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/*
* $ProjectName$
* $ProjectRevision$
* -----------------------------------------------------------
* $Id$
* -----------------------------------------------------------
*
* $Author$
*
* Description:
*
* Copyright 2002-2003 Tor-Einar Jarnbjo
* -----------------------------------------------------------
*
* Change History
* -----------------------------------------------------------
* $Log$
* Revision 1.1 2005/07/11 15:42:36 hcl
* Songdb java version, source. only 1.5 compatible
*
* Revision 1.1.1.1 2004/04/04 22:09:12 shred
* First Import
*
* Revision 1.2 2003/04/10 19:48:31 jarnbjo
* no message
*
*/
package de.jarnbjo.util.io;
import java.io.IOException;
import de.jarnbjo.util.io.BitInputStream;
/**
* Representation of a node in a Huffman tree, used to read
* Huffman compressed codewords from e.g. a Vorbis stream.
*/
final public class HuffmanNode {
private HuffmanNode parent;
private int depth=0;
protected HuffmanNode o0, o1;
protected Integer value;
private boolean full=false;
/**
* creates a new Huffman tree root node
*/
public HuffmanNode() {
this(null);
}
protected HuffmanNode(HuffmanNode parent) {
this.parent=parent;
if(parent!=null) {
depth=parent.getDepth()+1;
}
}
protected HuffmanNode(HuffmanNode parent, int value) {
this(parent);
this.value=new Integer(value);
full=true;
}
protected int read(BitInputStream bis) throws IOException {
HuffmanNode iter=this;
while(iter.value==null) {
iter=bis.getBit()?iter.o1:iter.o0;
}
return iter.value.intValue();
}
protected HuffmanNode get0() {
return o0==null?set0(new HuffmanNode(this)):o0;
}
protected HuffmanNode get1() {
return o1==null?set1(new HuffmanNode(this)):o1;
}
protected Integer getValue() {
return value;
}
private HuffmanNode getParent() {
return parent;
}
protected int getDepth() {
return depth;
}
private boolean isFull() {
return full?true:(full=o0!=null&&o0.isFull()&&o1!=null&&o1.isFull());
}
private HuffmanNode set0(HuffmanNode value) {
return o0=value;
}
private HuffmanNode set1(HuffmanNode value) {
return o1=value;
}
private void setValue(Integer value) {
full=true;
this.value=value;
}
/**
* creates a new tree node at the first free location at the given
* depth, and assigns the value to it
*
* @param depth the tree depth of the new node (codeword length in bits)
* @param value the node's new value
*/
public boolean setNewValue(int depth, int value) {
if(isFull()) {
return false;
}
if(depth==1) {
if(o0==null) {
set0(new HuffmanNode(this, value));
return true;
}
else if(o1==null) {
set1(new HuffmanNode(this, value));
return true;
}
else {
return false;
}
}
else {
return get0().setNewValue(depth-1, value)?
true:
get1().setNewValue(depth-1, value);
}
}
}
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