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