Merge pull request #18 from vicajilau/bugfix/jpeg-magic-number-issue

Fixed JPEG Magic Number

Author: vicajilau

CHANGELOG.md

@@ -1,3 +1,10 @@
+## 1.4.0
+* Fixed an issue where JPEG files were detected as TIFF files [#17](https://github.com/vicajilau/file_magic_number/issues/17).
+* Added webp support.
+* Added AVI support.
+* Improved WAV support.
+* Added magic number detection byRange.
+
 ## 1.3.2
 * Fixed an issue where PDFA files were not detected.
 * Removed Cocoapods on example project.

example/pubspec.lock

@@ -87,7 +87,7 @@ packages:
       path: ".."
       relative: true
     source: path
-    version: "1.3.2"
+    version: "1.4.0"
   file_picker:
     dependency: "direct main"
     description:

lib/src/file_magic_number.dart

@@ -3,6 +3,7 @@ import 'dart:typed_data';
 import 'package:file_magic_number/src/magic_number_list.dart';
 
 import '../file_magic_number.dart';
+import 'file_magic_number_match_type.dart';
 
 /// A utility class for detecting file types based on their magic numbers.
 ///
@@ -27,13 +28,46 @@ class FileMagicNumber {
     }
 
     for (var entry in MagicNumberList.magicNumbers.entries) {
-      if (_matchesWithOffset(bytes, entry.key)) {
-        return entry.value;
+      switch (FileMagicNumberMatchType.get(entry.value)) {
+        case FileMagicNumberMatchType.exact:
+          if (_matchAt(bytes, entry.key, 0)) {
+            return entry.value;
+          }
+        case FileMagicNumberMatchType.offset:
+          if (_matchesWithOffset(bytes, entry.key)) {
+            return entry.value;
+          }
+        case FileMagicNumberMatchType.byRange:
+          final value = _detectRiffBasedFormat(bytes);
+          if (value != null) return value;
       }
     }
     return FileMagicNumberType.unknown;
   }
 
+  static FileMagicNumberType? _detectRiffBasedFormat(Uint8List bytes) {
+    if (bytes.length < 12) return null;
+
+    final isRIFF = bytes[0] == 0x52 &&
+        bytes[1] == 0x49 &&
+        bytes[2] == 0x46 &&
+        bytes[3] == 0x46;
+
+    if (!isRIFF) return null;
+
+    final format = String.fromCharCodes(bytes.sublist(8, 12));
+    switch (format) {
+      case 'WEBP':
+        return FileMagicNumberType.webp;
+      case 'WAVE':
+        return FileMagicNumberType.wav;
+      case 'AVI ':
+        return FileMagicNumberType.avi;
+      default:
+        return null;
+    }
+  }
+
   /// Detects the file type from a byte array using its magic number.
   ///
   /// - [bytes]: The byte data of the file.
@@ -88,7 +122,7 @@ class FileMagicNumber {
   /// Check whether the byte sequence (representing a file signature) exists within the data stream.
   static bool _matchAt(Uint8List data, List<int> pattern, int offset) {
     for (int i = 0; i < pattern.length; i++) {
-      if (data[offset + i] != pattern[i]) {
+      if (offset + i < data.length && data[offset + i] != pattern[i]) {
         return false;
       }
     }

lib/src/file_magic_number_match_type.dart

@@ -7,7 +7,8 @@ import '../file_magic_number.dart';
 /// or if it can appear at any position within a predefined range (`offset`).
 enum FileMagicNumberMatchType {
   exact,
-  offset;
+  offset,
+  byRange;
 
   /// Determines how the magic number should be matched for this file type.
   ///
@@ -16,13 +17,18 @@ enum FileMagicNumberMatchType {
   /// offset, so they are matched differently (`offset`).
   ///
   /// This method is used internally by the library during file type detection.
-  static bool isExact(FileMagicNumberType type) {
+  static FileMagicNumberMatchType get(FileMagicNumberType type) {
     switch (type) {
       case FileMagicNumberType.mp4:
       case FileMagicNumberType.heic:
-        return false;
+      case FileMagicNumberType.pdf:
+        return offset;
+      case FileMagicNumberType.webp:
+      case FileMagicNumberType.wav:
+      case FileMagicNumberType.avi:
+        return byRange;
       default:
-        return true;
+        return exact;
     }
   }
 }

lib/src/file_magic_number_type.dart

@@ -53,6 +53,12 @@ enum FileMagicNumberType {
   /// MP4 (MPEG-4 Part 14) video file format.
   mp4,
 
+  /// WebP (WebP)
+  webp,
+
+  /// AVI video file format.
+  avi,
+
   // Other formats
   /// PDF (Portable Document Format) file.
   pdf,

lib/src/magic_number_list.dart

@@ -36,10 +36,12 @@ class MagicNumberList {
     [0x7F, 0x45, 0x4C, 0x46]: FileMagicNumberType.elf,
     [0x52, 0x49, 0x46, 0x46]: FileMagicNumberType.wav,
     [0x50, 0x4B, 0x03, 0x04]: FileMagicNumberType.zip,
+    [0xFF, 0xD8, 0xFF, 0xE0]: FileMagicNumberType.jpg, // JPEG (JFIF)
+    [0xFF, 0xD8, 0xFF, 0xE1]: FileMagicNumberType.jpg, // JPEG (EXIF)
 
     // 3 bytes
     [0x49, 0x44, 0x33]: FileMagicNumberType.mp3,
-    [0xFF, 0xD8, 0xFF]: FileMagicNumberType.jpg,
+    [0xFF, 0xD8, 0xFF]: FileMagicNumberType.jpg, // JPEG (generic)
 
     // 2 bytes
     [0x4D, 0x5A]: FileMagicNumberType.exe,

pubspec.yaml

@@ -1,6 +1,6 @@
 name: file_magic_number
 description: "A Flutter package to detect file types based on their magic number instead of MIME types. Supports Flutter on mobile, desktop, and web without native code."
-version: 1.3.2
+version: 1.4.0
 homepage: https://github.com/vicajilau/file_magic_number
 
 environment:

test/file_magic_number_bytes_test.dart

@@ -26,7 +26,7 @@ void main() {
     });
 
     test('Detects RAR v5 file', () {
-      final bytes = Uint8List.fromList([0x52, 0x61, 0x72, 0x21, 0x1A, 0x07]);
+      final bytes = Uint8List.fromList([0x52, 0x61, 0x72, 0x21, 0x1A, 0x07, 0x00]);
       final result = FileMagicNumber.detectFileTypeFromBytes(bytes);
       expect(result, FileMagicNumberType.rar);
     });
@@ -80,11 +80,38 @@ void main() {
     });
 
     test('Detects WAV file', () {
-      final bytes = Uint8List.fromList([0x52, 0x49, 0x46, 0x46]);
+      // RIFF....WAVE (offset 0: "RIFF", offset 8: "WAVE")
+      final bytes = Uint8List.fromList([
+        0x52, 0x49, 0x46, 0x46, // "RIFF"
+        0x00, 0x00, 0x00, 0x00, // dummy size
+        0x57, 0x41, 0x56, 0x45  // "WAVE"
+      ]);
       final result = FileMagicNumber.detectFileTypeFromBytes(bytes);
       expect(result, FileMagicNumberType.wav);
     });
 
+    test('Detects WebP file', () {
+      // RIFF....WEBP (offset 0: "RIFF", offset 8: "WEBP")
+      final bytes = Uint8List.fromList([
+        0x52, 0x49, 0x46, 0x46, // "RIFF"
+        0x00, 0x00, 0x00, 0x00, // dummy size
+        0x57, 0x45, 0x42, 0x50  // "WEBP"
+      ]);
+      final result = FileMagicNumber.detectFileTypeFromBytes(bytes);
+      expect(result, FileMagicNumberType.webp);
+    });
+
+    test('Detects AVI file', () {
+      // RIFF....AVI (offset 0: "RIFF", offset 8: "AVI ")
+      final bytes = Uint8List.fromList([
+        0x52, 0x49, 0x46, 0x46, // "RIFF"
+        0x00, 0x00, 0x00, 0x00, // dummy size
+        0x41, 0x56, 0x49, 0x20  // "AVI "
+      ]);
+      final result = FileMagicNumber.detectFileTypeFromBytes(bytes);
+      expect(result, FileMagicNumberType.avi);
+    });
+
     test('Detects MP4 file', () {
       final bytes =
           Uint8List.fromList([0x66, 0x74, 0x79, 0x70, 0x69, 0x73, 0x6F, 0x6D]);