酷狗.Krc加密歌词解析

function KrcToLrc(filename: string): string;
  function ZDecompressStr2(const S: TBytes): UTF8String;
  var
    BIn, BOut: TBytes;
  begin
    BIn := S;
    ZDecompress(BIn, BOut);
    Result := TEncoding.UTF8.GetString(BOut);
  end;

const
    miarry: array [0 .. 15] of Char = ('@', 'G', 'a', 'w', '^', '2', 't', 'G',
    'Q', '6', '1', '-', 'Î', 'Ò', 'n', 'i');
var
  Stream: TFileStream;
  Top: array [0 .. 3] of byte;
  k, j, l: Integer;
  zip_byte: TBytes;
  FileNameBuff: string;
begin
  FileNameBuff := ExtractFileExt(LowerCase(filename));
  if FileNameBuff <> '.krc' then begin
    result:='';
    Exit;
  end;

  Stream := TFileStream.Create(filename, fmOpenReadWrite);
  try
    j := Stream.SIZE;
    SetLength(zip_byte, j - 4);
    Stream.read(Top, 4);
    Stream.read(zip_byte, j - 4);
  finally
    Stream.Free;
  end;

  for k := Low(zip_byte) to High(zip_byte) do begin
    l := k mod 16;
    zip_byte[k] := zip_byte[k] xor byte(miarry[l]);
  end;

  result:= ZDecompressStr2(zip_byte);

 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