public void CalculatesCorrectChecksum()
{
var data = new byte[]
{
0,
255, 0, 0,
0, 0, 0,
0,
0, 0, 0,
255, 0, 0
};
var checksum = Adler32Checksum.Calculate(data);
Assert.Equal(268304895, checksum);
}
public void CalculatesCorrectChecksumWithLengthArgument()
{
var data = new byte[]
{
0,
255, 0, 0,
0, 0, 0,
0,
0, 0, 0,
255, 0, 0,
44, 12, 126, 200
};
var checksum = Adler32Checksum.Calculate(data, 14);
Assert.Equal(268304895, checksum);
}
public byte[] Encode(Stream input, DictionaryToken streamDictionary, int index)
{
const int headerLength = 2;
const int checksumLength = 4;
byte[] data;
using (var temp = new MemoryStream())
{
input.CopyTo(temp);
data = temp.ToArray();
}
using (var compressStream = new MemoryStream())
using (var compressor = new DeflateStream(compressStream, CompressionLevel.Fastest))
{
compressor.Write(data, 0, data.Length);
compressor.Close();
var compressed = compressStream.ToArray();
var result = new byte[headerLength + compressed.Length + checksumLength];
// Write the ZLib header.
result[0] = Deflate32KbWindow;
result[1] = ChecksumBits;
// Write the compressed data.
Array.Copy(compressed, 0, result, headerLength, compressed.Length);
// Write Checksum of raw data.
var checksum = Adler32Checksum.Calculate(data);
var offset = headerLength + compressed.Length;
result[offset++] = (byte)(checksum >> 24);
result[offset++] = (byte)(checksum >> 16);
result[offset++] = (byte)(checksum >> 8);
result[offset] = (byte)(checksum >> 0);
return(result);
}
}
