public static void WriteMatch(int matchLen, int matchPos, OutputBuffer output)
{
Debug.Assert(matchLen >= FastEncoderWindow.MinMatch && matchLen <= FastEncoderWindow.MaxMatch,
"Illegal currentMatch length!");
// Get the code information for a match code
var codeInfo =
FastEncoderStatics.FastEncoderLiteralCodeInfo[
(FastEncoderStatics.NumChars + 1 - FastEncoderWindow.MinMatch) + matchLen];
var codeLen = (int)codeInfo & 31;
Debug.Assert(codeLen != 0, "Invalid Match Length!");
if (codeLen <= 16)
{
output.WriteBits(codeLen, codeInfo >> 5);
}
else
{
output.WriteBits(16, (codeInfo >> 5) & 65535);
output.WriteBits(codeLen - 16, codeInfo >> (5 + 16));
}
// Get the code information for a distance code
codeInfo = FastEncoderStatics.FastEncoderDistanceCodeInfo[FastEncoderStatics.GetSlot(matchPos)];
output.WriteBits((int)(codeInfo & 15), codeInfo >> 8);
var extraBits = (int)(codeInfo >> 4) & 15;
if (extraBits != 0)
{
output.WriteBits(extraBits, (uint)matchPos & FastEncoderStatics.BitMask[extraBits]);
}
}
// Copy the compressed bytes to output buffer as a block. maxBytesToCopy limits the number of
// bytes we can copy from input. Set to any value < 1 if no limit
public void GetBlock(DeflateInput input, OutputBuffer output, int maxBytesToCopy)
{
Debug.Assert(InputAvailable(input), "call SetInput before trying to compress!");
WriteDeflatePreamble(output);
GetCompressedOutput(input, output, maxBytesToCopy);
WriteEndOfBlock(output);
}
// Copy the compressed bytes to output buffer as a block. maxBytesToCopy limits the number of
// bytes we can copy from input. Set to any value < 1 if no limit
public void GetBlock(DeflateInput input, OutputBuffer output, int maxBytesToCopy)
{
Debug.Assert(InputAvailable(input), "call SetInput before trying to compress!");
WriteDeflatePreamble(output);
GetCompressedOutput(input, output, maxBytesToCopy);
WriteEndOfBlock(output);
}
internal Deflater()
{
_deflateEncoder = new FastEncoder();
_copyEncoder = new CopyEncoder();
_input = new DeflateInput();
_output = new OutputBuffer();
_processingState = DeflaterState.NotStarted;
}
private static void WriteEndOfBlock(OutputBuffer output)
{
// The fast encoder outputs one long block, so it just needs to terminate this block
const int endOfBlockCode = 256;
var codeInfo = FastEncoderStatics.FastEncoderLiteralCodeInfo[endOfBlockCode];
var codeLen = (int)(codeInfo & 31);
output.WriteBits(codeLen, codeInfo >> 5);
}
// Output the block type and tree structure for our hard-coded trees.
// Contains following data:
// "final" block flag 1 bit
// BLOCKTYPE_DYNAMIC 2 bits
// FastEncoderLiteralTreeLength
// FastEncoderDistanceTreeLength
//
public static void WriteDeflatePreamble(OutputBuffer output)
{
//Debug.Assert( bitCount == 0, "bitCount must be zero before writing tree bit!");
output.WriteBytes(FastEncoderStatics.FastEncoderTreeStructureData, 0,
FastEncoderStatics.FastEncoderTreeStructureData.Length);
output.WriteBits(FastEncoderStatics.FastEncoderPostTreeBitCount,
FastEncoderStatics.FastEncoderPostTreeBitBuf);
}
internal Deflater()
{
_deflateEncoder = new FastEncoder();
_copyEncoder = new CopyEncoder();
_input = new DeflateInput();
_output = new OutputBuffer();
_processingState = DeflaterState.NotStarted;
}
private static void WriteLenNLen(ushort len, OutputBuffer output)
{
// len
output.WriteUInt16(len);
// nlen
var onesComp = (ushort)(~len);
output.WriteUInt16(onesComp);
}
private static void WriteLenNLen(ushort len, OutputBuffer output)
{
// len
output.WriteUInt16(len);
// nlen
var onesComp = (ushort) (~len);
output.WriteUInt16(onesComp);
}
// 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;
}
}
// compress the bytes in input history window
private void GetCompressedOutput(OutputBuffer output)
{
while (_inputWindow.BytesAvailable > 0 && SafeToWriteTo(output))
{
// Find next match. A match can be a symbol,
// a distance/length pair, a symbol followed by a distance/Length pair
_inputWindow.GetNextSymbolOrMatch(_currentMatch);
if (_currentMatch.State == MatchState.HasSymbol)
{
WriteChar(_currentMatch.Symbol, output);
}
else if (_currentMatch.State == MatchState.HasMatch)
{
WriteMatch(_currentMatch.Length, _currentMatch.Position, output);
}
else
{
WriteChar(_currentMatch.Symbol, output);
WriteMatch(_currentMatch.Length, _currentMatch.Position, output);
}
}
}
public static void WriteChar(byte b, OutputBuffer output)
{
var code = FastEncoderStatics.FastEncoderLiteralCodeInfo[b];
output.WriteBits((int)code & 31, code >> 5);
}
public void GetBlockFooter(OutputBuffer output)
{
WriteEndOfBlock(output);
}
public void GetBlockHeader(OutputBuffer output)
{
WriteDeflatePreamble(output);
}
// Compress data but don't format as block (doesn't have header and footer)
public void GetCompressedData(DeflateInput input, OutputBuffer output)
{
this.GetCompressedOutput(input, output, -1);
}
private static bool SafeToWriteTo(OutputBuffer output)
{
// can we safely continue writing to output buffer
return output.FreeBytes > FastEncoderStatics.MaxCodeLen;
}
private static void WriteEndOfBlock(OutputBuffer output)
{
// The fast encoder outputs one long block, so it just needs to terminate this block
const int endOfBlockCode = 256;
var codeInfo = FastEncoderStatics.FastEncoderLiteralCodeInfo[endOfBlockCode];
var codeLen = (int)(codeInfo & 31);
output.WriteBits(codeLen, codeInfo >> 5);
}
public static void WriteChar(byte b, OutputBuffer output)
{
var code = FastEncoderStatics.FastEncoderLiteralCodeInfo[b];
output.WriteBits((int)code & 31, code >> 5);
}
public void GetBlockHeader(OutputBuffer output)
{
WriteDeflatePreamble(output);
}
public void GetBlockFooter(OutputBuffer output)
{
WriteEndOfBlock(output);
}
private static bool SafeToWriteTo(OutputBuffer output)
{
// can we safely continue writing to output buffer
return(output.FreeBytes > FastEncoderStatics.MaxCodeLen);
}
// compress the bytes in input history window
private void GetCompressedOutput(OutputBuffer output)
{
while (_inputWindow.BytesAvailable > 0 && SafeToWriteTo(output))
{
// Find next match. A match can be a symbol,
// a distance/length pair, a symbol followed by a distance/Length pair
_inputWindow.GetNextSymbolOrMatch(_currentMatch);
if (_currentMatch.State == MatchState.HasSymbol)
{
WriteChar(_currentMatch.Symbol, output);
}
else if (_currentMatch.State == MatchState.HasMatch)
{
WriteMatch(_currentMatch.Length, _currentMatch.Position, output);
}
else
{
WriteChar(_currentMatch.Symbol, output);
WriteMatch(_currentMatch.Length, _currentMatch.Position, output);
}
}
}
// Output the block type and tree structure for our hard-coded trees.
// Contains following data:
// "final" block flag 1 bit
// BLOCKTYPE_DYNAMIC 2 bits
// FastEncoderLiteralTreeLength
// FastEncoderDistanceTreeLength
//
public static void WriteDeflatePreamble(OutputBuffer output)
{
//Debug.Assert( bitCount == 0, "bitCount must be zero before writing tree bit!");
output.WriteBytes(FastEncoderStatics.FastEncoderTreeStructureData, 0,
FastEncoderStatics.FastEncoderTreeStructureData.Length);
output.WriteBits(FastEncoderStatics.FastEncoderPostTreeBitCount,
FastEncoderStatics.FastEncoderPostTreeBitBuf);
}
public static void WriteMatch(int matchLen, int matchPos, OutputBuffer output)
{
Debug.Assert(matchLen >= FastEncoderWindow.MinMatch && matchLen <= FastEncoderWindow.MaxMatch,
"Illegal currentMatch length!");
// Get the code information for a match code
var codeInfo =
FastEncoderStatics.FastEncoderLiteralCodeInfo[
(FastEncoderStatics.NumChars + 1 - FastEncoderWindow.MinMatch) + matchLen];
var codeLen = (int)codeInfo & 31;
Debug.Assert(codeLen != 0, "Invalid Match Length!");
if (codeLen <= 16)
{
output.WriteBits(codeLen, codeInfo >> 5);
}
else
{
output.WriteBits(16, (codeInfo >> 5) & 65535);
output.WriteBits(codeLen - 16, codeInfo >> (5 + 16));
}
// Get the code information for a distance code
codeInfo = FastEncoderStatics.FastEncoderDistanceCodeInfo[FastEncoderStatics.GetSlot(matchPos)];
output.WriteBits((int)(codeInfo & 15), codeInfo >> 8);
var extraBits = (int)(codeInfo >> 4) & 15;
if (extraBits != 0)
{
output.WriteBits(extraBits, (uint)matchPos & FastEncoderStatics.BitMask[extraBits]);
}
}
// Compress data but don't format as block (doesn't have header and footer)
public void GetCompressedData(DeflateInput input, OutputBuffer output)
{
this.GetCompressedOutput(input, output, -1);
}
