public void Complete()
{
if (_state == FseCompressorState.Completed)
{
return;
}
if (_state == FseCompressorState.NeedInput)
{
Compress();
}
_state = FseCompressorState.WriteOutput;
Debug.Assert(_outputBuffer != null);
uint checksum = _hash.GetFinalHash();
checksum = (checksum >> 5) & ((1u << 22) - 1);
Span <byte> block = _outputBuffer.AsSpan(_outputOffset + _bytesGenerated);
block[2] = (byte)checksum;
block[1] = (byte)(checksum >> 8);
block[0] = (byte)((checksum >> 16) + (0b11 << 6));
_bytesGenerated += 3;
_headerWritten = false;
_hash = XxHash32.Initialize();
}
public void Reset()
{
if (_compressor is null)
{
throw new ObjectDisposedException(nameof(FsePipeCompressor));
}
_compressor.Reset();
_state = FseCompressorState.NeedInput;
}
public void Reset()
{
_state = FseCompressorState.NeedInput;
_headerWritten = false;
_hash = XxHash32.Initialize();
_bytesRead = 0;
_outputOffset = 0;
_bytesGenerated = 0;
}
public void NotifyFlushCompleted()
{
if (_compressor is null)
{
throw new ObjectDisposedException(nameof(FsePipeCompressor));
}
if (_state == FseCompressorState.WriteOutput)
{
_state = _compressor.State;
return;
}
throw new InvalidOperationException();
}
public void Complete()
{
if (_compressor is null)
{
throw new ObjectDisposedException(nameof(FsePipeCompressor));
}
_compressor.Complete();
if (_compressor.State == FseCompressorState.WriteOutput)
{
ArraySegment <byte> output = _compressor.Output;
_writer.Write(output.AsSpan());
_compressor.Advance(output.Count);
_state = FseCompressorState.WriteOutput;
}
}
public void Advance(int count)
{
if (_state != FseCompressorState.WriteOutput)
{
throw new InvalidOperationException();
}
if ((uint)count > (uint)_bytesGenerated)
{
throw new ArgumentOutOfRangeException(nameof(count));
}
_outputOffset += count;
_bytesGenerated -= count;
if (_bytesGenerated == 0)
{
_bytesRead = 0;
_outputOffset = 0;
_state = _headerWritten ? FseCompressorState.NeedInput : FseCompressorState.Completed;
}
}
public void Flush()
{
if (_compressor is null)
{
throw new ObjectDisposedException(nameof(FsePipeCompressor));
}
if (_state != FseCompressorState.NeedInput)
{
throw new InvalidOperationException();
}
_compressor.Flush();
if (_compressor.State == FseCompressorState.WriteOutput)
{
ArraySegment <byte> output = _compressor.Output;
_writer.Write(output.AsSpan());
_compressor.Advance(output.Count);
_state = FseCompressorState.WriteOutput;
}
}
public void Process(ReadOnlySequence <byte> buffer, out SequencePosition consumed, out SequencePosition examined)
{
if (_compressor is null)
{
throw new ObjectDisposedException(nameof(FsePipeCompressor));
}
if (_state == FseCompressorState.WriteOutput)
{
throw new InvalidOperationException();
}
if (buffer.IsEmpty)
{
consumed = examined = default;
return;
}
int consumedBytes = 0;
foreach (ReadOnlyMemory <byte> segment in buffer)
{
consumedBytes += _compressor.SetInput(segment.Span);
if (_compressor.State == FseCompressorState.WriteOutput)
{
ArraySegment <byte> output = _compressor.Output;
_writer.Write(output.AsSpan());
_compressor.Advance(output.Count);
_state = FseCompressorState.WriteOutput;
break;
}
}
consumed = examined = buffer.Slice(consumedBytes).Start;
}
public FsePipeCompressor(IBufferWriter <byte> writer)
{
_writer = writer ?? throw new ArgumentNullException(nameof(writer));
_compressor = new FseStreamCompressor();
_state = FseCompressorState.NeedInput;
}
private void Compress()
{
EnsureOutputBufferAllocated();
Debug.Assert(_state == FseCompressorState.NeedInput);
Debug.Assert(_bytesGenerated == 0);
int inSize = _bytesRead;
Span <byte> inputBuffer = _inputBuffer.AsSpan(0, inSize);
Span <byte> outputBuffer = _outputBuffer.AsSpan(0, _outputBufferBound);
int headerSize;
if (inSize == 0)
{
headerSize = 0;
}
else
{
_hash.Update(inputBuffer);
int cSize = FseBlockCompressor.Compress(outputBuffer.Slice(10), inputBuffer);
if (cSize == 0)
{
// raw
if (inSize == _inputBufferSize)
{
outputBuffer[9] = (0b01 << 6) + 0x20;
headerSize = 1;
}
else
{
outputBuffer[7] = (byte)(0b01 << 6);
outputBuffer[8] = (byte)(inSize >> 8);
outputBuffer[9] = (byte)inSize;
headerSize = 3;
}
inputBuffer.CopyTo(outputBuffer.Slice(10));
_bytesGenerated = inSize;
}
else if (cSize == 1)
{
// rle
if (inSize == _inputBufferSize)
{
outputBuffer[9] = (0b10 << 6) + 0x20;
headerSize = 1;
}
else
{
outputBuffer[7] = (byte)(0b10 << 6);
outputBuffer[8] = (byte)(inSize >> 8);
outputBuffer[9] = (byte)inSize;
headerSize = 3;
}
outputBuffer[10] = inputBuffer[0];
_bytesGenerated = 1;
}
else
{
// compressed
if (inSize == _inputBufferSize)
{
outputBuffer[7] = (0b00 << 6) + 0x20;
outputBuffer[8] = (byte)(cSize >> 8);
outputBuffer[9] = (byte)cSize;
headerSize = 3;
}
else
{
outputBuffer[5] = 0b00 << 6;
outputBuffer[6] = (byte)(inSize >> 8);
outputBuffer[7] = (byte)inSize;
outputBuffer[8] = (byte)(cSize >> 8);
outputBuffer[9] = (byte)cSize;
headerSize = 5;
}
_bytesGenerated = cSize;
}
}
if (!_headerWritten)
{
BinaryPrimitives.WriteInt32LittleEndian(outputBuffer.Slice(5 - headerSize, 4), (int)FseCompressingAlgorithm.Fse);
outputBuffer[9 - headerSize] = (byte)_blockSizeId;
headerSize += 5;
_headerWritten = true;
}
_outputOffset = 10 - headerSize;
_bytesGenerated += headerSize;
if (_bytesGenerated == 0)
{
_state = FseCompressorState.NeedInput;
}
else
{
_state = FseCompressorState.WriteOutput;
}
}
