public void Dispose()
{
if (oldData != null)
{
oldData.Dispose();
}
if (newData != null)
{
newData.Dispose();
}
if (windowEncoder != null)
{
windowEncoder = null;
}
}
/// <summary>
/// Encodes the data using the settings from initialization
/// </summary>
/// <param name="newData">the target data</param>
/// <param name="sout">the out stream</param>
public void EncodeChunk(IByteBuffer newData, ByteStreamWriter sout)
{
uint checksum = 0;
///If checksum needed
///Generate Adler32 checksum for the incoming bytes
if (hasChecksum)
{
newData.Position = 0;
byte[] bytes = newData.ReadBytes((int)newData.Length);
checksum = Checksum.ComputeAdler32(bytes);
bytes = null;
}
windowEncoder = new WindowEncoder(oldData.Length, checksum, interleaved, hasChecksum);
oldData.Position = 0;
newData.Position = 0;
this.newData = newData;
long nextEncode = newData.Position;
long targetEnd = newData.Length;
long startOfLastBlock = targetEnd - BlockHash.BlockSize;
long candidatePos = nextEncode;
//create the first hash
ulong hash = hasher.Hash(newData.PeekBytes(BlockHash.BlockSize));
while (true)
{
//if less than block size exit and then write as an ADD
if (newData.Length - nextEncode < BlockHash.BlockSize)
{
break;
}
//try and encode the copy and add instructions that best match
long bytesEncoded = EncodeCopyForBestMatch(hash, candidatePos, nextEncode, targetEnd);
if (bytesEncoded > 0)
{
nextEncode += bytesEncoded;
candidatePos = nextEncode;
if (candidatePos > startOfLastBlock)
{
break;
}
newData.Position = candidatePos;
//cannot use rolling hash since we skipped so many
hash = hasher.Hash(newData.ReadBytes(BlockHash.BlockSize));
}
else
{
if (candidatePos + 1 > startOfLastBlock)
{
break;
}
//update hash requires the first byte of the last hash as well as the byte that is first byte pos + blockSize
//in order to properly calculate the rolling hash
newData.Position = candidatePos;
byte peek0 = newData.ReadByte();
newData.Position = candidatePos + BlockHash.BlockSize;
byte peek1 = newData.ReadByte();
hash = hasher.UpdateHash(hash, peek0, peek1);
candidatePos++;
}
}
//Add the rest of the data that was not encoded
if (nextEncode < newData.Length)
{
int len = (int)(newData.Length - nextEncode);
newData.Position = nextEncode;
windowEncoder.Add(newData.ReadBytes(len));
}
//output the final window
windowEncoder.Output(sout);
}
