int IDeflater.GetDeflateOutput(byte[] outputBuffer)
{
Debug.Assert(outputBuffer != null, "Can't pass in a null output buffer!");
Debug.Assert(!NeedsInput(), "GetDeflateOutput should only be called after providing input");
output.UpdateBuffer(outputBuffer);
switch (processingState)
{
case DeflaterState.NotStarted: {
// first call. Try to compress but if we get bad compression ratio, switch to uncompressed blocks.
Debug.Assert(deflateEncoder.BytesInHistory == 0, "have leftover bytes in window");
// save these in case we need to switch to uncompressed format
DeflateInput.InputState initialInputState = input.DumpState();
OutputBuffer.BufferState initialOutputState = output.DumpState();
deflateEncoder.GetBlockHeader(output);
deflateEncoder.GetCompressedData(input, output);
if (!UseCompressed(deflateEncoder.LastCompressionRatio))
{
// we're expanding; restore state and switch to uncompressed
input.RestoreState(initialInputState);
output.RestoreState(initialOutputState);
copyEncoder.GetBlock(input, output, false);
FlushInputWindows();
processingState = DeflaterState.CheckingForIncompressible;
}
else
{
processingState = DeflaterState.CompressThenCheck;
}
break;
}
case DeflaterState.CompressThenCheck: {
// continue assuming data is compressible. If we reach data that indicates otherwise
// finish off remaining data in history and decide whether to compress on a
// block-by-block basis
deflateEncoder.GetCompressedData(input, output);
if (!UseCompressed(deflateEncoder.LastCompressionRatio))
{
processingState = DeflaterState.SlowDownForIncompressible1;
inputFromHistory = deflateEncoder.UnprocessedInput;
}
break;
}
case DeflaterState.SlowDownForIncompressible1: {
// finish off previous compressed block
deflateEncoder.GetBlockFooter(output);
processingState = DeflaterState.SlowDownForIncompressible2;
goto case DeflaterState.SlowDownForIncompressible2; // yeah I know, but there's no fallthrough
}
case DeflaterState.SlowDownForIncompressible2: {
// clear out data from history, but add them as uncompressed blocks
if (inputFromHistory.Count > 0)
{
copyEncoder.GetBlock(inputFromHistory, output, false);
}
if (inputFromHistory.Count == 0)
{
// now we're clean
deflateEncoder.FlushInput();
processingState = DeflaterState.CheckingForIncompressible;
}
break;
}
case DeflaterState.CheckingForIncompressible: {
// decide whether to compress on a block-by-block basis
Debug.Assert(deflateEncoder.BytesInHistory == 0, "have leftover bytes in window");
// save these in case we need to store as uncompressed
DeflateInput.InputState initialInputState = input.DumpState();
OutputBuffer.BufferState initialOutputState = output.DumpState();
// enforce max so we can ensure state between calls
deflateEncoder.GetBlock(input, output, CleanCopySize);
if (!UseCompressed(deflateEncoder.LastCompressionRatio))
{
// we're expanding; restore state and switch to uncompressed
input.RestoreState(initialInputState);
output.RestoreState(initialOutputState);
copyEncoder.GetBlock(input, output, false);
FlushInputWindows();
}
break;
}
case DeflaterState.StartingSmallData: {
// add compressed header and data, but not footer. Subsequent calls will keep
// adding compressed data (no header and no footer). We're doing this to
// avoid overhead of header and footer size relative to compressed payload.
deflateEncoder.GetBlockHeader(output);
processingState = DeflaterState.HandlingSmallData;
goto case DeflaterState.HandlingSmallData; // yeah I know, but there's no fallthrough
}
case DeflaterState.HandlingSmallData: {
// continue adding compressed data
deflateEncoder.GetCompressedData(input, output);
break;
}
}
return(output.BytesWritten);
}
public int GetDeflateOutput(byte[] outputBuffer)
{
this.output.UpdateBuffer(outputBuffer);
switch (this.processingState)
{
case DeflaterState.NotStarted:
{
DeflateInput.InputState state = this.input.DumpState();
OutputBuffer.BufferState state2 = this.output.DumpState();
this.deflateEncoder.GetBlockHeader(this.output);
this.deflateEncoder.GetCompressedData(this.input, this.output);
if (this.UseCompressed(this.deflateEncoder.LastCompressionRatio))
{
this.processingState = DeflaterState.CompressThenCheck;
}
else
{
this.input.RestoreState(state);
this.output.RestoreState(state2);
this.copyEncoder.GetBlock(this.input, this.output, false);
this.FlushInputWindows();
this.processingState = DeflaterState.CheckingForIncompressible;
}
goto Label_023A;
}
case DeflaterState.SlowDownForIncompressible1:
this.deflateEncoder.GetBlockFooter(this.output);
this.processingState = DeflaterState.SlowDownForIncompressible2;
break;
case DeflaterState.SlowDownForIncompressible2:
break;
case DeflaterState.StartingSmallData:
this.deflateEncoder.GetBlockHeader(this.output);
this.processingState = DeflaterState.HandlingSmallData;
goto Label_0223;
case DeflaterState.CompressThenCheck:
this.deflateEncoder.GetCompressedData(this.input, this.output);
if (!this.UseCompressed(this.deflateEncoder.LastCompressionRatio))
{
this.processingState = DeflaterState.SlowDownForIncompressible1;
this.inputFromHistory = this.deflateEncoder.UnprocessedInput;
}
goto Label_023A;
case DeflaterState.CheckingForIncompressible:
{
DeflateInput.InputState state3 = this.input.DumpState();
OutputBuffer.BufferState state4 = this.output.DumpState();
this.deflateEncoder.GetBlock(this.input, this.output, 0xf88);
if (!this.UseCompressed(this.deflateEncoder.LastCompressionRatio))
{
this.input.RestoreState(state3);
this.output.RestoreState(state4);
this.copyEncoder.GetBlock(this.input, this.output, false);
this.FlushInputWindows();
}
goto Label_023A;
}
case DeflaterState.HandlingSmallData:
goto Label_0223;
default:
goto Label_023A;
}
if (this.inputFromHistory.Count > 0)
{
this.copyEncoder.GetBlock(this.inputFromHistory, this.output, false);
}
if (this.inputFromHistory.Count == 0)
{
this.deflateEncoder.FlushInput();
this.processingState = DeflaterState.CheckingForIncompressible;
}
goto Label_023A;
Label_0223:
this.deflateEncoder.GetCompressedData(this.input, this.output);
Label_023A:
return(this.output.BytesWritten);
}