/// <summary>
/// Resets the inflater so that a new stream can be decompressed. All
/// pending input and output will be discarded.
/// </summary>
public void Reset()
{
this.mode = this.noHeader ? DECODE_BLOCKS : DECODE_HEADER;
this.totalIn = 0;
this.totalOut = 0;
this.input.Reset();
this.outputWindow.Reset();
this.dynHeader = null;
this.litlenTree = null;
this.distTree = null;
this.isLastBlock = false;
if (this.adler != null)
{
this.adler.Reset();
}
}
/// <summary>
/// Decodes the deflated stream.
/// </summary>
/// <returns>
/// false if more input is needed, or if finished.
/// </returns>
/// <exception cref="SharpZipBaseException">
/// if deflated stream is invalid.
/// </exception>
private bool Decode()
{
switch (this.mode)
{
case DECODE_HEADER:
return(this.DecodeHeader());
case DECODE_DICT:
return(this.DecodeDict());
case DECODE_CHKSUM:
return(this.DecodeChksum());
case DECODE_BLOCKS:
if (this.isLastBlock)
{
if (this.noHeader)
{
this.mode = FINISHED;
return(false);
}
else
{
this.input.SkipToByteBoundary();
this.neededBits = 32;
this.mode = DECODE_CHKSUM;
return(true);
}
}
int type = this.input.PeekBits(3);
if (type < 0)
{
return(false);
}
this.input.DropBits(3);
this.isLastBlock |= (type & 1) != 0;
switch (type >> 1)
{
case DeflaterConstants.STORED_BLOCK:
this.input.SkipToByteBoundary();
this.mode = DECODE_STORED_LEN1;
break;
case DeflaterConstants.STATIC_TREES:
this.litlenTree = InflaterHuffmanTree.defLitLenTree;
this.distTree = InflaterHuffmanTree.defDistTree;
this.mode = DECODE_HUFFMAN;
break;
case DeflaterConstants.DYN_TREES:
this.dynHeader = new InflaterDynHeader(this.input);
this.mode = DECODE_DYN_HEADER;
break;
default:
throw new SharpZipBaseException("Unknown block type " + type);
}
return(true);
case DECODE_STORED_LEN1:
{
if ((this.uncomprLen = this.input.PeekBits(16)) < 0)
{
return(false);
}
this.input.DropBits(16);
this.mode = DECODE_STORED_LEN2;
}
goto case DECODE_STORED_LEN2; // fall through
case DECODE_STORED_LEN2:
{
int nlen = this.input.PeekBits(16);
if (nlen < 0)
{
return(false);
}
this.input.DropBits(16);
if (nlen != (this.uncomprLen ^ 0xffff))
{
throw new SharpZipBaseException("broken uncompressed block");
}
this.mode = DECODE_STORED;
}
goto case DECODE_STORED; // fall through
case DECODE_STORED:
{
int more = this.outputWindow.CopyStored(this.input, this.uncomprLen);
this.uncomprLen -= more;
if (this.uncomprLen == 0)
{
this.mode = DECODE_BLOCKS;
return(true);
}
return(!this.input.IsNeedingInput);
}
case DECODE_DYN_HEADER:
if (!this.dynHeader.AttemptRead())
{
return(false);
}
this.litlenTree = this.dynHeader.LiteralLengthTree;
this.distTree = this.dynHeader.DistanceTree;
this.mode = DECODE_HUFFMAN;
goto case DECODE_HUFFMAN; // fall through
case DECODE_HUFFMAN:
case DECODE_HUFFMAN_LENBITS:
case DECODE_HUFFMAN_DIST:
case DECODE_HUFFMAN_DISTBITS:
return(this.DecodeHuffman());
case FINISHED:
return(false);
default:
throw new SharpZipBaseException("Inflater.Decode unknown mode");
}
}
