Java Power of 2 nextPowerOfTwo(int x)

Description

Return the least power of two greater than or equal to the specified value.

License

Apache License

Parameter

Parameter	Description
x	an integer smaller than or equal to 2<sup>30</sup>.

Return

the least power of two greater than or equal to the specified value.

Declaration

public static int nextPowerOfTwo(int x) 

Method Source Code

//package com.java2s;
/*/* w  ww .jav  a  2s  .  c o  m*/
 * Copyright (C) 2002-2011 Sebastiano Vigna
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

public class Main {
    /** Return the least power of two greater than or equal to the specified value.
     *
     * <p>Note that this function will return 1 when the argument is 0.
     *
     * @param x an integer smaller than or equal to 2<sup>30</sup>.
     * @return the least power of two greater than or equal to the specified value.
     */
    public static int nextPowerOfTwo(int x) {
        if (x == 0)
            return 1;
        x--;
        x |= x >> 1;
        x |= x >> 2;
        x |= x >> 4;
        x |= x >> 8;
        return (x | x >> 16) + 1;
    }

    /** Return the least power of two greater than or equal to the specified value.
     *
     * <p>Note that this function will return 1 when the argument is 0.
     *
     * @param x a long integer smaller than or equal to 2<sup>62</sup>.
     * @return the least power of two greater than or equal to the specified value.
     */
    public static long nextPowerOfTwo(long x) {
        if (x == 0)
            return 1;
        x--;
        x |= x >> 1;
        x |= x >> 2;
        x |= x >> 4;
        x |= x >> 8;
        x |= x >> 16;
        return (x | x >> 32) + 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. nextPowerOfTwoExact(int n)
9. nextPowerOfTwoValue(double value)