/// <summary>
/// The method to perform tree reconfiguration
/// </summary>
/// <param name="n1">
/// A <see cref="Node"/>
/// Reference to the first node
/// </param>
/// <param name="n2">
/// A <see cref="Node"/>
/// Reference to the second node
/// </param>
private void SwapNodes(Node n1,Node n2)
{
int tmp = n1.freq;
n1.freq = n2.freq;
n2.freq = tmp;
Node t1 = n1.parent.left;
Node t2 = n2.parent.left;
//Determine if n1 was the left or the right child
if (t1 == n1)
n1.parent.left = n2;
else
n1.parent.right = n2;
//Same thing for the second node
if (t2 == n2)
n2.parent.left = n1;
else
n2.parent.right = n1;
//Swap the nodes
Node t3 = n1.parent;
n1.parent = n2.parent;
n2.parent = t3;
}
public int DecodeBinary(int bit)
{
try {
if (ptr == null) ptr = root;
if (InNyt) {
_tempcode <<= 1;
_tempcode |= bit;
_count++;
if (_count == 8) {
UpdateTree(_tempcode);
int sym = _tempcode;
_tempcode = _count = 0;
InNyt = false;
return sym;
}
return CharIsEof;
}
if (bit == 1) ptr = ptr.right;
else ptr = ptr.left;
if (ptr.nt == NodeType.NYT && ptr.sym == 257) {
ptr = root;
InNyt = true;
return CharIsEof;
}
if (ptr.nt == NodeType.SYM) {
int sym = ptr.sym;
UpdateTree(sym);
ptr = root;
return sym;
}
return CharIsEof;
}
catch (System.NullReferenceException) {
throw new Exception("Corrupted Huffman sequence supplied for decoding");
}
}
/// <summary>
/// Returns the reference to the node that has the same frequency
/// as the argument and highest order
/// </summary>
/// <param name="nd">
/// A <see cref="Node"/>
/// Reference to the node
/// </param>
/// <returns>
/// A <see cref="Node"/>
/// </returns>
private Node FindHighestWithSameFreq(Node nd)
{
Node current = nd;
if (nd.parent != null) {
Node nd2 = current.parent;
if ((nd2.left == current) && (nd2.right.freq == current.freq))
current = nd2.right;
if (nd2.parent != null) {
Node nd3 = nd2.parent;
if ((nd3.left == nd2) && (nd3.right.freq == current.freq))
current = nd3.right;
else if ((nd3.right == nd2) && (nd3.left.freq == current.freq))
current = nd3.left;
}
}
return current;
}
/// <summary>
/// The constructor for the Tree class
/// </summary>
public Tree()
{
root = new Node (NodeType.INT, 258, 0, 516);
root.right = new Node (NodeType.NYT, 257, 0, root.order - 1);
root.left = new Node (NodeType.EOF, 256, 0, root.order - 2);
root.left.parent = root.right.parent = root;
nodes = new Node[259];
nodes[256] = root.left;
nodes[257] = root.right;
nodeCount = 258;
}