Java Power of 2 nextPowerOfTwo(int x)

Description

Calculate the next power of 2, greater than or equal to x.

From Hacker's Delight, Chapter 3, Harry S.

License

Open Source License

Parameter

Parameter	Description
x	integer greater than 0

Return

next power of two

Declaration

private static int nextPowerOfTwo(int x) 

Method Source Code

//package com.java2s;
/*******************************************************************************
 * Copyright (c) 2009, 2015 Oracle and/or its affiliates. All rights reserved.
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v1.0 and Eclipse Distribution License v. 1.0
 * which accompanies this distribution./*from  w w  w. java  2s .com*/
 * The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
 * and the Eclipse Distribution License is available at
 * http://www.eclipse.org/org/documents/edl-v10.php.
 *
 * Contributors:
 *      Marcel Valovy - <marcelv3612@gmail.com>
 ******************************************************************************/

public class Main {
    /**
     * Calculate the next power of 2, greater than or equal to x.<p>
     * From Hacker's Delight, Chapter 3, Harry S. Warren Jr.
     *
     * @param x integer greater than 0
     * @return next power of two
     */
    private static int nextPowerOfTwo(int x) {
        assert x > 0;
        x |= --x >> 1;
        x |= x >> 2;
        x |= x >> 4;
        x |= x >> 8;
        x |= x >> 16;
        return x + 1;
    }
}

Related

1. nextPowerOfTwo(int x)
2. nextPowerOfTwo(int x)
3. nextPowerOfTwo(int x)
4. nextPowerOfTwo(int x)
5. nextPowerOfTwo(int x)
6. nextPowerOfTwo(int x)
7. nextPowerOfTwo(int x)
8. nextPowerOfTwo(int x)
9. nextPowerOfTwoExact(int n)