/*
* Copyright 2008-2009 Sun Microsystems, Inc. All Rights Reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code 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
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
* CA 95054 USA or visit www.sun.com if you need additional information or
* have any questions.
*/
package org.visage.runtime.util;
/**
* MathUtil
*
* @author Brian Goetz
*/
public class MathUtil {
private static final byte[] lookupTable = new byte[256];
public static int log2(/* unsigned */ int x) {
if (x == 0)
return 0;
else {
/* Compute number of leading zeros for an unsigned int; from Hacker's Delight, fig 5-6. */
int n = 1;
if ((x >>> 16) == 0) { n += 16; x <<= 16; }
if ((x >>> 24) == 0) { n += 8; x <<= 8; }
if ((x >>> 28) == 0) { n += 4; x <<= 4; }
if ((x >>> 30) == 0) { n += 2; x <<= 2; }
n -= (x >>> 31);
return 31 - n;
}
}
}