酷狗.Krc加密歌词解析

 1 function KrcToLrc(filename: string): string;
 2   function ZDecompressStr2(const S: TBytes): UTF8String;
 3   var
 4     BIn, BOut: TBytes;
 5   begin
 6     BIn := S;
 7     ZDecompress(BIn, BOut);
 8     Result := TEncoding.UTF8.GetString(BOut);
 9   end;
10 
11 const
12     miarry: array [0 .. 15] of Char = ('@', 'G', 'a', 'w', '^', '2', 't', 'G',
13     'Q', '6', '1', '-', 'Î', 'Ò', 'n', 'i');
14 var
15   Stream: TFileStream;
16   Top: array [0 .. 3] of byte;
17   k, j, l: Integer;
18   zip_byte: TBytes;
19   FileNameBuff: string;
20 begin
21   FileNameBuff := ExtractFileExt(LowerCase(filename));
22   if FileNameBuff <> '.krc' then begin
23     result:='';
24     Exit;
25   end;
26 
27   Stream := TFileStream.Create(filename, fmOpenReadWrite);
28   try
29     j := Stream.SIZE;
30     SetLength(zip_byte, j - 4);
31     Stream.read(Top, 4);
32     Stream.read(zip_byte, j - 4);
33   finally
34     Stream.Free;
35   end;
36 
37   for k := Low(zip_byte) to High(zip_byte) do begin
38     l := k mod 16;
39     zip_byte[k] := zip_byte[k] xor byte(miarry[l]);
40   end;
41 
42   result:= ZDecompressStr2(zip_byte);
43 
44  end;

对应的Delphi版本为Unicode版本 D7的Ansi版本不使用，添加System.Zlib即可使用

酷狗的异或加密串是从一位JAVA那边得到的

Top4字符是加密文件头，用于校验

Zip_byte是正文