/*
* ProGuard -- shrinking, optimization, obfuscation, and preverification
* of Java bytecode.
*
* Copyright (c) 2002-2014 Eric Lafortune (eric@graphics.cornell.edu)
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the Free
* Software Foundation; either version 2 of the License, or (at your option)
* any later version.
*
* This program 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 General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
package proguard.obfuscate;
import java.util.*;
/**
* This NameFactory
generates unique short names, using mixed-case
* characters or lower-case characters only.
*
* @author Eric Lafortune
*/
public class SimpleNameFactory implements NameFactory
{
private static final int CHARACTER_COUNT = 26;
private static final List cachedMixedCaseNames = new ArrayList();
private static final List cachedLowerCaseNames = new ArrayList();
private final boolean generateMixedCaseNames;
private int index = 0;
/**
* Creates a new SimpleNameFactory
that generates mixed-case names.
*/
public SimpleNameFactory()
{
this(true);
}
/**
* Creates a new SimpleNameFactory
.
* @param generateMixedCaseNames a flag to indicate whether the generated
* names will be mixed-case, or lower-case only.
*/
public SimpleNameFactory(boolean generateMixedCaseNames)
{
this.generateMixedCaseNames = generateMixedCaseNames;
}
// Implementations for NameFactory.
public void reset()
{
index = 0;
}
public String nextName()
{
return name(index++);
}
/**
* Returns the name at the given index.
*/
private String name(int index)
{
// Which cache do we need?
List cachedNames = generateMixedCaseNames ?
cachedMixedCaseNames :
cachedLowerCaseNames;
// Do we have the name in the cache?
if (index < cachedNames.size())
{
return (String)cachedNames.get(index);
}
// Create a new name and cache it.
String name = newName(index);
cachedNames.add(index, name);
return name;
}
/**
* Creates and returns the name at the given index.
*/
private String newName(int index)
{
// If we're allowed to generate mixed-case names, we can use twice as
// many characters.
int totalCharacterCount = generateMixedCaseNames ?
2 * CHARACTER_COUNT :
CHARACTER_COUNT;
int baseIndex = index / totalCharacterCount;
int offset = index % totalCharacterCount;
char newChar = charAt(offset);
String newName = baseIndex == 0 ?
new String(new char[] { newChar }) :
(name(baseIndex-1) + newChar);
return newName;
}
/**
* Returns the character with the given index, between 0 and the number of
* acceptable characters.
*/
private char charAt(int index)
{
return (char)((index < CHARACTER_COUNT ? 'a' - 0 :
'A' - CHARACTER_COUNT) + index);
}
public static void main(String[] args)
{
System.out.println("Some mixed-case names:");
printNameSamples(new SimpleNameFactory(true), 60);
System.out.println("Some lower-case names:");
printNameSamples(new SimpleNameFactory(false), 60);
System.out.println("Some more mixed-case names:");
printNameSamples(new SimpleNameFactory(true), 80);
System.out.println("Some more lower-case names:");
printNameSamples(new SimpleNameFactory(false), 80);
}
private static void printNameSamples(SimpleNameFactory factory, int count)
{
for (int counter = 0; counter < count; counter++)
{
System.out.println(" ["+factory.nextName()+"]");
}
}
}