public static HTreeGroup[] New(int num_htree_groups, int table_size)
{
var tables = new HuffmanCode[num_htree_groups * table_size];
var htree_groups = new HTreeGroup[num_htree_groups];
for (int i = 0; i < num_htree_groups; ++i)
{
htree_groups[i] = new HTreeGroup();
htree_groups[i].tables = tables;
}
return(htree_groups);
}
void BuildPackedTable(HTreeGroup htree_group)
{
var huff = htree_group.packed_table;
for (int code = 0; code < Huffman.PackedTableSize; ++code)
{
uint bits = (uint)code;
var hcode = htree_group.GetCode (HuffIndex.Green, code);
if (hcode.value >= Huffman.NumLiteralCodes)
{
huff[code].bits = hcode.bits + BitsSpecialMarker;
huff[code].value = hcode.value;
}
else
{
huff[code].bits = 0;
huff[code].value = 0;
bits >>= AccumulateHCode (hcode, 8, ref huff[code]);
bits >>= AccumulateHCode (htree_group.GetCode (HuffIndex.Red, (int)bits), 16, ref huff[code]);
bits >>= AccumulateHCode (htree_group.GetCode (HuffIndex.Blue, (int)bits), 0, ref huff[code]);
bits >>= AccumulateHCode (htree_group.GetCode (HuffIndex.Alpha, (int)bits), 24, ref huff[code]);
}
}
}
int ReadPackedSymbols(HTreeGroup group, uint[] data, int dst)
{
uint val = br_.PrefetchBits() & (Huffman.PackedTableSize - 1);
var code = group.packed_table[val];
if (code.bits < BitsSpecialMarker)
{
br_.SkipBits (code.bits);
data[dst] = code.value;
return PackedNonLiteralCode;
}
else
{
br_.SkipBits (code.bits - BitsSpecialMarker);
return (int)code.value;
}
}
