import { QmcMapCipher, QmcRC4Cipher, QmcStaticCipher, QmcStreamCipher } from './qmc_cipher'; import { AudioMimeType, GetArrayBuffer, SniffAudioExt } from '@/decrypt/utils'; import { DecryptResult } from '@/decrypt/entity'; import { QmcDeriveKey } from '@/decrypt/qmc_key'; import { DecryptQMCWasm } from '@/decrypt/qmc_wasm'; import { extractQQMusicMeta } from '@/utils/qm_meta'; interface Handler { ext: string; version: number; } export const HandlerMap: { [key: string]: Handler } = { mgg: { ext: 'ogg', version: 2 }, mgg1: { ext: 'ogg', version: 2 }, mflac: { ext: 'flac', version: 2 }, mflac0: { ext: 'flac', version: 2 }, // qmcflac / qmcogg: // 有可能是 v2 加密但混用同一个后缀名。 qmcflac: { ext: 'flac', version: 2 }, qmcogg: { ext: 'ogg', version: 2 }, qmc0: { ext: 'mp3', version: 1 }, qmc2: { ext: 'ogg', version: 1 }, qmc3: { ext: 'mp3', version: 1 }, bkcmp3: { ext: 'mp3', version: 1 }, bkcflac: { ext: 'flac', version: 1 }, tkm: { ext: 'm4a', version: 1 }, '666c6163': { ext: 'flac', version: 1 }, '6d7033': { ext: 'mp3', version: 1 }, '6f6767': { ext: 'ogg', version: 1 }, '6d3461': { ext: 'm4a', version: 1 }, '776176': { ext: 'wav', version: 1 }, }; export async function Decrypt(file: Blob, raw_filename: string, raw_ext: string): Promise { if (!(raw_ext in HandlerMap)) throw `Qmc cannot handle type: ${raw_ext}`; const handler = HandlerMap[raw_ext]; let { version } = handler; const fileBuffer = await GetArrayBuffer(file); let musicDecoded: Uint8Array | undefined; let musicID: number | string | undefined; if (version === 2 && globalThis.WebAssembly) { console.log('qmc: using wasm decoder'); const v2Decrypted = await DecryptQMCWasm(fileBuffer); // 若 v2 检测失败,降级到 v1 再尝试一次 if (v2Decrypted.success) { musicDecoded = v2Decrypted.data; musicID = v2Decrypted.songId; } else { console.warn('qmc2-wasm failed with error %s', v2Decrypted.error || '(no error)'); } } if (!musicDecoded) { // may throw error console.log('qmc: using js decoder'); const d = new QmcDecoder(new Uint8Array(fileBuffer)); musicDecoded = d.decrypt(); musicID = d.songID; } const ext = SniffAudioExt(musicDecoded, handler.ext); const mime = AudioMimeType[ext]; const { album, artist, imgUrl, blob, title } = await extractQQMusicMeta( new Blob([musicDecoded], { type: mime }), raw_filename, ext, musicID, ); return { title: title, artist: artist, ext: ext, album: album, picture: imgUrl, file: URL.createObjectURL(blob), blob: blob, mime: mime, }; } export class QmcDecoder { private static readonly BYTE_COMMA = ','.charCodeAt(0); private readonly file: Uint8Array; private readonly size: number; private decoded: boolean = false; private audioSize?: number; private cipher?: QmcStreamCipher; public constructor(file: Uint8Array) { this.file = file; this.size = file.length; this.searchKey(); } private _songID?: number; public get songID() { return this._songID; } public decrypt(): Uint8Array { if (!this.cipher) { throw new Error('no cipher found'); } if (!this.audioSize || this.audioSize <= 0) { throw new Error('invalid audio size'); } const audioBuf = this.file.subarray(0, this.audioSize); if (!this.decoded) { this.cipher.decrypt(audioBuf, 0); this.decoded = true; } return audioBuf; } private searchKey() { const last4Byte = this.file.slice(-4); const textEnc = new TextDecoder(); if (textEnc.decode(last4Byte) === 'QTag') { const sizeBuf = this.file.slice(-8, -4); const sizeView = new DataView(sizeBuf.buffer, sizeBuf.byteOffset); const keySize = sizeView.getUint32(0, false); this.audioSize = this.size - keySize - 8; const rawKey = this.file.subarray(this.audioSize, this.size - 8); const keyEnd = rawKey.findIndex((v) => v == QmcDecoder.BYTE_COMMA); if (keyEnd < 0) { throw new Error('invalid key: search raw key failed'); } this.setCipher(rawKey.subarray(0, keyEnd)); const idBuf = rawKey.subarray(keyEnd + 1); const idEnd = idBuf.findIndex((v) => v == QmcDecoder.BYTE_COMMA); if (keyEnd < 0) { throw new Error('invalid key: search song id failed'); } this._songID = parseInt(textEnc.decode(idBuf.subarray(0, idEnd)), 10); } else { const sizeView = new DataView(last4Byte.buffer, last4Byte.byteOffset); const keySize = sizeView.getUint32(0, true); if (keySize < 0x300) { this.audioSize = this.size - keySize - 4; const rawKey = this.file.subarray(this.audioSize, this.size - 4); this.setCipher(rawKey); } else { this.audioSize = this.size; this.cipher = new QmcStaticCipher(); } } } private setCipher(keyRaw: Uint8Array) { const keyDec = QmcDeriveKey(keyRaw); if (keyDec.length > 300) { this.cipher = new QmcRC4Cipher(keyDec); } else { this.cipher = new QmcMapCipher(keyDec); } } }