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private CloneExpandedIfRequired ( ) : |
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| return | ||
/// <summary>
/// Returns an automaton that accepts the union of the languages of the given
/// automata.
/// <para/>
/// Complexity: linear in number of states.
/// </summary>
public static Automaton Union(Automaton a1, Automaton a2)
{
if ((a1.IsSingleton && a2.IsSingleton && a1.singleton.Equals(a2.singleton, StringComparison.Ordinal)) || a1 == a2)
{
return(a1.CloneIfRequired());
}
if (a1 == a2)
{
a1 = a1.CloneExpanded();
a2 = a2.CloneExpanded();
}
else
{
a1 = a1.CloneExpandedIfRequired();
a2 = a2.CloneExpandedIfRequired();
}
State s = new State();
s.AddEpsilon(a1.initial);
s.AddEpsilon(a2.initial);
a1.initial = s;
a1.deterministic = false;
//a1.clearHashCode();
a1.ClearNumberedStates();
a1.CheckMinimizeAlways();
return(a1);
}
/// <summary>
/// Returns a (deterministic) automaton that accepts the complement of the
/// language of the given automaton.
/// <para/>
/// Complexity: linear in number of states (if already deterministic).
/// </summary>
public static Automaton Complement(Automaton a)
{
a = a.CloneExpandedIfRequired();
a.Determinize();
a.Totalize();
foreach (State p in a.GetNumberedStates())
{
p.accept = !p.accept;
}
a.RemoveDeadTransitions();
return(a);
}
/// <summary>
/// Returns an automaton that accepts the union of the empty string and the
/// language of the given automaton.
/// <para/>
/// Complexity: linear in number of states.
/// </summary>
public static Automaton Optional(Automaton a)
{
a = a.CloneExpandedIfRequired();
State s = new State();
s.AddEpsilon(a.initial);
s.accept = true;
a.initial = s;
a.deterministic = false;
//a.clearHashCode();
a.ClearNumberedStates();
a.CheckMinimizeAlways();
return(a);
}
/// <summary>
/// Returns an automaton that accepts the union of the languages of the given
/// automata.
/// <para/>
/// Complexity: linear in number of states.
/// </summary>
public static Automaton Union(ICollection <Automaton> l)
{
JCG.HashSet <int> ids = new JCG.HashSet <int>();
foreach (Automaton a in l)
{
ids.Add(a.GetHashCode());
}
bool has_aliases = ids.Count != l.Count;
State s = new State();
foreach (Automaton b in l)
{
if (BasicOperations.IsEmpty(b))
{
continue;
}
Automaton bb = b;
if (has_aliases)
{
bb = bb.CloneExpanded();
}
else
{
bb = bb.CloneExpandedIfRequired();
}
s.AddEpsilon(bb.initial);
}
Automaton a_ = new Automaton
{
initial = s,
deterministic = false
};
//a.clearHashCode();
a_.ClearNumberedStates();
a_.CheckMinimizeAlways();
return(a_);
}
/// <summary>
/// Returns an automaton that accepts the concatenation of the languages of the
/// given automata.
/// <para/>
/// Complexity: linear in number of states.
/// </summary>
public static Automaton Concatenate(Automaton a1, Automaton a2)
{
if (a1.IsSingleton && a2.IsSingleton)
{
return(BasicAutomata.MakeString(a1.singleton + a2.singleton));
}
if (IsEmpty(a1) || IsEmpty(a2))
{
return(BasicAutomata.MakeEmpty());
}
// adding epsilon transitions with the NFA concatenation algorithm
// in this case always produces a resulting DFA, preventing expensive
// redundant determinize() calls for this common case.
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.deterministic = deterministic;
//a1.clearHashCode();
a1.ClearNumberedStates();
a1.CheckMinimizeAlways();
return(a1);
}
/// <summary>
/// Returns an automaton that accepts the concatenation of the languages of the
/// given automata.
/// <para/>
/// Complexity: linear in total number of states.
/// </summary>
public static Automaton Concatenate(IList <Automaton> l)
{
if (l.Count == 0)
{
return(BasicAutomata.MakeEmptyString());
}
bool all_singleton = true;
foreach (Automaton a in l)
{
if (!a.IsSingleton)
{
all_singleton = false;
break;
}
}
if (all_singleton)
{
StringBuilder b = new StringBuilder();
foreach (Automaton a in l)
{
b.Append(a.singleton);
}
return(BasicAutomata.MakeString(b.ToString()));
}
else
{
foreach (Automaton a in l)
{
if (BasicOperations.IsEmpty(a))
{
return(BasicAutomata.MakeEmpty());
}
}
HashSet <int> ids = new HashSet <int>();
foreach (Automaton a in l)
{
ids.Add(a.GetHashCode());
}
bool has_aliases = ids.Count != l.Count;
Automaton b = l[0];
if (has_aliases)
{
b = b.CloneExpanded();
}
else
{
b = b.CloneExpandedIfRequired();
}
ISet <State> ac = b.GetAcceptStates();
bool first = true;
foreach (Automaton a in l)
{
if (first)
{
first = false;
}
else
{
if (a.IsEmptyString)
{
continue;
}
Automaton aa = a;
if (has_aliases)
{
aa = aa.CloneExpanded();
}
else
{
aa = aa.CloneExpandedIfRequired();
}
ISet <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.deterministic = false;
//b.clearHashCode();
b.ClearNumberedStates();
b.CheckMinimizeAlways();
return(b);
}
}
