Add SQLite scanner (#28)

Author: ostafen

internal/format/header.go

@@ -54,6 +54,8 @@ var fileHeaders = []FileHeader{
 	zipFileHeader,
 	rarFileHeader,
 	pdfFileHeader,
+	// database formats
+	sqliteFileHeader,
 }
 
 func GetFileScanners(ext ...string) ([]FileScanner, error) {

internal/format/sqlite.go

@@ -0,0 +1,108 @@
+// Copyright (c) 2025 Stefano Scafiti
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+package format
+
+import (
+	"bytes"
+	"encoding/binary"
+	"fmt"
+)
+
+const SQLiteSignature = "SQLite format 3\x00"
+
+var sqliteFileHeader = FileHeader{
+	Ext:         "sqlite",
+	Description: "SQLite Database Format",
+	Signatures: [][]byte{
+		[]byte(SQLiteSignature),
+	},
+	ScanFile: ScanSQLite,
+}
+
+// ScanSqlite tries to carve a single SQLite DB starting at offset 0 in the reader.
+func ScanSQLite(r *Reader) (*ScanResult, error) {
+	// SQLite 3 Database Header Structure: https://www.sqlite.org/fileformat2.html#the_database_header
+	// -----------------------------------------
+	// Magic                (16 bytes)       "SQLite format 3\0" magic string
+	// PageSize             (2 bytes)        Big-endian uint16; DB page size in bytes (must be power of 2, 512–65536)
+	// FFWrite              (1 byte)         File format write version
+	// FFRead               (1 byte)         File format read version
+	// Reserved             (1 byte)         Reserved for future use
+	// MaxEmbPayloadFrac    (1 byte)         Maximum embedded payload fraction
+	// MinEmbPayloadFrac    (1 byte)         Minimum embedded payload fraction
+	// LeafPayloadFrac      (1 byte)         Leaf payload fraction
+	// FileChangeCounter    (4 bytes)        Big-endian uint32; file change counter
+	// FileSizeInPage       (4 bytes)        Big-endian uint32; total DB size in pages
+	// FirstFreelistPage    (4 bytes)        Big-endian uint32; first freelist trunk page
+	// FreelistPages        (4 bytes)        Big-endian uint32; total number of freelist pages
+	// SchemaCookie         (4 bytes)        Big-endian uint32; schema cookie
+	// SchemaFormat         (4 bytes)        Big-endian uint32; schema format number
+	// DefaultPageCacheSize (4 bytes)        Big-endian uint32; default page cache size
+	// LargestRootBtree     (4 bytes)        Big-endian uint32; root b-tree page number
+	// TextEncoding         (4 bytes)        Big-endian uint32; text encoding used
+	// UserVersion          (4 bytes)        Big-endian uint32; user version
+	// IncVacuumMode        (4 bytes)        Big-endian uint32; incremental vacuum mode flag
+	// AppID                (4 bytes)        Big-endian uint32; application ID
+	// ReservedForExpansion (20 bytes)       Reserved space for future expansion
+	// VersionValidFor      (4 bytes)        Big-endian uint32; version valid for number
+	// Version              (4 bytes)        Big-endian uint32; SQLite version number
+
+	var hdr [100]byte
+	_, err := r.Read(hdr[:])
+	if err != nil {
+		return nil, fmt.Errorf("failed to read SQLite header: %w", err)
+	}
+
+	if !bytes.Equal(hdr[:len(SQLiteSignature)], []byte(SQLiteSignature)) {
+		return nil, fmt.Errorf("invalid SQLite magic header: expected %q, got %q", SQLiteSignature, string(hdr[:16]))
+	}
+
+	// Read PageSize: bytes 16-17 big-endian uint16
+	pageSize := int(binary.BigEndian.Uint16(hdr[16:18]))
+	if pageSize == 1 {
+		pageSize = 65536
+	}
+
+	if !isPowerOfTwo(uint32(pageSize)) || pageSize < 512 || pageSize > 65536 {
+		return nil, fmt.Errorf("invalid SQLite page size: %d", pageSize)
+	}
+
+	// Read FileChangeCounter: bytes 24-27 big-endian uint32
+	fileChangeCounter := binary.BigEndian.Uint32(hdr[24:28])
+
+	// Read FileSizeInPage: bytes 28-31 big-endian uint32
+	fileSizeInPage := binary.BigEndian.Uint32(hdr[28:32])
+
+	// Read VersionValidFor: bytes 92-95 big-endian uint32
+	versionValidFor := binary.BigEndian.Uint32(hdr[92:96])
+
+	var size uint64 = 0
+	if fileSizeInPage != 0 && fileChangeCounter == versionValidFor {
+		size = uint64(fileSizeInPage) * uint64(pageSize)
+	}
+
+	return &ScanResult{
+		Size: size,
+	}, nil
+}
+
+func isPowerOfTwo(x uint32) bool {
+	return x != 0 && (x&(x-1)) == 0
+}