public override byte[] Decompress(byte[] buf)
{
var ret = new BitList();
var bits = new BitList(buf);
var tableID = BitList.From(bits.Subbit(0, 16)).ToUInt16(); // [TA]
var nextBitIndex = 16;
Debug.Assert(tableID == TableID);
var table = Table;
//=== READ HUFFMAN CODE ===
var len = (int)BitList.GetNumberFromVariableBits(bits.Subbit(nextBitIndex), out var nobits); // [DA] Data Bytes
nextBitIndex += nobits;
var outdat = new List <byte>();
for (var i = 0; i < len; i++)
{
var hb = new BitList();
for (var j = 0; j < 32768; j++)
{
hb.Add(bits[nextBitIndex++]);
if (table.TryGetValue(hb, out var value))
{
outdat.Add(value); // [DB]
break;
}
}
}
return(outdat.ToArray());
}
public static Dictionary <BitList, byte> ReadTableBinary(BitList bits, out int nextBitIndex)
{
// === READ TABLE ===
var table = new Dictionary <BitList, byte>();
var tableCount = BitList.From(bits.Subbit(0, 16)).SetMinimumSize(16).ToUInt16(); // [TA]
Debug.Assert(tableCount < 32768);
nextBitIndex = 16;
for (var i = 0; i < tableCount; i++)
{
var value = BitList.From(bits.Subbit(nextBitIndex, 8)).ToByte(); // [TB]
nextBitIndex += 8;
var bitLen = (int)BitList.GetNumberFromVariableBits(bits.Subbit(nextBitIndex), out var numbits);
nextBitIndex += numbits;
table[BitList.From(bits.Subbit(nextBitIndex, bitLen))] = value; // [TE]
nextBitIndex += bitLen;
}
if (nextBitIndex % 8 != 0)
{
nextBitIndex += 8 - nextBitIndex % 8; // [TF]
}
return(table);
}