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Open Source Chemistry Library
package com.actelion.research.util;
/*
* Copyright (c) 1997 - 2016
* Actelion Pharmaceuticals Ltd.
* Gewerbestrasse 16
* CH-4123 Allschwil, Switzerland
*
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* 3. Neither the name of the the copyright holder nor the
* names of its contributors may be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
public class BitUtils {
public final static long MASK_FIRST_SHORT = 0x000000000000FFFFl;
public final static long MASK_SEC_SHORT = 0x00000000FFFF0000l;
public final static long MASK_THIRD_SHORT = 0x0000FFFF00000000l;
public final static long MASK_FOURTH_SHORT = 0xFFFF000000000000l;
private static int[] BIT_COUNTS = new int[65536];
static {
for (int i = 0; i < BIT_COUNTS.length; i++) {
BIT_COUNTS[i] = countBitsSlow(i);
}
}
/** Count the number of set bits in an int;
* @returns the number of bits set in x
*/
static int countBitsSlow(int x) {
int temp;
temp = 0x55555555;
x = (x & temp) + (x >>> 1 & temp);
temp = 0x33333333;
x = (x & temp) + (x >>> 2 & temp);
temp = 0x07070707;
x = (x & temp) + (x >>> 4 & temp);
temp = 0x000F000F;
x = (x & temp) + (x >>> 8 & temp);
return (x & 0x1F) + (x >>> 16);
}
/**
*
* The fastest Method (by Thomas Sander)
* @param x
* @return
* @deprecated use Integer.bitCount() instead.
*/
public static int bitCount(int x) {
int t1 = (0xFFFF0000 & x) >>> 16;
int t2 = 0x0000FFFF & x;
return BIT_COUNTS[t1] + BIT_COUNTS[t2];
}
public static int bitCount(long x) {
int t1 = (int)((MASK_FOURTH_SHORT & x) >>> 48);
int t2 = (int)((MASK_THIRD_SHORT & x) >>> 32);
int t3 = (int)((MASK_SEC_SHORT & x) >>> 16);
int t4 = (int)((MASK_FIRST_SHORT & x));
return BIT_COUNTS[t1] + BIT_COUNTS[t2] + BIT_COUNTS[t3] + BIT_COUNTS[t4];
}
public static void setBit(int [] data, int i) {
int ind = i / Integer.SIZE;
int indInInt = i % Integer.SIZE;
int mask = 1;
mask = mask << indInInt;
data[ind] = data[ind] | mask;
}
public static void unsetBit(int [] data, int i) {
int ind = i / Integer.SIZE;
int indInInt = i % Integer.SIZE;
int mask = 1;
mask = mask << indInInt;
data[ind] = data[ind] & ~mask;
}
public static boolean isBitSet(int [] a, int i) {
int ind = i / Integer.SIZE;
int indInInt = i % Integer.SIZE;
int mask = 1;
mask = mask << indInInt;
if((a[ind] & mask) != 0)
return true;
else
return false;
}
public static boolean isValidBitIndex(int [] data, int i) {
boolean valid = false;
int ind = (i / Integer.SIZE);
if(ind < data.length){
valid=true;
}
return valid;
}
}