/*
 * Copyright (c) 2002 - 2014 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.cfg.exc.intra;

import com.ibm.wala.cfg.IBasicBlock;
import com.ibm.wala.ipa.cfg.EdgeFilter;
import com.ibm.wala.util.graph.Graph;

/**
 * An EdgeFilter that ignores all edges contained in a given graph. This ca be used to subtract a
 * subgraph from its main graph.
 *
 * @author Juergen Graf &lt;graf@kit.edu&gt;
 */
public class NegativeGraphFilter<T extends IBasicBlock<?>> implements EdgeFilter<T> {

  private final Graph<T> deleted;

  public NegativeGraphFilter(Graph<T> deleted) {
    this.deleted = deleted;
  }

  /* (non-Javadoc)
   * @see com.ibm.wala.ipa.cfg.EdgeFilter#hasExceptionalEdge(com.ibm.wala.cfg.IBasicBlock, com.ibm.wala.cfg.IBasicBlock)
   */
  @Override
  public boolean hasExceptionalEdge(T src, T dst) {
    return !deleted.hasEdge(src, dst);
  }

  /* (non-Javadoc)
   * @see com.ibm.wala.ipa.cfg.EdgeFilter#hasNormalEdge(com.ibm.wala.cfg.IBasicBlock, com.ibm.wala.cfg.IBasicBlock)
   */
  @Override
  public boolean hasNormalEdge(T src, T dst) {
    return !deleted.hasEdge(src, dst);
  }
}
