filetype.es6.js

/*!
 * Library to detect file mime type of a Uint8Array.
 *
 * Modified from https://github.com/sindresorhus/file-type to be used standalone on browser based apps.
 *
 * This library requires Node "buffer" module as a pre-requisite. The "buffer" module is made available in this repo
 * for standalone use via the `buffer.js` script which needs to be loaded before this file on the page.
 *
 * Author: Kartik Visweswaran, Krajee.com
 */
var KrajeeFileTypeConfig = {
    minimumBytes: 4100, // A fair amount of file-types are detectable within this range,
    defaultMessages: 'End-Of-Stream',
    tarHeaderChecksumMatches: function (buffer, offset = 0) {
        var readSum = Number.parseInt(buffer.toString('utf8', 148, 154).replace(/\0.*$/, '').trim(), 8); // Read sum in header
        if (Number.isNaN(readSum)) {
            return false;
        }

        var sum = 8 * 0x20; // Initialize signed bit sum

        for (let i = offset; i < offset + 148; i++) {
            sum += buffer[i];
        }

        for (let i = offset + 156; i < offset + 512; i++) {
            sum += buffer[i];
        }

        return readSum === sum;
    },
    uint32SyncSafeToken: {
        get: function (buffer, offset) {
            return (buffer[offset + 3] & 0x7F) | ((buffer[offset + 2]) << 7) | ((buffer[offset + 1]) << 14) | ((buffer[offset]) << 21);
        },
        len: 4,
    },
    dv: function (array) {
        return new DataView(array.buffer, array.byteOffset);
    },
    Token: {
        /**
         * 8-bit unsigned integer
         */
        UINT8: {
            len: 1,
            get: function (array, offset) {
                return KrajeeFileTypeConfig.dv(array).getUint8(offset);
            },
            put: function (array, offset, value) {
                KrajeeFileTypeConfig.dv(array).setUint8(offset, value);
                return offset + 1;
            }
        },
        /**
         * 16-bit unsigned integer, Little Endian byte order
         */
        UINT16_LE: {
            len: 2,
            get: function (array, offset) {
                return KrajeeFileTypeConfig.dv(array).getUint16(offset, true);
            },
            put: function (array, offset, value) {
                KrajeeFileTypeConfig.dv(array).setUint16(offset, value, true);
                return offset + 2;
            }
        },
        /**
         * 16-bit unsigned integer, Big Endian byte order
         */
        UINT16_BE: {
            len: 2,
            get: function (array, offset) {
                return KrajeeFileTypeConfig.dv(array).getUint16(offset);
            },
            put: function (array, offset, value) {
                KrajeeFileTypeConfig.dv(array).setUint16(offset, value);
                return offset + 2;
            }
        },
        /**
         * 32-bit unsigned integer, Big Endian byte order
         */
        INT32_BE: {
            len: 4,
            get: function (array, offset) {
                return KrajeeFileTypeConfig.dv(array).getInt32(offset);
            },
            put: function (array, offset, value) {
                KrajeeFileTypeConfig.dv(array).setInt32(offset, value);
                return offset + 4;
            }
        },
        /**
         * 32-bit unsigned integer, Little Endian byte order
         */
        UINT32_LE: {
            len: 4,
            get: function (array, offset) {
                return KrajeeFileTypeConfig.dv(array).getUint32(offset, true);
            },
            put: function (array, offset, value) {
                KrajeeFileTypeConfig.dv(array).setUint32(offset, value, true);
                return offset + 4;
            }
        },
        /**
         * 32-bit unsigned integer, Big Endian byte order
         */
        UINT32_BE: {
            len: 4,
            get: function (array, offset) {
                return KrajeeFileTypeConfig.dv(array).getUint32(offset);
            },
            put: function (array, offset, value) {
                KrajeeFileTypeConfig.dv(array).setUint32(offset, value);
                return offset + 4;
            }
        },

        /**
         * 64-bit unsigned integer, Little Endian byte order
         */
        UINT64_LE: {
            len: 8,
            get: function (array, offset) {
                return KrajeeFileTypeConfig.dv(array).getBigUint64(offset, true);
            },
            put: function (array, offset, value) {
                KrajeeFileTypeConfig.dv(array).setBigUint64(offset, value, true);
                return offset + 8;
            }
        },
        /**
         * 64-bit unsigned integer, Big Endian byte order
         */
        UINT64_BE: {
            len: 8,
            get: function (array, offset) {
                return KrajeeFileTypeConfig.dv(array).getBigUint64(offset);
            },
            put: function (array, offset, value) {
                KrajeeFileTypeConfig.dv(array).setBigUint64(offset, value);
                return offset + 8;
            }
        }
    }
};

class EndOfStreamError extends Error {
    constructor() {
        super(KrajeeFileTypeConfig.defaultMessages);
    }
}

class StringType {
    constructor(len, encoding) {
        this.len = len;
        this.encoding = encoding;
    }

    get(uint8Array, offset) {
        return Buffer.from(uint8Array).toString(this.encoding, offset, offset + this.len);
    }
}

async function fileTypeFromTokenizer(tokenizer) {
    try {
        return new FileTypeParser().parse(tokenizer);
    } catch (error) {
        if (!(error instanceof EndOfStreamError)) {
            throw error;
        }
    }
}

class BufferTokenizer {
    /**
     * Construct BufferTokenizer
     * @param uint8Array - Uint8Array to tokenize
     * @param fileInfo - Pass additional file information to the tokenizer
     */
    constructor(uint8Array, fileInfo) {
        /**
         * Tokenizer-stream position
         */
        this.position = 0;
        this.numBuffer = new Uint8Array(8);
        this.fileInfo = fileInfo ? fileInfo : {};
        this.uint8Array = uint8Array;
        this.fileInfo.size = this.fileInfo.size ? this.fileInfo.size : uint8Array.length;
    }

    /**
     * Read a token from the tokenizer-stream
     * @param token - The token to read
     * @param position - If provided, the desired position in the tokenizer-stream
     * @returns Promise with token data
     */
    async readToken(token, position = this.position) {
        const uint8Array = Buffer.alloc(token.len);
        const len = await this.readBuffer(uint8Array, {position});
        if (len < token.len)
            throw new EndOfStreamError();
        return token.get(uint8Array, 0);
    }

    /**
     * Peek a token from the tokenizer-stream.
     * @param token - Token to peek from the tokenizer-stream.
     * @param position - Offset where to begin reading within the file. If position is null, data will be read from the current file position.
     * @returns Promise with token data
     */
    async peekToken(token, position = this.position) {
        const uint8Array = Buffer.alloc(token.len);
        const len = await this.peekBuffer(uint8Array, {position});
        if (len < token.len)
            throw new EndOfStreamError();
        return token.get(uint8Array, 0);
    }

    /**
     * Read buffer from tokenizer
     * @param uint8Array - Uint8Array to tokenize
     * @param options - Read behaviour options
     * @returns {Promise<number>}
     */
    async readBuffer(uint8Array, options) {
        if (options && options.position) {
            if (options.position < this.position) {
                throw new Error('`options.position` must be equal or greater than `tokenizer.position`');
            }
            this.position = options.position;
        }
        const bytesRead = await this.peekBuffer(uint8Array, options);
        this.position += bytesRead;
        return bytesRead;
    }

    /**
     * Peek (read ahead) buffer from tokenizer
     * @param uint8Array
     * @param options - Read behaviour options
     * @returns {Promise<number>}
     */
    async peekBuffer(uint8Array, options) {
        const normOptions = this.normalizeOptions(uint8Array, options);
        const bytes2read = Math.min(this.uint8Array.length - normOptions.position, normOptions.length);
        if ((!normOptions.mayBeLess) && bytes2read < normOptions.length) {
            throw new EndOfStreamError();
        } else {
            uint8Array.set(this.uint8Array.subarray(normOptions.position, normOptions.position + bytes2read), normOptions.offset);
            return bytes2read;
        }
    }

    /**
     * Read a numeric token from the stream
     * @param token - Numeric token
     * @returns Promise with number
     */
    async readNumber(token) {
        const len = await this.readBuffer(this.numBuffer, {length: token.len});
        if (len < token.len)
            throw new EndOfStreamError();
        return token.get(this.numBuffer, 0);
    }

    /**
     * Read a numeric token from the stream
     * @param token - Numeric token
     * @returns Promise with number
     */
    async peekNumber(token) {
        const len = await this.peekBuffer(this.numBuffer, {length: token.len});
        if (len < token.len)
            throw new EndOfStreamError();
        return token.get(this.numBuffer, 0);
    }

    async close() {
        // empty
    }

    /**
     *  Ignore number of bytes, advances the pointer in under tokenizer-stream.
     * @param length - Number of bytes to ignore
     * @return resolves the number of bytes ignored, equals length if this available, otherwise the number of bytes available
     */
    async ignore(length) {
        if (this.fileInfo.size !== undefined) {
            const bytesLeft = this.fileInfo.size - this.position;
            if (length > bytesLeft) {
                this.position += bytesLeft;
                return bytesLeft;
            }
        }
        this.position += length;
        return length;
    }

    normalizeOptions(uint8Array, options) {
        if (options && options.position !== undefined && options.position < this.position) {
            throw new Error('`options.position` must be equal or greater than `tokenizer.position`');
        }
        if (options) {
            return {
                mayBeLess: options.mayBeLess === true,
                offset: options.offset ? options.offset : 0,
                length: options.length ? options.length : (uint8Array.length - (options.offset ? options.offset : 0)),
                position: options.position ? options.position : this.position
            };
        }
        return {
            mayBeLess: false,
            offset: 0,
            length: uint8Array.length,
            position: this.position
        };
    }
}

class FileTypeParser {
    _check(buffer, headers, options) {
        options = {
            offset: 0,
            ...options,
        };

        for (const [index, header] of headers.entries()) {
            // If a bitmask is set
            if (options.mask) {
                // If header doesn't equal `buf` with bits masked off
                if (header !== (options.mask[index] & buffer[index + options.offset])) {
                    return false;
                }
            } else if (header !== buffer[index + options.offset]) {
                return false;
            }
        }

        return true;
    }

    check(header, options) {
        return this._check(this.buffer, header, options);
    }

    stringToBytes(string) {
        return [...string].map(character => character.charCodeAt(0));
    }

    checkString(header, options) {
        return this.check(this.stringToBytes(header), options);
    }

    async parse(input) {
        if (!(input instanceof Uint8Array || input instanceof ArrayBuffer || input instanceof BufferTokenizer)) {
            throw new TypeError(`Expected the \`input\` argument to be of type \`Uint8Array\` or \`Buffer\` or \`ArrayBuffer\`, got \`${typeof input}\``);
        }
        let tokenizer = input;
        if (!(tokenizer instanceof BufferTokenizer)) {
            const buffer = input instanceof Uint8Array ? input : new Uint8Array(input);
            if (!(buffer && buffer.length > 1)) {
                return;
            }
            tokenizer = new BufferTokenizer(buffer);
        }

        try {
            return this.parseTokenizer(tokenizer);
        } catch (error) {
            if (!(error instanceof EndOfStreamError)) {
                throw error;
            }
        }
    }

    async parseTokenizer(tokenizer) {
        const Token = KrajeeFileTypeConfig.Token;

        this.buffer = Buffer.alloc(KrajeeFileTypeConfig.minimumBytes);
        // Keep reading until EOF if the file size is unknown.
        if (tokenizer.fileInfo.size === undefined) {
            tokenizer.fileInfo.size = Number.MAX_SAFE_INTEGER;
        }

        this.tokenizer = tokenizer;

        await tokenizer.peekBuffer(this.buffer, {length: 12, mayBeLess: true});

        // -- 2-byte signatures --

        if (this.check([0x42, 0x4D])) {
            return {
                ext: 'bmp',
                mime: 'image/bmp',
            };
        }

        if (this.check([0x0B, 0x77])) {
            return {
                ext: 'ac3',
                mime: 'audio/vnd.dolby.dd-raw',
            };
        }

        if (this.check([0x78, 0x01])) {
            return {
                ext: 'dmg',
                mime: 'application/x-apple-diskimage',
            };
        }

        if (this.check([0x4D, 0x5A])) {
            return {
                ext: 'exe',
                mime: 'application/x-msdownload',
            };
        }

        if (this.check([0x25, 0x21])) {
            await tokenizer.peekBuffer(this.buffer, {length: 24, mayBeLess: true});

            if (
                this.checkString('PS-Adobe-', {offset: 2})
                && this.checkString(' EPSF-', {offset: 14})
            ) {
                return {
                    ext: 'eps',
                    mime: 'application/eps',
                };
            }

            return {
                ext: 'ps',
                mime: 'application/postscript',
            };
        }

        if (this.check([0x1F, 0xA0]) || this.check([0x1F, 0x9D])) {
            return {
                ext: 'Z',
                mime: 'application/x-compress',
            };
        }

        // -- 3-byte signatures --
        if (this.check([0x47, 0x49, 0x46])) {
            return {
                ext: 'gif',
                mime: 'image/gif',
            };
        }

        if (this.check([0xFF, 0xD8, 0xFF])) {
            return {
                ext: 'jpg',
                mime: 'image/jpeg',
            };
        }

        if (this.check([0x49, 0x49, 0xBC])) {
            return {
                ext: 'jxr',
                mime: 'image/vnd.ms-photo',
            };
        }

        if (this.check([0x1F, 0x8B, 0x8])) {
            return {
                ext: 'gz',
                mime: 'application/gzip',
            };
        }

        if (this.check([0x42, 0x5A, 0x68])) {
            return {
                ext: 'bz2',
                mime: 'application/x-bzip2',
            };
        }

        if (this.checkString('ID3')) {
            await tokenizer.ignore(6); // Skip ID3 header until the header size
            const id3HeaderLength = await tokenizer.readToken(KrajeeFileTypeConfig.uint32SyncSafeToken);
            if (tokenizer.position + id3HeaderLength > tokenizer.fileInfo.size) {
                // Guess file type based on ID3 header for backward compatibility
                return {
                    ext: 'mp3',
                    mime: 'audio/mpeg',
                };
            }

            await tokenizer.ignore(id3HeaderLength);
            return fileTypeFromTokenizer(tokenizer); // Skip ID3 header, recursion
        }

        // Musepack, SV7
        if (this.checkString('MP+')) {
            return {
                ext: 'mpc',
                mime: 'audio/x-musepack',
            };
        }

        if (
            (this.buffer[0] === 0x43 || this.buffer[0] === 0x46)
            && this.check([0x57, 0x53], {offset: 1})
        ) {
            return {
                ext: 'swf',
                mime: 'application/x-shockwave-flash',
            };
        }

        // -- 4-byte signatures --

        if (this.checkString('FLIF')) {
            return {
                ext: 'flif',
                mime: 'image/flif',
            };
        }

        if (this.checkString('8BPS')) {
            return {
                ext: 'psd',
                mime: 'image/vnd.adobe.photoshop',
            };
        }

        if (this.checkString('WEBP', {offset: 8})) {
            return {
                ext: 'webp',
                mime: 'image/webp',
            };
        }

        // Musepack, SV8
        if (this.checkString('MPCK')) {
            return {
                ext: 'mpc',
                mime: 'audio/x-musepack',
            };
        }

        if (this.checkString('FORM')) {
            return {
                ext: 'aif',
                mime: 'audio/aiff',
            };
        }

        if (this.checkString('icns', {offset: 0})) {
            return {
                ext: 'icns',
                mime: 'image/icns',
            };
        }

        // Zip-based file formats
        // Need to be before the `zip` check
        if (this.check([0x50, 0x4B, 0x3, 0x4])) { // Local file header signature
            try {
                while (tokenizer.position + 30 < tokenizer.fileInfo.size) {
                    await tokenizer.readBuffer(this.buffer, {length: 30});

                    // https://en.wikipedia.org/wiki/Zip_(file_format)#File_headers
                    const zipHeader = {
                        compressedSize: this.buffer.readUInt32LE(18),
                        uncompressedSize: this.buffer.readUInt32LE(22),
                        filenameLength: this.buffer.readUInt16LE(26),
                        extraFieldLength: this.buffer.readUInt16LE(28),
                    };

                    zipHeader.filename = await tokenizer.readToken(new StringType(zipHeader.filenameLength, 'utf-8'));
                    await tokenizer.ignore(zipHeader.extraFieldLength);

                    // Assumes signed `.xpi` from addons.mozilla.org
                    if (zipHeader.filename === 'META-INF/mozilla.rsa') {
                        return {
                            ext: 'xpi',
                            mime: 'application/x-xpinstall',
                        };
                    }

                    if (zipHeader.filename.endsWith('.rels') || zipHeader.filename.endsWith('.xml')) {
                        const type = zipHeader.filename.split('/')[0];
                        switch (type) {
                            case '_rels':
                                break;
                            case 'word':
                                return {
                                    ext: 'docx',
                                    mime: 'application/vnd.openxmlformats-officedocument.wordprocessingml.document',
                                };
                            case 'ppt':
                                return {
                                    ext: 'pptx',
                                    mime: 'application/vnd.openxmlformats-officedocument.presentationml.presentation',
                                };
                            case 'xl':
                                return {
                                    ext: 'xlsx',
                                    mime: 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet',
                                };
                            default:
                                break;
                        }
                    }

                    if (zipHeader.filename.startsWith('xl/')) {
                        return {
                            ext: 'xlsx',
                            mime: 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet',
                        };
                    }

                    if (zipHeader.filename.startsWith('3D/') && zipHeader.filename.endsWith('.model')) {
                        return {
                            ext: '3mf',
                            mime: 'model/3mf',
                        };
                    }

                    // The docx, xlsx and pptx file types extend the Office Open XML file format:
                    // https://en.wikipedia.org/wiki/Office_Open_XML_file_formats
                    // We look for:
                    // - one entry named '[Content_Types].xml' or '_rels/.rels',
                    // - one entry indicating specific type of file.
                    // MS Office, OpenOffice and LibreOffice may put the parts in different order, so the check should not rely on it.
                    if (zipHeader.filename === 'mimetype' && zipHeader.compressedSize === zipHeader.uncompressedSize) {
                        const mimeType = (await tokenizer.readToken(new StringType(zipHeader.compressedSize, 'utf-8'))).trim();

                        switch (mimeType) {
                            case 'application/epub+zip':
                                return {
                                    ext: 'epub',
                                    mime: 'application/epub+zip',
                                };
                            case 'application/vnd.oasis.opendocument.text':
                                return {
                                    ext: 'odt',
                                    mime: 'application/vnd.oasis.opendocument.text',
                                };
                            case 'application/vnd.oasis.opendocument.spreadsheet':
                                return {
                                    ext: 'ods',
                                    mime: 'application/vnd.oasis.opendocument.spreadsheet',
                                };
                            case 'application/vnd.oasis.opendocument.presentation':
                                return {
                                    ext: 'odp',
                                    mime: 'application/vnd.oasis.opendocument.presentation',
                                };
                            default:
                        }
                    }

                    // Try to find next header manually when current one is corrupted
                    if (zipHeader.compressedSize === 0) {
                        let nextHeaderIndex = -1;

                        while (nextHeaderIndex < 0 && (tokenizer.position < tokenizer.fileInfo.size)) {
                            await tokenizer.peekBuffer(this.buffer, {mayBeLess: true});

                            nextHeaderIndex = this.buffer.indexOf('504B0304', 0, 'hex');
                            // Move position to the next header if found, skip the whole buffer otherwise
                            await tokenizer.ignore(nextHeaderIndex >= 0 ? nextHeaderIndex : this.buffer.length);
                        }
                    } else {
                        await tokenizer.ignore(zipHeader.compressedSize);
                    }
                }
            } catch (error) {
                if (!(error instanceof EndOfStreamError)) {
                    throw error;
                }
            }

            return {
                ext: 'zip',
                mime: 'application/zip',
            };
        }

        if (this.checkString('OggS')) {
            // This is an OGG container
            await tokenizer.ignore(28);
            const type = Buffer.alloc(8);
            await tokenizer.readBuffer(type);

            // Needs to be before `ogg` check
            if (this._check(type, [0x4F, 0x70, 0x75, 0x73, 0x48, 0x65, 0x61, 0x64])) {
                return {
                    ext: 'opus',
                    mime: 'audio/opus',
                };
            }

            // If ' theora' in header.
            if (this._check(type, [0x80, 0x74, 0x68, 0x65, 0x6F, 0x72, 0x61])) {
                return {
                    ext: 'ogv',
                    mime: 'video/ogg',
                };
            }

            // If '\x01video' in header.
            if (this._check(type, [0x01, 0x76, 0x69, 0x64, 0x65, 0x6F, 0x00])) {
                return {
                    ext: 'ogm',
                    mime: 'video/ogg',
                };
            }

            // If ' FLAC' in header  https://xiph.org/flac/faq.html
            if (this._check(type, [0x7F, 0x46, 0x4C, 0x41, 0x43])) {
                return {
                    ext: 'oga',
                    mime: 'audio/ogg',
                };
            }

            // 'Speex  ' in header https://en.wikipedia.org/wiki/Speex
            if (this._check(type, [0x53, 0x70, 0x65, 0x65, 0x78, 0x20, 0x20])) {
                return {
                    ext: 'spx',
                    mime: 'audio/ogg',
                };
            }

            // If '\x01vorbis' in header
            if (this._check(type, [0x01, 0x76, 0x6F, 0x72, 0x62, 0x69, 0x73])) {
                return {
                    ext: 'ogg',
                    mime: 'audio/ogg',
                };
            }

            // Default OGG container https://www.iana.org/assignments/media-types/application/ogg
            return {
                ext: 'ogx',
                mime: 'application/ogg',
            };
        }

        if (
            this.check([0x50, 0x4B])
            && (this.buffer[2] === 0x3 || this.buffer[2] === 0x5 || this.buffer[2] === 0x7)
            && (this.buffer[3] === 0x4 || this.buffer[3] === 0x6 || this.buffer[3] === 0x8)
        ) {
            return {
                ext: 'zip',
                mime: 'application/zip',
            };
        }

        //

        // File Type Box (https://en.wikipedia.org/wiki/ISO_base_media_file_format)
        // It's not required to be first, but it's recommended to be. Almost all ISO base media files start with `ftyp` box.
        // `ftyp` box must contain a brand major identifier, which must consist of ISO 8859-1 printable characters.
        // Here we check for 8859-1 printable characters (for simplicity, it's a mask which also catches one non-printable character).
        if (
            this.checkString('ftyp', {offset: 4})
            && (this.buffer[8] & 0x60) !== 0x00 // Brand major, first character ASCII?
        ) {
            // They all can have MIME `video/mp4` except `application/mp4` special-case which is hard to detect.
            // For some cases, we're specific, everything else falls to `video/mp4` with `mp4` extension.
            const brandMajor = this.buffer.toString('binary', 8, 12).replace('\0', ' ').trim();
            switch (brandMajor) {
                case 'avif':
                case 'avis':
                    return {ext: 'avif', mime: 'image/avif'};
                case 'mif1':
                    return {ext: 'heic', mime: 'image/heif'};
                case 'msf1':
                    return {ext: 'heic', mime: 'image/heif-sequence'};
                case 'heic':
                case 'heix':
                    return {ext: 'heic', mime: 'image/heic'};
                case 'hevc':
                case 'hevx':
                    return {ext: 'heic', mime: 'image/heic-sequence'};
                case 'qt':
                    return {ext: 'mov', mime: 'video/quicktime'};
                case 'M4V':
                case 'M4VH':
                case 'M4VP':
                    return {ext: 'm4v', mime: 'video/x-m4v'};
                case 'M4P':
                    return {ext: 'm4p', mime: 'video/mp4'};
                case 'M4B':
                    return {ext: 'm4b', mime: 'audio/mp4'};
                case 'M4A':
                    return {ext: 'm4a', mime: 'audio/x-m4a'};
                case 'F4V':
                    return {ext: 'f4v', mime: 'video/mp4'};
                case 'F4P':
                    return {ext: 'f4p', mime: 'video/mp4'};
                case 'F4A':
                    return {ext: 'f4a', mime: 'audio/mp4'};
                case 'F4B':
                    return {ext: 'f4b', mime: 'audio/mp4'};
                case 'crx':
                    return {ext: 'cr3', mime: 'image/x-canon-cr3'};
                default:
                    if (brandMajor.startsWith('3g')) {
                        if (brandMajor.startsWith('3g2')) {
                            return {ext: '3g2', mime: 'video/3gpp2'};
                        }

                        return {ext: '3gp', mime: 'video/3gpp'};
                    }

                    return {ext: 'mp4', mime: 'video/mp4'};
            }
        }

        if (this.checkString('MThd')) {
            return {
                ext: 'mid',
                mime: 'audio/midi',
            };
        }

        if (
            this.checkString('wOFF')
            && (
                this.check([0x00, 0x01, 0x00, 0x00], {offset: 4})
                || this.checkString('OTTO', {offset: 4})
            )
        ) {
            return {
                ext: 'woff',
                mime: 'font/woff',
            };
        }

        if (this.checkString('wOF2') && (this.check([0x00, 0x01, 0x00, 0x00], {offset: 4}) || this.checkString('OTTO', {offset: 4}))) {
            return {
                ext: 'woff2',
                mime: 'font/woff2',
            };
        }

        if (this.check([0xD4, 0xC3, 0xB2, 0xA1]) || this.check([0xA1, 0xB2, 0xC3, 0xD4])) {
            return {
                ext: 'pcap',
                mime: 'application/vnd.tcpdump.pcap',
            };
        }

        // Sony DSD Stream File (DSF)
        if (this.checkString('DSD ')) {
            return {
                ext: 'dsf',
                mime: 'audio/x-dsf', // Non-standard
            };
        }

        if (this.checkString('LZIP')) {
            return {
                ext: 'lz',
                mime: 'application/x-lzip',
            };
        }

        if (this.checkString('fLaC')) {
            return {
                ext: 'flac',
                mime: 'audio/x-flac',
            };
        }

        if (this.check([0x42, 0x50, 0x47, 0xFB])) {
            return {
                ext: 'bpg',
                mime: 'image/bpg',
            };
        }

        if (this.checkString('wvpk')) {
            return {
                ext: 'wv',
                mime: 'audio/wavpack',
            };
        }

        if (this.checkString('%PDF')) {
            await tokenizer.ignore(1350);
            const maxBufferSize = 10 * 1024 * 1024;
            const buffer = Buffer.alloc(Math.min(maxBufferSize, tokenizer.fileInfo.size));
            await tokenizer.readBuffer(buffer, {mayBeLess: true});

            // Check if this is an Adobe Illustrator file
            if (buffer.includes(Buffer.from('AIPrivateData'))) {
                return {
                    ext: 'ai',
                    mime: 'application/postscript',
                };
            }

            // Assume this is just a normal PDF
            return {
                ext: 'pdf',
                mime: 'application/pdf',
            };
        }

        if (this.check([0x00, 0x61, 0x73, 0x6D])) {
            return {
                ext: 'wasm',
                mime: 'application/wasm',
            };
        }

        // TIFF, little-endian type
        if (this.check([0x49, 0x49])) {
            const fileType = await this.readTiffHeader(false);
            if (fileType) {
                return fileType;
            }
        }

        // TIFF, big-endian type
        if (this.check([0x4D, 0x4D])) {
            const fileType = await this.readTiffHeader(true);
            if (fileType) {
                return fileType;
            }
        }

        if (this.checkString('MAC ')) {
            return {
                ext: 'ape',
                mime: 'audio/ape',
            };
        }

        // https://github.com/threatstack/libmagic/blob/master/magic/Magdir/matroska
        if (this.check([0x1A, 0x45, 0xDF, 0xA3])) { // Root element: EBML
            async function readField() {
                const msb = await tokenizer.peekNumber(Token.UINT8);
                let mask = 0x80;
                let ic = 0; // 0 = A, 1 = B, 2 = C, 3
                // = D

                while ((msb & mask) === 0) {
                    ++ic;
                    mask >>= 1;
                }

                const id = Buffer.alloc(ic + 1);
                await tokenizer.readBuffer(id);
                return id;
            }

            async function readElement() {
                const id = await readField();
                const lengthField = await readField();
                lengthField[0] ^= 0x80 >> (lengthField.length - 1);
                const nrLength = Math.min(6, lengthField.length); // JavaScript can max read 6 bytes integer
                return {
                    id: id.readUIntBE(0, id.length),
                    len: lengthField.readUIntBE(lengthField.length - nrLength, nrLength),
                };
            }

            async function readChildren(level, children) {
                while (children > 0) {
                    const element = await readElement();
                    if (element.id === 0x42_82) {
                        const rawValue = await tokenizer.readToken(new StringType(element.len, 'utf-8'));
                        return rawValue.replace(/\00.*$/g, ''); // Return DocType
                    }

                    await tokenizer.ignore(element.len); // ignore payload
                    --children;
                }
            }

            const re = await readElement();
            const docType = await readChildren(1, re.len);

            switch (docType) {
                case 'webm':
                    return {
                        ext: 'webm',
                        mime: 'video/webm',
                    };

                case 'matroska':
                    return {
                        ext: 'mkv',
                        mime: 'video/x-matroska',
                    };

                default:
                    return;
            }
        }

        // RIFF file format which might be AVI, WAV, QCP, etc
        if (this.check([0x52, 0x49, 0x46, 0x46])) {
            if (this.check([0x41, 0x56, 0x49], {offset: 8})) {
                return {
                    ext: 'avi',
                    mime: 'video/vnd.avi',
                };
            }

            if (this.check([0x57, 0x41, 0x56, 0x45], {offset: 8})) {
                return {
                    ext: 'wav',
                    mime: 'audio/vnd.wave',
                };
            }

            // QLCM, QCP file
            if (this.check([0x51, 0x4C, 0x43, 0x4D], {offset: 8})) {
                return {
                    ext: 'qcp',
                    mime: 'audio/qcelp',
                };
            }
        }

        if (this.checkString('SQLi')) {
            return {
                ext: 'sqlite',
                mime: 'application/x-sqlite3',
            };
        }

        if (this.check([0x4E, 0x45, 0x53, 0x1A])) {
            return {
                ext: 'nes',
                mime: 'application/x-nintendo-nes-rom',
            };
        }

        if (this.checkString('Cr24')) {
            return {
                ext: 'crx',
                mime: 'application/x-google-chrome-extension',
            };
        }

        if (
            this.checkString('MSCF')
            || this.checkString('ISc(')
        ) {
            return {
                ext: 'cab',
                mime: 'application/vnd.ms-cab-compressed',
            };
        }

        if (this.check([0xED, 0xAB, 0xEE, 0xDB])) {
            return {
                ext: 'rpm',
                mime: 'application/x-rpm',
            };
        }

        if (this.check([0xC5, 0xD0, 0xD3, 0xC6])) {
            return {
                ext: 'eps',
                mime: 'application/eps',
            };
        }

        if (this.check([0x28, 0xB5, 0x2F, 0xFD])) {
            return {
                ext: 'zst',
                mime: 'application/zstd',
            };
        }

        if (this.check([0x7F, 0x45, 0x4C, 0x46])) {
            return {
                ext: 'elf',
                mime: 'application/x-elf',
            };
        }

        // -- 5-byte signatures --

        if (this.check([0x4F, 0x54, 0x54, 0x4F, 0x00])) {
            return {
                ext: 'otf',
                mime: 'font/otf',
            };
        }

        if (this.checkString('#!AMR')) {
            return {
                ext: 'amr',
                mime: 'audio/amr',
            };
        }

        if (this.checkString('{\\rtf')) {
            return {
                ext: 'rtf',
                mime: 'application/rtf',
            };
        }

        if (this.check([0x46, 0x4C, 0x56, 0x01])) {
            return {
                ext: 'flv',
                mime: 'video/x-flv',
            };
        }

        if (this.checkString('IMPM')) {
            return {
                ext: 'it',
                mime: 'audio/x-it',
            };
        }

        if (
            this.checkString('-lh0-', {offset: 2})
            || this.checkString('-lh1-', {offset: 2})
            || this.checkString('-lh2-', {offset: 2})
            || this.checkString('-lh3-', {offset: 2})
            || this.checkString('-lh4-', {offset: 2})
            || this.checkString('-lh5-', {offset: 2})
            || this.checkString('-lh6-', {offset: 2})
            || this.checkString('-lh7-', {offset: 2})
            || this.checkString('-lzs-', {offset: 2})
            || this.checkString('-lz4-', {offset: 2})
            || this.checkString('-lz5-', {offset: 2})
            || this.checkString('-lhd-', {offset: 2})
        ) {
            return {
                ext: 'lzh',
                mime: 'application/x-lzh-compressed',
            };
        }

        // MPEG program stream (PS or MPEG-PS)
        if (this.check([0x00, 0x00, 0x01, 0xBA])) {
            //  MPEG-PS, MPEG-1 Part 1
            if (this.check([0x21], {offset: 4, mask: [0xF1]})) {
                return {
                    ext: 'mpg', // May also be .ps, .mpeg
                    mime: 'video/MP1S',
                };
            }

            // MPEG-PS, MPEG-2 Part 1
            if (this.check([0x44], {offset: 4, mask: [0xC4]})) {
                return {
                    ext: 'mpg', // May also be .mpg, .m2p, .vob or .sub
                    mime: 'video/MP2P',
                };
            }
        }

        if (this.checkString('ITSF')) {
            return {
                ext: 'chm',
                mime: 'application/vnd.ms-htmlhelp',
            };
        }

        // -- 6-byte signatures --

        if (this.check([0xFD, 0x37, 0x7A, 0x58, 0x5A, 0x00])) {
            return {
                ext: 'xz',
                mime: 'application/x-xz',
            };
        }

        if (this.checkString('<?xml ')) {
            return {
                ext: 'xml',
                mime: 'application/xml',
            };
        }

        if (this.check([0x37, 0x7A, 0xBC, 0xAF, 0x27, 0x1C])) {
            return {
                ext: '7z',
                mime: 'application/x-7z-compressed',
            };
        }

        if (
            this.check([0x52, 0x61, 0x72, 0x21, 0x1A, 0x7])
            && (this.buffer[6] === 0x0 || this.buffer[6] === 0x1)
        ) {
            return {
                ext: 'rar',
                mime: 'application/x-rar-compressed',
            };
        }

        if (this.checkString('solid ')) {
            return {
                ext: 'stl',
                mime: 'model/stl',
            };
        }

        // -- 7-byte signatures --

        if (this.checkString('BLENDER')) {
            return {
                ext: 'blend',
                mime: 'application/x-blender',
            };
        }

        if (this.checkString('!<arch>')) {
            await tokenizer.ignore(8);
            const string = await tokenizer.readToken(new StringType(13, 'ascii'));
            if (string === 'debian-binary') {
                return {
                    ext: 'deb',
                    mime: 'application/x-deb',
                };
            }

            return {
                ext: 'ar',
                mime: 'application/x-unix-archive',
            };
        }

        // -- 8-byte signatures --

        if (this.check([0x89, 0x50, 0x4E, 0x47, 0x0D, 0x0A, 0x1A, 0x0A])) {
            // APNG format (https://wiki.mozilla.org/APNG_Specification)
            // 1. Find the first IDAT (image data) chunk (49 44 41 54)
            // 2. Check if there is an "acTL" chunk before the IDAT one (61 63 54 4C)

            // Offset calculated as follows:
            // - 8 bytes: PNG signature
            // - 4 (length) + 4 (chunk type) + 13 (chunk data) + 4 (CRC): IHDR chunk

            await tokenizer.ignore(8); // ignore PNG signature

            async function readChunkHeader() {
                return {
                    length: await tokenizer.readToken(Token.INT32_BE),
                    type: await tokenizer.readToken(new StringType(4, 'binary')),
                };
            }

            do {
                const chunk = await readChunkHeader();
                if (chunk.length < 0) {
                    return; // Invalid chunk length
                }

                switch (chunk.type) {
                    case 'IDAT':
                        return {
                            ext: 'png',
                            mime: 'image/png',
                        };
                    case 'acTL':
                        return {
                            ext: 'apng',
                            mime: 'image/apng',
                        };
                    default:
                        await tokenizer.ignore(chunk.length + 4); // Ignore chunk-data + CRC
                }
            } while (tokenizer.position + 8 < tokenizer.fileInfo.size);

            return {
                ext: 'png',
                mime: 'image/png',
            };
        }

        if (this.check([0x41, 0x52, 0x52, 0x4F, 0x57, 0x31, 0x00, 0x00])) {
            return {
                ext: 'arrow',
                mime: 'application/x-apache-arrow',
            };
        }

        if (this.check([0x67, 0x6C, 0x54, 0x46, 0x02, 0x00, 0x00, 0x00])) {
            return {
                ext: 'glb',
                mime: 'model/gltf-binary',
            };
        }

        // `mov` format variants
        if (
            this.check([0x66, 0x72, 0x65, 0x65], {offset: 4}) // `free`
            || this.check([0x6D, 0x64, 0x61, 0x74], {offset: 4}) // `mdat` MJPEG
            || this.check([0x6D, 0x6F, 0x6F, 0x76], {offset: 4}) // `moov`
            || this.check([0x77, 0x69, 0x64, 0x65], {offset: 4}) // `wide`
        ) {
            return {
                ext: 'mov',
                mime: 'video/quicktime',
            };
        }

        if (this.check([0xEF, 0xBB, 0xBF]) && this.checkString('<?xml', {offset: 3})) { // UTF-8-BOM
            return {
                ext: 'xml',
                mime: 'application/xml',
            };
        }

        // -- 9-byte signatures --

        if (this.check([0x49, 0x49, 0x52, 0x4F, 0x08, 0x00, 0x00, 0x00, 0x18])) {
            return {
                ext: 'orf',
                mime: 'image/x-olympus-orf',
            };
        }

        if (this.checkString('gimp xcf ')) {
            return {
                ext: 'xcf',
                mime: 'image/x-xcf',
            };
        }

        // -- 12-byte signatures --

        if (this.check([0x49, 0x49, 0x55, 0x00, 0x18, 0x00, 0x00, 0x00, 0x88, 0xE7, 0x74, 0xD8])) {
            return {
                ext: 'rw2',
                mime: 'image/x-panasonic-rw2',
            };
        }

        // ASF_Header_Object first 80 bytes
        if (this.check([0x30, 0x26, 0xB2, 0x75, 0x8E, 0x66, 0xCF, 0x11, 0xA6, 0xD9])) {
            async function readHeader() {
                const guid = Buffer.alloc(16);
                await tokenizer.readBuffer(guid);
                return {
                    id: guid,
                    size: Number(await tokenizer.readToken(Token.UINT64_LE)),
                };
            }

            await tokenizer.ignore(30);
            // Search for header should be in first 1KB of file.
            while (tokenizer.position + 24 < tokenizer.fileInfo.size) {
                const header = await readHeader();
                let payload = header.size - 24;
                if (this._check(header.id, [0x91, 0x07, 0xDC, 0xB7, 0xB7, 0xA9, 0xCF, 0x11, 0x8E, 0xE6, 0x00, 0xC0, 0x0C, 0x20, 0x53, 0x65])) {
                    // Sync on Stream-Properties-Object (B7DC0791-A9B7-11CF-8EE6-00C00C205365)
                    const typeId = Buffer.alloc(16);
                    payload -= await tokenizer.readBuffer(typeId);

                    if (this._check(typeId, [0x40, 0x9E, 0x69, 0xF8, 0x4D, 0x5B, 0xCF, 0x11, 0xA8, 0xFD, 0x00, 0x80, 0x5F, 0x5C, 0x44, 0x2B])) {
                        // Found audio:
                        return {
                            ext: 'asf',
                            mime: 'audio/x-ms-asf',
                        };
                    }

                    if (this._check(typeId, [0xC0, 0xEF, 0x19, 0xBC, 0x4D, 0x5B, 0xCF, 0x11, 0xA8, 0xFD, 0x00, 0x80, 0x5F, 0x5C, 0x44, 0x2B])) {
                        // Found video:
                        return {
                            ext: 'asf',
                            mime: 'video/x-ms-asf',
                        };
                    }

                    break;
                }

                await tokenizer.ignore(payload);
            }

            // Default to ASF generic extension
            return {
                ext: 'asf',
                mime: 'application/vnd.ms-asf',
            };
        }

        if (this.check([0xAB, 0x4B, 0x54, 0x58, 0x20, 0x31, 0x31, 0xBB, 0x0D, 0x0A, 0x1A, 0x0A])) {
            return {
                ext: 'ktx',
                mime: 'image/ktx',
            };
        }

        if ((this.check([0x7E, 0x10, 0x04]) || this.check([0x7E, 0x18, 0x04])) && this.check([0x30, 0x4D, 0x49, 0x45], {offset: 4})) {
            return {
                ext: 'mie',
                mime: 'application/x-mie',
            };
        }

        if (this.check([0x27, 0x0A, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00], {offset: 2})) {
            return {
                ext: 'shp',
                mime: 'application/x-esri-shape',
            };
        }

        if (this.check([0x00, 0x00, 0x00, 0x0C, 0x6A, 0x50, 0x20, 0x20, 0x0D, 0x0A, 0x87, 0x0A])) {
            // JPEG-2000 family

            await tokenizer.ignore(20);
            const type = await tokenizer.readToken(new StringType(4, 'ascii'));
            switch (type) {
                case 'jp2 ':
                    return {
                        ext: 'jp2',
                        mime: 'image/jp2',
                    };
                case 'jpx ':
                    return {
                        ext: 'jpx',
                        mime: 'image/jpx',
                    };
                case 'jpm ':
                    return {
                        ext: 'jpm',
                        mime: 'image/jpm',
                    };
                case 'mjp2':
                    return {
                        ext: 'mj2',
                        mime: 'image/mj2',
                    };
                default:
                    return;
            }
        }

        if (
            this.check([0xFF, 0x0A])
            || this.check([0x00, 0x00, 0x00, 0x0C, 0x4A, 0x58, 0x4C, 0x20, 0x0D, 0x0A, 0x87, 0x0A])
        ) {
            return {
                ext: 'jxl',
                mime: 'image/jxl',
            };
        }

        if (
            this.check([0xFE, 0xFF, 0, 60, 0, 63, 0, 120, 0, 109, 0, 108]) // UTF-16-BOM-LE
            || this.check([0xFF, 0xFE, 60, 0, 63, 0, 120, 0, 109, 0, 108, 0]) // UTF-16-BOM-LE
        ) {
            return {
                ext: 'xml',
                mime: 'application/xml',
            };
        }

        // -- Unsafe signatures --

        if (
            this.check([0x0, 0x0, 0x1, 0xBA])
            || this.check([0x0, 0x0, 0x1, 0xB3])
        ) {
            return {
                ext: 'mpg',
                mime: 'video/mpeg',
            };
        }

        if (this.check([0x00, 0x01, 0x00, 0x00, 0x00])) {
            return {
                ext: 'ttf',
                mime: 'font/ttf',
            };
        }

        if (this.check([0x00, 0x00, 0x01, 0x00])) {
            return {
                ext: 'ico',
                mime: 'image/x-icon',
            };
        }

        if (this.check([0x00, 0x00, 0x02, 0x00])) {
            return {
                ext: 'cur',
                mime: 'image/x-icon',
            };
        }

        if (this.check([0xD0, 0xCF, 0x11, 0xE0, 0xA1, 0xB1, 0x1A, 0xE1])) {
            // Detected Microsoft Compound File Binary File (MS-CFB) Format.
            return {
                ext: 'cfb',
                mime: 'application/x-cfb',
            };
        }

        // Increase sample size from 12 to 256.
        await tokenizer.peekBuffer(this.buffer, {length: Math.min(256, tokenizer.fileInfo.size), mayBeLess: true});

        // -- 15-byte signatures --

        if (this.checkString('BEGIN:')) {
            if (this.checkString('VCARD', {offset: 6})) {
                return {
                    ext: 'vcf',
                    mime: 'text/vcard',
                };
            }

            if (this.checkString('VCALENDAR', {offset: 6})) {
                return {
                    ext: 'ics',
                    mime: 'text/calendar',
                };
            }
        }

        // `raf` is here just to keep all the raw image detectors together.
        if (this.checkString('FUJIFILMCCD-RAW')) {
            return {
                ext: 'raf',
                mime: 'image/x-fujifilm-raf',
            };
        }

        if (this.checkString('Extended Module:')) {
            return {
                ext: 'xm',
                mime: 'audio/x-xm',
            };
        }

        if (this.checkString('Creative Voice File')) {
            return {
                ext: 'voc',
                mime: 'audio/x-voc',
            };
        }

        if (this.check([0x04, 0x00, 0x00, 0x00]) && this.buffer.length >= 16) { // Rough & quick check Pickle/ASAR
            const jsonSize = this.buffer.readUInt32LE(12);
            if (jsonSize > 12 && this.buffer.length >= jsonSize + 16) {
                try {
                    const header = this.buffer.slice(16, jsonSize + 16).toString();
                    const json = JSON.parse(header);
                    // Check if Pickle is ASAR
                    if (json.files) { // Final check, assuring Pickle/ASAR format
                        return {
                            ext: 'asar',
                            mime: 'application/x-asar',
                        };
                    }
                } catch (err) {
                    console.log(err);
                }
            }
        }

        if (this.check([0x06, 0x0E, 0x2B, 0x34, 0x02, 0x05, 0x01, 0x01, 0x0D, 0x01, 0x02, 0x01, 0x01, 0x02])) {
            return {
                ext: 'mxf',
                mime: 'application/mxf',
            };
        }

        if (this.checkString('SCRM', {offset: 44})) {
            return {
                ext: 's3m',
                mime: 'audio/x-s3m',
            };
        }

        // Raw MPEG-2 transport stream (188-byte packets)
        if (this.check([0x47]) && this.check([0x47], {offset: 188})) {
            return {
                ext: 'mts',
                mime: 'video/mp2t',
            };
        }

        // Blu-ray Disc Audio-Video (BDAV) MPEG-2 transport stream has 4-byte TP_extra_header before each 188-byte packet
        if (this.check([0x47], {offset: 4}) && this.check([0x47], {offset: 196})) {
            return {
                ext: 'mts',
                mime: 'video/mp2t',
            };
        }

        if (this.check([0x42, 0x4F, 0x4F, 0x4B, 0x4D, 0x4F, 0x42, 0x49], {offset: 60})) {
            return {
                ext: 'mobi',
                mime: 'application/x-mobipocket-ebook',
            };
        }

        if (this.check([0x44, 0x49, 0x43, 0x4D], {offset: 128})) {
            return {
                ext: 'dcm',
                mime: 'application/dicom',
            };
        }

        if (this.check([0x4C, 0x00, 0x00, 0x00, 0x01, 0x14, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0xC0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x46])) {
            return {
                ext: 'lnk',
                mime: 'application/x.ms.shortcut', // Invented by us
            };
        }

        if (this.check([0x62, 0x6F, 0x6F, 0x6B, 0x00, 0x00, 0x00, 0x00, 0x6D, 0x61, 0x72, 0x6B, 0x00, 0x00, 0x00, 0x00])) {
            return {
                ext: 'alias',
                mime: 'application/x.apple.alias', // Invented by us
            };
        }

        if (
            this.check([0x4C, 0x50], {offset: 34})
            && (
                this.check([0x00, 0x00, 0x01], {offset: 8})
                || this.check([0x01, 0x00, 0x02], {offset: 8})
                || this.check([0x02, 0x00, 0x02], {offset: 8})
            )
        ) {
            return {
                ext: 'eot',
                mime: 'application/vnd.ms-fontobject',
            };
        }

        if (this.check([0x06, 0x06, 0xED, 0xF5, 0xD8, 0x1D, 0x46, 0xE5, 0xBD, 0x31, 0xEF, 0xE7, 0xFE, 0x74, 0xB7, 0x1D])) {
            return {
                ext: 'indd',
                mime: 'application/x-indesign',
            };
        }

        // Increase sample size from 256 to 512
        await tokenizer.peekBuffer(this.buffer, {length: Math.min(512, tokenizer.fileInfo.size), mayBeLess: true});

        // Requires a buffer size of 512 bytes
        if (KrajeeFileTypeConfig.tarHeaderChecksumMatches(this.buffer)) {
            return {
                ext: 'tar',
                mime: 'application/x-tar',
            };
        }

        if (this.check([0xFF, 0xFE, 0xFF, 0x0E, 0x53, 0x00, 0x6B, 0x00, 0x65, 0x00, 0x74, 0x00, 0x63, 0x00, 0x68, 0x00, 0x55, 0x00, 0x70, 0x00, 0x20, 0x00, 0x4D, 0x00, 0x6F, 0x00, 0x64, 0x00, 0x65, 0x00, 0x6C, 0x00])) {
            return {
                ext: 'skp',
                mime: 'application/vnd.sketchup.skp',
            };
        }

        if (this.checkString('-----BEGIN PGP MESSAGE-----')) {
            return {
                ext: 'pgp',
                mime: 'application/pgp-encrypted',
            };
        }

        // Check MPEG 1 or 2 Layer 3 header, or 'layer 0' for ADTS (MPEG sync-word 0xFFE)
        if (this.buffer.length >= 2 && this.check([0xFF, 0xE0], {offset: 0, mask: [0xFF, 0xE0]})) {
            if (this.check([0x10], {offset: 1, mask: [0x16]})) {
                // Check for (ADTS) MPEG-2
                if (this.check([0x08], {offset: 1, mask: [0x08]})) {
                    return {
                        ext: 'aac',
                        mime: 'audio/aac',
                    };
                }

                // Must be (ADTS) MPEG-4
                return {
                    ext: 'aac',
                    mime: 'audio/aac',
                };
            }

            // MPEG 1 or 2 Layer 3 header
            // Check for MPEG layer 3
            if (this.check([0x02], {offset: 1, mask: [0x06]})) {
                return {
                    ext: 'mp3',
                    mime: 'audio/mpeg',
                };
            }

            // Check for MPEG layer 2
            if (this.check([0x04], {offset: 1, mask: [0x06]})) {
                return {
                    ext: 'mp2',
                    mime: 'audio/mpeg',
                };
            }

            // Check for MPEG layer 1
            if (this.check([0x06], {offset: 1, mask: [0x06]})) {
                return {
                    ext: 'mp1',
                    mime: 'audio/mpeg',
                };
            }
        }
        return {};
    }

    async readTiffTag(bigEndian) {
        const Token = KrajeeFileTypeConfig.Token;
        let tagId = null;
        try {
            tagId = await this.tokenizer.readToken(bigEndian ? Token.UINT16_BE : Token.UINT16_LE);
        } catch (error) {
            if (error instanceof EndOfStreamError) {
                return null;
            }
            throw error;
        }

        this.tokenizer.ignore(10);
        switch (tagId) {
            case 50_341:
                return {
                    ext: 'arw',
                    mime: 'image/x-sony-arw',
                };
            case 50_706:
                return {
                    ext: 'dng',
                    mime: 'image/x-adobe-dng',
                };
            default:
                return null;
        }
    }

    async readTiffIFD(bigEndian) {
        const Token = KrajeeFileTypeConfig.Token;
        const numberOfTags = await this.tokenizer.readToken(bigEndian ? Token.UINT16_BE : Token.UINT16_LE);
        for (let n = 0; n < numberOfTags; ++n) {
            const fileType = await this.readTiffTag(bigEndian);
            if (fileType) {
                return fileType;
            }
        }
        return null;
    }

    async readTiffHeader(bigEndian) {
        const Token = KrajeeFileTypeConfig.Token;
        const version = (bigEndian ? Token.UINT16_BE : Token.UINT16_LE).get(this.buffer, 2);
        const ifdOffset = (bigEndian ? Token.UINT32_BE : Token.UINT32_LE).get(this.buffer, 4);
        const tiff = {ext: 'tif', mime: 'image/tiff'};

        if (version === 42) {
            // TIFF file header
            if (ifdOffset >= 6) {
                if (this.checkString('CR', {offset: 8})) {
                    return {
                        ext: 'cr2',
                        mime: 'image/x-canon-cr2',
                    };
                }

                if (ifdOffset >= 8 && (this.check([0x1C, 0x00, 0xFE, 0x00], {offset: 8}) || this.check([0x1F, 0x00, 0x0B, 0x00], {offset: 8}))) {
                    return {
                        ext: 'nef',
                        mime: 'image/x-nikon-nef',
                    };
                }
            }

            await this.tokenizer.ignore(ifdOffset);
            const fileType = await this.readTiffIFD(false);
            return fileType ? fileType : tiff;
        }

        if (version === 43) {	// Big TIFF file header
            return tiff;
        }
    }
}