private static int Codes(BitStream bitStream, Huffman lencode, Huffman distcode, bool lastBlock)
{
int symbol;
do
{
symbol = Decode(bitStream, lencode);
if (symbol < 0)
{
throw new ArgumentOutOfRangeException("invalid symbol.");
}
if (symbol < 256)
{
bitStream.OutBuffer.Add((byte)symbol);
//bitStream.OutBufferWithHeader.Add((byte)symbol);
//if (bitStream.OutBuffer.Count() % 65535 == 0)
//{
// Console.WriteLine("blocked");
// var blocks = bitStream.OutBuffer.Count() / 65535;
// bitStream.OutBufferWithHeader.InsertRange((65535 + 5) * (blocks - 1), BlockHeader(65535, false));
//}
}
else if (symbol > 256)
{
symbol -= 257;
if (symbol >= 29)
{
throw new Exception("Invalid fixed code.");
}
var len = lens[symbol] + bitStream.GetNextBitsReverse(lext[symbol]);
symbol = Decode(bitStream, distcode);
if (symbol < 0)
{
throw new ArgumentOutOfRangeException("invalid symbol.");
}
var dist = dists[symbol] + bitStream.GetNextBitsReverse(dext[symbol]);
// copy length bytes from distance bytes back.
for (int i = 0; i < len; i++)
{
bitStream.OutBuffer.Add(bitStream.OutBuffer[bitStream.OutBuffer.Count() - dist]);
//bitStream.OutBufferWithHeader.Add(bitStream.OutBuffer[bitStream.OutBuffer.Count() - dist]);
//if (bitStream.OutBuffer.Count() % 65535 == 0)
//{
// Console.WriteLine("blocked");
// var blocks = bitStream.OutBuffer.Count() / 65535;
// bitStream.OutBufferWithHeader.InsertRange((65535 + 5) * (blocks - 1), BlockHeader(65535, false));
//}
}
}
} while (symbol != 256);
//if (lastBlock)
//{
// var blocks = bitStream.OutBuffer.Count() / 65535;
// bitStream.OutBufferWithHeader.InsertRange((65535 + 5) * (blocks - 1), BlockHeader((ushort)(bitStream.OutBuffer.Count() % 65535), true));
//}
return(0);
}
public static int ParseDynamic(BitStream bitStream, bool lastBlock)
{
short[] lengths = new short[MAXCODES];
int nlen = bitStream.GetNextBitsReverse(5) + 257;
int ndist = bitStream.GetNextBitsReverse(5) + 1;
int ncode = bitStream.GetNextBitsReverse(4) + 4;
if (nlen > MAXLCODES || ndist > MAXDCODES)
{
throw new Exception("bad counts");
}
for (int i = 0; i < ncode; i++)
{
lengths[order[i]] = (short)bitStream.GetNextBitsReverse(3);
}
for (int i = ncode; i < 19; i++)
{
lengths[order[i]] = 0;
}
//for (int i = 0; i < lengths.Length; i++)
//{
// Console.WriteLine($"symbol {i} has a code length of {lengths[i]}");
//}
var lencode = new Huffman(new short[MAXBITS + 1], new short[MAXLCODES]);
var distcode = new Huffman(new short[MAXBITS + 1], new short[MAXDCODES]);
var err = Construct(ref lencode, lengths, 19);
if (err != 0)
{
throw new Exception("complete code set required here; code lengths codes incomplete.");
}
//for (int i = 0; i < lencode.count.Length; i++)
//{
// Console.WriteLine($"{lencode.count[i]} symbols of length {i}");
//}
var index = 0;
while (index < nlen + ndist)
{
var symbol = Decode(bitStream, lencode);
var len = 0;
if (symbol < 0)
{
throw new ArgumentOutOfRangeException("invalid symbol");
}
if (symbol < 16)
{
lengths[index++] = (short)symbol;
}
else
{
if (symbol == 16)
{
if (index == 0)
{
throw new ArgumentOutOfRangeException("no preceeding length to reference!");
}
len = lengths[index - 1];
symbol = 3 + bitStream.GetNextBitsReverse(2);
}
else if (symbol == 17)
{
symbol = 3 + bitStream.GetNextBitsReverse(3);
}
else
{
symbol = 11 + bitStream.GetNextBitsReverse(7);
}
if (index + symbol > nlen + ndist)
{
throw new ArgumentOutOfRangeException("too many lengths!");
}
while (symbol-- > 0)
{
lengths[index++] = (short)len;
}
}
}
if (lengths[256] == 0)
{
throw new Exception("no end of block code");
}
err = Construct(ref lencode, lengths, nlen);
if (err != 0 & (err < 0 || nlen != lencode.count[0] + lencode.count[1]))
{
throw new ArgumentException("incomplete code ok only for single length 1 code.");
}
var _lengths = new short[MAXDCODES];
Array.Copy(lengths, nlen, _lengths, 0, MAXDCODES);
err = Construct(ref distcode, _lengths, ndist);
if (err != 0 & (err < 0 || nlen != distcode.count[0] + distcode.count[1]))
{
throw new ArgumentException("incomplete code ok only for single length 1 code.");
}
return(Codes(bitStream, lencode, distcode, lastBlock));
}