99 lines
2.8 KiB
JavaScript
99 lines
2.8 KiB
JavaScript
const musicMetadata = require("music-metadata-browser");
|
||
const util = require("./util");
|
||
export {Decrypt}
|
||
const FLAC_HEADER = [0x66, 0x4C, 0x61, 0x43, 0x00];
|
||
|
||
async function Decrypt(file, raw_filename, raw_ext) {
|
||
// 获取扩展名
|
||
if (raw_ext !== "mflac") return {
|
||
status: false,
|
||
message: "File type is incorrect!",
|
||
};
|
||
// 读取文件
|
||
const fileBuffer = await util.GetArrayBuffer(file);
|
||
const audioData = new Uint8Array(fileBuffer.slice(0, -0x170));
|
||
const audioDataLen = audioData.length;
|
||
|
||
// 转换数据
|
||
const seed = new Mask();
|
||
if (!seed.DetectMask(audioData)) return {
|
||
status: false,
|
||
message: "此音乐无法解锁，目前mflac格式不提供完整支持",
|
||
};
|
||
for (let cur = 0; cur < audioDataLen; ++cur) {
|
||
audioData[cur] ^= seed.NextMask();
|
||
}
|
||
// 导出
|
||
const musicData = new Blob([audioData], {type: "audio/flac"});
|
||
|
||
// 读取Meta
|
||
let tag = await musicMetadata.parseBlob(musicData);
|
||
const info = util.GetFileInfo(tag.common.artist, tag.common.title, raw_filename);
|
||
// 返回
|
||
return {
|
||
status: true,
|
||
title: info.title,
|
||
artist: info.artist,
|
||
ext: 'flac',
|
||
album: tag.common.album,
|
||
picture: util.GetCoverURL(tag),
|
||
file: URL.createObjectURL(musicData),
|
||
mime: "audio/flac"
|
||
}
|
||
}
|
||
|
||
class Mask {
|
||
|
||
|
||
constructor() {
|
||
this.index = -1;
|
||
this.mask_index = -1;
|
||
this.mask = Array(128).fill(0x00);
|
||
}
|
||
|
||
DetectMask(data) {
|
||
|
||
let search_len = data.length - 256, mask;
|
||
for (let block_idx = 0; block_idx < search_len; block_idx += 128) {
|
||
let flag = true;
|
||
mask = data.slice(block_idx, block_idx + 128);
|
||
let next_mask = data.slice(block_idx + 128, block_idx + 256);
|
||
for (let idx = 0; idx < 128; idx++) {
|
||
if (mask[idx] !== next_mask[idx]) {
|
||
flag = false;
|
||
break;
|
||
}
|
||
}
|
||
if (!flag) continue;
|
||
|
||
|
||
for (let test_idx = 0; test_idx < FLAC_HEADER.length; test_idx++) {
|
||
let p = data[test_idx] ^ mask[test_idx];
|
||
if (p !== FLAC_HEADER[test_idx]) {
|
||
flag = false;
|
||
debugger;
|
||
break;
|
||
}
|
||
}
|
||
if (!flag) continue;
|
||
this.mask = mask;
|
||
return true;
|
||
}
|
||
return false;
|
||
}
|
||
|
||
NextMask() {
|
||
this.index++;
|
||
this.mask_index++;
|
||
if (this.index === 0x8000 || (this.index > 0x8000 && (this.index + 1) % 0x8000 === 0)) {
|
||
this.index++;
|
||
this.mask_index++;
|
||
}
|
||
if (this.mask_index >= 128) {
|
||
this.mask_index -= 128;
|
||
}
|
||
return this.mask[this.mask_index]
|
||
}
|
||
|
||
}
|