void DoDyn() // Dynamic huffman encoding, the most complex case, RFC1951 page 12.
{
uint nLitCode = 257 + GetBits(5), nDistCode = 1 + GetBits(5), nLenCode = 4 + GetBits(4);
for (uint i = 0; i < nLenCode; i += 1)
{
ClenLen[ClenAlphabet[i]] = (byte)GetBits(3);
}
for (uint i = nLenCode; i < 19; i += 1)
{
ClenLen[ClenAlphabet[i]] = 0;
}
Clen.MakeTree(ClenLen, 19);
Plenc = 0; uint carry = GetLengths(LitLen, nLitCode, 0); GetLengths(DistLen, nDistCode, carry);
Lit.MakeTree(LitLen, nLitCode);
Dist.MakeTree(DistLen, nDistCode);
while (true)
{
uint x = Lit.Decode(this);
if (x < 256)
{
OB.Add((byte)x);
}
else if (x == 256)
{
break;
}
else
{
x -= 257;
uint length = MatchOff[x] + GetBits(MatchExtra[x]);
uint dc = Dist.Decode(this);
uint distance = DistOff[dc] + GetBits(DistExtra[dc]);
if (TraceLevel > 1)
{
System.Console.WriteLine("Copy at " + OB.Count + " length=" + length + " distance=" + distance);
}
OB.Copy(distance, length);
}
}
} // end DoDyn
