org.sosy_lab.cpachecker.cpa.edgeexclusion.EdgeExclusionPrecision.java Source code

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Here is the source code for org.sosy_lab.cpachecker.cpa.edgeexclusion.EdgeExclusionPrecision.java

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/*
 *  CPAchecker is a tool for configurable software verification.
 *  This file is part of CPAchecker.
 *
 *  Copyright (C) 2007-2014  Dirk Beyer
 *  All rights reserved.
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 *
 *  CPAchecker web page:
 *    http://cpachecker.sosy-lab.org
 */
package org.sosy_lab.cpachecker.cpa.edgeexclusion;

import java.util.ArrayDeque;
import java.util.Collection;
import java.util.Queue;

import org.sosy_lab.cpachecker.cfa.model.CFAEdge;
import org.sosy_lab.cpachecker.cfa.model.MultiEdge;
import org.sosy_lab.cpachecker.core.interfaces.Precision;

import com.google.common.collect.FluentIterable;
import com.google.common.collect.ImmutableSet;

/**
 * Instances of this class are precisions for the edge exclusion CPA. They
 * control which edges are excluded.
 *
 * The instances of this class are immutable.
 */
public class EdgeExclusionPrecision implements Precision {

    /**
     * The empty precision does not exclude any edges.
     */
    private static final EdgeExclusionPrecision EMPTY = new EdgeExclusionPrecision(ImmutableSet.<CFAEdge>of());

    /**
     * The excluded edges.
     */
    private final ImmutableSet<CFAEdge> excludedEdges;

    /**
     * Gets the empty precision, which does not exclude any edges.
     *
     * @return the empty precision, which does not exclude any edges.
     */
    public static EdgeExclusionPrecision getEmptyPrecision() {
        return EMPTY;
    }

    /**
     * Creates a new edge exclusion precision for excluding the given edges.
     *
     * @param pExcludedEdges the edges to exclude.
     */
    private EdgeExclusionPrecision(ImmutableSet<CFAEdge> pExcludedEdges) {
        this.excludedEdges = pExcludedEdges;
    }

    /**
     * Returns a precision that excludes all edges excluded by this precision
     * plus all given edges.
     *
     * @param pAdditionalExcludedEdges the additional edges to exclude.
     *
     * @return a precision that excludes all edges excluded by this precision
     * plus all given edges.
     */
    public EdgeExclusionPrecision excludeMoreEdges(Iterable<CFAEdge> pAdditionalExcludedEdges) {
        if (pAdditionalExcludedEdges instanceof Collection) {
            return excludeMoreEdges((Collection<CFAEdge>) pAdditionalExcludedEdges);
        }
        return excludeMoreEdges(FluentIterable.from(pAdditionalExcludedEdges).toSet());
    }

    /**
     * Returns a precision that excludes all edges excluded by this precision
     * plus all given edges.
     *
     * @param pAdditionalExcludedEdges the additional edges to exclude.
     *
     * @return a precision that excludes all edges excluded by this precision
     * plus all given edges.
     */
    public EdgeExclusionPrecision excludeMoreEdges(Collection<CFAEdge> pAdditionalExcludedEdges) {
        if (excludedEdges.containsAll(pAdditionalExcludedEdges)) {
            return this;
        }
        ImmutableSet.Builder<CFAEdge> setBuilder = ImmutableSet.<CFAEdge>builder();
        setBuilder.addAll(excludedEdges);
        Queue<CFAEdge> waitlist = new ArrayDeque<>(pAdditionalExcludedEdges);
        while (!waitlist.isEmpty()) {
            CFAEdge current = waitlist.poll();
            if (current instanceof MultiEdge) {
                for (CFAEdge edge : (MultiEdge) current) {
                    waitlist.offer(edge);
                }
            }
            setBuilder.add(current);
        }
        return new EdgeExclusionPrecision(setBuilder.build());
    }

    /**
     * Checks if the given edge is excluded.
     *
     * @param pEdge the edge to check.
     *
     * @return {@code true} if the edge is excluded, {@code false} otherwise.
     */
    public boolean isExcluded(CFAEdge pEdge) {
        if (excludedEdges.contains(pEdge)) {
            return true;
        }
        if (pEdge instanceof MultiEdge) {
            for (CFAEdge edge : (MultiEdge) pEdge) {
                if (isExcluded(edge)) {
                    return true;
                }
            }
        }
        return false;
    }

    @Override
    public String toString() {
        return excludedEdges.isEmpty() ? "no precision" : excludedEdges.toString();
    }

}