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JQF: Feedback-directed Quickcheck for Java - Guided fuzzing interface
/*
* Copyright (c) 2017-2018 The Regents of the University of California
*
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package edu.berkeley.cs.jqf.fuzz.util;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
/**
* Maps integer keys to integer counts using a fixed-size table.
*
* Hash collisions are completely ignored; therefore, the counts
* are unreliable.
*
* @author Rohan Padhye
*/
public class MapOfCounters {
/** The number of counters to map. */
private final int numCounters;
/** The size of each counter in the map. */
private final int counterSize;
/** The table of counters. */
private final Counter[] counters;
public MapOfCounters(int numCounters, int counterSize) {
this.numCounters = numCounters;
this.counterSize = counterSize;
this.counters = new Counter[numCounters];
}
public void clear() {
for (int i = 0; i < counters.length; i++) {
counters[i] = null;
}
}
private int idx(int key) {
return Hashing.hash(key, numCounters);
}
public void increment(int k1, int k2) {
int idx = idx(k1);
if (counters[idx] == null) {
counters[idx] = new Counter(counterSize);
}
counters[idx].increment(k2);
}
public Collection nonZeroCountsAtIndex(int idx) {
if (counters[idx] != null) {
return counters[idx].getNonZeroValues();
} else {
return Collections.emptyList();
}
}
public Collection nonEmptyCountersIndices() {
List keys = new ArrayList<>(numCounters);
for (int i = 0; i < numCounters; i++) {
if (counters[i] != null) {
keys.add(i);
}
}
return keys;
}
}