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feature: use online info to correct qmc meta 

(cherry picked from commit 7c62f35adb268509f543d67b4a36f49ada3ae206)
This commit is contained in:
MengYX 2021-12-25 14:41:05 +08:00
parent b710255100
commit 0b786b9885
No known key found for this signature in database
GPG Key ID: E63F9C7303E8F604
1 changed files with 37 additions and 16 deletions
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53
src/decrypt/qmc.ts
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@ -1,6 +1,5 @@
import { QmcMapCipher, QmcRC4Cipher, QmcStaticCipher, QmcStreamCipher } from './qmc_cipher';
import { AudioMimeType, GetArrayBuffer, SniffAudioExt } from '@/decrypt/utils';
import { DecryptQMCWasm } from './qmc_wasm';
import { DecryptResult } from '@/decrypt/entity';
import { QmcDeriveKey } from '@/decrypt/qmc_key';
@ -42,20 +41,24 @@ export async function Decrypt(file: Blob, raw_filename: string, raw_ext: string)
const fileBuffer = await GetArrayBuffer(file);
let musicDecoded: Uint8Array | undefined;
let musicID: number | undefined;
// todo: wasm decoder doesn't support extract the song id for .mgg1/.mflac0 currently
// if (version === 2 && globalThis.WebAssembly) {
// console.log('qmc: using wasm decoder');
// const v2Decrypted = await DecryptQMCWasm(fileBuffer);
// // 如果 v2 检测失败，降级到 v1 再尝试一次
// if (v2Decrypted) {
// musicDecoded = v2Decrypted;
// }
// }
if (version === 2 && globalThis.WebAssembly) {
console.log('qmc: using wasm decoder');
const v2Decrypted = await DecryptQMCWasm(fileBuffer);
// 如果 v2 检测失败，降级到 v1 再尝试一次
if (v2Decrypted) {
musicDecoded = v2Decrypted;
}
}
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);
@ -65,6 +68,7 @@ export async function Decrypt(file: Blob, raw_filename: string, raw_ext: string)
new Blob([musicDecoded], { type: mime }),
raw_filename,
ext,
musicID,
);
return {
@ -81,19 +85,25 @@ export async function Decrypt(file: Blob, raw_filename: string, raw_ext: string)
export class QmcDecoder {
private static readonly BYTE_COMMA = ','.charCodeAt(0);
file: Uint8Array;
size: number;
decoded: boolean = false;
audioSize?: number;
cipher?: QmcStreamCipher;
private readonly file: Uint8Array;
private readonly size: number;
private decoded: boolean = false;
private audioSize?: number;
private cipher?: QmcStreamCipher;
constructor(file: Uint8Array) {
public constructor(file: Uint8Array) {
this.file = file;
this.size = file.length;
this.searchKey();
}
decrypt(): Uint8Array {
private _songID?: number;
public get songID() {
return this._songID;
}
public decrypt(): Uint8Array {
if (!this.cipher) {
throw new Error('no cipher found');
}
@ -118,9 +128,20 @@ export class QmcDecoder {
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)));
} else {
const sizeView = new DataView(last4Byte.buffer, last4Byte.byteOffset);
const keySize = sizeView.getUint32(0, true);