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);
}
}
protected virtual void OptimizeEOTBranches(DFAState state)
{
if (state == null)
{
throw new ArgumentNullException("state");
}
int sI = state.StateNumber;
if (_visited.Contains(sI))
{
return; // already visited
}
_visited.Add(sI);
for (int i = 0; i < state.NumberOfTransitions; i++)
{
Transition edge = state.GetTransition(i);
DFAState edgeTarget = ((DFAState)edge.Target);
/*
* [email protected](d.stateNumber+"-"+
* edge.label.toString(d.dfa.nfa.grammar)+"->"+
* edgeTarget.stateNumber);
*/
// if only one edge coming out, it is EOT, and target is accept prune
if (PRUNE_TOKENS_RULE_SUPERFLUOUS_EOT_EDGES &&
edgeTarget.IsAcceptState &&
state.NumberOfTransitions == 1 &&
edge.Label.IsAtom &&
edge.Label.Atom == Label.EOT)
{
//[email protected]("state "+d+" can be pruned");
// remove the superfluous EOT edge
state.RemoveTransition(i);
state.IsAcceptState = true; // make it an accept state
// force it to uniquely predict the originally predicted state
state.CachedUniquelyPredicatedAlt = edgeTarget.GetUniquelyPredictedAlt();
i--; // back up one so that i++ of loop iteration stays within bounds
}
OptimizeEOTBranches(edgeTarget);
}
}
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 );
}
}
protected virtual void OptimizeEOTBranches( DFAState d )
{
int sI = d.stateNumber;
if ( _visited.Contains( sI ) )
{
return; // already visited
}
_visited.Add( sI );
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 only one edge coming out, it is EOT, and target is accept prune
if ( PRUNE_TOKENS_RULE_SUPERFLUOUS_EOT_EDGES &&
edgeTarget.IsAcceptState &&
d.NumberOfTransitions == 1 &&
edge.label.IsAtom &&
edge.label.Atom == Label.EOT )
{
//[email protected]("state "+d+" can be pruned");
// remove the superfluous EOT edge
d.RemoveTransition( i );
d.IsAcceptState = true; // make it an accept state
// force it to uniquely predict the originally predicted state
d.cachedUniquelyPredicatedAlt =
edgeTarget.GetUniquelyPredictedAlt();
i--; // back up one so that i++ of loop iteration stays within bounds
}
OptimizeEOTBranches( edgeTarget );
}
}
