private static int CombineChainedEpsilons(ATN atn)
{
int removedEdges = 0;
foreach (ATNState state in atn.states)
{
if (!state.OnlyHasEpsilonTransitions || state is RuleStopState)
{
continue;
}
IList <Transition> optimizedTransitions = null;
for (int i = 0; i < state.NumberOfOptimizedTransitions; i++)
{
Transition transition = state.GetOptimizedTransition(i);
ATNState intermediate = transition.target;
if (transition.TransitionType != TransitionType.EPSILON || ((EpsilonTransition)transition).OutermostPrecedenceReturn != -1 || intermediate.StateType != StateType.Basic || !intermediate.OnlyHasEpsilonTransitions)
{
if (optimizedTransitions != null)
{
optimizedTransitions.Add(transition);
}
goto nextTransition_continue;
}
for (int j = 0; j < intermediate.NumberOfOptimizedTransitions; j++)
{
if (intermediate.GetOptimizedTransition(j).TransitionType != TransitionType.EPSILON || ((EpsilonTransition)intermediate.GetOptimizedTransition(j)).OutermostPrecedenceReturn != -1)
{
if (optimizedTransitions != null)
{
optimizedTransitions.Add(transition);
}
goto nextTransition_continue;
}
}
removedEdges++;
if (optimizedTransitions == null)
{
optimizedTransitions = new List <Transition>();
for (int j_1 = 0; j_1 < i; j_1++)
{
optimizedTransitions.Add(state.GetOptimizedTransition(j_1));
}
}
for (int j_2 = 0; j_2 < intermediate.NumberOfOptimizedTransitions; j_2++)
{
ATNState target = intermediate.GetOptimizedTransition(j_2).target;
optimizedTransitions.Add(new EpsilonTransition(target));
}
nextTransition_continue :;
}
if (optimizedTransitions != null)
{
if (state.IsOptimized)
{
while (state.NumberOfOptimizedTransitions > 0)
{
state.RemoveOptimizedTransition(state.NumberOfOptimizedTransitions - 1);
}
}
foreach (Transition transition in optimizedTransitions)
{
state.AddOptimizedTransition(transition);
}
}
}
return(removedEdges);
}
private static int InlineSetRules(ATN atn)
{
int inlinedCalls = 0;
Transition[] ruleToInlineTransition = new Transition[atn.ruleToStartState.Length];
for (int i = 0; i < atn.ruleToStartState.Length; i++)
{
RuleStartState startState = atn.ruleToStartState[i];
ATNState middleState = startState;
while (middleState.OnlyHasEpsilonTransitions && middleState.NumberOfOptimizedTransitions == 1 && middleState.GetOptimizedTransition(0).TransitionType == TransitionType.EPSILON)
{
middleState = middleState.GetOptimizedTransition(0).target;
}
if (middleState.NumberOfOptimizedTransitions != 1)
{
continue;
}
Transition matchTransition = middleState.GetOptimizedTransition(0);
ATNState matchTarget = matchTransition.target;
if (matchTransition.IsEpsilon || !matchTarget.OnlyHasEpsilonTransitions || matchTarget.NumberOfOptimizedTransitions != 1 || !(matchTarget.GetOptimizedTransition(0).target is RuleStopState))
{
continue;
}
switch (matchTransition.TransitionType)
{
case TransitionType.ATOM:
case TransitionType.RANGE:
case TransitionType.SET:
{
ruleToInlineTransition[i] = matchTransition;
break;
}
case TransitionType.NOT_SET:
case TransitionType.WILDCARD:
{
// not implemented yet
continue;
}
default:
{
continue;
}
}
}
for (int stateNumber = 0; stateNumber < atn.states.Count; stateNumber++)
{
ATNState state = atn.states[stateNumber];
if (state.ruleIndex < 0)
{
continue;
}
IList <Transition> optimizedTransitions = null;
for (int i_1 = 0; i_1 < state.NumberOfOptimizedTransitions; i_1++)
{
Transition transition = state.GetOptimizedTransition(i_1);
if (!(transition is RuleTransition))
{
if (optimizedTransitions != null)
{
optimizedTransitions.Add(transition);
}
continue;
}
RuleTransition ruleTransition = (RuleTransition)transition;
Transition effective = ruleToInlineTransition[ruleTransition.target.ruleIndex];
if (effective == null)
{
if (optimizedTransitions != null)
{
optimizedTransitions.Add(transition);
}
continue;
}
if (optimizedTransitions == null)
{
optimizedTransitions = new List <Transition>();
for (int j = 0; j < i_1; j++)
{
optimizedTransitions.Add(state.GetOptimizedTransition(i_1));
}
}
inlinedCalls++;
ATNState target = ruleTransition.followState;
ATNState intermediateState = new BasicState();
intermediateState.SetRuleIndex(target.ruleIndex);
atn.AddState(intermediateState);
optimizedTransitions.Add(new EpsilonTransition(intermediateState));
switch (effective.TransitionType)
{
case TransitionType.ATOM:
{
intermediateState.AddTransition(new AtomTransition(target, ((AtomTransition)effective).token));
break;
}
case TransitionType.RANGE:
{
intermediateState.AddTransition(new RangeTransition(target, ((RangeTransition)effective).from, ((RangeTransition)effective).to));
break;
}
case TransitionType.SET:
{
intermediateState.AddTransition(new SetTransition(target, effective.Label));
break;
}
default:
{
throw new NotSupportedException();
}
}
}
if (optimizedTransitions != null)
{
if (state.IsOptimized)
{
while (state.NumberOfOptimizedTransitions > 0)
{
state.RemoveOptimizedTransition(state.NumberOfOptimizedTransitions - 1);
}
}
foreach (Transition transition in optimizedTransitions)
{
state.AddOptimizedTransition(transition);
}
}
}
return(inlinedCalls);
}