public virtual int GetUniquelyPredictedAlt()
{
if ( _cachedUniquelyPredicatedAlt.HasValue )
{
return _cachedUniquelyPredicatedAlt.Value;
}
int alt = NFA.INVALID_ALT_NUMBER;
int numConfigs = _nfaConfigurations.Count;
for ( int i = 0; i < numConfigs; i++ )
{
NFAConfiguration configuration = _nfaConfigurations[i];
// ignore anything we resolved; predicates will still result
// in transitions out of this state, so must count those
// configurations; i.e., don't ignore resolveWithPredicate configs
if ( configuration.Resolved )
{
continue;
}
if ( alt == NFA.INVALID_ALT_NUMBER )
{
alt = configuration.Alt; // found first nonresolved alt
}
else if ( configuration.Alt != alt )
{
return NFA.INVALID_ALT_NUMBER;
}
}
this._cachedUniquelyPredicatedAlt = alt;
return alt;
}
protected virtual void OptimizeExitBranches(DFAState d)
{
int sI = d.stateNumber;
if (_visited.Contains(sI))
{
return; // already visited
}
_visited.Add(sI);
int nAlts = d.dfa.NumberOfAlts;
for (int i = 0; i < d.NumberOfTransitions; i++)
{
Transition edge = (Transition)d.Transition(i);
DFAState edgeTarget = ((DFAState)edge.target);
/*
* [email protected](d.stateNumber+"-"+
* edge.label.toString(d.dfa.nfa.grammar)+"->"+
* edgeTarget.stateNumber);
*/
// if target is an accept state and that alt is the exit alt
if (edgeTarget.IsAcceptState &&
edgeTarget.GetUniquelyPredictedAlt() == nAlts)
{
/*
* [email protected]("ignoring transition "+i+" to max alt "+
* d.dfa.getNumberOfAlts());
*/
d.RemoveTransition(i);
i--; // back up one so that i++ of loop iteration stays within bounds
}
OptimizeExitBranches(edgeTarget);
}
}
