Codeword NextCodeword(Codeword codeword, uint suffixBit)
{
var c = Codeword.Clone(codeword);
c.AppendBit(suffixBit);
return(c);
}
// turn the codewords into canonical ordered ones
// needed for make table later
void MakeCanonical(List <Node> leaves1)
{
// see https://pineight.com/mw/index.php?title=Canonical_Huffman_code
// http://www.compressconsult.com/huffman
// https://en.wikipedia.org/wiki/Canonical_Huffman_code
// sort by bit lengths to order symbol values.
// on ties, sort by symbol
leaves1.Sort((a, b) =>
{
int result = a.Codeword.BitLength.CompareTo(b.Codeword.BitLength);
if (result == 0)
{
return(a.Symbol.CompareTo(b.Symbol));
}
return(result);
});
// rewrite symbols in increasing order, maintaining code lengths
if (Options.HasFlag(OptionFlags.DumpDictionary))
{
WriteLine("Huffman dictionary: ");
}
var codeValue = new Codeword();
codeValue.AppendBit(0); // start at the 1-bit code of 0
foreach (var leaf in leaves1)
{
// lengthen code
while (codeValue.BitLength < leaf.Codeword.BitLength)
{
codeValue.AppendBit(0);
}
leaf.Codeword = Codeword.Clone(codeValue);
if (Options.HasFlag(OptionFlags.DumpDictionary))
{
WriteLine($" x{leaf.Symbol:X2}->{leaf.Codeword}");
}
codeValue.Increment();
}
}