/// <summary>
/// Resets the inflater so that a new stream can be decompressed. All
/// pending input and output will be discarded.
/// </summary>
public void Reset()
{
mode = noHeader ? State.Blocks : State.Header;
totalIn = 0;
TotalOut = 0;
input.Reset();
outputWindow.Reset();
dynHeader = null;
litlenTree = null;
distTree = null;
isLastBlock = false;
adler.Reset();
}
/// <summary>
/// Decodes the deflated stream.
/// </summary>
/// <returns>
/// false if more input is needed, or if State.Done.
/// </returns>
/// <exception cref="InvalidDataException">
/// if deflated stream is invalid.
/// </exception>
bool Decode()
{
switch (mode)
{
case State.Header:
return(DecodeHeader());
case State.Dictionary:
return(DecodeDict());
case State.Checksum:
return(DecodeChksum());
case State.Blocks:
if (isLastBlock)
{
if (noHeader)
{
mode = State.Done;
return(false);
}
else
{
input.SkipToByteBoundary();
neededBits = 32;
mode = State.Checksum;
return(true);
}
}
var type = input.PeekBits(3);
if (type < 0)
{
return(false);
}
input.DropBits(3);
isLastBlock |= (type & 1) != 0;
switch (type >> 1)
{
case DeflaterConstants.StoredBlock:
input.SkipToByteBoundary();
mode = State.StoredLen1;
break;
case DeflaterConstants.StaticTree:
litlenTree = InflaterHuffmanTree.DefLitLenTree;
distTree = InflaterHuffmanTree.DefDistTree;
mode = State.Huffman;
break;
case DeflaterConstants.DynamicTree:
dynHeader = new InflaterDynHeader();
mode = State.DynamicHeader;
break;
default:
throw new NotSupportedException("Unknown block type " + type);
}
return(true);
case State.StoredLen1:
{
if ((uncomprLen = input.PeekBits(16)) < 0)
{
return(false);
}
input.DropBits(16);
mode = State.StoredLen2;
}
goto case State.StoredLen2; // fall through
case State.StoredLen2:
{
var nlen = input.PeekBits(16);
if (nlen < 0)
{
return(false);
}
input.DropBits(16);
if (nlen != (uncomprLen ^ 0xffff))
{
throw new InvalidDataException("broken uncompressed block");
}
mode = State.Stored;
goto case State.Stored; // fall through
}
case State.Stored:
{
var more = outputWindow.CopyStored(input, uncomprLen);
uncomprLen -= more;
if (uncomprLen == 0)
{
mode = State.Blocks;
return(true);
}
return(!input.IsNeedingInput);
}
case State.DynamicHeader:
if (!dynHeader.Decode(input))
{
return(false);
}
litlenTree = dynHeader.BuildLitLenTree();
distTree = dynHeader.BuildDistTree();
mode = State.Huffman;
goto case State.Huffman; // fall through
case State.Huffman:
case State.HuffmanLenBits:
case State.HuffmanDist:
case State.HuffmanDistBits:
return(DecodeHuffman());
case State.Done:
return(false);
default:
throw new InvalidDataException("Inflater.Decode unknown mode");
}
}