forked from um/web
91 lines
2.5 KiB
JavaScript
91 lines
2.5 KiB
JavaScript
const musicMetadata = require("music-metadata-browser");
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const util = require("./util");
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export {Decrypt}
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const SEED_MAP = [
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[0x4a, 0xd6, 0xca, 0x90, 0x67, 0xf7, 0x52],
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[0x5e, 0x95, 0x23, 0x9f, 0x13, 0x11, 0x7e],
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[0x47, 0x74, 0x3d, 0x90, 0xaa, 0x3f, 0x51],
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[0xc6, 0x09, 0xd5, 0x9f, 0xfa, 0x66, 0xf9],
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[0xf3, 0xd6, 0xa1, 0x90, 0xa0, 0xf7, 0xf0],
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[0x1d, 0x95, 0xde, 0x9f, 0x84, 0x11, 0xf4],
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[0x0e, 0x74, 0xbb, 0x90, 0xbc, 0x3f, 0x92],
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[0x00, 0x09, 0x5b, 0x9f, 0x62, 0x66, 0xa1]];
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const OriginalExtMap = {
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"qmc0": "mp3",
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"qmc3": "mp3",
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"qmcogg": "ogg",
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"qmcflac": "flac",
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"bkcmp3": "mp3",
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"bkcflac": "flac",
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"tkm": "m4a"
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};
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async function Decrypt(file, raw_filename, raw_ext) {
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// 获取扩展名
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if (!(raw_ext in OriginalExtMap)) {
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return {status: false, message: "File type is incorrect!"}
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}
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let new_ext = OriginalExtMap[raw_ext]
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const mime = util.AudioMimeType[new_ext];
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// 读取文件
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const fileBuffer = await util.GetArrayBuffer(file);
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const audioData = new Uint8Array(fileBuffer);
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// 转换数据
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const seed = new Mask();
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for (let cur = 0; cur < audioData.length; ++cur) {
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audioData[cur] ^= seed.NextMask();
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}
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// 导出
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const musicData = new Blob([audioData], {type: mime});
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const musicUrl = URL.createObjectURL(musicData);
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// 读取Meta
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let tag = await musicMetadata.parseBlob(musicData);
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const info = util.GetFileInfo(tag.common.artist, tag.common.title, raw_filename, new_ext);
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let picUrl = util.GetCoverURL(tag);
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// 返回
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return {
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status: true,
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filename: info.filename,
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title: info.title,
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artist: info.artist,
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ext: new_ext,
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album: tag.common.album,
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picture: picUrl,
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file: musicUrl,
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mime: mime
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}
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}
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class Mask {
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constructor() {
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this.x = -1;
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this.y = 8;
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this.dx = 1;
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this.index = -1;
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}
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NextMask() {
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let ret;
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this.index++;
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if (this.x < 0) {
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this.dx = 1;
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this.y = (8 - this.y) % 8;
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ret = 0xc3
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} else if (this.x > 6) {
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this.dx = -1;
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this.y = 7 - this.y;
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ret = 0xd8
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} else {
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ret = SEED_MAP[this.y][this.x]
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}
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this.x += this.dx;
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if (this.index === 0x8000 || (this.index > 0x8000 && (this.index + 1) % 0x8000 === 0)) {
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return this.NextMask()
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}
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return ret
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}
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}
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