/** Build a time bounded reachability query into a PTA; return the new target location set. */
private BitSet buildTimeBoundIntoPta(
PTA pta, BitSet targetLocs, int timeBound, boolean timeBoundStrict) {
String timerClock = null;
int timerClockIndex, numLocs, newTargetLoc;
String newTargetLocString;
List<Transition> trNewList;
Transition trNew;
BitSet targetLocsNew;
boolean toTarget;
int i;
// Add a timer clock
timerClock = "time";
while (pta.getClockIndex(timerClock) != -1) timerClock += "_";
timerClockIndex = pta.addClock(timerClock);
// Add a new target location
numLocs = pta.getNumLocations();
newTargetLocString = "target";
while (pta.getLocationIndex(newTargetLocString) != -1) newTargetLocString += "_";
newTargetLoc = pta.addLocation(newTargetLocString);
// Go through old (on-target) locations
for (i = 0; i < numLocs; i++) {
trNewList = new ArrayList<Transition>();
for (Transition tr : pta.getTransitions(i)) {
// See if the transition can go to a target location
toTarget = false;
for (Edge e : tr.getEdges()) {
if (targetLocs.get(e.getDestination())) {
toTarget = true;
break;
}
}
// Copy transition, modify edges going to target and add guard
if (toTarget) {
trNew = new Transition(tr);
for (Edge e : trNew.getEdges()) {
if (targetLocs.get(e.getDestination())) {
e.setDestination(newTargetLoc);
}
}
if (timeBoundStrict)
trNew.addGuardConstraint(Constraint.buildLt(timerClockIndex, timeBound));
else trNew.addGuardConstraint(Constraint.buildLeq(timerClockIndex, timeBound));
trNewList.add(trNew);
// Modify guard of copied transition
if (timeBoundStrict)
tr.addGuardConstraint(Constraint.buildGeq(timerClockIndex, timeBound));
else tr.addGuardConstraint(Constraint.buildGt(timerClockIndex, timeBound));
}
}
// Add new transitions to PTA
for (Transition tr : trNewList) {
pta.addTransition(tr);
}
}
// Re-generate set of target locations
targetLocsNew = new BitSet(pta.getNumLocations());
targetLocsNew.set(newTargetLoc);
return targetLocsNew;
}
