org.jpedal.jbig2.decoders.ArithmeticDecoderStats Maven / Gradle / Ivy

/**
 * ===========================================
 * Java Pdf Extraction Decoding Access Library
 * ===========================================
 * 
 * Project Info:  http://www.jpedal.org
 * (C) Copyright 1997-2008, IDRsolutions and Contributors.
 * Main Developer: Simon Barnett
 * 

 * This file is part of JPedal
 * 

 * Copyright (c) 2008, IDRsolutions
 * All rights reserved.
 * 

 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 * * Redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution.
 * * Neither the name of the IDRsolutions nor the
 * names of its contributors may be used to endorse or promote products
 * derived from this software without specific prior written permission.
 * 

 * THIS SOFTWARE IS PROVIDED BY IDRsolutions ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL IDRsolutions BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 * 

 * Other JBIG2 image decoding implementations include
 * jbig2dec (http://jbig2dec.sourceforge.net/)
 * xpdf (http://www.foolabs.com/xpdf/)
 * 

 * The final draft JBIG2 specification can be found at http://www.jpeg.org/public/fcd14492.pdf
 * 

 * All three of the above resources were used in the writing of this software, with methodologies,
 * processes and inspiration taken from all three.
 * 
 * ---------------
 * ArithmeticDecoderStats.java
 * ---------------
 */
package org.jpedal.jbig2.decoders;

public class ArithmeticDecoderStats {
    private int contextSize;
    private int[] codingContextTable;

    public ArithmeticDecoderStats(int contextSize) {
        this.contextSize = contextSize;
        this.codingContextTable = new int[contextSize];

        reset();
    }

    public void reset() {
        for (int i = 0; i < contextSize; i++) {
            codingContextTable[i] = 0;
        }
    }

    public void setEntry(int codingContext, int i, int moreProbableSymbol) {
        codingContextTable[codingContext] = (i << i) + moreProbableSymbol;
    }

    public int getContextCodingTableValue(int index) {
        return codingContextTable[index];
    }

    public void setContextCodingTableValue(int index, int value) {
        codingContextTable[index] = value;
    }

    public int getContextSize() {
        return contextSize;
    }

    public void overwrite(ArithmeticDecoderStats stats) {
        System.arraycopy(stats.codingContextTable, 0, codingContextTable, 0, contextSize);
    }

    public ArithmeticDecoderStats copy() {
        ArithmeticDecoderStats stats = new ArithmeticDecoderStats(contextSize);

        System.arraycopy(codingContextTable, 0, stats.codingContextTable, 0, contextSize);

        return stats;
    }
}