private void ReadLengths(HuffmanTree preTree, uint[] lengths, int offset, int count)
{
int i = 0;
while (i < count)
{
uint value = preTree.NextSymbol(_bitStream);
if (value == 17)
{
uint numZeros = 4 + _bitStream.Read(4);
for (uint j = 0; j < numZeros; ++j)
{
lengths[offset + i] = 0;
++i;
}
}
else if (value == 18)
{
uint numZeros = 20 + _bitStream.Read(5);
for (uint j = 0; j < numZeros; ++j)
{
lengths[offset + i] = 0;
++i;
}
}
else if (value == 19)
{
uint same = _bitStream.Read(1);
value = preTree.NextSymbol(_bitStream);
if (value > 16)
{
throw new InvalidDataException("Invalid table encoding");
}
uint symbol = (17 + lengths[offset + i] - value) % 17;
for (uint j = 0; j < 4 + same; ++j)
{
lengths[offset + i] = symbol;
++i;
}
}
else
{
lengths[offset + i] = (17 + lengths[offset + i] - value) % 17;
++i;
}
}
}
