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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.List;
/**
* An extension of {@link Counter} that caches which entries
* are non-zero.
*
* This version of counter is used by classes such as
* {@link Coverage}, which require frequent queries of
* the non-zero locations.
*/
public class NonZeroCachingCounter extends Counter {
private int nonZeroCount;
private Collection nonZeroIndices;
public NonZeroCachingCounter(int size) {
super(size);
this.nonZeroCount = 0;
this.nonZeroIndices = new ArrayList<>();
}
@Override
public void clear() {
for (int idx : nonZeroIndices) {
counts[idx] = 0;
}
this.nonZeroCount = 0;
this.nonZeroIndices.clear();
}
@Override
public int incrementAtIndex(int index, int delta) {
int newValue = super.incrementAtIndex(index, delta);
// A count becomes non-zero if it was incremented to delta
if (newValue == delta) {
nonZeroIndices.add(index);
nonZeroCount++;
}
return newValue;
}
@Override
public int getNonZeroSize() {
return nonZeroCount;
}
@Override
public Collection getNonZeroIndices() {
return nonZeroIndices;
}
@Override
public Collection getNonZeroValues() {
List values = new ArrayList<>(size /2);
for (int idx : nonZeroIndices) {
int count = counts[idx];
assert (count != 0);
values.add(count);
}
return values;
}
@Override
public void setAtIndex(int index, int newValue) {
int oldValue = counts[index];
super.setAtIndex(index, newValue);
if (oldValue == 0 && newValue != 0) {
nonZeroIndices.add(index);
nonZeroCount++;
}
}
}