/*______________________________________________________________________________
*
* Copyright 2005 Arnaud Bailly - NORSYS/LIFL
*
* 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.
*
* (3) The name of the author may not be used to endorse or promote
* products derived from this software without specific prior
* written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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,
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
*
* Created on 5 avr. 2005
*
*/
package rationals.transformations;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
import rationals.Automaton;
import rationals.NoSuchStateException;
import rationals.State;
import rationals.Transition;
/**
* A transformation that computes the complement of an automaton.
* <p>
* This transformation computes the complement of an automaton: Terminal states
* are inverted and missing transitions are added.
*
* @author nono
* @version $Id: Complement.java 2 2006-08-24 14:41:48Z oqube $
*/
public class Complement implements UnaryTransformation {
/*
* (non-Javadoc)
*
* @see rationals.transformations.UnaryTransformation#transform(rationals.Automaton)
*/
public Automaton transform(Automaton a) {
Automaton ret = new Automaton();
List todo = new ArrayList();
Map sm = new HashMap();
Set done = new HashSet();
Set s = a.initials();
todo.addAll(s);
while (!todo.isEmpty()) {
State st = (State) todo.remove(0);
State ns = (State) sm.get(st);
if (ns == null) {
ns = ret.addState(st.isInitial(), !st.isTerminal());
sm.put(st, ns);
}
done.add(st);
for (Iterator it = a.alphabet().iterator(); it.hasNext();) {
Object l = it.next();
Set ends = a.delta(st, l);
if (ends.isEmpty())
try {
ret.addTransition(new Transition(ns, l, ns));
} catch (NoSuchStateException e) {
}
else {
for (Iterator i = ends.iterator(); i.hasNext();) {
State end = ((Transition) i.next()).end();
State ne = (State) sm.get(end);
if (ne == null) {
ne = ret.addState(end.isInitial(), !end
.isTerminal());
sm.put(end, ne);
todo.add(end);
}
try {
ret.addTransition(new Transition(ns, l, ne));
} catch (NoSuchStateException e) {
}
}
}
}
}
return ret;
}
}