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/*
* Copyright (c) 2007 innoSysTec (R) GmbH, Germany. All rights reserved.
* Original author: Edmund Wagner
* Creation date: 31.05.2007
*
* Source: $HeadURL$
* Last changed: $LastChangedDate$
*
* the unrar licence applies to all junrar source and binary distributions
* you are not allowed to use this source to re-create the RAR compression algorithm
*
* Here some html entities which can be used for escaping javadoc tags:
* "&": "&" or "&"
* "<": "<" or "<"
* ">": ">" or ">"
* "@": "@"
*/
package org.fox.ttcomics2.junrar.unpack.ppm;
import org.fox.ttcomics2.junrar.exception.RarException;
import org.fox.ttcomics2.junrar.unpack.Unpack;
import java.io.IOException;
public class RangeCoder {
public static final int TOP = 1 << 24;
public static final int BOT = 1 << 15;
private static final long uintMask = 0xFFFFffffL;
private final SubRange subRange = new SubRange();
// uint low, code, range;
private long low, code, range;
private Unpack unpackRead;
public SubRange getSubRange() {
return subRange;
}
public void initDecoder(Unpack unpackRead) throws IOException, RarException {
this.unpackRead = unpackRead;
low = code = 0L;
range = 0xFFFFffffL;
for (int i = 0; i < 4; i++) {
code = ((code << 8) | getChar()) & uintMask;
}
}
public int getCurrentCount() {
range = (range / subRange.getScale()) & uintMask;
return (int) ((code - low) / (range));
}
public long getCurrentShiftCount(int SHIFT) {
range = range >>> SHIFT;
return ((code - low) / (range)) & uintMask;
}
public void decode() {
low = (low + (range * subRange.getLowCount())) & uintMask;
range = (range * (subRange.getHighCount() - subRange.getLowCount())) & uintMask;
}
private int getChar() throws IOException, RarException {
return (unpackRead.getChar());
}
public void ariDecNormalize() throws IOException, RarException {
// while ((low ^ (low + range)) < TOP || range < BOT && ((range = -low & (BOT - 1)) != 0 ? true : true))
// {
// code = ((code << 8) | unpackRead.getChar()&0xff)&uintMask;
// range = (range << 8)&uintMask;
// low = (low << 8)&uintMask;
// }
// Rewrote for clarity
boolean c2 = false;
while ((low ^ (low + range)) < TOP || (c2 = range < BOT)) {
if (c2) {
range = (-low & (BOT - 1)) & uintMask;
c2 = false;
}
code = ((code << 8) | getChar()) & uintMask;
range = (range << 8) & uintMask;
low = (low << 8) & uintMask;
}
}
// Debug
public String toString() {
StringBuilder buffer = new StringBuilder();
buffer.append("RangeCoder[");
buffer.append("\n low=");
buffer.append(low);
buffer.append("\n code=");
buffer.append(code);
buffer.append("\n range=");
buffer.append(range);
buffer.append("\n subrange=");
buffer.append(subRange);
buffer.append("]");
return buffer.toString();
}
public static class SubRange {
// uint LowCount, HighCount, scale;
private long lowCount, highCount, scale;
public long getHighCount() {
return highCount;
}
public void setHighCount(long highCount) {
this.highCount = highCount & uintMask;
}
public long getLowCount() {
return lowCount & uintMask;
}
public void setLowCount(long lowCount) {
this.lowCount = lowCount & uintMask;
}
public long getScale() {
return scale;
}
public void setScale(long scale) {
this.scale = scale & uintMask;
}
public void incScale(int dScale) {
setScale(getScale() + dScale);
}
// Debug
public String toString() {
StringBuilder buffer = new StringBuilder();
buffer.append("SubRange[");
buffer.append("\n lowCount=");
buffer.append(lowCount);
buffer.append("\n highCount=");
buffer.append(highCount);
buffer.append("\n scale=");
buffer.append(scale);
buffer.append("]");
return buffer.toString();
}
}
}
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