import QmcCryptoModule from '@/QmcWasm/QmcWasmBundle'; import { MergeUint8Array } from '@/utils/MergeUint8Array'; // 每次处理 2M 的数据 const DECRYPTION_BUF_SIZE = 2 *1024 * 1024; export interface QMCDecryptionResult { success: boolean; data: Uint8Array; songId: string | number; error: string; } /** * 解密一个 QMC 加密的文件。 * * 如果检测并解密成功,返回解密后的 Uint8Array 数据。 * @param {ArrayBuffer} qmcBlob 读入的文件 Blob */ export async function DecryptQmcWasm(qmcBlob: ArrayBuffer, ext: string): Promise { const result: QMCDecryptionResult = { success: false, data: new Uint8Array(), songId: 0, error: '' }; // 初始化模组 let QmcCrypto: any; try { QmcCrypto = await QmcCryptoModule(); } catch (err: any) { result.error = err?.message || 'wasm 加载失败'; return result; } if (!QmcCrypto) { result.error = 'wasm 加载失败'; return result; } // 申请内存块,并文件末端数据到 WASM 的内存堆 const qmcBuf = new Uint8Array(qmcBlob); const pQmcBuf = QmcCrypto._malloc(DECRYPTION_BUF_SIZE); QmcCrypto.writeArrayToMemory(qmcBuf.slice(-DECRYPTION_BUF_SIZE), pQmcBuf); // 进行解密初始化 ext = '.' + ext; const tailSize = QmcCrypto.preDec(pQmcBuf, DECRYPTION_BUF_SIZE, ext); if (tailSize == -1) { result.error = QmcCrypto.getError(); return result; } else { result.songId = QmcCrypto.getSongId(); result.songId = result.songId == "0" ? 0 : result.songId; } const decryptedParts = []; let offset = 0; let bytesToDecrypt = qmcBuf.length - tailSize; while (bytesToDecrypt > 0) { const blockSize = Math.min(bytesToDecrypt, DECRYPTION_BUF_SIZE); // 解密一些片段 const blockData = new Uint8Array(qmcBuf.slice(offset, offset + blockSize)); QmcCrypto.writeArrayToMemory(blockData, pQmcBuf); decryptedParts.push(QmcCrypto.HEAPU8.slice(pQmcBuf, pQmcBuf + QmcCrypto.decBlob(pQmcBuf, blockSize, offset))); offset += blockSize; bytesToDecrypt -= blockSize; } QmcCrypto._free(pQmcBuf); result.data = MergeUint8Array(decryptedParts); result.success = true; return result; }