85 lines
2.4 KiB
JavaScript
85 lines
2.4 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 FLAC_HEADER = [0x4F, 0x67, 0x67, 0x53, 0x00];
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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 !== "mgg") return {
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status: false,
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message: "File type is incorrect!",
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};
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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.slice(0, -0x170));
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const audioDataLen = audioData.length;
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const keyData = new Uint8Array(fileBuffer.slice(-0x170));
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const headData = new Uint8Array(fileBuffer.slice(0, 170));
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let seed;
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try {
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let resp = await queryKeyInfo(keyData, headData, raw_filename);
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let data = await resp.json();
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seed = new Mask(data.Mask);
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} catch (e) {
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return {
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status: false,
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message: "此音乐无法解锁，目前mgg格式仅提供试验性支持",
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};
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}
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for (let cur = 0; cur < audioDataLen; ++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: "audio/ogg"});
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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);
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// 返回
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return {
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status: true,
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title: info.title,
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artist: info.artist,
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ext: 'ogg',
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album: tag.common.album,
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picture: util.GetCoverURL(tag),
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file: URL.createObjectURL(musicData),
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mime: "audio/ogg"
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}
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}
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class Mask {
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constructor(mask) {
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this.index = -1;
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this.mask_index = -1;
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this.mask128 = mask;
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}
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NextMask() {
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this.index++;
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this.mask_index++;
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if (this.index === 0x8000 || (this.index > 0x8000 && (this.index + 1) % 0x8000 === 0)) {
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this.index++;
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this.mask_index++;
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}
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if (this.mask_index >= 128) {
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this.mask_index -= 128;
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}
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return this.mask128[this.mask_index]
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}
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}
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function queryKeyInfo(keyData, headData, filename) {
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return fetch("https://stats.ixarea.com/collect/mgg/query", {
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method: "POST",
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headers: {"Content-Type": "application/json"},
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body: JSON.stringify({Key: Array.from(keyData), Head: Array.from(headData), Filename: filename}),
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})
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}
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