MengYX
5 years ago
3 changed files with 89 additions and 1 deletions
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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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