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Common Java functionality for core functionality
/**
*
* jerry - Common Java Functionality
* Copyright (c) 2012-2015, Sandeep Gupta
*
* http://sangupta.com/projects/jerry
*
* 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 com.sangupta.jerry.util;
/**
* Utility class to work with bits and bit operations.
*
* @author sangupta
*
*/
public class BitUtils {
private static final int LEAST_BIT = 0;
private static final int MAX_BIT_INT = 31;
private static final int MAX_BIT_LONG = 63;
/**
* Check if a bit is set in an int value.
*
* @param value
* the integer value to look in
*
* @param bit
* the bit number to look for
*
* @return true if bit is set, false otherwise
*/
public static boolean isBitSet(int value, int bit) {
CheckUtils.checkArgument(bit >= LEAST_BIT, "Bit to set cannot be less than zero");
CheckUtils.checkArgument(bit <= MAX_BIT_INT, "Bit to set cannot be greater than " + MAX_BIT_INT);
int mask = 1 << bit;
return (value & mask) != 0;
}
/**
* Set a bit in an int value
*
* @param value
* the integer value to operate on
*
* @param bit
* the bit to set
*
* @return true if the bit was modified, false
* otherwise
*/
public static int setBit(int value, int bit) {
CheckUtils.checkArgument(bit >= LEAST_BIT, "Bit to set cannot be less than zero");
CheckUtils.checkArgument(bit <= MAX_BIT_INT, "Bit to set cannot be greater than " + MAX_BIT_INT);
int mask = 1 << bit;
return value | mask;
}
/**
* Clear a bit in an int value
*
* @param value
* the integer value to operate on
*
* @param bit
* the bit to clear
*
* @return true if bit was modified, false
* otherwise
*/
public static int clearBit(int value, int bit) {
CheckUtils.checkArgument(bit >= LEAST_BIT, "Bit to set cannot be less than zero");
CheckUtils.checkArgument(bit <= MAX_BIT_INT, "Bit to set cannot be greater than " + MAX_BIT_INT);
int mask = ~setBit(0, bit);
return value & mask;
}
/**
* Check if a bit is set in a long value
*
* @param value
* the long value to operate on
*
* @param bit
* the bit to check
*
* @return true if bit is set, false
* otherwise
*/
public static boolean isBitSet(long value, int bit) {
CheckUtils.checkArgument(bit >= LEAST_BIT, "Bit to set cannot be less than zero");
CheckUtils.checkArgument(bit <= MAX_BIT_LONG, "Bit to set cannot be greater than " + MAX_BIT_LONG);
long mask = 1l << bit;
return ((long) (value & mask)) != 0l;
}
/**
* Set a bit in a long value
*
* @param value
* the long value to operate on
*
* @param bit
* the bit to set
*
* @return true if bit was modified, false
* otherwise
*/
public static long setBit(long value, int bit) {
CheckUtils.checkArgument(bit >= LEAST_BIT, "Bit to set cannot be less than zero");
CheckUtils.checkArgument(bit <= MAX_BIT_LONG, "Bit to set cannot be greater than " + MAX_BIT_LONG);
long mask = 1L << bit;
return value | mask;
}
/**
* Clear a bit in a long value
*
* @param value
* the long value to operate on
*
* @param bit
* the bit to clear
*
* @return true if bit was modified, false
* otherwise
*/
public static long clearBit(long value, int bit) {
CheckUtils.checkArgument(bit >= LEAST_BIT, "Bit to set cannot be less than zero");
CheckUtils.checkArgument(bit <= MAX_BIT_LONG, "Bit to set cannot be greater than " + MAX_BIT_LONG);
long mask = ~setBit(0L, bit);
return value & mask;
}
/**
* Find the index of the highest bit that is set. Bits on the left are
* considered the highest bit.
*
* @param byteValue
* the value to check
*
* @return the index of the highest bit set, or -1 if none is
* set
*/
public static int getHighestSetBitIndex(byte byteValue) {
int value = byteValue;
if(byteValue < 0) {
value = byteValue & 0xFF;
}
if(value == 0) {
return -1;
}
for(int index = 7; index >= 0; index--) {
int bitValue = 1 << index;
if((value & bitValue) == bitValue) {
return index;
}
}
return -1;
}
/**
* Find the index of the lowest bit that is set. Bits on the left are
* considered the highest bit.
*
* @param byteValue
* the value to check
*
* @return the index of the lowest bit set, or -1 if none is
* set
*/
public static int getLowestSetBitIndex(byte byteValue) {
int value = byteValue;
if(byteValue < 0) {
value = byteValue & 0xFF;
}
if(value == 0) {
return -1;
}
for(int index = 0; index < 8; index++) {
int bitValue = 1 << index;
if((value & bitValue) == bitValue) {
return index;
}
}
return -1;
}
/**
* Find the index of the highest bit that is set. Bits on the left are
* considered the highest bit.
*
* @param shortValue
* the value to check
*
* @return the index of the highest bit set, or -1 if none is
* set
*/
public static int getHighestSetBitIndex(short shortValue) {
int value = shortValue;
if(shortValue < 0) {
value = shortValue & 0xFFFF;
}
if(value == 0) {
return -1;
}
for(int index = 15; index >= 0; index--) {
int bitValue = 1 << index;
if((value & bitValue) == bitValue) {
return index;
}
}
return -1;
}
/**
* Find the index of the lowest bit that is set. Bits on the left are
* considered the highest bit.
*
* @param shortValue
* the value to check
*
* @return the index of the lowest bit set, or -1 if none is
* set
*/
public static int getLowestSetBitIndex(short shortValue) {
int value = shortValue;
if(shortValue < 0) {
value = shortValue & 0xFFFF;
}
if(value == 0) {
return -1;
}
for(int index = 0; index < 16; index++) {
int bitValue = 1 << index;
if((value & bitValue) == bitValue) {
return index;
}
}
return -1;
}
/**
* Find the index of the highest bit that is set. Bits on the left are
* considered the highest bit.
*
* @param intValue
* the value to check
*
* @return the index of the highest bit set, or -1 if none is
* set
*/
public static int getHighestSetBitIndex(int intValue) {
if(intValue < 0) {
intValue = intValue & 0xFFFFFFFF;
}
if(intValue == 0) {
return -1;
}
for(int index = 31; index >= 0; index--) {
int bitValue = 1 << index;
if((intValue & bitValue) == bitValue) {
return index;
}
}
return -1;
}
/**
* Find the index of the lowest bit that is set. Bits on the left are
* considered the highest bit.
*
* @param intValue
* the value to check
*
* @return the index of the lowest bit set, or -1 if none is
* set
*/
public static int getLowestSetBitIndex(int intValue) {
int value = intValue;
if(intValue < 0) {
value = intValue & 0xFFFFFFFF;
}
if(value == 0) {
return -1;
}
for(int index = 0; index < 32; index++) {
int bitValue = 1 << index;
if((value & bitValue) == bitValue) {
return index;
}
}
return -1;
}
/**
* Find the index of the highest bit that is set. Bits on the left are
* considered the highest bit.
*
* @param longValue
* the value to check
*
* @return the index of the highest bit set, or -1 if none is
* set
*/
public static int getHighestSetBitIndex(long longValue) {
if(longValue < 0) {
longValue = longValue & 0xFFFFFFFF;
}
if(longValue == 0) {
return -1;
}
for(int index = 63; index >= 0; index--) {
long bitValue = 1l << index;
if((longValue & bitValue) == bitValue) {
return index;
}
}
return -1;
}
/**
* Find the index of the lowest bit that is set. Bits on the left are considered
* the highest bit.
*
* @param longValue the value to check
*
* @return the index of the lowest bit set, or -1 if none is
* set
*/
public static int getLowestSetBitIndex(long longValue) {
if(longValue < 0) {
longValue = longValue & 0xFFFFFFFF;
}
if(longValue == 0) {
return -1;
}
for(int index = 0; index < 64; index++) {
long bitValue = 1l << index;
if((longValue & bitValue) == bitValue) {
return index;
}
}
return -1;
}
}
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