/// <summary>
/// Creates a static Huffman tree for encoding/decoding based on a tree emitted from WriteTable.
/// </summary>
/// <param name="symbolReader">Delegate for reading symbols.</param>
/// <param name="valueReader">Delegate for reading unsigned integers.</param>
public StaticHuffman(ReadSymbolDelegate <TSymbolType> symbolReader, ReadUInt32Delegate valueReader)
{
SymbolCount = valueReader();
_entries = new Entry[2 * SymbolCount - 1];
_map = new Dictionary <TSymbolType, SymbolInfo>((int)SymbolCount);
for (uint i = 0; i < SymbolCount; ++i)
{
var symbol = symbolReader();
_entries[i].Symbol = symbol;
SymbolInfo info;
info.Index = i;
info.Bits = null;
_map[symbol] = info;
}
for (var i = SymbolCount; i < _entries.Length; ++i)
{
_entries[i].ChildIndex = new uint[2];
_entries[i].ChildIndex[0] = valueReader();
_entries[i].ChildIndex[1] = valueReader();
}
ComputeParents();
Height = GetHeight();
Validate();
}
/// <summary>
/// Retrieves a symbol. If the bit sequence from <paramref name="bitReader" />
/// identifies a symbol literal, <paramref name="symbolReader" /> is called.
/// </summary>
public TSymbolType GetSymbol(ReadBitDelegate bitReader, ReadSymbolDelegate <TSymbolType> symbolReader)
{
var result = GetSymbolInternal(bitReader);
if (result.IsValid)
{
UpdateSymbolInternal(result, 1);
UpdateSymbolInternal(SymbolSpace.NotYetTransmitted, GetTweak(result.Symbol, false));
return(result.Symbol);
}
result = symbolReader();
UpdateSymbolInternal(SymbolSpace.NotYetTransmitted, GetTweak(result.Symbol, true));
UpdateSymbolInternal(result, 1);
return(result.Symbol);
}
