/// <summary>
/// Sets input data to be deflated. Should only be called when <see cref="NeedsInput"/>
/// returns true
/// </summary>
/// <param name="buffer">The buffer containing input data.</param>
/// <param name="offset">The offset of the first byte of data.</param>
/// <param name="count">The number of bytes of data to use as input.</param>
public void SetInput(byte[] buffer, int offset, int count)
{
if (buffer is null)
{
DeflateThrowHelper.ThrowNull(nameof(buffer));
}
if (offset < 0)
{
DeflateThrowHelper.ThrowOutOfRange(nameof(offset));
}
if (count < 0)
{
DeflateThrowHelper.ThrowOutOfRange(nameof(count));
}
if (this.inputOff < this.inputEnd)
{
DeflateThrowHelper.ThrowNotProcessed();
}
int end = offset + count;
// We want to throw an ArgumentOutOfRangeException early.
// The check is very tricky: it also handles integer wrap around.
if ((offset > end) || (end > buffer.Length))
{
DeflateThrowHelper.ThrowOutOfRange(nameof(count));
}
this.inputBuf = buffer;
this.inputOff = offset;
this.inputEnd = end;
}
/// <summary>
/// Deflate drives actual compression of data
/// </summary>
/// <param name="flush">True to flush input buffers</param>
/// <param name="finish">Finish deflation with the current input.</param>
/// <returns>Returns true if progress has been made.</returns>
public bool Deflate(bool flush, bool finish)
{
bool progress = false;
do
{
this.FillWindow();
bool canFlush = flush && (this.inputOff == this.inputEnd);
switch (this.compressionFunction)
{
case DeflaterConstants.DEFLATE_STORED:
progress = this.DeflateStored(canFlush, finish);
break;
case DeflaterConstants.DEFLATE_FAST:
progress = this.DeflateFast(canFlush, finish);
break;
case DeflaterConstants.DEFLATE_SLOW:
progress = this.DeflateSlow(canFlush, finish);
break;
default:
DeflateThrowHelper.ThrowUnknownCompression();
break;
}
}while (this.Pending.IsFlushed && progress); // repeat while we have no pending output and progress was made
return(progress);
}
public void SetInput(byte[] input, int offset, int count)
{
if ((this.state & IsFinishing) != 0)
{
DeflateThrowHelper.ThrowAlreadyFinished();
}
this.engine.SetInput(input, offset, count);
}
/// <summary>
/// Deflates the current input block to the given array.
/// </summary>
/// <param name="output">Buffer to store the compressed data.</param>
/// <param name="offset">Offset into the output array.</param>
/// <param name="length">The maximum number of bytes that may be stored.</param>
/// <returns>
/// The number of compressed bytes added to the output, or 0 if either
/// <see cref="IsNeedingInput"/> or <see cref="IsFinished"/> returns true or length is zero.
/// </returns>
public int Deflate(Span <byte> output, int offset, int length)
{
int origLength = length;
if (this.state == ClosedState)
{
DeflateThrowHelper.ThrowAlreadyClosed();
}
while (true)
{
int count = this.engine.Pending.Flush(output, offset, length);
offset += count;
length -= count;
if (length == 0 || this.state == FinishedState)
{
break;
}
if (!this.engine.Deflate((this.state & IsFlushing) != 0, (this.state & IsFinishing) != 0))
{
switch (this.state)
{
case BusyState:
// We need more input now
return(origLength - length);
case FlushingState:
if (this.level != NoCompression)
{
// We have to supply some lookahead. 8 bit lookahead
// is needed by the zlib inflater, and we must fill
// the next byte, so that all bits are flushed.
int neededbits = 8 + ((-this.engine.Pending.BitCount) & 7);
while (neededbits > 0)
{
// Write a static tree block consisting solely of an EOF:
this.engine.Pending.WriteBits(2, 10);
neededbits -= 10;
}
}
this.state = BusyState;
break;
case FinishingState:
this.engine.Pending.AlignToByte();
this.state = FinishedState;
break;
}
}
}
return(origLength - length);
}
/// <summary>
/// Set the deflate level (0-9)
/// </summary>
/// <param name="level">The value to set the level to.</param>
public void SetLevel(int level)
{
if ((level < 0) || (level > 9))
{
DeflateThrowHelper.ThrowOutOfRange(nameof(level));
}
this.goodLength = DeflaterConstants.GOOD_LENGTH[level];
this.maxLazy = DeflaterConstants.MAX_LAZY[level];
this.niceLength = DeflaterConstants.NICE_LENGTH[level];
this.maxChain = DeflaterConstants.MAX_CHAIN[level];
if (DeflaterConstants.COMPR_FUNC[level] != this.compressionFunction)
{
switch (this.compressionFunction)
{
case DeflaterConstants.DEFLATE_STORED:
if (this.strstart > this.blockStart)
{
this.huffman.FlushStoredBlock(this.window.Span, this.blockStart, this.strstart - this.blockStart, false);
this.blockStart = this.strstart;
}
this.UpdateHash();
break;
case DeflaterConstants.DEFLATE_FAST:
if (this.strstart > this.blockStart)
{
this.huffman.FlushBlock(this.window.Span, this.blockStart, this.strstart - this.blockStart, false);
this.blockStart = this.strstart;
}
break;
case DeflaterConstants.DEFLATE_SLOW:
if (this.prevAvailable)
{
this.huffman.TallyLit(this.pinnedWindowPointer[this.strstart - 1] & 0xFF);
}
if (this.strstart > this.blockStart)
{
this.huffman.FlushBlock(this.window.Span, this.blockStart, this.strstart - this.blockStart, false);
this.blockStart = this.strstart;
}
this.prevAvailable = false;
this.matchLen = DeflaterConstants.MIN_MATCH - 1;
break;
}
this.compressionFunction = DeflaterConstants.COMPR_FUNC[level];
}
}