420 lines
9.8 KiB
Java
420 lines
9.8 KiB
Java
/*******************************************************************************
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* Copyright (c) 2002 - 2006 IBM Corporation.
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* All rights reserved. This program and the accompanying materials
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* are made available under the terms of the Eclipse Public License v1.0
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* which accompanies this distribution, and is available at
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* http://www.eclipse.org/legal/epl-v10.html
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*
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* Contributors:
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* IBM Corporation - initial API and implementation
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*******************************************************************************/
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package com.ibm.wala.util.intset;
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/**
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*/
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public class BitVector extends BitVectorBase<BitVector> {
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private static final long serialVersionUID = 9087259335807761617L;
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private final static int MAX_BITS = Integer.MAX_VALUE / 4;
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public BitVector() {
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this(1);
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}
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/**
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* Creates an empty string with the specified size.
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*
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* @param nbits the size of the string
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*/
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public BitVector(int nbits) {
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if (nbits > MAX_BITS || nbits < 0) {
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throw new IllegalArgumentException("invalid nbits: " + nbits);
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}
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bits = new int[subscript(nbits) + 1];
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}
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/**
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* Expand this bit vector to size newCapacity.
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*/
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void expand(int newCapacity) {
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int[] oldbits = bits;
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bits = new int[subscript(newCapacity) + 1];
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for (int i = 0; i < oldbits.length; i++) {
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bits[i] = oldbits[i];
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}
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}
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/**
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* Creates a copy of a Bit String
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*
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* @param s the string to copy
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* @throws IllegalArgumentException if s is null
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*/
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public BitVector(BitVector s) {
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if (s == null) {
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throw new IllegalArgumentException("s is null");
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}
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bits = new int[s.bits.length];
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copyBits(s);
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}
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/**
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* Sets a bit.
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*
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* @param bit the bit to be set
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*/
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@Override
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public final void set(int bit) {
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int shiftBits = bit & LOW_MASK;
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int subscript = subscript(bit);
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if (subscript >= bits.length) {
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expand(bit);
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}
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try {
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bits[subscript] |= (1 << shiftBits);
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} catch (RuntimeException e) {
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// TODO Auto-generated catch block
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e.printStackTrace();
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}
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}
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/**
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* Clears a bit.
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*
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* @param bit the bit to be cleared
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*/
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@Override
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public final void clear(int bit) {
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if (bit < 0) {
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throw new IllegalArgumentException("invalid bit: " + bit);
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}
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int ss = subscript(bit);
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if (ss >= bits.length) {
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return;
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}
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int shiftBits = bit & LOW_MASK;
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bits[ss] &= ~(1 << shiftBits);
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}
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/**
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* Gets a bit.
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*
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* @param bit the bit to be gotten
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*/
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@Override
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public final boolean get(int bit) {
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if (bit < 0) {
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throw new IllegalArgumentException("illegal bit: " + bit);
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}
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int ss = subscript(bit);
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if (ss >= bits.length) {
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return false;
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}
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int shiftBits = bit & LOW_MASK;
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return ((bits[ss] & (1 << shiftBits)) != 0);
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}
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/**
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* Return the NOT of a bit string
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*/
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public static BitVector not(BitVector s) {
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BitVector b = new BitVector(s);
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b.not();
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return b;
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}
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/**
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* Logically ANDs this bit set with the specified set of bits.
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*
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* @param set the bit set to be ANDed with
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*/
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@Override
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public final void and(BitVector set) {
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if (set == null) {
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throw new IllegalArgumentException("null set");
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}
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if (this == set) {
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return;
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}
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int n = Math.min(bits.length, set.bits.length);
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for (int i = n - 1; i >= 0;) {
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bits[i] &= set.bits[i];
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i--;
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}
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for (int i = n; i < bits.length; i++) {
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bits[i] = 0;
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}
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}
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/**
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* Return a new bit string as the AND of two others.
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*/
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public static BitVector and(BitVector b1, BitVector b2) {
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if (b1 == null) {
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throw new IllegalArgumentException("null b1");
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}
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if (b2 == null) {
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throw new IllegalArgumentException("null b2");
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}
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BitVector b = new BitVector(b1);
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b.and(b2);
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return b;
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}
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/**
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* Logically ORs this bit set with the specified set of bits.
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*
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* @param set the bit set to be ORed with
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*/
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@Override
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public final void or(BitVector set) {
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if (set == null) {
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throw new IllegalArgumentException("null set");
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}
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if (this == set) { // should help alias analysis
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return;
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}
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ensureCapacity(set);
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int n = Math.min(bits.length, set.bits.length);
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for (int i = n - 1; i >= 0;) {
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bits[i] |= set.bits[i];
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i--;
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}
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}
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private void ensureCapacity(BitVector set) {
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if (set.bits.length > bits.length) {
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expand(BITS_PER_UNIT * set.bits.length - 1);
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}
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}
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/**
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* Logically ORs this bit set with the specified set of bits. This is performance-critical, and so, a little ugly in an attempt to
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* help out the compiler.
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*
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* @param set
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* @return the number of bits added to this.
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* @throws IllegalArgumentException if set is null
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*/
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public final int orWithDelta(BitVector set) {
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if (set == null) {
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throw new IllegalArgumentException("set is null");
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}
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int delta = 0;
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ensureCapacity(set);
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int[] otherBits = set.bits;
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int n = Math.min(bits.length, otherBits.length);
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for (int i = n - 1; i >= 0;) {
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int v1 = bits[i];
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int v2 = otherBits[i];
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if (v1 != v2) {
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delta -= Bits.populationCount(v1);
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int v3 = v1 | v2;
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delta += Bits.populationCount(v3);
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bits[i] = v3;
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}
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i--;
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}
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return delta;
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}
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/**
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* Return a new FixedSizeBitVector as the OR of two others
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*/
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public static BitVector or(BitVector b1, BitVector b2) {
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if (b1 == null) {
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throw new IllegalArgumentException("null b1");
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}
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if (b2 == null) {
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throw new IllegalArgumentException("null b2");
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}
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BitVector b = new BitVector(b1);
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b.or(b2);
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return b;
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}
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/**
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* Return a new FixedSizeBitVector as the XOR of two others
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*/
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public static BitVector xor(BitVector b1, BitVector b2) {
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if (b1 == null) {
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throw new IllegalArgumentException("null b1");
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}
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if (b2 == null) {
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throw new IllegalArgumentException("null b2");
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}
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BitVector b = new BitVector(b1);
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b.xor(b2);
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return b;
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}
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/**
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* Logically XORs this bit set with the specified set of bits.
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*
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* @param set the bit set to be XORed with
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* @throws IllegalArgumentException if set is null
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*/
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@Override
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public final void xor(BitVector set) {
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if (set == null) {
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throw new IllegalArgumentException("set is null");
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}
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ensureCapacity(set);
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int n = Math.min(bits.length, set.bits.length);
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for (int i = n - 1; i >= 0;) {
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bits[i] ^= set.bits[i];
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i--;
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}
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}
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/**
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* Check if the intersection of the two sets is empty
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*
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* @param other the set to check intersection with
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* @throws IllegalArgumentException if other is null
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*/
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@Override
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public final boolean intersectionEmpty(BitVector other) {
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if (other == null) {
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throw new IllegalArgumentException("other is null");
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}
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int n = Math.min(bits.length, other.bits.length);
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for (int i = n - 1; i >= 0;) {
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if ((bits[i] & other.bits[i]) != 0) {
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return false;
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}
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i--;
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}
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return true;
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}
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/**
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* Calculates and returns the set's size in bits. The maximum element in the set is the size - 1st element.
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*/
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@Override
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public final int length() {
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return bits.length << LOG_BITS_PER_UNIT;
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}
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/**
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* Compares this object against the specified object.
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*
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* @param B the object to compare with
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* @return true if the objects are the same; false otherwise.
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*/
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@Override
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public final boolean sameBits(BitVector B) {
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if (B == null) {
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throw new IllegalArgumentException("null B");
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}
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if (this == B) { // should help alias analysis
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return true;
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}
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int n = Math.min(bits.length, B.bits.length);
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if (bits.length > B.bits.length) {
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for (int i = n; i < bits.length; i++) {
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if (bits[i] != 0)
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return false;
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}
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} else if (B.bits.length > bits.length) {
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for (int i = n; i < B.bits.length; i++) {
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if (B.bits[i] != 0)
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return false;
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}
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}
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for (int i = n - 1; i >= 0;) {
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if (bits[i] != B.bits[i]) {
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return false;
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}
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i--;
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}
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return true;
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}
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/**
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* @return true iff this is a subset of other
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*/
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@Override
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public boolean isSubset(BitVector other) {
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if (other == null) {
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throw new IllegalArgumentException("null other");
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}
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if (this == other) { // should help alias analysis
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return true;
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}
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for (int i = 0; i < bits.length; i++) {
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if (i >= other.bits.length) {
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if (bits[i] != 0) {
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return false;
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}
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} else {
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if ((bits[i] & ~other.bits[i]) != 0) {
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return false;
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}
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}
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}
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return true;
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}
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@Override
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public void andNot(BitVector vector) {
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if (vector == null) {
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throw new IllegalArgumentException("null vector");
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}
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int ai = 0;
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int bi = 0;
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for (ai = 0, bi = 0; ai < bits.length && bi < vector.bits.length; ai++, bi++) {
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bits[ai] = bits[ai] & (~vector.bits[bi]);
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}
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}
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/**
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* Compares this object against the specified object.
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*
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* @param obj the object to compare with
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* @return true if the objects are the same; false otherwise.
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*/
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@Override
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public boolean equals(Object obj) {
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if ((obj != null) && (obj instanceof BitVector)) {
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if (this == obj) { // should help alias analysis
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return true;
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}
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BitVector set = (BitVector) obj;
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return sameBits(set);
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}
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return false;
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}
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/**
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* Sets all bits.
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*/
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public final void setAll() {
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for (int i = 0; i < bits.length; i++) {
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bits[i] = MASK;
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}
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}
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/**
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* Logically NOT this bit string
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*/
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public final void not() {
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for (int i = 0; i < bits.length; i++) {
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bits[i] ^= MASK;
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}
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}
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/**
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* Return a new bit string as the AND of two others.
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*/
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public static BitVector andNot(BitVector b1, BitVector b2) {
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BitVector b = new BitVector(b1);
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b.andNot(b2);
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return b;
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}
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}
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