/*
 * 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.IFDS;

import com.ibm.wala.util.intset.SparseIntSet;

/** A flow function which has only the edge 0 -&gt; dest */
public class SingletonFlowFunction implements IReversibleFlowFunction {

  private static final SparseIntSet zeroSet = SparseIntSet.singleton(0);

  final int dest;

  private SingletonFlowFunction(int dest) {
    this.dest = dest;
  }

  @Override
  public SparseIntSet getTargets(int i) {
    if (i == 0) {
      return SparseIntSet.add(zeroSet, dest);
    } else {
      return null;
    }
  }

  @Override
  public SparseIntSet getSources(int i) {
    if (i == dest || i == 0) {
      return zeroSet;
    } else {
      return null;
    }
  }

  public static SingletonFlowFunction create(int dest) {
    return new SingletonFlowFunction(dest);
  }
}
