Java Bit Mask bitMask(final int numberOfBits)

Description

Returns a bit mask for the specified number of bits.

License

Apache License

Declaration

public static int bitMask(final int numberOfBits) 

Method Source Code

//package com.java2s;
/*//  ww  w  .j a v a2s  .c o m
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 {
    /**
     * Returns a bit mask for the specified number of bits.
     */
    public static int bitMask(final int numberOfBits) {
        if (numberOfBits >= 32) {
            return -1;
        }
        return (numberOfBits == 0 ? 0 : powerOf(2, numberOfBits) - 1);
    }

    /**
     * Power of method for integer math.
     */
    public static int powerOf(final int value, final int powerOf) {
        if (powerOf == 0) {
            return 0;
        }
        int r = value;
        for (int x = 1; x < powerOf; x++) {
            r = r * value;
        }
        return r;
    }
}

Related

1. bitMask(int bit)
2. bitMask(int bitSize)
3. bitMask(int i)