/*
 * 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:
 * "&":  "&#038;" or "&amp;"
 * "<":  "&#060;" or "&lt;"
 * ">":  "&#062;" or "&gt;"
 * "@":  "&#064;" 
 */
package com.innosystec.unrar.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;
	}
}
