
+}

ext/hash/hash_test.go

@@ -0,0 +1,98 @@
+package hash
+
+import (
+	_ "crypto/md5"
+	_ "crypto/sha1"
+	_ "crypto/sha256"
+	_ "crypto/sha512"
+	"testing"
+
+	_ "golang.org/x/crypto/blake2b"
+	_ "golang.org/x/crypto/blake2s"
+	_ "golang.org/x/crypto/md4"
+	_ "golang.org/x/crypto/ripemd160"
+	_ "golang.org/x/crypto/sha3"
+
+	"github.com/ncruces/go-sqlite3/driver"
+	_ "github.com/ncruces/go-sqlite3/embed"
+	_ "github.com/ncruces/go-sqlite3/internal/testcfg"
+	"github.com/ncruces/go-sqlite3/vfs/memdb"
+)
+
+func TestRegister(t *testing.T) {
+	t.Parallel()
+	tmp := memdb.TestDB(t)
+
+	tests := []struct {
+		name string
+		hash string
+	}{
+		{"md4(NULL)", ""},
+		{"md4(X'')", "31D6CFE0D16AE931B73C59D7E0C089C0"},
+		{"md4('The quick brown fox jumps over the lazy dog')", "1BEE69A46BA811185C194762ABAEAE90"},
+
+		{"md5('')", "D41D8CD98F00B204E9800998ECF8427E"},
+		{"sha1('')", "DA39A3EE5E6B4B0D3255BFEF95601890AFD80709"},
+		{"ripemd160('')", "9C1185A5C5E9FC54612808977EE8F548B2258D31"},
+
+		{"sha224('')", "D14A028C2A3A2BC9476102BB288234C415A2B01F828EA62AC5B3E42F"},
+		{"sha256('')", "E3B0C44298FC1C149AFBF4C8996FB92427AE41E4649B934CA495991B7852B855"},
+		{"sha256('', 224)", "D14A028C2A3A2BC9476102BB288234C415A2B01F828EA62AC5B3E42F"},
+		{"sha384('')", "38B060A751AC96384CD9327EB1B1E36A21FDB71114BE07434C0CC7BF63F6E1DA274EDEBFE76F65FBD51AD2F14898B95B"},
+		{"sha512('')", "CF83E1357EEFB8BDF1542850D66D8007D620E4050B5715DC83F4A921D36CE9CE47D0D13C5D85F2B0FF8318D2877EEC2F63B931BD47417A81A538327AF927DA3E"},
+		{"sha512('', 224)", "6ED0DD02806FA89E25DE060C19D3AC86CABB87D6A0DDD05C333B84F4"},
+		{"sha512('', 256)", "C672B8D1EF56ED28AB87C3622C5114069BDD3AD7B8F9737498D0C01ECEF0967A"},
+		{"sha512('', 384)", "38B060A751AC96384CD9327EB1B1E36A21FDB71114BE07434C0CC7BF63F6E1DA274EDEBFE76F65FBD51AD2F14898B95B"},
+
+		{"sha3('')", "A7FFC6F8BF1ED76651C14756A061D662F580FF4DE43B49FA82D80A4B80F8434A"},
+		{"sha3('', 224)", "6B4E03423667DBB73B6E15454F0EB1ABD4597F9A1B078E3F5B5A6BC7"},
+		{"sha3('', 384)", "0C63A75B845E4F7D01107D852E4C2485C51A50AAAA94FC61995E71BBEE983A2AC3713831264ADB47FB6BD1E058D5F004"},
+		{"sha3('', 512)", "A69F73CCA23A9AC5C8B567DC185A756E97C982164FE25859E0D1DCC1475C80A615B2123AF1F5F94C11E3E9402C3AC558F500199D95B6D3E301758586281DCD26"},
+
+		{"blake2s('')", "69217A3079908094E11121D042354A7C1F55B6482CA1A51E1B250DFD1ED0EEF9"},
+		{"blake2b('')", "786A02F742015903C6C6FD852552D272912F4740E15847618A86E217F71F5419D25E1031AFEE585313896444934EB04B903A685B1448B755D56F701AFE9BE2CE"},
+		{"blake2b('', 384)", "B32811423377F52D7862286EE1A72EE540524380FDA1724A6F25D7978C6FD3244A6CAF0498812673C5E05EF583825100"},
+		{"blake2b('', 256)", "0E5751C026E543B2E8AB2EB06099DAA1D1E5DF47778F7787FAAB45CDF12FE3A8"},
+	}
+
+	db, err := driver.Open(tmp, Register)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			var hash string
+
+			err = db.QueryRow(`SELECT hex(` + tt.name + `)`).Scan(&hash)
+			if err != nil {
+				t.Fatal(err)
+			}
+
+			if hash != tt.hash {
+				t.Errorf("got %s, want %s", hash, tt.hash)
+			}
+		})
+	}
+
+	_, err = db.Exec(`SELECT sha256('', 255)`)
+	if err == nil {
+		t.Error("want error")
+	}
+
+	_, err = db.Exec(`SELECT sha512('', 255)`)
+	if err == nil {
+		t.Error("want error")
+	}
+
+	_, err = db.Exec(`SELECT sha3('', 255)`)
+	if err == nil {
+		t.Error("want error")
+	}
+
+	_, err = db.Exec(`SELECT blake2b('', 255)`)
+	if err == nil {
+		t.Error("want error")
+	}
+}

ext/hash/sha2.go

@@ -0,0 +1,53 @@
+package hash
+
+import (
+	"crypto"
+
+	"github.com/ncruces/go-sqlite3"
+	"github.com/ncruces/go-sqlite3/internal/util"
+)
+
+func sha224Func(ctx sqlite3.Context, arg ...sqlite3.Value) {
+	hashFunc(ctx, arg[0], crypto.SHA224)
+}
+
+func sha384Func(ctx sqlite3.Context, arg ...sqlite3.Value) {
+	hashFunc(ctx, arg[0], crypto.SHA384)
+}
+
+func sha256Func(ctx sqlite3.Context, arg ...sqlite3.Value) {
+	size := 256
+	if len(arg) > 1 {
+		size = arg[1].Int()
+	}
+
+	switch size {
+	case 224:
+		hashFunc(ctx, arg[0], crypto.SHA224)
+	case 256:
+		hashFunc(ctx, arg[0], crypto.SHA256)
+	default:
+		ctx.ResultError(util.ErrorString("sha256: size must be 224, 256"))
+	}
+}
+
+func sha512Func(ctx sqlite3.Context, arg ...sqlite3.Value) {
+	size := 512
+	if len(arg) > 1 {
+		size = arg[1].Int()
+	}
+
+	switch size {
+	case 224:
+		hashFunc(ctx, arg[0], crypto.SHA512_224)
+	case 256:
+		hashFunc(ctx, arg[0], crypto.SHA512_256)
+	case 384:
+		hashFunc(ctx, arg[0], crypto.SHA384)
+	case 512:
+		hashFunc(ctx, arg[0], crypto.SHA512)
+	default:
+		ctx.ResultError(util.ErrorString("sha512: size must be 224, 256, 384, 512"))
+	}
+
+}

ext/hash/sha3.go

@@ -0,0 +1,28 @@
+package hash
+
+import (
+	"crypto"
+
+	"github.com/ncruces/go-sqlite3"
+	"github.com/ncruces/go-sqlite3/internal/util"
+)
+
+func sha3Func(ctx sqlite3.Context, arg ...sqlite3.Value) {
+	size := 256
+	if len(arg) > 1 {
+		size = arg[1].Int()
+	}
+
+	switch size {
+	case 224:
+		hashFunc(ctx, arg[0], crypto.SHA3_224)
+	case 256:
+		hashFunc(ctx, arg[0], crypto.SHA3_256)
+	case 384:
+		hashFunc(ctx, arg[0], crypto.SHA3_384)
+	case 512:
+		hashFunc(ctx, arg[0], crypto.SHA3_512)
+	default:
+		ctx.ResultError(util.ErrorString("sha3: size must be 224, 256, 384, 512"))
+	}
+}

ext/ipaddr/ipaddr.go

@@ -0,0 +1,113 @@
+// Package ipaddr provides functions to manipulate IPs and CIDRs.
+//
+// It provides the following functions:
+//   - ipcontains(prefix, ip)
+//   - ipoverlaps(prefix1, prefix2)
+//   - ipfamily(ip/prefix)
+//   - iphost(ip/prefix)
+//   - ipmasklen(prefix)
+//   - ipnetwork(prefix)
+package ipaddr
+
+import (
+	"errors"
+	"net/netip"
+
+	"github.com/ncruces/go-sqlite3"
+)
+
+// Register IP/CIDR functions for a database connection.
+func Register(db *sqlite3.Conn) error {
+	const flags = sqlite3.DETERMINISTIC | sqlite3.INNOCUOUS
+	return errors.Join(
+		db.CreateFunction("ipcontains", 2, flags, contains),
+		db.CreateFunction("ipoverlaps", 2, flags, overlaps),
+		db.CreateFunction("ipfamily", 1, flags, family),
+		db.CreateFunction("iphost", 1, flags, host),
+		db.CreateFunction("ipmasklen", 1, flags, masklen),
+		db.CreateFunction("ipnetwork", 1, flags, network))
+}
+
+func contains(ctx sqlite3.Context, arg ...sqlite3.Value) {
+	prefix, err := netip.ParsePrefix(arg[0].Text())
+	if err != nil {
+		ctx.ResultError(err)
+		return // notest
+	}
+	addr, err := netip.ParseAddr(arg[1].Text())
+	if err != nil {
+		ctx.ResultError(err)
+		return // notest
+	}
+	ctx.ResultBool(prefix.Contains(addr))
+}
+
+func overlaps(ctx sqlite3.Context, arg ...sqlite3.Value) {
+	prefix1, err := netip.ParsePrefix(arg[0].Text())
+	if err != nil {
+		ctx.ResultError(err)
+		return // notest
+	}
+	prefix2, err := netip.ParsePrefix(arg[0].Text())
+	if err != nil {
+		ctx.ResultError(err)
+		return // notest
+	}
+	ctx.ResultBool(prefix1.Overlaps(prefix2))
+}
+
+func family(ctx sqlite3.Context, arg ...sqlite3.Value) {
+	addr, err := addr(arg[0].Text())
+	if err != nil {
+		ctx.ResultError(err)
+		return // notest
+	}
+	switch {
+	case addr.Is4():
+		ctx.ResultInt(4)
+	case addr.Is6():
+		ctx.ResultInt(6)
+	}
+}
+
+func host(ctx sqlite3.Context, arg ...sqlite3.Value) {
+	addr, err := addr(arg[0].Text())
+	if err != nil {
+		ctx.ResultError(err)
+		return // notest
+	}
+	buf, _ := addr.MarshalText()
+	ctx.ResultRawText(buf)
+}
+
+func masklen(ctx sqlite3.Context, arg ...sqlite3.Value) {
+	prefix, err := netip.ParsePrefix(arg[0].Text())
+	if err != nil {
+		ctx.ResultError(err)
+		return // notest
+	}
+	ctx.ResultInt(prefix.Bits())
+}
+
+func network(ctx sqlite3.Context, arg ...sqlite3.Value) {
+	prefix, err := netip.ParsePrefix(arg[0].Text())
+	if err != nil {
+		ctx.ResultError(err)
+		return // notest
+	}
+	buf, _ := prefix.Masked().MarshalText()
+	ctx.ResultRawText(buf)
+}
+
+func addr(text string) (netip.Addr, error) {
+	addr, err := netip.ParseAddr(text)
+	if err != nil {
+		if prefix, err := netip.ParsePrefix(text); err == nil {
+			return prefix.Addr(), nil
+		}
+		if addrpt, err := netip.ParseAddrPort(text); err == nil {
+			return addrpt.Addr(), nil
+		}
+	}
+	return addr, err
+}

ext/ipaddr/ipaddr_test.go

@@ -0,0 +1,88 @@
+package ipaddr_test
+
+import (
+	"testing"
+
+	"github.com/ncruces/go-sqlite3/driver"
+	_ "github.com/ncruces/go-sqlite3/embed"
+	"github.com/ncruces/go-sqlite3/ext/ipaddr"
+	_ "github.com/ncruces/go-sqlite3/internal/testcfg"
+	"github.com/ncruces/go-sqlite3/vfs/memdb"
+)
+
+func TestRegister(t *testing.T) {
+	t.Parallel()
+	tmp := memdb.TestDB(t)
+
+	db, err := driver.Open(tmp, ipaddr.Register)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+
+	var got string
+
+	err = db.QueryRow(`SELECT ipfamily('::1')`).Scan(&got)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got != "6" {
+		t.Fatalf("got %s", got)
+	}
+
+	err = db.QueryRow(`SELECT ipfamily('[::1]:80')`).Scan(&got)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got != "6" {
+		t.Fatalf("got %s", got)
+	}
+
+	err = db.QueryRow(`SELECT ipfamily('192.168.1.5/24')`).Scan(&got)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got != "4" {
+		t.Fatalf("got %s", got)
+	}
+
+	err = db.QueryRow(`SELECT iphost('192.168.1.5/24')`).Scan(&got)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got != "192.168.1.5" {
+		t.Fatalf("got %s", got)
+	}
+
+	err = db.QueryRow(`SELECT ipmasklen('192.168.1.5/24')`).Scan(&got)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got != "24" {
+		t.Fatalf("got %s", got)
+	}
+
+	err = db.QueryRow(`SELECT ipnetwork('192.168.1.5/24')`).Scan(&got)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got != "192.168.1.0/24" {
+		t.Fatalf("got %s", got)
+	}
+
+	err = db.QueryRow(`SELECT ipcontains('192.168.1.0/24', '192.168.1.5')`).Scan(&got)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got != "1" {
+		t.Fatalf("got %s", got)
+	}
+
+	err = db.QueryRow(`SELECT ipoverlaps('192.168.1.0/24', '192.168.1.5/32')`).Scan(&got)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got != "1" {
+		t.Fatalf("got %s", got)
+	}
+}

ext/lines/lines.go

@@ -1,65 +1,126 @@
-// Package lines provides a virtual table to read large files line-by-line.
+// Package lines provides a virtual table to read data line-by-line.
+//
+// It is particularly useful for line-oriented datasets,
+// like [ndjson] or [JSON Lines],
+// when paired with SQLite's JSON support.
+//
+// https://github.com/asg017/sqlite-lines
+//
+// [ndjson]: https://ndjson.org/
+// [JSON Lines]: https://jsonlines.org/
 package lines
 
 import (
 	"bufio"
 	"bytes"
+	"errors"
 	"fmt"
 	"io"
-	"math"
-	"os"
+	"io/fs"
 
 	"github.com/ncruces/go-sqlite3"
+	"github.com/ncruces/go-sqlite3/util/osutil"
 )
 
-// Register registers the lines and lines_read virtual tables.
-// The lines virtual table reads from a database blob or text.
-// The lines_read virtual table reads from a file or an [io.ReaderAt].
-func Register(db *sqlite3.Conn) {
-	sqlite3.CreateModule[lines](db, "lines", nil,
-		func(db *sqlite3.Conn, arg ...string) (lines, error) {
-			err := db.DeclareVtab(`CREATE TABLE x(line TEXT, data HIDDEN)`)
-			db.VtabConfig(sqlite3.VTAB_INNOCUOUS)
-			return false, err
-		})
-	sqlite3.CreateModule[lines](db, "lines_read", nil,
-		func(db *sqlite3.Conn, arg ...string) (lines, error) {
-			err := db.DeclareVtab(`CREATE TABLE x(line TEXT, data HIDDEN)`)
-			db.VtabConfig(sqlite3.VTAB_DIRECTONLY)
-			return true, err
-		})
+// Register registers the lines and lines_read table-valued functions.
+// The lines function reads from a database blob or text.
+// The lines_read function reads from a file or an [io.Reader].
+// If a filename is specified, [os.Open] is used to open the file.
+func Register(db *sqlite3.Conn) error {
+	return RegisterFS(db, osutil.FS{})
 }
 
-type lines bool
+// RegisterFS registers the lines and lines_read table-valued functions.
+// The lines function reads from a database blob or text.
+// The lines_read function reads from a file or an [io.Reader].
+// If a filename is specified, fsys is used to open the file.
+func RegisterFS(db *sqlite3.Conn, fsys fs.FS) error {
+	return errors.Join(
+		sqlite3.CreateModule(db, "lines", nil,
+			func(db *sqlite3.Conn, _, _, _ string, _ ...string) (lines, error) {
+				err := db.DeclareVTab(`CREATE TABLE x(line TEXT, data HIDDEN, delim HIDDEN)`)
+				if err == nil {
+					err = db.VTabConfig(sqlite3.VTAB_INNOCUOUS)
+				}
+				return lines{}, err
+			}),
+		sqlite3.CreateModule(db, "lines_read", nil,
+			func(db *sqlite3.Conn, _, _, _ string, _ ...string) (lines, error) {
+				err := db.DeclareVTab(`CREATE TABLE x(line TEXT, data HIDDEN, delim HIDDEN)`)
+				if err == nil {
+					err = db.VTabConfig(sqlite3.VTAB_DIRECTONLY)
+				}
+				return lines{fsys}, err
+			}))
+}
 
-func (l lines) BestIndex(idx *sqlite3.IndexInfo) error {
+type lines struct {
+	fsys fs.FS
+}
+
+func (l lines) BestIndex(idx *sqlite3.IndexInfo) (err error) {
+	err = sqlite3.CONSTRAINT
 	for i, cst := range idx.Constraint {
-		if cst.Column == 1 && cst.Op == sqlite3.INDEX_CONSTRAINT_EQ && cst.Usable {
+		if !cst.Usable || cst.Op != sqlite3.INDEX_CONSTRAINT_EQ {
+			continue
+		}
+		switch cst.Column {
+		case 1:
 			idx.ConstraintUsage[i] = sqlite3.IndexConstraintUsage{
 				Omit:      true,
 				ArgvIndex: 1,
 			}
 			idx.EstimatedCost = 1e6
 			idx.EstimatedRows = 100
-			return nil
+			err = nil
+		case 2:
+			idx.ConstraintUsage[i] = sqlite3.IndexConstraintUsage{
+				Omit:      true,
+				ArgvIndex: 2,
+			}
 		}
 	}
-	return sqlite3.CONSTRAINT
+	return err
 }
 
 func (l lines) Open() (sqlite3.VTabCursor, error) {
-	return &cursor{reader: bool(l)}, nil
+	if l.fsys != nil {
+		return &reader{fsys: l.fsys}, nil
+	} else {
+		return &buffer{}, nil
+	}
 }
 
 type cursor struct {
-	reader  bool
-	scanner *bufio.Scanner
-	closer  io.Closer
-	rowID   int64
-	eof     bool
+	line  []byte
+	rowID int64
+	eof   bool
+	delim byte
 }
 
-func (c *cursor) Close() (err error) {
+func (c *cursor) EOF() bool {
+	return c.eof
+}
+
+func (c *cursor) RowID() (int64, error) {
+	return c.rowID, nil
+}
+
+func (c *cursor) Column(ctx sqlite3.Context, n int) error {
+	if n == 0 {
+		ctx.ResultRawText(c.line)
+	}
+	return nil
+}
+
+type reader struct {
+	fsys   fs.FS
+	reader *bufio.Reader
+	closer io.Closer
+	cursor
+}
+
+func (c *reader) Close() (err error) {
 	if c.closer != nil {
 		err = c.closer.Close()
 		c.closer = nil
@@ -67,55 +128,106 @@ func (c *cursor) Close() (err error) {
 	return err
 }
 
-func (c *cursor) EOF() bool {
-	return c.eof
-}
-
-func (c *cursor) Next() error {
-	c.rowID++
-	c.eof = !c.scanner.Scan()
-	return c.scanner.Err()
-}
-
-func (c *cursor) RowID() (int64, error) {
-	return c.rowID, nil
-}
-
-func (c *cursor) Column(ctx *sqlite3.Context, n int) error {
-	if n == 0 {
-		ctx.ResultRawText(c.scanner.Bytes())
-	}
-	return nil
-}
-
-func (c *cursor) Filter(idxNum int, idxStr string, arg ...sqlite3.Value) error {
+func (c *reader) Filter(idxNum int, idxStr string, arg ...sqlite3.Value) error {
 	if err := c.Close(); err != nil {
 		return err
 	}
 
 	var r io.Reader
-	data := arg[0]
-	if c.reader {
-		if data.Type() == sqlite3.NULL {
-			if p, ok := data.Pointer().(io.ReaderAt); ok {
-				r = io.NewSectionReader(p, 0, math.MaxInt64)
-			}
-		} else {
-			f, err := os.Open(data.Text())
-			if err != nil {
-				return err
-			}
-			c.closer = f
-			r = f
+	typ := arg[0].Type()
+	switch typ {
+	case sqlite3.NULL:
+		if p, ok := arg[0].Pointer().(io.Reader); ok {
+			r = p
 		}
-	} else if data.Type() != sqlite3.NULL {
-		r = bytes.NewReader(data.RawBlob())
+	case sqlite3.TEXT:
+		f, err := c.fsys.Open(arg[0].Text())
+		if err != nil {
+			return err
+		}
+		r = f
+	}
+	if r == nil {
+		return fmt.Errorf("lines: unsupported argument:%.0w %v", sqlite3.MISMATCH, typ)
 	}
 
-	if r == nil {
-		return fmt.Errorf("lines: unsupported argument:%.0w %v", sqlite3.MISMATCH, data.Type())
+	c.delim = '\n'
+	if len(arg) > 1 {
+		b := arg[1].RawText()
+		if len(b) != 1 {
+			return fmt.Errorf("lines: delimiter must be a single byte%.0w", sqlite3.MISMATCH)
+		}
+		c.delim = b[0]
 	}
-	c.scanner = bufio.NewScanner(r)
+
+	c.reader = bufio.NewReader(r)
+	c.closer, _ = r.(io.Closer)
 	c.rowID = 0
 	return c.Next()
 }
+
+func (c *reader) Next() (err error) {
+	c.line = c.line[:0]
+	for more := true; more; {
+		var line []byte
+		if c.delim == '\n' {
+			line, more, err = c.reader.ReadLine()
+		} else {
+			line, err = c.reader.ReadSlice(c.delim)
+			more = err == bufio.ErrBufferFull
+		}
+		c.line = append(c.line, line...)
+	}
+	if err == io.EOF {
+		c.eof = true
+		err = nil
+	}
+	c.rowID++
+	return err
+}
+
+type buffer struct {
+	data []byte
+	cursor
+}
+
+func (c *buffer) Filter(idxNum int, idxStr string, arg ...sqlite3.Value) error {
+	typ := arg[0].Type()
+	switch typ {
+	case sqlite3.TEXT:
+		c.data = arg[0].RawText()
+	case sqlite3.BLOB:
+		c.data = arg[0].RawBlob()
+	default:
+		return fmt.Errorf("lines: unsupported argument:%.0w %v", sqlite3.MISMATCH, typ)
+	}
+
+	c.delim = '\n'
+	if len(arg) > 1 {
+		b := arg[1].RawText()
+		if len(b) != 1 {
+			return fmt.Errorf("lines: delimiter must be a single byte%.0w", sqlite3.MISMATCH)
+		}
+		c.delim = b[0]
+	}
+
+	c.rowID = 0
+	return c.Next()
+}
+
+func (c *buffer) Next() error {
+	i := bytes.IndexByte(c.data, c.delim)
+	j := i + 1
+	switch {
+	case i < 0:
+		i = len(c.data)
+		j = i
+	case i > 0 && c.delim == '\n' && c.data[i-1] == '\r':
+		i--
+	}
+	c.eof = len(c.data) == 0
+	c.line = c.data[:i]
+	c.data = c.data[j:]
+	c.rowID++
+	return nil
+}

ext/lines/lines_test.go

@@ -5,6 +5,7 @@ import (
 	"errors"
 	"fmt"
 	"log"
+	"net/http"
 	"os"
 	"strings"
 	"testing"
@@ -13,24 +14,22 @@ import (
 	"github.com/ncruces/go-sqlite3/driver"
 	_ "github.com/ncruces/go-sqlite3/embed"
 	"github.com/ncruces/go-sqlite3/ext/lines"
+	_ "github.com/ncruces/go-sqlite3/internal/testcfg"
+	"github.com/ncruces/go-sqlite3/vfs/memdb"
 )
 
 func Example() {
-	db, err := driver.Open(":memory:", func(c *sqlite3.Conn) error {
-		lines.Register(c)
-		return nil
-	})
+	db, err := driver.Open("file:/test.db?vfs=memdb", lines.Register)
 	if err != nil {
 		log.Fatal(err)
 	}
 	defer db.Close()
 
-	// https://storage.googleapis.com/quickdraw_dataset/full/simplified/calendar.ndjson
-	f, err := os.Open("calendar.ndjson")
+	res, err := http.Get("https://storage.googleapis.com/quickdraw_dataset/full/simplified/calendar.ndjson")
 	if err != nil {
 		log.Fatal(err)
 	}
-	defer f.Close()
+	defer res.Body.Close()
 
 	rows, err := db.Query(`
 		SELECT
@@ -40,7 +39,7 @@ func Example() {
   		GROUP BY 1
   		ORDER BY 2 DESC
   		LIMIT 5`,
-		sqlite3.Pointer(f))
+		sqlite3.Pointer(res.Body))
 	if err != nil {
 		log.Fatal(err)
 	}
@@ -58,7 +57,7 @@ func Example() {
 	if err := rows.Err(); err != nil {
 		log.Fatal(err)
 	}
-	// Sample output:
+	// Expected output:
 	// US: 141001
 	// GB: 22560
 	// CA: 11759
@@ -67,16 +66,16 @@ func Example() {
 }
 
 func Test_lines(t *testing.T) {
-	db, err := driver.Open(":memory:", func(c *sqlite3.Conn) error {
-		lines.Register(c)
-		return nil
-	})
+	t.Parallel()
+	tmp := memdb.TestDB(t)
+
+	db, err := driver.Open(tmp, lines.Register)
 	if err != nil {
 		log.Fatal(err)
 	}
 	defer db.Close()
 
-	const data = "line 1\nline 2\nline 3"
+	const data = "line 1\nline 2\r\nline 3\n"
 
 	rows, err := db.Query(`SELECT rowid, line FROM lines(?)`, data)
 	if err != nil {
@@ -91,14 +90,17 @@ func Test_lines(t *testing.T) {
 		if err != nil {
 			t.Fatal(err)
 		}
+		if want := fmt.Sprintf("line %d", id); line != want {
+			t.Errorf("got %q, want %q", line, want)
+		}
 	}
 }
 
 func Test_lines_error(t *testing.T) {
-	db, err := driver.Open(":memory:", func(c *sqlite3.Conn) error {
-		lines.Register(c)
-		return nil
-	})
+	t.Parallel()
+	tmp := memdb.TestDB(t)
+
+	db, err := driver.Open(tmp, lines.Register)
 	if err != nil {
 		log.Fatal(err)
 	}
@@ -120,16 +122,16 @@ func Test_lines_error(t *testing.T) {
 }
 
 func Test_lines_read(t *testing.T) {
-	db, err := driver.Open(":memory:", func(c *sqlite3.Conn) error {
-		lines.Register(c)
-		return nil
-	})
+	t.Parallel()
+	tmp := memdb.TestDB(t)
+
+	db, err := driver.Open(tmp, lines.Register)
 	if err != nil {
 		log.Fatal(err)
 	}
 	defer db.Close()
 
-	const data = "line 1\nline 2\nline 3"
+	const data = "line 1\nline 2\r\nline 3\n"
 
 	rows, err := db.Query(`SELECT rowid, line FROM lines_read(?)`,
 		sqlite3.Pointer(strings.NewReader(data)))
@@ -145,20 +147,23 @@ func Test_lines_read(t *testing.T) {
 		if err != nil {
 			t.Fatal(err)
 		}
+		if want := fmt.Sprintf("line %d", id); line != want {
+			t.Errorf("got %q, want %q", line, want)
+		}
 	}
 }
 
 func Test_lines_test(t *testing.T) {
-	db, err := driver.Open(":memory:", func(c *sqlite3.Conn) error {
-		lines.Register(c)
-		return nil
-	})
+	t.Parallel()
+	tmp := memdb.TestDB(t)
+
+	db, err := driver.Open(tmp, lines.Register)
 	if err != nil {
 		log.Fatal(err)
 	}
 	defer db.Close()
 
-	rows, err := db.Query(`SELECT rowid, line FROM lines_read(?)`, "lines_test.go")
+	rows, err := db.Query(`SELECT rowid, line FROM lines_read(?, '}')`, "lines_test.go")
 	if errors.Is(err, os.ErrNotExist) {
 		t.Skip(err)
 	}

ext/pivot/op_test.go

@@ -0,0 +1,34 @@
+package pivot
+
+import (
+	"testing"
+
+	"github.com/ncruces/go-sqlite3"
+)
+
+func Test_operator(t *testing.T) {
+	tests := []struct {
+		op   sqlite3.IndexConstraintOp
+		want string
+	}{
+		{sqlite3.INDEX_CONSTRAINT_EQ, "="},
+		{sqlite3.INDEX_CONSTRAINT_LT, "<"},
+		{sqlite3.INDEX_CONSTRAINT_GT, ">"},
+		{sqlite3.INDEX_CONSTRAINT_LE, "<="},
+		{sqlite3.INDEX_CONSTRAINT_GE, ">="},
+		{sqlite3.INDEX_CONSTRAINT_NE, "<>"},
+		{sqlite3.INDEX_CONSTRAINT_IS, "IS"},
+		{sqlite3.INDEX_CONSTRAINT_ISNOT, "IS NOT"},
+		{sqlite3.INDEX_CONSTRAINT_REGEXP, "REGEXP"},
+		{sqlite3.INDEX_CONSTRAINT_MATCH, "MATCH"},
+		{sqlite3.INDEX_CONSTRAINT_GLOB, "GLOB"},
+		{sqlite3.INDEX_CONSTRAINT_LIKE, "LIKE"},
+	}
+	for _, tt := range tests {
+		t.Run(tt.want, func(t *testing.T) {
+			if got := operator(tt.op); got != tt.want {
+				t.Errorf("operator() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}

ext/pivot/pivot.go

@@ -0,0 +1,276 @@
+// Package pivot implements a pivot virtual table.
+//
+// https://github.com/jakethaw/pivot_vtab
+package pivot
+
+import (
+	"errors"
+	"fmt"
+	"strings"
+
+	"github.com/ncruces/go-sqlite3"
+	"github.com/ncruces/go-sqlite3/internal/util"
+)
+
+// Register registers the pivot virtual table.
+func Register(db *sqlite3.Conn) error {
+	return sqlite3.CreateModule(db, "pivot", declare, declare)
+}
+
+type table struct {
+	db   *sqlite3.Conn
+	scan string
+	cell string
+	keys []string
+	cols []*sqlite3.Value
+}
+
+func declare(db *sqlite3.Conn, _, _, _ string, arg ...string) (ret *table, err error) {
+	if len(arg) != 3 {
+		return nil, fmt.Errorf("pivot: wrong number of arguments")
+	}
+
+	t := &table{db: db}
+	defer func() {
+		if ret == nil {
+			t.Close()
+		}
+	}()
+
+	var sep string
+	var create strings.Builder
+	create.WriteString("CREATE TABLE x(")
+
+	// Row key query.
+	t.scan = "SELECT * FROM\n" + arg[0]
+	stmt, _, err := db.Prepare(t.scan)
+	if err != nil {
+		return nil, err
+	}
+	defer stmt.Close()
+
+	t.keys = make([]string, stmt.ColumnCount())
+	for i := range t.keys {
+		name := sqlite3.QuoteIdentifier(stmt.ColumnName(i))
+		t.keys[i] = name
+		create.WriteString(sep)
+		create.WriteString(name)
+		sep = ","
+	}
+	stmt.Close()
+
+	// Column definition query.
+	stmt, _, err = db.Prepare("SELECT * FROM\n" + arg[1])
+	if err != nil {
+		return nil, err
+	}
+
+	if stmt.ColumnCount() != 2 {
+		return nil, util.ErrorString("pivot: column definition query expects 2 result columns")
+	}
+	for stmt.Step() {
+		name := sqlite3.QuoteIdentifier(stmt.ColumnText(1))
+		t.cols = append(t.cols, stmt.ColumnValue(0).Dup())
+		create.WriteString(",")
+		create.WriteString(name)
+	}
+	stmt.Close()
+
+	// Pivot cell query.
+	t.cell = "SELECT * FROM\n" + arg[2]
+	stmt, _, err = db.Prepare(t.cell)
+	if err != nil {
+		return nil, err
+	}
+
+	if stmt.ColumnCount() != 1 {
+		return nil, util.ErrorString("pivot: cell query expects 1 result columns")
+	}
+	if stmt.BindCount() != len(t.keys)+1 {
+		return nil, fmt.Errorf("pivot: cell query expects %d bound parameters", len(t.keys)+1)
+	}
+
+	create.WriteByte(')')
+	err = db.DeclareVTab(create.String())
+	if err != nil {
+		return nil, err
+	}
+	return t, nil
+}
+
+func (t *table) Close() error {
+	var errs []error
+	for _, c := range t.cols {
+		errs = append(errs, c.Close())
+	}
+	return errors.Join(errs...)
+}
+
+func (t *table) BestIndex(idx *sqlite3.IndexInfo) error {
+	var idxStr strings.Builder
+	idxStr.WriteString(t.scan)
+
+	argvIndex := 1
+	sep := " WHERE "
+	for i, cst := range idx.Constraint {
+		if !cst.Usable || !(0 <= cst.Column && cst.Column < len(t.keys)) {
+			continue
+		}
+		op := operator(cst.Op)
+		if op == "" {
+			continue
+		}
+
+		idxStr.WriteString(sep)
+		idxStr.WriteString(t.keys[cst.Column])
+		idxStr.WriteString(" ")
+		idxStr.WriteString(op)
+		idxStr.WriteString(" ?")
+
+		idx.ConstraintUsage[i] = sqlite3.IndexConstraintUsage{
+			ArgvIndex: argvIndex,
+			Omit:      true,
+		}
+		sep = " AND "
+		argvIndex++
+	}
+
+	sep = " ORDER BY "
+	idx.OrderByConsumed = true
+	for _, ord := range idx.OrderBy {
+		if !(0 <= ord.Column && ord.Column < len(t.keys)) {
+			idx.OrderByConsumed = false
+			continue
+		}
+		idxStr.WriteString(sep)
+		idxStr.WriteString(t.keys[ord.Column])
+		idxStr.WriteString(" COLLATE ")
+		idxStr.WriteString(idx.Collation(ord.Column))
+		if ord.Desc {
+			idxStr.WriteString(" DESC")
+		}
+		sep = ","
+	}
+
+	idx.EstimatedCost = 1e9 / float64(argvIndex)
+	idx.IdxStr = idxStr.String()
+	return nil
+}
+
+func (t *table) Open() (sqlite3.VTabCursor, error) {
+	return &cursor{table: t}, nil
+}
+
+func (t *table) Rename(new string) error {
+	return nil
+}
+
+type cursor struct {
+	table *table
+	scan  *sqlite3.Stmt
+	cell  *sqlite3.Stmt
+	rowID int64
+}
+
+func (c *cursor) Close() error {
+	return errors.Join(c.scan.Close(), c.cell.Close())
+}
+
+func (c *cursor) Filter(idxNum int, idxStr string, arg ...sqlite3.Value) error {
+	err := c.scan.Close()
+	if err != nil {
+		return err
+	}
+
+	c.scan, _, err = c.table.db.Prepare(idxStr)
+	if err != nil {
+		return err
+	}
+	for i, arg := range arg {
+		err := c.scan.BindValue(i+1, arg)
+		if err != nil {
+			return err
+		}
+	}
+
+	if c.cell == nil {
+		c.cell, _, err = c.table.db.Prepare(c.table.cell)
+		if err != nil {
+			return err
+		}
+	}
+
+	c.rowID = 0
+	return c.Next()
+}
+
+func (c *cursor) Next() error {
+	if c.scan.Step() {
+		count := c.scan.ColumnCount()
+		for i := range count {
+			err := c.cell.BindValue(i+1, c.scan.ColumnValue(i))
+			if err != nil {
+				return err
+			}
+		}
+		c.rowID++
+	}
+	return c.scan.Err()
+}
+
+func (c *cursor) EOF() bool {
+	return !c.scan.Busy()
+}
+
+func (c *cursor) RowID() (int64, error) {
+	return c.rowID, nil
+}
+
+func (c *cursor) Column(ctx sqlite3.Context, col int) error {
+	count := c.scan.ColumnCount()
+	if col < count {
+		ctx.ResultValue(c.scan.ColumnValue(col))
+		return nil
+	}
+
+	err := c.cell.BindValue(count+1, *c.table.cols[col-count])
+	if err != nil {
+		return err
+	}
+
+	if c.cell.Step() {
+		ctx.ResultValue(c.cell.ColumnValue(0))
+	}
+	return c.cell.Reset()
+}
+
+func operator(op sqlite3.IndexConstraintOp) string {
+	switch op {
+	case sqlite3.INDEX_CONSTRAINT_EQ:
+		return "="
+	case sqlite3.INDEX_CONSTRAINT_LT:
+		return "<"
+	case sqlite3.INDEX_CONSTRAINT_GT:
+		return ">"
+	case sqlite3.INDEX_CONSTRAINT_LE:
+		return "<="
+	case sqlite3.INDEX_CONSTRAINT_GE:
+		return ">="
+	case sqlite3.INDEX_CONSTRAINT_NE:
+		return "<>"
+	case sqlite3.INDEX_CONSTRAINT_MATCH:
+		return "MATCH"
+	case sqlite3.INDEX_CONSTRAINT_LIKE:
+		return "LIKE"
+	case sqlite3.INDEX_CONSTRAINT_GLOB:
+		return "GLOB"
+	case sqlite3.INDEX_CONSTRAINT_REGEXP:
+		return "REGEXP"
+	case sqlite3.INDEX_CONSTRAINT_IS, sqlite3.INDEX_CONSTRAINT_ISNULL:
+		return "IS"
+	case sqlite3.INDEX_CONSTRAINT_ISNOT, sqlite3.INDEX_CONSTRAINT_ISNOTNULL:
+		return "IS NOT"
+	default:
+		return ""
+	}
+}

ext/pivot/pivot_test.go

@@ -0,0 +1,227 @@
+package pivot_test
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"strings"
+	"testing"
+
+	"github.com/ncruces/go-sqlite3"
+	_ "github.com/ncruces/go-sqlite3/embed"
+	"github.com/ncruces/go-sqlite3/ext/pivot"
+	_ "github.com/ncruces/go-sqlite3/internal/testcfg"
+)
+
+// https://antonz.org/sqlite-pivot-table/
+func Example() {
+	sqlite3.AutoExtension(pivot.Register)
+
+	db, err := sqlite3.Open(":memory:")
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer db.Close()
+
+	err = db.Exec(`
+		CREATE TABLE sales(product TEXT, year INT, income DECIMAL);
+		INSERT INTO  sales(product, year, income) VALUES
+			('alpha', 2020, 100),
+			('alpha', 2021, 120),
+			('alpha', 2022, 130),
+			('alpha', 2023, 140),
+			('beta',  2020, 10),
+			('beta',  2021, 20),
+			('beta',  2022, 40),
+			('beta',  2023, 80),
+			('gamma', 2020, 80),
+			('gamma', 2021, 75),
+			('gamma', 2022, 78),
+			('gamma', 2023, 80);
+	`)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	err = db.Exec(`
+		CREATE VIRTUAL TABLE v_sales USING pivot(
+			-- rows
+			(SELECT DISTINCT product FROM sales),
+			-- columns
+			(SELECT DISTINCT year, year FROM sales),
+			-- cells
+			(SELECT sum(income) FROM sales WHERE product = ? AND year = ?)
+		)`)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	stmt, _, err := db.Prepare(`SELECT * FROM v_sales`)
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer stmt.Close()
+
+	cols := make([]string, stmt.ColumnCount())
+	for i := range cols {
+		cols[i] = stmt.ColumnName(i)
+	}
+	fmt.Println(pretty(cols))
+	for stmt.Step() {
+		for i := range cols {
+			cols[i] = stmt.ColumnText(i)
+		}
+		fmt.Println(pretty(cols))
+	}
+	if err := stmt.Reset(); err != nil {
+		log.Fatal(err)
+	}
+
+	// Output:
+	// product 2020    2021    2022    2023
+	// alpha   100     120     130     140
+	// beta    10      20      40      80
+	// gamma   80      75      78      80
+}
+
+func TestMain(m *testing.M) {
+	sqlite3.AutoExtension(pivot.Register)
+	os.Exit(m.Run())
+}
+
+func TestRegister(t *testing.T) {
+	t.Parallel()
+
+	db, err := sqlite3.Open(":memory:")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+
+	err = db.Exec(`
+		CREATE TABLE r AS
+			SELECT 1 id UNION SELECT 2 UNION SELECT 3;
+
+		CREATE TABLE c(
+			id   INTEGER PRIMARY KEY,
+			name TEXT
+		);
+		INSERT INTO c (name) VALUES
+			('a'),('b'),('c'),('d');
+
+		CREATE TABLE x(
+			r_id INT,
+			c_id INT,
+			val  TEXT
+		);
+		INSERT INTO x (r_id, c_id, val)
+			SELECT r.id, c.id, c.name || r.id
+			FROM c, r;				
+	`)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = db.Exec(`
+		CREATE VIRTUAL TABLE v_x USING pivot(
+			-- rows
+			(SELECT id r_id FROM r),
+			-- columns
+			(SELECT id c_id, name FROM c),
+			-- cells
+			(SELECT val FROM x WHERE r_id = ?1 AND c_id = ?2)
+		)`)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	stmt, _, err := db.Prepare(`SELECT * FROM v_x WHERE rowid <> 0 AND r_id <> 1 ORDER BY rowid, r_id DESC LIMIT 1`)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer stmt.Close()
+
+	if stmt.Step() {
+		if got := stmt.ColumnInt(0); got != 3 {
+			t.Errorf("got %d, want 3", got)
+		}
+	}
+
+	err = db.Exec(`ALTER TABLE v_x RENAME TO v_y`)
+	if err != nil {
+		t.Fatal(err)
+	}
+}
+
+func TestRegister_errors(t *testing.T) {
+	t.Parallel()
+
+	db, err := sqlite3.Open(":memory:")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+
+	err = db.Exec(`CREATE VIRTUAL TABLE pivot USING pivot()`)
+	if err == nil {
+		t.Fatal("want error")
+	} else {
+		t.Log(err)
+	}
+
+	err = db.Exec(`CREATE VIRTUAL TABLE split_date USING pivot(SELECT 1, SELECT 2, SELECT 3)`)
+	if err == nil {
+		t.Fatal("want error")
+	} else {
+		t.Log(err)
+	}
+
+	err = db.Exec(`CREATE VIRTUAL TABLE split_date USING pivot((SELECT 1), SELECT 2, SELECT 3)`)
+	if err == nil {
+		t.Fatal("want error")
+	} else {
+		t.Log(err)
+	}
+
+	err = db.Exec(`CREATE VIRTUAL TABLE split_date USING pivot((SELECT 1), (SELECT 2), SELECT 3)`)
+	if err == nil {
+		t.Fatal("want error")
+	} else {
+		t.Log(err)
+	}
+
+	err = db.Exec(`CREATE VIRTUAL TABLE split_date USING pivot((SELECT 1), (SELECT 1, 2), SELECT 3)`)
+	if err == nil {
+		t.Fatal("want error")
+	} else {
+		t.Log(err)
+	}
+
+	err = db.Exec(`CREATE VIRTUAL TABLE split_date USING pivot((SELECT 1), (SELECT 1, 2), (SELECT 3, 4))`)
+	if err == nil {
+		t.Fatal("want error")
+	} else {
+		t.Log(err)
+	}
+
+	err = db.Exec(`CREATE VIRTUAL TABLE split_date USING pivot((SELECT 1), (SELECT 1, 2), (SELECT 3))`)
+	if err == nil {
+		t.Fatal("want error")
+	} else {
+		t.Log(err)
+	}
+}
+
+func pretty(cols []string) string {
+	var buf strings.Builder
+	for i, s := range cols {
+		if i != 0 {
+			buf.WriteByte(' ')
+		}
+		for buf.Len()%8 != 0 {
+			buf.WriteByte(' ')
+		}
+		buf.WriteString(s)
+	}
+	return buf.String()
+}

ext/regexp/regexp.go

@@ -0,0 +1,291 @@
+// Package regexp provides additional regular expression functions.
+//
+// It provides the following Unicode aware functions:
+//   - regexp_like(text, pattern),
+//   - regexp_count(text, pattern [, start]),
+//   - regexp_instr(text, pattern [, start [, N [, endoption [, subexpr ]]]]),
+//   - regexp_substr(text, pattern [, start [, N [, subexpr ]]]),
+//   - regexp_replace(text, pattern, replacement [, start [, N ]]),
+//   - and a REGEXP operator.
+//
+// The implementation uses Go [regexp/syntax] for regular expressions.
+//
+// https://github.com/nalgeon/sqlean/blob/main/docs/regexp.md
+package regexp
+
+import (
+	"errors"
+	"regexp"
+	"regexp/syntax"
+	"strings"
+	"unicode/utf8"
+
+	"github.com/ncruces/go-sqlite3"
+)
+
+// Register registers Unicode aware functions for a database connection.
+func Register(db *sqlite3.Conn) error {
+	const flags = sqlite3.DETERMINISTIC | sqlite3.INNOCUOUS
+	return errors.Join(
+		db.CreateFunction("regexp", 2, flags, regex),
+		db.CreateFunction("regexp_like", 2, flags, regexLike),
+		db.CreateFunction("regexp_count", 2, flags, regexCount),
+		db.CreateFunction("regexp_count", 3, flags, regexCount),
+		db.CreateFunction("regexp_instr", 2, flags, regexInstr),
+		db.CreateFunction("regexp_instr", 3, flags, regexInstr),
+		db.CreateFunction("regexp_instr", 4, flags, regexInstr),
+		db.CreateFunction("regexp_instr", 5, flags, regexInstr),
+		db.CreateFunction("regexp_instr", 6, flags, regexInstr),
+		db.CreateFunction("regexp_substr", 2, flags, regexSubstr),
+		db.CreateFunction("regexp_substr", 3, flags, regexSubstr),
+		db.CreateFunction("regexp_substr", 4, flags, regexSubstr),
+		db.CreateFunction("regexp_substr", 5, flags, regexSubstr),
+		db.CreateFunction("regexp_replace", 3, flags, regexReplace),
+		db.CreateFunction("regexp_replace", 4, flags, regexReplace),
+		db.CreateFunction("regexp_replace", 5, flags, regexReplace))
+}
+
+// GlobPrefix returns a GLOB for a regular expression
+// appropriate to take advantage of the [LIKE optimization]
+// in a query such as:
+//
+//	SELECT column WHERE column GLOB :glob_prefix AND column REGEXP :regexp
+//
+// [LIKE optimization]: https://sqlite.org/optoverview.html#the_like_optimization
+func GlobPrefix(expr string) string {
+	re, err := syntax.Parse(expr, syntax.Perl)
+	if err != nil {
+		return "" // no match possible
+	}
+	prog, err := syntax.Compile(re.Simplify())
+	if err != nil {
+		return "" // notest
+	}
+
+	i := &prog.Inst[prog.Start]
+
+	var empty syntax.EmptyOp
+loop1:
+	for {
+		switch i.Op {
+		case syntax.InstFail:
+			return "" // notest
+		case syntax.InstCapture, syntax.InstNop:
+			// skip
+		case syntax.InstEmptyWidth:
+			empty |= syntax.EmptyOp(i.Arg)
+		default:
+			break loop1
+		}
+		i = &prog.Inst[i.Out]
+	}
+	if empty&syntax.EmptyBeginText == 0 {
+		return "*" // not anchored
+	}
+
+	var glob strings.Builder
+loop2:
+	for {
+		switch i.Op {
+		case syntax.InstFail:
+			return "" // notest
+		case syntax.InstCapture, syntax.InstEmptyWidth, syntax.InstNop:
+			// skip
+		case syntax.InstRune, syntax.InstRune1:
+			if len(i.Rune) != 1 || syntax.Flags(i.Arg)&syntax.FoldCase != 0 {
+				break loop2
+			}
+			switch r := i.Rune[0]; r {
+			case '*', '?', '[', utf8.RuneError:
+				break loop2
+			default:
+				glob.WriteRune(r)
+			}
+		default:
+			break loop2
+		}
+		i = &prog.Inst[i.Out]
+	}
+
+	glob.WriteByte('*')
+	return glob.String()
+}
+
+func load(ctx sqlite3.Context, arg []sqlite3.Value, i int) (*regexp.Regexp, error) {
+	re, ok := ctx.GetAuxData(i).(*regexp.Regexp)
+	if !ok {
+		re, ok = arg[i].Pointer().(*regexp.Regexp)
+		if !ok {
+			r, err := regexp.Compile(arg[i].Text())
+			if err != nil {
+				return nil, err
+			}
+			re = r
+		}
+		ctx.SetAuxData(i, re)
+	}
+	return re, nil
+}
+
+func regex(ctx sqlite3.Context, arg ...sqlite3.Value) {
+	re, err := load(ctx, arg, 0)
+	if err != nil {
+		ctx.ResultError(err)
+		return // notest
+	}
+	text := arg[1].RawText()
+	ctx.ResultBool(re.Match(text))
+}
+
+func regexLike(ctx sqlite3.Context, arg ...sqlite3.Value) {
+	re, err := load(ctx, arg, 1)
+	if err != nil {
+		ctx.ResultError(err)
+		return // notest
+	}
+	text := arg[0].RawText()
+	ctx.ResultBool(re.Match(text))
+}
+
+func regexCount(ctx sqlite3.Context, arg ...sqlite3.Value) {
+	re, err := load(ctx, arg, 1)
+	if err != nil {
+		ctx.ResultError(err)
+		return // notest
+	}
+
+	text := arg[0].RawText()
+	if len(arg) > 2 {
+		pos := arg[2].Int()
+		text = text[skip(text, pos):]
+	}
+	ctx.ResultInt(len(re.FindAll(text, -1)))
+}
+
+func regexSubstr(ctx sqlite3.Context, arg ...sqlite3.Value) {
+	re, err := load(ctx, arg, 1)
+	if err != nil {
+		ctx.ResultError(err)
+		return // notest
+	}
+
+	text := arg[0].RawText()
+	var pos, n, subexpr int
+	if len(arg) > 2 {
+		pos = arg[2].Int()
+	}
+	if len(arg) > 3 {
+		n = arg[3].Int()
+	}
+	if len(arg) > 4 {
+		subexpr = arg[4].Int()
+	}
+
+	loc := regexFind(re, text, pos, n, subexpr)
+	if loc != nil {
+		ctx.ResultRawText(text[loc[0]:loc[1]])
+	}
+}
+
+func regexInstr(ctx sqlite3.Context, arg ...sqlite3.Value) {
+	re, err := load(ctx, arg, 1)
+	if err != nil {
+		ctx.ResultError(err)
+		return // notest
+	}
+
+	text := arg[0].RawText()
+	var pos, n, end, subexpr int
+	if len(arg) > 2 {
+		pos = arg[2].Int()
+	}
+	if len(arg) > 3 {
+		n = arg[3].Int()
+	}
+	if len(arg) > 4 && arg[4].Bool() {
+		end = 1
+	}
+	if len(arg) > 5 {
+		subexpr = arg[5].Int()
+	}
+
+	loc := regexFind(re, text, pos, n, subexpr)
+	if loc != nil {
+		ctx.ResultInt(loc[end] + 1)
+	}
+}
+
+func regexReplace(ctx sqlite3.Context, arg ...sqlite3.Value) {
+	re, err := load(ctx, arg, 1)
+	if err != nil {
+		ctx.ResultError(err)
+		return // notest
+	}
+
+	repl := arg[2].RawText()
+	text := arg[0].RawText()
+	var pos, n int
+	if len(arg) > 3 {
+		pos = arg[3].Int()
+	}
+	if len(arg) > 4 {
+		n = arg[4].Int()
+	}
+
+	res := text
+	pos = skip(text, pos)
+	if n > 0 {
+		all := re.FindAllSubmatchIndex(text[pos:], n)
+		if n <= len(all) {
+			loc := all[n-1]
+			res = text[:pos+loc[0]]
+			res = re.Expand(res, repl, text[pos:], loc)
+			res = append(res, text[pos+loc[1]:]...)
+		}
+	} else {
+		res = append(text[:pos], re.ReplaceAll(text[pos:], repl)...)
+	}
+	ctx.ResultRawText(res)
+}
+
+func regexFind(re *regexp.Regexp, text []byte, pos, n, subexpr int) (loc []int) {
+	pos = skip(text, pos)
+	text = text[pos:]
+
+	if n <= 1 {
+		if subexpr == 0 {
+			loc = re.FindIndex(text)
+		} else {
+			loc = re.FindSubmatchIndex(text)
+		}
+	} else {
+		if subexpr == 0 {
+			all := re.FindAllIndex(text, n)
+			if n <= len(all) {
+				loc = all[n-1]
+			}
+		} else {
+			all := re.FindAllSubmatchIndex(text, n)
+			if n <= len(all) {
+				loc = all[n-1]
+			}
+		}
+	}
+
+	if 2+2*subexpr <= len(loc) {
+		loc = loc[2*subexpr : 2+2*subexpr]
+		loc[0] += pos
+		loc[1] += pos
+		return loc
+	}
+	return nil
+}
+
+func skip(text []byte, start int) int {
+	for pos := range string(text) {
+		if start--; start <= 0 {
+			return pos
+		}
+	}
+	return len(text)
+}

ext/regexp/regexp_test.go

@@ -0,0 +1,185 @@
+package regexp
+
+import (
+	"database/sql"
+	"regexp"
+	"strings"
+	"testing"
+
+	"github.com/ncruces/go-sqlite3"
+	"github.com/ncruces/go-sqlite3/driver"
+	_ "github.com/ncruces/go-sqlite3/embed"
+	_ "github.com/ncruces/go-sqlite3/internal/testcfg"
+	"github.com/ncruces/go-sqlite3/vfs/memdb"
+)
+
+func TestRegister(t *testing.T) {
+	t.Parallel()
+	tmp := memdb.TestDB(t)
+
+	db, err := driver.Open(tmp, Register)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+
+	tests := []struct {
+		test string
+		want string
+	}{
+		{`'Hello' REGEXP 'elo'`, "0"},
+		{`'Hello' REGEXP 'ell'`, "1"},
+		{`'Hello' REGEXP 'el.'`, "1"},
+		{`regexp_like('Hello', 'elo')`, "0"},
+		{`regexp_like('Hello', 'ell')`, "1"},
+		{`regexp_like('Hello', 'el.')`, "1"},
+		{`regexp_count('Hello', 'l')`, "2"},
+		{`regexp_instr('Hello', 'el.')`, "2"},
+		{`regexp_instr('Hello', '.', 6)`, ""},
+		{`regexp_substr('Hello', 'el.')`, "ell"},
+		{`regexp_replace('Hello', 'llo', 'll')`, "Hell"},
+		// https://postgresql.org/docs/current/functions-matching.html
+		{`regexp_count('ABCABCAXYaxy', 'A.')`, "3"},
+		{`regexp_count('ABCABCAXYaxy', '(?i)A.', 1)`, "4"},
+		{`regexp_instr('number of your street, town zip, FR', '[^,]+', 1, 2)`, "23"},
+		{`regexp_instr('ABCDEFGHI', '(?i)(c..)(...)', 1, 1, 0, 2)`, "6"},
+		{`regexp_substr('number of your street, town zip, FR', '[^,]+', 1, 2)`, " town zip"},
+		{`regexp_substr('ABCDEFGHI', '(?i)(c..)(...)', 1, 1, 2)`, "FGH"},
+		{`regexp_replace('foobarbaz', 'b..', 'X', 1, 1)`, "fooXbaz"},
+		{`regexp_replace('foobarbaz', 'b..', 'X')`, "fooXX"},
+		{`regexp_replace('foobarbaz', 'b(..)', 'X${1}Y')`, "fooXarYXazY"},
+		{`regexp_replace('A PostgreSQL function', '(?i)a|e|i|o|u', 'X', 1, 0)`, "X PXstgrXSQL fXnctXXn"},
+		{`regexp_replace('A PostgreSQL function', '(?i)a|e|i|o|u', 'X', 1, 3)`, "A PostgrXSQL function"},
+		// https://docs.oracle.com/en/database/oracle/oracle-database/21/sqlrf/REGEXP_COUNT.html
+		{`regexp_count('123123123123123', '(12)3', 1)`, "5"},
+		{`regexp_count('123123123123', '123', 3)`, "3"},
+		{`regexp_instr('500 Oracle Parkway, Redwood Shores, CA', '[^ ]+', 1, 6)`, "37"},
+		{`regexp_instr('500 Oracle Parkway, Redwood Shores, CA', '(?i)[s|r|p][[:alpha:]]{6}', 3, 2, 1)`, "28"},
+		{`regexp_instr('1234567890', '(123)(4(56)(78))', 1, 1, 0, 1)`, "1"},
+		{`regexp_instr('1234567890', '(123)(4(56)(78))', 1, 1, 0, 2)`, "4"},
+		{`regexp_instr('1234567890', '(123)(4(56)(78))', 1, 1, 0, 4)`, "7"},
+		{`regexp_substr('500 Oracle Parkway, Redwood Shores, CA', ',[^,]+,')`, ", Redwood Shores,"},
+		{`regexp_substr('http://www.example.com/products', 'http://([[:alnum:]]+\.?){3,4}/?')`, "http://www.example.com/"},
+		{`regexp_substr('1234567890', '(123)(4(56)(78))', 1, 1, 1)`, "123"},
+		{`regexp_substr('1234567890', '(123)(4(56)(78))', 1, 1, 4)`, "78"},
+		{`regexp_substr('123123123123', '1(.)3', 3, 2, 1)`, "2"},
+		{`regexp_replace('500   Oracle     Parkway,    Redwood  Shores, CA', '( ){2,}', ' ')`, "500 Oracle Parkway, Redwood Shores, CA"},
+	}
+
+	for _, tt := range tests {
+		var got sql.NullString
+		err := db.QueryRow(`SELECT ` + tt.test).Scan(&got)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if got.String != tt.want {
+			t.Errorf("got %q, want %q", got.String, tt.want)
+		}
+	}
+}
+
+func TestRegister_errors(t *testing.T) {
+	t.Parallel()
+	tmp := memdb.TestDB(t)
+
+	db, err := driver.Open(tmp, Register)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+
+	tests := []string{
+		`'' REGEXP ?`,
+		`regexp_like('', ?)`,
+		`regexp_count('', ?)`,
+		`regexp_instr('', ?)`,
+		`regexp_substr('', ?)`,
+		`regexp_replace('', ?, '')`,
+	}
+
+	for _, tt := range tests {
+		err := db.QueryRow(`SELECT `+tt, `\`).Scan(nil)
+		if err == nil {
+			t.Fatal("want error")
+		}
+	}
+}
+
+func TestRegister_pointer(t *testing.T) {
+	t.Parallel()
+	tmp := memdb.TestDB(t)
+
+	db, err := driver.Open(tmp, Register)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+
+	var got int
+	err = db.QueryRow(`SELECT regexp_count('ABCABCAXYaxy', ?, 1)`,
+		sqlite3.Pointer(regexp.MustCompile(`(?i)A.`))).Scan(&got)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got != 4 {
+		t.Errorf("got %d, want %d", got, 4)
+	}
+}
+
+func TestGlobPrefix(t *testing.T) {
+	tests := []struct {
+		re   string
+		want string
+	}{
+		{`[`, ""},
+		{``, "*"},
+		{`^`, "*"},
+		{`a`, "*"},
+		{`ab`, "*"},
+		{`^a`, "a*"},
+		{`^a*`, "*"},
+		{`^a+`, "a*"},
+		{`^ab*`, "a*"},
+		{`^ab+`, "ab*"},
+		{`^a\?b`, "a*"},
+		{`^[a-z]`, "*"},
+	}
+	for _, tt := range tests {
+		t.Run(tt.re, func(t *testing.T) {
+			if got := GlobPrefix(tt.re); got != tt.want {
+				t.Errorf("GlobPrefix(%v) = %v, want %v", tt.re, got, tt.want)
+			}
+		})
+	}
+}
+
+func FuzzGlobPrefix(f *testing.F) {
+	f.Add(``, ``)
+	f.Add(`[`, ``)
+	f.Add(`^`, ``)
+	f.Add(`a`, `a`)
+	f.Add(`ab`, `b`)
+	f.Add(`^a`, `a`)
+	f.Add(`^a*`, `ab`)
+	f.Add(`^a+`, `ab`)
+	f.Add(`^ab*`, `ab`)
+	f.Add(`^ab+`, `ab`)
+	f.Add(`^a\?b`, `ab`)
+	f.Add(`^[a-z]`, `ab`)
+
+	f.Fuzz(func(t *testing.T, lit, str string) {
+		re, err := regexp.Compile(lit)
+		if err != nil {
+			t.SkipNow()
+		}
+		if re.MatchString(str) {
+			prefix, ok := strings.CutSuffix(GlobPrefix(lit), "*")
+			if !ok {
+				t.Fatalf("missing * after %q for %q with %q", prefix, lit, str)
+			}
+			if !strings.HasPrefix(str, prefix) {
+				t.Fatalf("missing prefix %q for %q with %q", prefix, lit, str)
+			}
+		}
+	})
+}

ext/serdes/serdes.go

@@ -0,0 +1,140 @@
+// Package serdes provides functions to (de)serialize databases.
+package serdes
+
+import (
+	"io"
+
+	"github.com/ncruces/go-sqlite3"
+	"github.com/ncruces/go-sqlite3/vfs"
+)
+
+const vfsName = "github.com/ncruces/go-sqlite3/ext/serdes.sliceVFS"
+
+func init() {
+	vfs.Register(vfsName, sliceVFS{})
+}
+
+var fileToOpen = make(chan *sliceFile, 1)
+
+// Serialize backs up a database into a byte slice.
+//
+// https://sqlite.org/c3ref/serialize.html
+func Serialize(db *sqlite3.Conn, schema string) ([]byte, error) {
+	var file sliceFile
+	fileToOpen <- &file
+	err := db.Backup(schema, "file:serdes.db?vfs="+vfsName)
+	return file.data, err
+}
+
+// Deserialize restores a database from a byte slice,
+// DESTROYING any contents previously stored in schema.
+//
+// To non-destructively open a database from a byte slice,
+// consider alternatives like the ["reader"] or ["memdb"] VFSes.
+//
+// This differs from the similarly named SQLite API
+// in that it DOES NOT disconnect from schema
+// to reopen as an in-memory database.
+//
+// https://sqlite.org/c3ref/deserialize.html
+//
+// ["memdb"]: https://pkg.go.dev/github.com/ncruces/go-sqlite3/vfs/memdb
+// ["reader"]: https://pkg.go.dev/github.com/ncruces/go-sqlite3/vfs/readervfs
+func Deserialize(db *sqlite3.Conn, schema string, data []byte) error {
+	fileToOpen <- &sliceFile{data}
+	return db.Restore(schema, "file:serdes.db?vfs="+vfsName)
+}
+
+type sliceVFS struct{}
+
+func (sliceVFS) Open(name string, flags vfs.OpenFlag) (vfs.File, vfs.OpenFlag, error) {
+	if flags&vfs.OPEN_MAIN_DB == 0 || name != "serdes.db" {
+		return nil, flags, sqlite3.CANTOPEN
+	}
+	select {
+	case file := <-fileToOpen:
+		return file, flags | vfs.OPEN_MEMORY, nil
+	default:
+		return nil, flags, sqlite3.MISUSE
+	}
+}
+
+func (sliceVFS) Delete(name string, dirSync bool) error {
+	// notest // OPEN_MEMORY
+	return sqlite3.IOERR_DELETE
+}
+
+func (sliceVFS) Access(name string, flag vfs.AccessFlag) (bool, error) {
+	return name == "serdes.db", nil
+}
+
+func (sliceVFS) FullPathname(name string) (string, error) {
+	return name, nil
+}
+
+type sliceFile struct{ data []byte }
+
+func (f *sliceFile) ReadAt(b []byte, off int64) (n int, err error) {
+	if d := f.data; off < int64(len(d)) {
+		n = copy(b, d[off:])
+	}
+	if n == 0 {
+		err = io.EOF
+	}
+	return
+}
+
+func (f *sliceFile) WriteAt(b []byte, off int64) (n int, err error) {
+	if d := f.data; off > int64(len(d)) {
+		f.data = append(d, make([]byte, off-int64(len(d)))...)
+	}
+	d := append(f.data[:off], b...)
+	if len(d) > len(f.data) {
+		f.data = d
+	}
+	return len(b), nil
+}
+
+func (f *sliceFile) Size() (int64, error) {
+	return int64(len(f.data)), nil
+}
+
+func (f *sliceFile) Truncate(size int64) error {
+	if d := f.data; size < int64(len(d)) {
+		f.data = d[:size]
+	}
+	return nil
+}
+
+func (f *sliceFile) SizeHint(size int64) error {
+	if d := f.data; size > int64(len(d)) {
+		f.data = append(d, make([]byte, size-int64(len(d)))...)
+	}
+	return nil
+}
+
+func (*sliceFile) Close() error { return nil }
+
+func (*sliceFile) Sync(flag vfs.SyncFlag) error { return nil }
+
+func (*sliceFile) Lock(lock vfs.LockLevel) error { return nil }
+
+func (*sliceFile) Unlock(lock vfs.LockLevel) error { return nil }
+
+func (*sliceFile) CheckReservedLock() (bool, error) {
+	// notest // OPEN_MEMORY
+	return false, nil
+}
+
+func (*sliceFile) SectorSize() int {
+	// notest // IOCAP_POWERSAFE_OVERWRITE
+	return 0
+}
+
+func (*sliceFile) DeviceCharacteristics() vfs.DeviceCharacteristic {
+	return vfs.IOCAP_ATOMIC |
+		vfs.IOCAP_SAFE_APPEND |
+		vfs.IOCAP_SEQUENTIAL |
+		vfs.IOCAP_POWERSAFE_OVERWRITE |
+		vfs.IOCAP_SUBPAGE_READ
+}

ext/serdes/serdes_test.go

@@ -0,0 +1,87 @@
+package serdes_test
+
+import (
+	"errors"
+	"io"
+	"net/http"
+	"testing"
+
+	"github.com/ncruces/go-sqlite3"
+	_ "github.com/ncruces/go-sqlite3/embed"
+	"github.com/ncruces/go-sqlite3/ext/serdes"
+)
+
+func TestDeserialize(t *testing.T) {
+	if testing.Short() {
+		t.Skip("skipping in short mode")
+	}
+
+	input, err := httpGet()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	db, err := sqlite3.Open(":memory:")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+
+	err = serdes.Deserialize(db, "temp", input)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	output, err := serdes.Serialize(db, "temp")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if len(input) != len(output) {
+		t.Fatal("lengths are different")
+	}
+	for i := range input {
+		// These may be different.
+		switch {
+		case 24 <= i && i < 28:
+			// File change counter.
+			continue
+		case 40 <= i && i < 44:
+			// Schema cookie.
+			continue
+		case 92 <= i && i < 100:
+			// SQLite version that wrote the file.
+			continue
+		}
+		if input[i] != output[i] {
+			t.Errorf("difference at %d: %d %d", i, input[i], output[i])
+		}
+	}
+}
+
+func httpGet() ([]byte, error) {
+	res, err := http.Get("https://raw.githubusercontent.com/jpwhite3/northwind-SQLite3/refs/heads/main/dist/northwind.db")
+	if err != nil {
+		return nil, err
+	}
+	defer res.Body.Close()
+	return io.ReadAll(res.Body)
+}
+
+func TestOpen_errors(t *testing.T) {
+	_, err := sqlite3.Open("file:test.db?vfs=github.com/ncruces/go-sqlite3/ext/serdes.sliceVFS")
+	if err == nil {
+		t.Error("want error")
+	}
+	if !errors.Is(err, sqlite3.CANTOPEN) {
+		t.Errorf("got %v, want sqlite3.CANTOPEN", err)
+	}
+
+	_, err = sqlite3.Open("file:serdes.db?vfs=github.com/ncruces/go-sqlite3/ext/serdes.sliceVFS")
+	if err == nil {
+		t.Error("want error")
+	}
+	if !errors.Is(err, sqlite3.MISUSE) {
+		t.Errorf("got %v, want sqlite3.MISUSE", err)
+	}
+}

ext/statement/stmt.go

@@ -0,0 +1,216 @@
+// Package statement defines table-valued functions using SQL.
+//
+// It can be used to create "parametrized views":
+// pre-packaged queries that can be parametrized at query execution time.
+//
+// https://github.com/0x09/sqlite-statement-vtab
+package statement
+
+import (
+	"encoding/json"
+	"errors"
+	"strconv"
+	"strings"
+	"unsafe"
+
+	"github.com/ncruces/go-sqlite3"
+	"github.com/ncruces/go-sqlite3/internal/util"
+)
+
+// Register registers the statement virtual table.
+func Register(db *sqlite3.Conn) error {
+	return sqlite3.CreateModule(db, "statement", declare, declare)
+}
+
+type table struct {
+	stmt  *sqlite3.Stmt
+	sql   string
+	inuse bool
+}
+
+func declare(db *sqlite3.Conn, _, _, _ string, arg ...string) (*table, error) {
+	if len(arg) != 1 {
+		return nil, util.ErrorString("statement: wrong number of arguments")
+	}
+
+	sql := "SELECT * FROM\n" + arg[0]
+
+	stmt, _, err := db.PrepareFlags(sql, sqlite3.PREPARE_PERSISTENT)
+	if err != nil {
+		return nil, err
+	}
+
+	var sep string
+	var str strings.Builder
+	str.WriteString("CREATE TABLE x(")
+	outputs := stmt.ColumnCount()
+	for i := range outputs {
+		name := sqlite3.QuoteIdentifier(stmt.ColumnName(i))
+		str.WriteString(sep)
+		str.WriteString(name)
+		str.WriteString(" ")
+		str.WriteString(stmt.ColumnDeclType(i))
+		sep = ","
+	}
+	inputs := stmt.BindCount()
+	for i := 1; i <= inputs; i++ {
+		str.WriteString(sep)
+		name := stmt.BindName(i)
+		if name == "" {
+			str.WriteString("[")
+			str.WriteString(strconv.Itoa(i))
+			str.WriteString("] HIDDEN")
+		} else {
+			str.WriteString(sqlite3.QuoteIdentifier(name[1:]))
+			str.WriteString(" HIDDEN")
+		}
+		sep = ","
+	}
+	str.WriteByte(')')
+
+	err = db.DeclareVTab(str.String())
+	if err != nil {
+		stmt.Close()
+		return nil, err
+	}
+
+	return &table{sql: sql, stmt: stmt}, nil
+}
+
+func (t *table) Close() error {
+	return t.stmt.Close()
+}
+
+func (t *table) BestIndex(idx *sqlite3.IndexInfo) error {
+	idx.EstimatedCost = 1000
+
+	var argvIndex = 1
+	var needIndex bool
+	var listIndex []int
+	outputs := t.stmt.ColumnCount()
+	for i, cst := range idx.Constraint {
+		// Skip if this is a constraint on one of our output columns.
+		if cst.Column < outputs {
+			continue
+		}
+
+		// A given query plan is only usable if all provided input columns
+		// are usable and have equal constraints only.
+		if !cst.Usable || cst.Op != sqlite3.INDEX_CONSTRAINT_EQ {
+			return sqlite3.CONSTRAINT
+		}
+
+		// The non-zero argvIdx values must be contiguous.
+		// If they're not, build a list and serialize it through IdxStr.
+		nextIndex := cst.Column - outputs + 1
+		idx.ConstraintUsage[i] = sqlite3.IndexConstraintUsage{
+			ArgvIndex: argvIndex,
+			Omit:      true,
+		}
+		if nextIndex != argvIndex {
+			needIndex = true
+		}
+		listIndex = append(listIndex, nextIndex)
+		argvIndex++
+	}
+
+	if needIndex {
+		buf, err := json.Marshal(listIndex)
+		if err != nil {
+			return err
+		}
+		idx.IdxStr = unsafe.String(&buf[0], len(buf))
+	}
+	return nil
+}
+
+func (t *table) Open() (_ sqlite3.VTabCursor, err error) {
+	stmt := t.stmt
+	if !t.inuse {
+		t.inuse = true
+	} else {
+		stmt, _, err = t.stmt.Conn().Prepare(t.sql)
+		if err != nil {
+			return nil, err
+		}
+	}
+	return &cursor{table: t, stmt: stmt}, nil
+}
+
+func (t *table) Rename(new string) error {
+	return nil
+}
+
+type cursor struct {
+	table *table
+	stmt  *sqlite3.Stmt
+	arg   []sqlite3.Value
+	rowID int64
+}
+
+func (c *cursor) Close() error {
+	if c.stmt == c.table.stmt {
+		c.table.inuse = false
+		return errors.Join(
+			c.stmt.Reset(),
+			c.stmt.ClearBindings())
+	}
+	return c.stmt.Close()
+}
+
+func (c *cursor) Filter(idxNum int, idxStr string, arg ...sqlite3.Value) error {
+	err := errors.Join(
+		c.stmt.Reset(),
+		c.stmt.ClearBindings())
+	if err != nil {
+		return err
+	}
+
+	var list []int
+	if idxStr != "" {
+		buf := unsafe.Slice(unsafe.StringData(idxStr), len(idxStr))
+		err := json.Unmarshal(buf, &list)
+		if err != nil {
+			return err
+		}
+	}
+
+	for i, arg := range arg {
+		param := i + 1
+		if list != nil {
+			param = list[i]
+		}
+		err := c.stmt.BindValue(param, arg)
+		if err != nil {
+			return err
+		}
+	}
+	c.arg = append(c.arg[:0], arg...)
+	c.rowID = 0
+	return c.Next()
+}
+
+func (c *cursor) Next() error {
+	if c.stmt.Step() {
+		c.rowID++
+	}
+	return c.stmt.Err()
+}
+
+func (c *cursor) EOF() bool {
+	return !c.stmt.Busy()
+}
+
+func (c *cursor) RowID() (int64, error) {
+	return c.rowID, nil
+}
+
+func (c *cursor) Column(ctx sqlite3.Context, col int) error {
+	switch outputs := c.stmt.ColumnCount(); {
+	case col < outputs:
+		ctx.ResultValue(c.stmt.ColumnValue(col))
+	case col-outputs < len(c.arg):
+		ctx.ResultValue(c.arg[col-outputs])
+	}
+	return nil
+}

ext/statement/stmt_test.go

@@ -0,0 +1,148 @@
+package statement_test
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"testing"
+
+	"github.com/ncruces/go-sqlite3"
+	_ "github.com/ncruces/go-sqlite3/embed"
+	"github.com/ncruces/go-sqlite3/ext/statement"
+	_ "github.com/ncruces/go-sqlite3/internal/testcfg"
+)
+
+func Example() {
+	sqlite3.AutoExtension(statement.Register)
+
+	db, err := sqlite3.Open(":memory:")
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer db.Close()
+
+	err = db.Exec(`
+		CREATE VIRTUAL TABLE split_date USING statement((
+			SELECT
+				strftime('%Y', :date) AS year,
+				strftime('%m', :date) AS month,
+				strftime('%d', :date) AS day
+		))`)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	stmt, _, err := db.Prepare(`SELECT * FROM split_date('2022-02-22')`)
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer stmt.Close()
+
+	if stmt.Step() {
+		fmt.Printf("Twosday was %d-%d-%d", stmt.ColumnInt(0), stmt.ColumnInt(1), stmt.ColumnInt(2))
+	}
+	if err := stmt.Reset(); err != nil {
+		log.Fatal(err)
+	}
+
+	// Output:
+	// Twosday was 2022-2-22
+}
+
+func TestMain(m *testing.M) {
+	sqlite3.AutoExtension(statement.Register)
+	os.Exit(m.Run())
+}
+
+func TestRegister(t *testing.T) {
+	t.Parallel()
+
+	db, err := sqlite3.Open(":memory:")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+
+	err = db.Exec(`
+		CREATE VIRTUAL TABLE arguments USING statement((SELECT ? AS a, ? AS b, ? AS c))
+	`)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = db.Exec(`
+		SELECT * from arguments WHERE [2] = 'y' AND [3] = 'z'
+	`)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = db.Exec(`
+		CREATE VIRTUAL TABLE hypot USING statement((SELECT sqrt(:x * :x + :y * :y) AS hypotenuse))
+	`)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	stmt, _, err := db.Prepare(`
+		SELECT x, y, * FROM hypot WHERE x = 3 AND y = 4
+	`)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer stmt.Close()
+
+	if stmt.Step() {
+		x := stmt.ColumnInt(0)
+		y := stmt.ColumnInt(1)
+		hypot := stmt.ColumnInt(2)
+		if x != 3 || y != 4 || hypot != 5 {
+			t.Errorf("hypot(%d, %d) = %d", x, y, hypot)
+		}
+	}
+}
+
+func TestRegister_errors(t *testing.T) {
+	t.Parallel()
+
+	db, err := sqlite3.Open(":memory:")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+
+	err = db.Exec(`CREATE VIRTUAL TABLE split_date USING statement()`)
+	if err == nil {
+		t.Fatal("want error")
+	} else {
+		t.Log(err)
+	}
+
+	err = db.Exec(`CREATE VIRTUAL TABLE split_date USING statement(SELECT 1, SELECT 2)`)
+	if err == nil {
+		t.Fatal("want error")
+	} else {
+		t.Log(err)
+	}
+
+	err = db.Exec(`CREATE VIRTUAL TABLE split_date USING statement((SELECT 1, SELECT 2))`)
+	if err == nil {
+		t.Fatal("want error")
+	} else {
+		t.Log(err)
+	}
+
+	err = db.Exec(`CREATE VIRTUAL TABLE split_date USING statement((SELECT 1; SELECT 2))`)
+	if err == nil {
+		t.Fatal("want error")
+	} else {
+		t.Log(err)
+	}
+
+	err = db.Exec(`CREATE VIRTUAL TABLE split_date USING statement((CREATE TABLE x(val)))`)
+	if err == nil {
+		t.Fatal("want error")
+	} else {
+		t.Log(err)
+	}
+}

ext/stats/TODO.md

@@ -0,0 +1,56 @@
+# ANSI SQL Aggregate Functions
+
+https://oreilly.com/library/view/sql-in-a/9780596155322/ch04s02.html
+
+## Built in aggregates
+
+- [x] `COUNT(*)`
+- [x] `COUNT(expression)`
+- [x] `SUM(expression)`
+- [x] `AVG(expression)`
+- [x] `MIN(expression)`
+- [x] `MAX(expression)`
+
+https://sqlite.org/lang_aggfunc.html
+
+## Statistical aggregates
+
+- [x] `STDDEV_POP(expression)`
+- [x] `STDDEV_SAMP(expression)`
+- [x] `VAR_POP(expression)`
+- [x] `VAR_SAMP(expression)`
+- [x] `COVAR_POP(dependent, independent)`
+- [x] `COVAR_SAMP(dependent, independent)`
+- [x] `CORR(dependent, independent)`
+
+## Linear regression aggregates
+
+- [X] `REGR_AVGX(dependent, independent)`
+- [X] `REGR_AVGY(dependent, independent)`
+- [X] `REGR_SXX(dependent, independent)`
+- [X] `REGR_SYY(dependent, independent)`
+- [X] `REGR_SXY(dependent, independent)`
+- [X] `REGR_COUNT(dependent, independent)`
+- [X] `REGR_SLOPE(dependent, independent)`
+- [X] `REGR_INTERCEPT(dependent, independent)`
+- [X] `REGR_R2(dependent, independent)`
+
+## Set aggregates
+
+- [X] `CUME_DIST() OVER window`
+- [X] `RANK() OVER window`
+- [X] `DENSE_RANK() OVER window`
+- [X] `PERCENT_RANK() OVER window`
+
+https://sqlite.org/windowfunctions.html#builtins
+
+## Boolean aggregates
+
+- [X] `EVERY(boolean)`
+- [X] `SOME(boolean)`
+
+## Additional aggregates
+
+- [X] `MEDIAN(expression)`
+- [X] `PERCENTILE_CONT(expression, fraction)`
+- [X] `PERCENTILE_DISC(expression, fraction)`

ext/stats/boolean.go

@@ -0,0 +1,46 @@
+package stats
+
+import "github.com/ncruces/go-sqlite3"
+
+const (
+	every = iota
+	some
+)
+
+func newBoolean(kind int) sqlite3.AggregateConstructor {
+	return func() sqlite3.AggregateFunction { return &boolean{kind: kind} }
+}
+
+type boolean struct {
+	count int
+	total int
+	kind  int
+}
+
+func (b *boolean) Value(ctx sqlite3.Context) {
+	if b.kind == every {
+		ctx.ResultBool(b.count == b.total)
+	} else {
+		ctx.ResultBool(b.count > 0)
+	}
+}
+
+func (b *boolean) Step(ctx sqlite3.Context, arg ...sqlite3.Value) {
+	a := arg[0]
+	if a.Bool() {
+		b.count++
+	}
+	if a.Type() != sqlite3.NULL {
+		b.total++
+	}
+}
+
+func (b *boolean) Inverse(ctx sqlite3.Context, arg ...sqlite3.Value) {
+	a := arg[0]
+	if a.Bool() {
+		b.count--
+	}
+	if a.Type() != sqlite3.NULL {
+		b.total--
+	}
+}

ext/stats/boolean_test.go

@@ -0,0 +1,71 @@
+package stats_test
+
+import (
+	"testing"
+
+	"github.com/ncruces/go-sqlite3"
+	_ "github.com/ncruces/go-sqlite3/embed"
+	_ "github.com/ncruces/go-sqlite3/internal/testcfg"
+)
+
+func TestRegister_boolean(t *testing.T) {
+	t.Parallel()
+
+	db, err := sqlite3.Open(":memory:")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+
+	err = db.Exec(`CREATE TABLE data (x)`)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = db.Exec(`INSERT INTO data (x) VALUES (4), (7.0), (13), (NULL), (16), (3.14)`)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	stmt, _, err := db.Prepare(`
+		SELECT
+			every(x > 0),
+			every(x > 10),
+			some(x > 10),
+			some(x > 20)
+		FROM data`)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if stmt.Step() {
+		if got := stmt.ColumnBool(0); got != true {
+			t.Errorf("got %v, want true", got)
+		}
+		if got := stmt.ColumnBool(1); got != false {
+			t.Errorf("got %v, want false", got)
+		}
+		if got := stmt.ColumnBool(2); got != true {
+			t.Errorf("got %v, want true", got)
+		}
+		if got := stmt.ColumnBool(3); got != false {
+			t.Errorf("got %v, want false", got)
+		}
+	}
+	stmt.Close()
+
+	stmt, _, err = db.Prepare(`SELECT every(x > 10) OVER (ROWS 1 PRECEDING) FROM data`)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	want := [...]bool{false, false, false, true, true, false}
+	for i := 0; stmt.Step(); i++ {
+		if got := stmt.ColumnBool(0); got != want[i] {
+			t.Errorf("got %v, want %v", got, want[i])
+		}
+		if got := stmt.ColumnType(0); got != sqlite3.INTEGER {
+			t.Errorf("got %v, want INTEGER", got)
+		}
+	}
+	stmt.Close()
+}

ext/stats/kahan.go

@@ -0,0 +1,19 @@
+package stats
+
+// https://en.wikipedia.org/wiki/Kahan_summation_algorithm
+
+type kahan struct{ hi, lo float64 }
+
+func (k *kahan) add(x float64) {
+	y := k.lo + x
+	t := k.hi + y
+	k.lo = y - (t - k.hi)
+	k.hi = t
+}
+
+func (k *kahan) sub(x float64) {
+	y := k.lo - x
+	t := k.hi + y
+	k.lo = y - (t - k.hi)
+	k.hi = t
+}

ext/stats/mode.go

@@ -0,0 +1,112 @@
+package stats
+
+import (
+	"unsafe"
+
+	"github.com/ncruces/go-sqlite3"
+)
+
+func newMode() sqlite3.AggregateFunction {
+	return &mode{}
+}
+
+type mode struct {
+	ints  counter[int64]
+	reals counter[float64]
+	texts counter[string]
+	blobs counter[string]
+}
+
+func (m mode) Value(ctx sqlite3.Context) {
+	var (
+		max = 0
+		typ = sqlite3.NULL
+		i64 int64
+		f64 float64
+		str string
+	)
+	for k, v := range m.ints {
+		if v > max || v == max && k < i64 {
+			typ = sqlite3.INTEGER
+			max = v
+			i64 = k
+		}
+	}
+	f64 = float64(i64)
+	for k, v := range m.reals {
+		if v > max || v == max && k < f64 {
+			typ = sqlite3.FLOAT
+			max = v
+			f64 = k
+		}
+	}
+	for k, v := range m.texts {
+		if v > max || v == max && typ == sqlite3.TEXT && k < str {
+			typ = sqlite3.TEXT
+			max = v
+			str = k
+		}
+	}
+	for k, v := range m.blobs {
+		if v > max || v == max && typ == sqlite3.BLOB && k < str {
+			typ = sqlite3.BLOB
+			max = v
+			str = k
+		}
+	}
+	switch typ {
+	case sqlite3.INTEGER:
+		ctx.ResultInt64(i64)
+	case sqlite3.FLOAT:
+		ctx.ResultFloat(f64)
+	case sqlite3.TEXT:
+		ctx.ResultText(str)
+	case sqlite3.BLOB:
+		ctx.ResultBlob(unsafe.Slice(unsafe.StringData(str), len(str)))
+	}
+}
+
+func (b *mode) Step(ctx sqlite3.Context, arg ...sqlite3.Value) {
+	switch arg[0].Type() {
+	case sqlite3.INTEGER:
+		b.ints.add(arg[0].Int64())
+	case sqlite3.FLOAT:
+		b.reals.add(arg[0].Float())
+	case sqlite3.TEXT:
+		b.texts.add(arg[0].Text())
+	case sqlite3.BLOB:
+		b.blobs.add(string(arg[0].RawBlob()))
+	}
+}
+
+func (b *mode) Inverse(ctx sqlite3.Context, arg ...sqlite3.Value) {
+	switch arg[0].Type() {
+	case sqlite3.INTEGER:
+		b.ints.del(arg[0].Int64())
+	case sqlite3.FLOAT:
+		b.reals.del(arg[0].Float())
+	case sqlite3.TEXT:
+		b.texts.del(arg[0].Text())
+	case sqlite3.BLOB:
+		b.blobs.del(string(arg[0].RawBlob()))
+	}
+}
+
+type counter[T comparable] map[T]int
+
+func (c *counter[T]) add(k T) {
+	if (*c) == nil {
+		(*c) = make(counter[T])
+	}
+	(*c)[k]++
+}
+
+func (c counter[T]) del(k T) {
+	switch n := c[k]; n {
+	default:
+		c[k] = n - 1
+	case 1:
+		delete(c, k)
+	case 0:
+	}
+}

ext/stats/mode_test.go

@@ -0,0 +1,85 @@
+package stats_test
+
+import (
+	"testing"
+
+	"github.com/ncruces/go-sqlite3"
+	_ "github.com/ncruces/go-sqlite3/embed"
+	_ "github.com/ncruces/go-sqlite3/internal/testcfg"
+)
+
+func TestRegister_mode(t *testing.T) {
+	t.Parallel()
+
+	db, err := sqlite3.Open(":memory:")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+
+	stmt, _, err := db.Prepare(`SELECT mode(column1) FROM (VALUES (NULL), (1), (NULL), (2), (NULL), (3), (3))`)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if stmt.Step() {
+		if got := stmt.ColumnInt(0); got != 3 {
+			t.Errorf("got %v, want 3", got)
+		}
+	}
+	stmt.Close()
+
+	stmt, _, err = db.Prepare(`SELECT mode(column1) FROM (VALUES (1), (1), (2), (2), (3))`)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if stmt.Step() {
+		if got := stmt.ColumnInt(0); got != 1 {
+			t.Errorf("got %v, want 1", got)
+		}
+	}
+	stmt.Close()
+
+	stmt, _, err = db.Prepare(`SELECT mode(column1) FROM (VALUES (0.5), (1), (2.5), (2), (2.5))`)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if stmt.Step() {
+		if got := stmt.ColumnFloat(0); got != 2.5 {
+			t.Errorf("got %v, want 2.5", got)
+		}
+	}
+	stmt.Close()
+
+	stmt, _, err = db.Prepare(`SELECT mode(column1) FROM (VALUES ('red'), ('green'), ('blue'), ('red'))`)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if stmt.Step() {
+		if got := stmt.ColumnText(0); got != "red" {
+			t.Errorf("got %q, want red", got)
+		}
+	}
+	stmt.Close()
+
+	stmt, _, err = db.Prepare(`SELECT mode(column1) FROM (VALUES (X'cafebabe'), ('green'), ('blue'), (X'cafebabe'))`)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if stmt.Step() {
+		if got := stmt.ColumnText(0); got != "\xca\xfe\xba\xbe" {
+			t.Errorf("got %q, want cafebabe", got)
+		}
+	}
+	stmt.Close()
+
+	stmt, _, err = db.Prepare(`
+		SELECT mode(column1) OVER (ROWS BETWEEN 1 PRECEDING AND 1 FOLLOWING)
+		FROM (VALUES (1), (1), (2.5), ('blue'), (X'cafebabe'), (1), (1))
+	`)
+	if err != nil {
+		t.Fatal(err)
+	}
+	for stmt.Step() {
+	}
+	stmt.Close()
+}

ext/stats/moments.go

@@ -0,0 +1,101 @@
+package stats
+
+import "math"
+
+// Fisher–Pearson skewness and kurtosis using
+// Terriberry's algorithm with Kahan summation:
+// https://en.wikipedia.org/wiki/Algorithms_for_calculating_variance#Higher-order_statistics
+
+type moments struct {
+	m1, m2, m3, m4 kahan
+	n              int64
+}
+
+func (m moments) mean() float64 {
+	return m.m1.hi
+}
+
+func (m moments) var_pop() float64 {
+	return m.m2.hi / float64(m.n)
+}
+
+func (m moments) var_samp() float64 {
+	return m.m2.hi / float64(m.n-1) // Bessel's correction
+}
+
+func (m moments) stddev_pop() float64 {
+	return math.Sqrt(m.var_pop())
+}
+
+func (m moments) stddev_samp() float64 {
+	return math.Sqrt(m.var_samp())
+}
+
+func (m moments) skewness_pop() float64 {
+	m2 := m.m2.hi
+	if div := m2 * m2 * m2; div != 0 {
+		return m.m3.hi * math.Sqrt(float64(m.n)/div)
+	}
+	return math.NaN()
+}
+
+func (m moments) skewness_samp() float64 {
+	n := m.n
+	// https://mathworks.com/help/stats/skewness.html#f1132178
+	return m.skewness_pop() * math.Sqrt(float64(n*(n-1))) / float64(n-2)
+}
+
+func (m moments) kurtosis_pop() float64 {
+	return m.raw_kurtosis_pop() - 3
+}
+
+func (m moments) raw_kurtosis_pop() float64 {
+	m2 := m.m2.hi
+	if div := m2 * m2; div != 0 {
+		return m.m4.hi * float64(m.n) / div
+	}
+	return math.NaN()
+}
+
+func (m moments) kurtosis_samp() float64 {
+	n := m.n
+	k := math.FMA(m.raw_kurtosis_pop(), float64(n+1), float64(3-3*n))
+	return k * float64(n-1) / float64((n-2)*(n-3))
+}
+
+func (m moments) raw_kurtosis_samp() float64 {
+	n := m.n
+	// https://mathworks.com/help/stats/kurtosis.html#f4975293
+	k := math.FMA(m.raw_kurtosis_pop(), float64(n+1), float64(3-3*n))
+	return math.FMA(k, float64(n-1)/float64((n-2)*(n-3)), 3)
+}
+
+func (m *moments) enqueue(x float64) {
+	n := m.n + 1
+	m.n = n
+	d1 := x - m.m1.hi - m.m1.lo
+	dn := d1 / float64(n)
+	d2 := dn * dn
+	t1 := d1 * dn * float64(n-1)
+	m.m4.add(t1*d2*float64(n*n-3*n+3) + 6*d2*m.m2.hi - 4*dn*m.m3.hi)
+	m.m3.add(t1*dn*float64(n-2) - 3*dn*m.m2.hi)
+	m.m2.add(t1)
+	m.m1.add(dn)
+}
+
+func (m *moments) dequeue(x float64) {
+	n := m.n - 1
+	if n <= 0 {
+		*m = moments{}
+		return
+	}
+	m.n = n
+	d1 := x - m.m1.hi - m.m1.lo
+	dn := d1 / float64(n)
+	d2 := dn * dn
+	t1 := d1 * dn * float64(n+1)
+	m.m4.sub(t1*d2*float64(n*n+3*n+3) - 6*d2*m.m2.hi - 4*dn*m.m3.hi)
+	m.m3.sub(t1*dn*float64(n+2) - 3*dn*m.m2.hi)
+	m.m2.sub(t1)
+	m.m1.sub(dn)
+}