private void DumpNode(HuffmanNode node,string tag, int i, TextWriter writer)
{
for (int j = 0; j < i; j++)
{
writer.Write(" ");
}
writer.Write('-');
if (node.IsBranch)
writer.Write(" {0} '{2}' x {1:4} = ", tag, node.Freq, (char)node.Symbol);
else
writer.Write(" {1} Freq {0} = ", node.Freq, tag);
if (node.IsBranch == false)
{
foreach (var bit in node.Bits)
{
writer.Write(bit ? "1" : "0");
}
}
writer.WriteLine();
if (node.IsBranch == false)
return;
DumpNode(node.Left, "left", i+1, writer);
DumpNode(node.Right, "right", i + 1, writer);
}
public HuffmanTable Build()
{
var leaves = new Queue<HuffmanNode>(_leaves.Values.OrderBy(node => node.Freq == 0 ? 1 : node.Freq));
var branches = new Queue<HuffmanNode>();
while (leaves.Count + branches.Count > 1)
{
Queue<HuffmanNode> q1 = null, q2 = null;
int candidateWeight = int.MaxValue;
if (leaves.Count > 0 && branches.Count > 0)
{
var weight = leaves.Peek().Freq + branches.Peek().Freq;
if (weight < candidateWeight)
{
candidateWeight = weight;
q1 = leaves;
q2 = branches;
}
}
if (leaves.Count > 1)
{
var weight = leaves.Peek().Freq + leaves.Peek().Freq;
if (weight < candidateWeight)
{
candidateWeight = weight;
q1 = q2 = leaves;
}
}
if (branches.Count > 1)
{
var weight = branches.Peek().Freq + branches.Peek().Freq;
if (weight< candidateWeight)
{
candidateWeight = weight;
q1 = q2 = branches;
}
}
System.Diagnostics.Debug.Assert(q1 != null && q2 != null);
var left = q1.Dequeue();
var right = q2.Dequeue();
var parent = new HuffmanNode(-1, candidateWeight)
{
Left = left,
Right = right
};
left.Parent = parent;
right.Parent = parent;
branches.Enqueue(parent);
}
foreach (var huffmanNode in _leaves.Values)
{
huffmanNode.SetupBitPattern();
}
return new HuffmanTable(_leaves, branches.Dequeue());
}
public static HuffmanNode Load(BinaryReader reader, Dictionary<int, HuffmanNode> leaves)
{
var branch = reader.ReadBoolean();
if (branch == false)
{
var huffmanNode = new HuffmanNode(BinaryWriterExtensions.Read7BitEncodedInt(reader), -2/* we don't actually need this, so we don't save it*/);
leaves.Add(huffmanNode.Symbol, huffmanNode);
return huffmanNode;
}
var left = Load(reader, leaves);
var right = Load(reader,leaves);
var parent = new HuffmanNode(-1, -2)
{
Left = left,
Right = right
};
left.Parent = parent;
right.Parent = parent;
return parent;
}
public static HuffmanNode Load(BinaryReader reader, Dictionary <int, HuffmanNode> leaves)
{
var branch = reader.ReadBoolean();
if (branch == false)
{
var huffmanNode = new HuffmanNode(BinaryWriterExtensions.Read7BitEncodedInt(reader), -2 /* we don't actually need this, so we don't save it*/);
leaves.Add(huffmanNode.Symbol, huffmanNode);
return(huffmanNode);
}
var left = Load(reader, leaves);
var right = Load(reader, leaves);
var parent = new HuffmanNode(-1, -2)
{
Left = left,
Right = right
};
left.Parent = parent;
right.Parent = parent;
return(parent);
}
public HuffmanTable(Dictionary <int, HuffmanNode> leaves, HuffmanNode root)
{
_leaves = leaves;
_root = root;
}
public HuffmanTable(Dictionary<int, HuffmanNode> leaves, HuffmanNode root)
{
_leaves = leaves;
_root = root;
}
public void Add(int symbol, int freq)
{
var node = new HuffmanNode(symbol, freq);
_leaves.Add(symbol, node);
}
public void Add(int symbol, int freq)
{
var node = new HuffmanNode(symbol, freq);
_leaves.Add(symbol, node);
}