64 lines
1.6 KiB
Java
64 lines
1.6 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.dataflow.graph;
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import com.ibm.wala.fixpoint.BitVectorVariable;
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import com.ibm.wala.fixpoint.UnaryOperator;
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/**
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* Operator U(n) = U(n) U U(j)
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*/
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public class UnaryBitVectorUnion extends UnaryOperator<BitVectorVariable> {
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private final static UnaryBitVectorUnion SINGLETON = new UnaryBitVectorUnion();
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public static UnaryBitVectorUnion instance() {
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return SINGLETON;
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}
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private UnaryBitVectorUnion() {
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}
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@Override
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public byte evaluate(BitVectorVariable lhs, BitVectorVariable rhs) throws IllegalArgumentException {
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if (lhs == null) {
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throw new IllegalArgumentException("lhs == null");
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}
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BitVectorVariable U = new BitVectorVariable();
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U.copyState(lhs);
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U.addAll(rhs);
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if (lhs.sameValue(U)) {
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return NOT_CHANGED;
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} else {
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lhs.copyState(U);
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return CHANGED;
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}
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}
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@Override
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public String toString() {
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return "UNION";
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}
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@Override
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public int hashCode() {
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return 9901;
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}
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@Override
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public boolean equals(Object o) {
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return (o instanceof UnaryBitVectorUnion);
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}
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}
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