/*  BitUtils - A class with utility methods to manipulate bitmasks.  Copyright (C) 2003 The Java-Chess team <info@java-chess.de>  This program is free software; you can redistribute it and/or  modify it under the terms of the GNU General Public License  as published by the Free Software Foundation; either version 2  of the License, or (at your option) any later version.  This program is distributed in the hope that it will be useful,  but WITHOUT ANY WARRANTY; without even the implied warranty of  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the  GNU General Public License for more details.  You should have received a copy of the GNU General Public License  along with this program; if not, write to the Free Software  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.*/ package de.java_chess.javaChess.engine;/** * This class provides utility methods to manipulate bitmasks. */public class BitUtils {    /**     * The highest set bit for all byte values.     */    private static int [] _highestBit = { -1,0,1,1,2,2,2,2,3,3,3,3,3,3,3,3,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,					  5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,					  6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,					  6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,					  7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,					  7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,					  7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,					  7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7 };    /**     * Find the index of highest set bit in a long bitmask.     *     * @param bitmask The bitmask to operate on.     *     * @return The index of the highest set bit or 0, if no bits are set.     */    public static final int getHighestBit( long bitmask) {	int highestBit = 0;	// The following 3 statements split the 64 bit word down to	// a byte.	int dwordPart = (int)(bitmask >>> 32);	if( dwordPart != 0) {	    highestBit += 32;	} else {	    dwordPart = (int)bitmask;	}		int wordPart = (dwordPart >>> 16) & 0xFFFF;		if( wordPart != 0) {	    highestBit += 16;	} else {	    wordPart = dwordPart & 0xFFFF;	}		int bytePart = (wordPart >>> 8) & 0xFF;		if( bytePart != 0) {	    highestBit += 8;	} else {	    bytePart = wordPart & 0xFF;	}	// Use the byte as a index for a precomputed array	// of bit indexes.	return highestBit + _highestBit[ bytePart];    }}