// null input means write an empty payload with formatting info. This is needed for the final block.
public void GetBlock(DeflateInput input, OutputBuffer output, bool isFinal)
{
Debug.Assert(output != null);
Debug.Assert(output.FreeBytes >= PaddingSize);
// determine number of bytes to write
var count = 0;
if (input != null)
{
// allow space for padding and bits not yet flushed to buffer
count = Math.Min(input.Count, output.FreeBytes - PaddingSize - output.BitsInBuffer);
// we don't expect the output buffer to ever be this big (currently 4K), but we'll check this
// just in case that changes.
if (count > MaxUncompressedBlockSize - PaddingSize)
{
count = MaxUncompressedBlockSize - PaddingSize;
}
}
// write header and flush bits
if (isFinal)
{
output.WriteBits(FastEncoderStatics.BFinalNoCompressionHeaderBitCount, FastEncoderStatics.BFinalNoCompressionHeader);
}
else
{
output.WriteBits(FastEncoderStatics.NoCompressionHeaderBitCount, FastEncoderStatics.NoCompressionHeader);
}
// now we're aligned
output.FlushBits();
// write len, nlen
WriteLenNLen((ushort)count, output);
if (input == null || count <= 0)
{
return;
}
// write uncompressed bytes
output.WriteBytes(input.Buffer, input.StartIndex, count);
input.ConsumeBytes(count);
}
// null input means write an empty payload with formatting info. This is needed for the final block.
public void GetBlock(DeflateInput input, OutputBuffer output, bool isFinal)
{
Debug.Assert(output != null);
Debug.Assert(output.FreeBytes >= PaddingSize);
// determine number of bytes to write
var count = 0;
if (input != null)
{
// allow space for padding and bits not yet flushed to buffer
count = Math.Min(input.Count, output.FreeBytes - PaddingSize - output.BitsInBuffer);
// we don't expect the output buffer to ever be this big (currently 4K), but we'll check this
// just in case that changes.
if (count > MaxUncompressedBlockSize - PaddingSize)
{
count = MaxUncompressedBlockSize - PaddingSize;
}
}
// write header and flush bits
if (isFinal)
{
output.WriteBits(FastEncoderStatics.BFinalNoCompressionHeaderBitCount, FastEncoderStatics.BFinalNoCompressionHeader);
}
else
{
output.WriteBits(FastEncoderStatics.NoCompressionHeaderBitCount, FastEncoderStatics.NoCompressionHeader);
}
// now we're aligned
output.FlushBits();
// write len, nlen
WriteLenNLen((ushort) count, output);
if (input == null || count <= 0)
return;
// write uncompressed bytes
output.WriteBytes(input.Buffer, input.StartIndex, count);
input.ConsumeBytes(count);
}
// maxBytesToCopy limits the number of bytes we can copy from input. Set to any value < 1 if no limit
private void GetCompressedOutput(DeflateInput input, OutputBuffer output, int maxBytesToCopy)
{
// snapshot for compression ratio stats
var bytesWrittenPre = output.BytesWritten;
var bytesConsumedFromInput = 0;
var inputBytesPre = BytesInHistory + input.Count;
do
{
// read more input data into the window if there is space available
var bytesToCopy = (input.Count < _inputWindow.FreeWindowSpace)
? input.Count
: _inputWindow.FreeWindowSpace;
if (maxBytesToCopy >= 1)
{
bytesToCopy = Math.Min(bytesToCopy, maxBytesToCopy - bytesConsumedFromInput);
}
if (bytesToCopy > 0)
{
// copy data into history window
_inputWindow.CopyBytes(input.Buffer, input.StartIndex, bytesToCopy);
input.ConsumeBytes(bytesToCopy);
bytesConsumedFromInput += bytesToCopy;
}
this.GetCompressedOutput(output);
}while (SafeToWriteTo(output) && InputAvailable(input) && (maxBytesToCopy < 1 || bytesConsumedFromInput < maxBytesToCopy));
// determine compression ratio, save
var bytesWrittenPost = output.BytesWritten;
var bytesWritten = bytesWrittenPost - bytesWrittenPre;
var inputBytesPost = BytesInHistory + input.Count;
var totalBytesConsumed = inputBytesPre - inputBytesPost;
if (bytesWritten != 0)
{
this.LastCompressionRatio = bytesWritten / (double)totalBytesConsumed;
}
}
// maxBytesToCopy limits the number of bytes we can copy from input. Set to any value < 1 if no limit
private void GetCompressedOutput(DeflateInput input, OutputBuffer output, int maxBytesToCopy)
{
// snapshot for compression ratio stats
var bytesWrittenPre = output.BytesWritten;
var bytesConsumedFromInput = 0;
var inputBytesPre = BytesInHistory + input.Count;
do
{
// read more input data into the window if there is space available
var bytesToCopy = (input.Count < _inputWindow.FreeWindowSpace)
? input.Count
: _inputWindow.FreeWindowSpace;
if (maxBytesToCopy >= 1)
{
bytesToCopy = Math.Min(bytesToCopy, maxBytesToCopy - bytesConsumedFromInput);
}
if (bytesToCopy > 0)
{
// copy data into history window
_inputWindow.CopyBytes(input.Buffer, input.StartIndex, bytesToCopy);
input.ConsumeBytes(bytesToCopy);
bytesConsumedFromInput += bytesToCopy;
}
this.GetCompressedOutput(output);
}
while (SafeToWriteTo(output) && InputAvailable(input) && (maxBytesToCopy < 1 || bytesConsumedFromInput < maxBytesToCopy));
// determine compression ratio, save
var bytesWrittenPost = output.BytesWritten;
var bytesWritten = bytesWrittenPost - bytesWrittenPre;
var inputBytesPost = BytesInHistory + input.Count;
var totalBytesConsumed = inputBytesPre - inputBytesPost;
if (bytesWritten != 0)
this.LastCompressionRatio = bytesWritten / (double)totalBytesConsumed;
}
