internal static Automaton Concatenate(Automaton a1, Automaton a2) { if (a1.IsSingleton && a2.IsSingleton) { return(BasicAutomata.MakeString(a1.Singleton + a2.Singleton)); } if (BasicOperations.IsEmpty(a1) || BasicOperations.IsEmpty(a2)) { return(BasicAutomata.MakeEmpty()); } bool deterministic = a1.IsSingleton && a2.IsDeterministic; if (a1 == a2) { a1 = a1.CloneExpanded(); a2 = a2.CloneExpanded(); } else { a1 = a1.CloneExpandedIfRequired(); a2 = a2.CloneExpandedIfRequired(); } foreach (State s in a1.GetAcceptStates()) { s.Accept = false; s.AddEpsilon(a2.Initial); } a1.IsDeterministic = deterministic; a1.ClearHashCode(); a1.CheckMinimizeAlways(); return(a1); }
internal static Automaton Concatenate(IList <Automaton> l) { if (l.Count == 0) { return(BasicAutomata.MakeEmptyString()); } bool allSingleton = l.All(a => a.IsSingleton); if (allSingleton) { var b = new StringBuilder(); foreach (Automaton a in l) { b.Append(a.Singleton); } return(BasicAutomata.MakeString(b.ToString())); } else { if (l.Any(a => a.IsEmpty)) { return(BasicAutomata.MakeEmpty()); } var ids = new HashSet <int>(); foreach (Automaton a in l) { ids.Add(RuntimeHelpers.GetHashCode(a)); } bool hasAliases = ids.Count != l.Count; Automaton b = l[0]; b = hasAliases ? b.CloneExpanded() : b.CloneExpandedIfRequired(); var ac = b.GetAcceptStates(); bool first = true; foreach (Automaton a in l) { if (first) { first = false; } else { if (a.IsEmptyString()) { continue; } Automaton aa = a; aa = hasAliases ? aa.CloneExpanded() : aa.CloneExpandedIfRequired(); HashSet <State> ns = aa.GetAcceptStates(); foreach (State s in ac) { s.Accept = false; s.AddEpsilon(aa.Initial); if (s.Accept) { ns.Add(s); } } ac = ns; } } b.IsDeterministic = false; b.ClearHashCode(); b.CheckMinimizeAlways(); return(b); } }