BitInput.java

/*
 * 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 "&"
 * "<":  "&#060;" or "&lt;"
 * ">":  "&#062;" or "&gt;"
 * "@":  "&#064;"
 */
package com.github.junrar.unpack.vm;

/**
 * DOCUMENT ME
 *
 * @author $LastChangedBy$
 * @version $LastChangedRevision$
 */
public class BitInput {

    /**
     * the max size of the input
     */
    public static final int MAX_SIZE = 0x8000;
    protected int inAddr;
    protected int inBit;
    protected byte[] inBuf;


    public void InitBitInput() {
        inAddr = 0;
        inBit = 0;
    }
    /**
     * @param Bits .
     */
    public void addbits(int Bits) {
        Bits += inBit;
        inAddr += Bits >>> 3;
        inBit = Bits & 7;
    }

    /**
     * @return the bits (unsigned short)
     */
    public int getbits() {
//      int BitField=0;
//      BitField|=(int)(inBuf[inAddr] << 16)&0xFF0000;
//      BitField|=(int)(inBuf[inAddr+1] << 8)&0xff00;
//      BitField|=(int)(inBuf[inAddr+2])&0xFF;
//      BitField >>>= (8-inBit);
//      return (BitField & 0xffff);
        return (((((inBuf[inAddr] & 0xff) << 16)
                + ((inBuf[inAddr + 1] & 0xff) << 8)
                + ((inBuf[inAddr + 2] & 0xff))) >>> (8 - inBit)) & 0xffff);
    }

    /**
     *
     */
    public BitInput() {
        inBuf = new byte[MAX_SIZE];
    }

    /**
     * @param Bits add the bits
     */
    public void faddbits(int Bits) {
        addbits(Bits);
    }


    /**
     * @return get the bits
     */
    public int fgetbits() {
        return (getbits());
    }

    /**
     * Indicates an Overfow
     * @param IncPtr how many bytes to inc
     * @return true if an Oververflow would occur
     */
    public boolean Overflow(int IncPtr) {
        return (inAddr + IncPtr >= MAX_SIZE);
    }
    public byte[] getInBuf() {
        return inBuf;
    }


}