org.activiti.engine.impl.util.BitMaskUtil Maven / Gradle / Ivy
/* 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.
*/
package org.activiti.engine.impl.util;
/**
* Util class for manipulating bit-flag in ints.
*
* Currently, only 8-bits are supported, but can be extended to use all 31 bits in the integer (1st of 32 bits is used for sign).
*
*/
public class BitMaskUtil {
// First 8 masks as constant to prevent having to math.pow() every time a
// bit needs flipping.
private static final int FLAG_BIT_1 = 1; // 000...00000001
private static final int FLAG_BIT_2 = 2; // 000...00000010
private static final int FLAG_BIT_3 = 4; // 000...00000100
private static final int FLAG_BIT_4 = 8; // 000...00001000
private static final int FLAG_BIT_5 = 16; // 000...00010000
private static final int FLAG_BIT_6 = 32; // 000...00100000
private static final int FLAG_BIT_7 = 64; // 000...01000000
private static final int FLAG_BIT_8 = 128; // 000...10000000
private static int[] MASKS = { FLAG_BIT_1, FLAG_BIT_2, FLAG_BIT_3, FLAG_BIT_4, FLAG_BIT_5, FLAG_BIT_6, FLAG_BIT_7, FLAG_BIT_8 };
/**
* Set bit to '1' in the given int.
*
* @param current
* integer value
* @param bitNumber
* number of the bit to set to '1' (right first bit starting at 1).
*/
public static int setBitOn(int value, int bitNumber) {
if (bitNumber <= 0 || bitNumber > 8) {
throw new IllegalArgumentException("Only bits 1 through 8 are supported");
}
// To turn on, OR with the correct mask
return value | MASKS[bitNumber - 1];
}
/**
* Set bit to '0' in the given int.
*
* @param current
* integer value
* @param bitNumber
* number of the bit to set to '0' (right first bit starting at 1).
*/
public static int setBitOff(int value, int bitNumber) {
if (bitNumber <= 0 || bitNumber > 8) {
throw new IllegalArgumentException("Only bits 1 through 8 are supported");
}
// To turn on, OR with the correct mask
return value & ~MASKS[bitNumber - 1];
}
/**
* Check if the bit is set to '1'
*
* @param value
* integer to check bit
* @param number
* of bit to check (right first bit starting at 1)
*/
public static boolean isBitOn(int value, int bitNumber) {
if (bitNumber <= 0 || bitNumber > 8) {
throw new IllegalArgumentException("Only bits 1 through 8 are supported");
}
return ((value & MASKS[bitNumber - 1]) == MASKS[bitNumber - 1]);
}
/**
* Set bit to '0' or '1' in the given int.
*
* @param current
* integer value
* @param bitNumber
* number of the bit to set to '0' or '1' (right first bit starting at 1).
* @param bitValue
* if true, bit set to '1'. If false, '0'.
*/
public static int setBit(int value, int bitNumber, boolean bitValue) {
if (bitValue) {
return setBitOn(value, bitNumber);
} else {
return setBitOff(value, bitNumber);
}
}
}