/// <summary> /// Encodes the data using the settings from initialization /// </summary> /// <param name="newData">the target data</param> /// <param name="outputStream">the out stream</param> public unsafe void EncodeChunk(ByteBuffer newData, Stream outputStream) { newData.Position = 0; ReadOnlyMemory <byte> checksumBytes = newData.ReadBytes((int)newData.Length); uint checksum = this.checksumFormat switch { ChecksumFormat.SDCH => Checksum.ComputeGoogleAdler32(checksumBytes), ChecksumFormat.Xdelta3 => Checksum.ComputeXdelta3Adler32(checksumBytes), ChecksumFormat.None => 0, _ => 0 }; windowEncoder = new WindowEncoder(oldData.Length, checksum, this.checksumFormat, this.interleaved); oldData.Position = 0; newData.Position = 0; long nextEncode = newData.Position; long targetEnd = newData.Length; long startOfLastBlock = targetEnd - this.dictionary.blockSize; long candidatePos = nextEncode; ulong hash; //create the first hash hash = hasher.Hash(newData.DangerousGetBytePointerAtCurrentPositionAndIncreaseOffsetAfter(0), this.dictionary.blockSize); byte *newDataPtr = newData.DangerousGetBytePointer(); while (true) { //if less than block size exit and then write as an ADD if (newData.Length - nextEncode < this.dictionary.blockSize) { break; } //try and encode the copy and add instructions that best match var bytesEncoded = EncodeCopyForBestMatch(hash, candidatePos, nextEncode, targetEnd, newDataPtr, newData); 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.DangerousGetBytePointerAtCurrentPositionAndIncreaseOffsetAfter(this.dictionary.blockSize), this.dictionary.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 + this.dictionary.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).Span); } //output the final window windowEncoder.Output(outputStream); }
/// <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; System.GC.Collect(); } windowEncoder = new WindowEncoder(oldData.Length, checksum, this.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); }