/// <summary>
/// Decodage des bits pour en faire des lettres
/// </summary>
/// <param name="bits">Tableau bit</param>
/// <returns>Mot courant</returns>
public string Decode(BitArray bits)
{
NodeHuffman current = this.Root;
string decoded = "";
foreach (bool bit in bits)
{
if (bit)
{
if (current.Right != null)
{
current = current.Right;
}
}
else
{
if (current.Left != null)
{
current = current.Left;
}
}
if (IsLeaf(current))
{
decoded += current.Symbol;
current = this.Root;
}
}
return(decoded);
}
/// <summary>
///
/// </summary>
/// <param name="source"></param>
public void Build(string source)
{
for (int i = 0; i < source.Length; i++)
{
if (!Frequencies.ContainsKey(source[i]))
{
Frequencies.Add(source[i], 0);
}
Frequencies[source[i]]++;
}
foreach (KeyValuePair <char, int> symbol in Frequencies)
{
nodes.Add(new NodeHuffman()
{
Symbol = symbol.Key, Frequency = symbol.Value
});
}
while (nodes.Count > 1)
{
List <NodeHuffman> orderedNodes = nodes.OrderBy(node => node.Frequency).ToList <NodeHuffman>();
if (orderedNodes.Count >= 2)
{
// Take first two items
List <NodeHuffman> taken = orderedNodes.Take(2).ToList <NodeHuffman>();
// Create a parent node by combining the frequencies
NodeHuffman parent = new NodeHuffman()
{
Symbol = '*',
Frequency = taken[0].Frequency + taken[1].Frequency,
Left = taken[0],
Right = taken[1]
};
nodes.Remove(taken[0]);
nodes.Remove(taken[1]);
nodes.Add(parent);
}
this.Root = nodes.FirstOrDefault();
}
}
/// <summary>
///
/// </summary>
/// <param name="source"></param>
public void Build(string source)
{
for (int i = 0; i < source.Length; i++)
{
if (!Frequencies.ContainsKey(source[i]))
{
Frequencies.Add(source[i], 0);
}
Frequencies[source[i]]++;
}
foreach (KeyValuePair<char, int> symbol in Frequencies)
{
nodes.Add(new NodeHuffman() { Symbol = symbol.Key, Frequency = symbol.Value });
}
while (nodes.Count > 1)
{
List<NodeHuffman> orderedNodes = nodes.OrderBy(node => node.Frequency).ToList<NodeHuffman>();
if (orderedNodes.Count >= 2)
{
// Take first two items
List<NodeHuffman> taken = orderedNodes.Take(2).ToList<NodeHuffman>();
// Create a parent node by combining the frequencies
NodeHuffman parent = new NodeHuffman()
{
Symbol = '*',
Frequency = taken[0].Frequency + taken[1].Frequency,
Left = taken[0],
Right = taken[1]
};
nodes.Remove(taken[0]);
nodes.Remove(taken[1]);
nodes.Add(parent);
}
this.Root = nodes.FirstOrDefault();
}
}
/// <summary>
/// Si le noeud est une feuille
/// </summary>
/// <param name="node">noeud</param>
/// <returns>booléen</returns>
public bool IsLeaf(NodeHuffman node)
{
return(node.Left == null && node.Right == null);
}
/// <summary>
/// Si le noeud est une feuille
/// </summary>
/// <param name="node">noeud</param>
/// <returns>booléen</returns>
public bool IsLeaf(NodeHuffman node)
{
return (node.Left == null && node.Right == null);
}
