Antlr4.Runtime.Atn.ATNDeserializer.InlineSetRules C# (CSharp) Method

        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;
        }