微信图片解决方法-windows版的dat文件

public string decodeImg(string filepath)
        {
            Dictionary<string,byte[]> headers = new Dictionary<string,byte[]>
            {
                { "jpg",new byte[]{ 0xff,0xd8 }},{ "png",new byte[]{ 0x89,0x50 }},{ "gif",new byte[]{ 0x47,0x49 }},};
            for (int i = 0; i < 10; i++)
            {
                try
                {
                    byte[] buf = File.ReadAllBytes(filepath);
                    foreach (string encoding in headers.Keys)
                    {
                        byte header_code = headers[encoding][0];
                        byte check_code = headers[encoding][1];
                        byte magic = do_magic(header_code,buf);
                        byte code = (byte)(buf[1] ^ magic);
                        if (check_code == code)
                        {
                            byte[] outbytes = decode(magic,buf);
                            string outpath = filepath.Replace("dat",encoding);
                            File.WriteAllBytes(outpath,outbytes);
                            return outpath;
                        }
                    }
                    break;
                }
                catch (FileNotFoundException ex)
                {
                    Thread.Sleep(1000);
                }
            }
            return null;
        }

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