酷狗 KRC 文件的解析

清理硬盘发现以前写过一个进行一半的代码，这次补全并从硬盘删掉。

格式说明来自 https://shansing.com/read/392/

krc解码并解压缩后得到一个字符串，例子：

[id:$00000000]
[ar:信乐团]
[ti:北京一夜]
[by:韩佯Τé]
[hash:766fe295bf2722a9ede2abdd61d580c1]
[total:278438]
[sign:大家去北京玩一夜吧!!!!]
[53883,3092]<0,632,0>One <632,784,0>Night <1416,372,0>in <1788,548,0>北<2336,755,0>京
[56675,3539]<0,560,0>我<560,416,0>留<976,392,0>下<1368,412,0>许<1780,392,0>多<2172,1366,0>情
[59914,2577]<0,549,0>不<549,276,0>管<825,252,0>你<1077,214,0>爱<1291,182,0>与<1473,212,0>不 <1685,887,0>爱
[62191,3344]<0,560,0>都<560,210,0>是<770,210,0>历<980,204,0>史<1184,202,0>的<1386,564,0>尘<1950,1387,0>埃

开头的几行就不用解释了，lrc也有。

其中快速匹配歌词的可能方式是靠计算歌曲文件的hash，以及匹配歌词与歌曲的total

歌词开始的行格式：

[此行开始时刻距0时刻的毫秒数,此行持续的毫秒数]<0,此字持续的毫秒数,0>歌<此字开始的时刻距此行开始时刻的毫秒数,此字持续的毫秒数,0>词<此字开始的时刻距此行开始时刻的毫秒数,此字持续的毫秒数,0>正<此字开始的时刻距此行开始时刻的毫秒数,此字持续的毫秒数,0>文

 

具体代码如下：

 

  1 using System;
  2 using System.Collections.Generic;
  3 using System.Linq;
  4 using System.Text;
  5 using System.IO;
  6 using System.IO.Compression;
  7 using ICSharpCode.SharpZipLib.Zip.Compression;
  8 using ICSharpCode.SharpZipLib.Zip.Compression.Streams;
  9 using System.Diagnostics;
 10 
 11 namespace KRC.KRCLib
 12 {
 13     public static class KRCFile
 14     {
 15         /// <summary>
 16         /// 异或加密 密钥
 17         /// </summary>
 18         public static readonly char[] KRCFileXorKey = { '@', 'G', 'a', 'w', '^', '2', 't', 'G', 'Q', '6', '1', '-', 'Î', 'Ò', 'n', 'i' };
 19 
 20         /// <summary>
 21         /// KRC 文件头
 22         /// </summary>
 23         public static readonly char[] KRCFileHead = { 'k', 'r', 'c', '1' };
 24 
 25         /// <summary>
 26         /// KRC 文件头的字节
 27         /// </summary>
 28         public static readonly byte[] KRCFileHeadBytes = { 0x6B, 0x72, 0x63, 0x31 };
 29 
 30 
 31         /// <summary>
 32         /// 解码
 33         /// </summary>
 34         public static string DecodeFileToString(string krcFilePath)
 35         {
 36             //krc1
 37             var headBytes = new byte[4];
 38             byte[] encodedBytes;
 39             byte[] zipedBytes;
 40 
 41             using (var krcfs = new FileStream(krcFilePath, FileMode.Open))
 42             {
 43                 encodedBytes = new byte[krcfs.Length - headBytes.Length];
 44                 zipedBytes = new byte[krcfs.Length - headBytes.Length];
 45 
 46                 //读文件头标记
 47                 krcfs.Read(headBytes, 0, headBytes.Length);
 48 
 49                 //读XOR加密的内容
 50                 krcfs.Read(encodedBytes, 0, encodedBytes.Length);
 51 
 52                 //关闭文件
 53                 krcfs.Close();
 54             }
 55 
 56             for (var i = 0; i < encodedBytes.Length; i++)
 57             {
 58                 zipedBytes[i] = (byte)(encodedBytes[i] ^ KRCFileXorKey[i % 16]);
 59             }
 60 
 61             //前面3字节是 UTF-8 的 BOM
 62             var unzipedBytes = Decompress(zipedBytes);
 63 
 64             //编码器带有BOM输出时多了3字节，所以跳过开头的3字节bom
 65             var text = RemoveBom(Encoding.UTF8.GetString(unzipedBytes));
 66 
 67             return text;
 68         }
 69 
 70         /// <summary>
 71         /// 编码到字节数组
 72         /// </summary>
 73         /// <param name="inText"></param>
 74         /// <returns></returns>
 75         public static byte[] EncodeStringToBytes(string inText)
 76         {
 77             //用默认的，编码时带有UTF-8的BOM
 78             byte[] inbytes = Encoding.UTF8.GetPreamble().Concat(Encoding.UTF8.GetBytes(inText)).ToArray();
 79 
 80             byte[] zipedBytes = Compress(inbytes);
 81 
 82             int encodedBytesLength = zipedBytes.Length;
 83 
 84             var encodedBytes = new byte[zipedBytes.Length];
 85 
 86 
 87             for (int i = 0; i < encodedBytesLength; i++)
 88             {
 89                 int l = i % 16;
 90 
 91                 encodedBytes[i] = (byte)(zipedBytes[i] ^ KRCFileXorKey[l]);
 92             }
 93 
 94             byte[] byets = null;
 95 
 96             using (var ms = new MemoryStream())
 97             {
 98                 ms.Write(KRCFileHeadBytes, 0, KRCFileHeadBytes.Length);
 99                 ms.Write(encodedBytes, 0, encodedBytes.Length);
100                 ms.Flush();
101                 byets = ms.ToArray();
102             }
103 
104             return byets;
105         }
106 
107         /// <summary>
108         /// 移除UTF-8 BOM
109         /// </summary>
110         /// <param name="p"></param>
111         /// <returns></returns>
112         private static string RemoveBom(string p)
113         {
114             string bomMarkUtf8 = Encoding.UTF8.GetString(Encoding.UTF8.GetPreamble());
115             if (p.StartsWith(bomMarkUtf8))
116                 p = p.Remove(0, bomMarkUtf8.Length);
117             return p.Replace("\0", "");
118         }
119 
120         #region 压缩 解压缩
121         private static byte[] Compress(byte[] pBytes)
122         {
123             byte[] outdata = null;
124             using (var mMemory = new MemoryStream(pBytes))
125             using (var mStream = new DeflaterOutputStream(mMemory, new Deflater(Deflater.DEFAULT_COMPRESSION), 131072))
126             {
127                 mStream.Write(pBytes, 0, pBytes.Length);
128                 mStream.Flush();
129                 mMemory.Flush();
130                 outdata = mMemory.ToArray();
131             }
132             return outdata;
133         }
134 
135         /// <summary>
136         /// 解压缩
137         /// </summary>
138         /// <param name="data"></param>
139         /// <returns></returns>
140         private static byte[] Decompress(byte[] data)
141         {
142             byte[] outdata = null;
143             using (var ms = new MemoryStream())
144             using (var inputStream = new InflaterInputStream(new MemoryStream(data), new Inflater(false)))
145             {
146                 inputStream.CopyTo(ms);
147                 ms.Flush();
148 
149                 outdata = ms.ToArray();
150                 ms.Close();
151             }
152             return outdata;
153         }
154         #endregion
155 
156 
157     }
158 }

KRCFile