public PKLibDecompress(Stream Input)
{
mStream = new BitStream(Input);
mCType = (CompressionType)Input.ReadByte();
if (mCType != CompressionType.Binary && mCType != CompressionType.Ascii)
throw new MpqParserException("Invalid compression type: " + mCType);
mDSizeBits = Input.ReadByte();
// This is 6 in test cases
if (4 > mDSizeBits || mDSizeBits > 6)
throw new MpqParserException("Invalid dictionary size: " + mDSizeBits);
}
private static LinkedNode Decode(BitStream Input, LinkedNode Head)
{
LinkedNode node = Head;
while(node.Child0 != null)
{
int bit = Input.ReadBits(1);
if (bit == -1)
throw new MpqParserException("Unexpected end of file");
node = bit == 0 ? node.Child0 : node.Child1;
}
return node;
}
public static byte[] Decompress(Stream Data)
{
int comptype = Data.ReadByte();
if (comptype == 0)
throw new NotImplementedException("Compression type 0 is not currently supported");
LinkedNode tail = BuildList(sPrime[comptype]);
LinkedNode head = BuildTree(tail);
MemoryStream outputstream = new MemoryStream();
BitStream bitstream = new BitStream(Data);
int decoded;
do
{
LinkedNode node = Decode(bitstream, head);
decoded = node.DecompressedValue;
switch(decoded)
{
case 256:
break;
case 257:
int newvalue = bitstream.ReadBits(8);
outputstream.WriteByte((byte)newvalue);
tail = InsertNode(tail, newvalue);
break;
default:
outputstream.WriteByte((byte)decoded);
break;
}
} while (decoded != 256);
return outputstream.ToArray();
}
