//Regram --> NDFA
public static NDFA <T, S> ConvertToNDFA(Regram <T, S> regram, S epsilon)
{
NDFA <T, S> ndfa = new NDFA <T, S>(regram.Alphabet, epsilon);
foreach (T fromState in regram.GetStates())
{
Dictionary <S, HashSet <T> > states = regram.GetStates(fromState);
foreach (S key in states.Keys)
{
foreach (T toState in states[key])
{
ndfa.AddTransition(fromState, toState, key);
}
}
}
foreach (T endstate in regram.EndStates)
{
ndfa.EndStates.Add(endstate);
}
ndfa.StartState = regram.StartState;
return(ndfa);
}
//NDFA --> Regram
public static Regram <MultiState <T>, S> ConvertToRegram(NDFA <T, S> ndfa, IMultiStateView <T> view)
{
Regram <MultiState <T>, S> regram = new Regram <MultiState <T>, S>(ndfa.Alphabet);
MultiState <T> startState = new MultiState <T>(view);
HashSet <MultiState <T> > todo = new HashSet <MultiState <T> >();
HashSet <MultiState <T> > done = new HashSet <MultiState <T> >();
foreach (T subStartState in ndfa.StartStates)
{
startState.Add(subStartState);
HashSet <T> otherStates = getAllEpsilonStatesFromState(ndfa, subStartState, ndfa.Epsilon);
foreach (T otherState in otherStates)
{
startState.Add(otherState);
}
}
todo.Add(startState);
//While there are items that needs to be progressed
while (todo.Count > 0)
{
MultiState <T> from = todo.First <MultiState <T> >();
foreach (T part in from)
{
if (isRegramStateValid(ndfa, part))
{
regram.AddState(from);
}
Dictionary <S, HashSet <T> > partStates = ndfa.GetStates(part);
foreach (S symbol in partStates.Keys)
{
if (symbol.Equals(ndfa.Epsilon))
{
continue;
}
HashSet <T> partToStates = partStates[symbol];
foreach (T partToState in partToStates)
{
MultiState <T> newState = new MultiState <T>(view);
newState.Add(partToState);
if (isRegramStateValid(ndfa, partToState) || ndfa.EndStates.Contains(partToState))
{
regram.AddTransition(from, newState, symbol);
}
if (!done.Contains(newState))
{
todo.Add(newState);
}
foreach (T epsilonState in getAllEpsilonStatesFromState(ndfa, partToState, ndfa.Epsilon))
{
MultiState <T> newEpsilonState = new MultiState <T>(view);
newEpsilonState.Add(epsilonState);
if (isRegramStateValid(ndfa, epsilonState) || ndfa.EndStates.Contains(epsilonState))
{
regram.AddTransition(from, newEpsilonState, symbol);
}
if (!done.Contains(newEpsilonState))
{
todo.Add(newEpsilonState);
}
}
}
}
}
todo.Remove(from);
done.Add(from);
}
foreach (MultiState <T> state in regram.GetStates().Where((t) => t.Any((a) => ndfa.EndStates.Contains(a))))
{
regram.EndStates.Add(state);
}
regram.StartState = startState;
return(regram);
}