lib/src/magic_number.dart

// Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

library mime.magic_number;

class MagicNumber {
  final String mimeType;
  final List<int> numbers;
  final List<int>? mask;

  const MagicNumber(this.mimeType, this.numbers, {this.mask});

  bool matches(List<int> header) {
    if (header.length < numbers.length) return false;

    for (var i = 0; i < numbers.length; i++) {
      if (mask != null) {
        if ((mask![i] & numbers[i]) != (mask![i] & header[i])) return false;
      } else {
        if (numbers[i] != header[i]) return false;
      }
    }

    return true;
  }
}

const int initialMagicNumbersMaxLength = 12;

const List<MagicNumber> initialMagicNumbers = [
  MagicNumber('application/pdf', [0x25, 0x50, 0x44, 0x46]),
  MagicNumber('application/postscript', [0x25, 0x51]),

  /// AIFF is based on the EA IFF 85 Standard for Interchange Format Files.
  /// -> 4 bytes have the ASCII characters 'F' 'O' 'R' 'M'.
  /// -> 4 bytes indicating the size of the file
  /// -> 4 bytes have the ASCII characters 'A' 'I' 'F' 'F'.
  /// http://www-mmsp.ece.mcgill.ca/Documents/AudioFormats/AIFF/Docs/AIFF-1.3.pdf
  MagicNumber('audio/x-aiff', [
    0x46,
    0x4F,
    0x52,
    0x4D,
    0x00,
    0x00,
    0x00,
    0x00,
    0x41,
    0x49,
    0x46,
    0x46
  ], mask: [
    0xFF,
    0xFF,
    0xFF,
    0xFF,
    0x00,
    0x00,
    0x00,
    0x00,
    0xFF,
    0xFF,
    0xFF,
    0xFF
  ]),

  /// -> 4 bytes have the ASCII characters 'f' 'L' 'a' 'C'.
  /// https://xiph.org/flac/format.html
  MagicNumber('audio/x-flac', [0x66, 0x4C, 0x61, 0x43]),

  /// The WAVE file format is based on the RIFF document format.
  /// -> 4 bytes have the ASCII characters 'R' 'I' 'F' 'F'.
  /// -> 4 bytes indicating the size of the file
  /// -> 4 bytes have the ASCII characters 'W' 'A' 'V' 'E'.
  /// http://www-mmsp.ece.mcgill.ca/Documents/AudioFormats/WAVE/Docs/riffmci.pdf
  MagicNumber('audio/x-wav', [
    0x52,
    0x49,
    0x46,
    0x46,
    0x00,
    0x00,
    0x00,
    0x00,
    0x57,
    0x41,
    0x56,
    0x45
  ], mask: [
    0xFF,
    0xFF,
    0xFF,
    0xFF,
    0x00,
    0x00,
    0x00,
    0x00,
    0xFF,
    0xFF,
    0xFF,
    0xFF
  ]),
  MagicNumber('image/gif', [0x47, 0x49, 0x46, 0x38, 0x37, 0x61]),
  MagicNumber('image/gif', [0x47, 0x49, 0x46, 0x38, 0x39, 0x61]),
  MagicNumber('image/jpeg', [0xFF, 0xD8]),
  MagicNumber('image/png', [0x89, 0x50, 0x4E, 0x47, 0x0D, 0x0A, 0x1A, 0x0A]),
  MagicNumber('image/tiff', [0x49, 0x49, 0x2A, 0x00]),
  MagicNumber('image/tiff', [0x4D, 0x4D, 0x00, 0x2A]),
  MagicNumber('video/mp4', [
    0x00,
    0x00,
    0x00,
    0x00,
    0x66,
    0x74,
    0x79,
    0x70,
    0x33,
    0x67,
    0x70,
    0x35
  ], mask: [
    0xFF,
    0xFF,
    0xFF,
    0x00,
    0xFF,
    0xFF,
    0xFF,
    0xFF,
    0xFF,
    0xFF,
    0xFF,
    0xFF
  ]),
  MagicNumber('model/gltf-binary', [0x46, 0x54, 0x6C, 0x67]),

  /// The WebP file format is based on the RIFF document format.
  /// -> 4 bytes have the ASCII characters 'R' 'I' 'F' 'F'.
  /// -> 4 bytes indicating the size of the file
  /// -> 4 bytes have the ASCII characters 'W' 'E' 'B' 'P'.
  /// https://developers.google.com/speed/webp/docs/riff_container
  MagicNumber('image/webp', [
    0x52,
    0x49,
    0x46,
    0x46,
    0x00,
    0x00,
    0x00,
    0x00,
    0x57,
    0x45,
    0x42,
    0x50
  ], mask: [
    0xFF,
    0xFF,
    0xFF,
    0xFF,
    0x00,
    0x00,
    0x00,
    0x00,
    0xFF,
    0xFF,
    0xFF,
    0xFF
  ])
];