com.ibm.wala.dataflow.graph.BooleanIdentity Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of com.ibm.wala.util Show documentation

T. J. Watson Libraries for Analysis

The newest version!

/*
 * Copyright (c) 2002 - 2006 IBM Corporation.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 */
package com.ibm.wala.dataflow.graph;

import com.ibm.wala.fixpoint.BooleanVariable;
import com.ibm.wala.fixpoint.UnaryOperator;
import org.jspecify.annotations.Nullable;

/** Operator OUT = IN */
public class BooleanIdentity extends UnaryOperator {

  private static final BooleanIdentity SINGLETON = new BooleanIdentity();

  public static BooleanIdentity instance() {
    return SINGLETON;
  }

  private BooleanIdentity() {}

  @Override
  public byte evaluate(@Nullable BooleanVariable lhs, BooleanVariable rhs)
      throws IllegalArgumentException {
    if (lhs == null) {
      throw new IllegalArgumentException("lhs == null");
    }

    if (lhs.sameValue(rhs)) {
      return NOT_CHANGED;
    } else {
      lhs.copyState(rhs);
      return CHANGED;
    }
  }

  @Override
  public String toString() {
    return "Id ";
  }

  @Override
  public int hashCode() {
    return 9802;
  }

  @Override
  public boolean equals(Object o) {
    return (o instanceof BooleanIdentity);
  }

  @Override
  public boolean isIdentity() {
    return true;
  }
}