/**
* Copyright (C) 2010-2017 Gordon Fraser, Andrea Arcuri and EvoSuite
* contributors
*
* This file is part of EvoSuite.
*
* EvoSuite is free software: you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published
* by the Free Software Foundation, either version 3.0 of the License, or
* (at your option) any later version.
*
* EvoSuite is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with EvoSuite. If not, see <http://www.gnu.org/licenses/>.
*/
/**
*
*/
package org.evosuite.testcase.localsearch;
import java.util.Arrays;
import org.evosuite.Properties;
import org.evosuite.ga.localsearch.LocalSearchBudget;
import org.evosuite.ga.localsearch.LocalSearchObjective;
import org.evosuite.testcase.TestChromosome;
import org.evosuite.testcase.execution.ExecutionResult;
import org.evosuite.testcase.statements.StringPrimitiveStatement;
import org.evosuite.utils.Randomness;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* <p>
* StringLocalSearch class.
* </p>
*
* @author fraser
*/
public class StringLocalSearch extends StatementLocalSearch {
private static final Logger logger = LoggerFactory.getLogger(StringLocalSearch.class);
private String oldValue;
private ExecutionResult oldResult;
private boolean oldChanged;
private void backup(TestChromosome test, StringPrimitiveStatement p) {
oldValue = new String(p.getValue());
oldResult = test.getLastExecutionResult();
oldChanged = test.isChanged();
}
private void restore(TestChromosome test, StringPrimitiveStatement p) {
p.setValue(new String(oldValue));
test.setLastExecutionResult(oldResult);
test.setChanged(oldChanged);
}
/* (non-Javadoc)
* @see org.evosuite.testcase.LocalSearch#doSearch(org.evosuite.testcase.TestChromosome, int, org.evosuite.ga.LocalSearchObjective)
*/
/** {@inheritDoc} */
@Override
public boolean doSearch(TestChromosome test, int statement,
LocalSearchObjective<TestChromosome> objective) {
StringPrimitiveStatement p = (StringPrimitiveStatement) test.getTestCase().getStatement(statement);
backup(test, p);
// TODO: First apply 10 random mutations to determine if string influences _uncovered_ branch
boolean affected = false;
String oldValue = p.getValue();
for (int i = 0; i < Properties.LOCAL_SEARCH_PROBES; i++) {
if (Randomness.nextDouble() > 0.5)
p.increment();
else
p.randomize();
logger.info("Probing string " + oldValue + " ->" + p.getCode());
int result = objective.hasChanged(test);
if (result < 0) {
backup(test, p);
} else {
restore(test, p);
}
if (result != 0) {
affected = true;
logger.info("String affects fitness");
break;
}
}
if (affected) {
boolean hasImproved = false;
logger.info("Applying local search to string " + p.getCode());
// First try to remove each of the characters
logger.info("Removing characters");
if (removeCharacters(objective, test, p, statement))
hasImproved = true;
logger.info("Statement: " + p.getCode());
// Second, try to replace each of the characters with each of the 64 possible characters
logger.info("Replacing characters");
if (replaceCharacters(objective, test, p, statement))
hasImproved = true;
logger.info("Statement: " + p.getCode());
// Third, try to add characters
logger.info("Adding characters");
if (addCharacters(objective, test, p, statement))
hasImproved = true;
logger.info("Statement: " + p.getCode());
logger.info("Resulting string: " + p.getValue());
return hasImproved;
//} else {
// logger.info("Not applying local search to string as it does not improve fitness");
}
return false;
}
private boolean removeCharacters(LocalSearchObjective<TestChromosome> objective,
TestChromosome test, StringPrimitiveStatement p, int statement) {
boolean improvement = false;
backup(test, p);
for (int i = oldValue.length() - 1; i >= 0; i--) {
String newString = oldValue.substring(0, i) + oldValue.substring(i + 1);
p.setValue(newString);
logger.info(" " + i + " " + oldValue + "/" + oldValue.length() + " -> "
+ newString + "/" + newString.length());
if (objective.hasImproved(test)) {
logger.info("Has improved");
backup(test, p);
improvement = true;
} else {
logger.info("Has not improved");
restore(test, p);
}
if(LocalSearchBudget.getInstance().isFinished())
break;
}
return improvement;
}
private boolean replaceCharacters(LocalSearchObjective<TestChromosome> objective,
TestChromosome test, StringPrimitiveStatement p, int statement) {
logger.info(" -> In replacement");
boolean improvement = false;
backup(test, p);
for (int i = 0; i < oldValue.length(); i++) {
char oldChar = oldValue.charAt(i);
logger.info(" -> Character " + i + ": " + oldChar);
char[] characters = oldValue.toCharArray();
for (char replacement = 9; replacement < 128; replacement++) {
if(LocalSearchBudget.getInstance().isFinished())
return improvement;
if (replacement != oldChar) {
characters[i] = replacement;
String newString = new String(characters);
p.setValue(newString);
logger.info(" " + i + " " + oldValue + "/" + oldValue.length()
+ " -> " + newString + "/" + newString.length());
//logger.debug(" " + i + " " + oldValue + "/" + oldValue.length()
// + " -> " + newString + "/" + newString.length());
if (objective.hasImproved(test)) {
backup(test, p);
//oldChar = replacement;
improvement = true;
// If this change has improved fitness we can move on to the next character
break;
} else {
characters[i] = oldChar;
restore(test, p);
}
}
}
}
return improvement;
}
private boolean addCharacters(LocalSearchObjective<TestChromosome> objective,
TestChromosome test, StringPrimitiveStatement p, int statement) {
boolean improvement = false;
backup(test, p);
boolean add = true;
while (add) {
add = false;
int position = oldValue.length();
char[] characters = Arrays.copyOf(oldValue.toCharArray(), position + 1);
for (char replacement = 9; replacement < 128; replacement++) {
if(LocalSearchBudget.getInstance().isFinished())
return improvement;
characters[position] = replacement;
String newString = new String(characters);
p.setValue(newString);
//logger.debug(" " + oldValue + "/" + oldValue.length() + " -> " + newString
// + "/" + newString.length());
if (objective.hasImproved(test)) {
backup(test, p);
improvement = true;
add = true;
break;
} else {
restore(test, p);
}
}
}
add = true;
while (add) {
add = false;
int position = 0;
char[] characters = (" " + oldValue).toCharArray();
for (char replacement = 9; replacement < 128; replacement++) {
if(LocalSearchBudget.getInstance().isFinished())
return improvement;
characters[position] = replacement;
String newString = new String(characters);
p.setValue(newString);
//logger.debug(" " + oldValue + "/" + oldValue.length() + " -> " + newString
// + "/" + newString.length());
if (objective.hasImproved(test)) {
backup(test, p);
improvement = true;
add = true;
break;
} else {
restore(test, p);
}
}
}
return improvement;
}
}