/// <summary>
/// Returns an automaton that accepts between <paramref name="min"/> and
/// <paramref name="max"/> (including both) concatenated repetitions of the language
/// of the given automaton.
/// <para/>
/// Complexity: linear in number of states and in <paramref name="min"/> and
/// <paramref name="max"/>.
/// </summary>
public static Automaton Repeat(Automaton a, int min, int max)
{
if (min > max)
{
return(BasicAutomata.MakeEmpty());
}
max -= min;
a.ExpandSingleton();
Automaton b;
if (min == 0)
{
b = BasicAutomata.MakeEmptyString();
}
else if (min == 1)
{
b = (Automaton)a.Clone();
}
else
{
IList <Automaton> @as = new List <Automaton>();
while (min-- > 0)
{
@as.Add(a);
}
b = Concatenate(@as);
}
if (max > 0)
{
Automaton d = (Automaton)a.Clone();
while (--max > 0)
{
Automaton c = (Automaton)a.Clone();
foreach (State p in c.GetAcceptStates())
{
p.AddEpsilon(d.initial);
}
d = c;
}
foreach (State p in b.GetAcceptStates())
{
p.AddEpsilon(d.initial);
}
b.deterministic = false;
//b.clearHashCode();
b.ClearNumberedStates();
b.CheckMinimizeAlways();
}
return(b);
}
/// <summary>
/// Returns the longest string that is a suffix of all accepted strings and
/// visits each state at most once.
/// </summary>
/// <returns> Common suffix. </returns>
public static string GetCommonSuffix(Automaton a)
{
if (a.IsSingleton) // if singleton, the suffix is the string itself.
{
return(a.singleton);
}
// reverse the language of the automaton, then reverse its common prefix.
Automaton r = (Automaton)a.Clone();
Reverse(r);
r.Determinize();
return((new StringBuilder(SpecialOperations.GetCommonPrefix(r))).Reverse().ToString());
}
public static BytesRef GetCommonSuffixBytesRef(Automaton a)
{
if (a.IsSingleton) // if singleton, the suffix is the string itself.
{
return(new BytesRef(a.singleton));
}
// reverse the language of the automaton, then reverse its common prefix.
Automaton r = (Automaton)a.Clone();
Reverse(r);
r.Determinize();
BytesRef @ref = SpecialOperations.GetCommonPrefixBytesRef(r);
ReverseBytes(@ref);
return(@ref);
}
private Automaton ToAutomaton(IDictionary <string, Automaton> automata, IAutomatonProvider automaton_provider)
{
IList <Automaton> list;
Automaton a = null;
switch (kind)
{
case Kind.REGEXP_UNION:
list = new List <Automaton>();
FindLeaves(exp1, Kind.REGEXP_UNION, list, automata, automaton_provider);
FindLeaves(exp2, Kind.REGEXP_UNION, list, automata, automaton_provider);
a = BasicOperations.Union(list);
MinimizationOperations.Minimize(a);
break;
case Kind.REGEXP_CONCATENATION:
list = new List <Automaton>();
FindLeaves(exp1, Kind.REGEXP_CONCATENATION, list, automata, automaton_provider);
FindLeaves(exp2, Kind.REGEXP_CONCATENATION, list, automata, automaton_provider);
a = BasicOperations.Concatenate(list);
MinimizationOperations.Minimize(a);
break;
case Kind.REGEXP_INTERSECTION:
a = exp1.ToAutomaton(automata, automaton_provider).Intersection(exp2.ToAutomaton(automata, automaton_provider));
MinimizationOperations.Minimize(a);
break;
case Kind.REGEXP_OPTIONAL:
a = exp1.ToAutomaton(automata, automaton_provider).Optional();
MinimizationOperations.Minimize(a);
break;
case Kind.REGEXP_REPEAT:
a = exp1.ToAutomaton(automata, automaton_provider).Repeat();
MinimizationOperations.Minimize(a);
break;
case Kind.REGEXP_REPEAT_MIN:
a = exp1.ToAutomaton(automata, automaton_provider).Repeat(min);
MinimizationOperations.Minimize(a);
break;
case Kind.REGEXP_REPEAT_MINMAX:
a = exp1.ToAutomaton(automata, automaton_provider).Repeat(min, max);
MinimizationOperations.Minimize(a);
break;
case Kind.REGEXP_COMPLEMENT:
a = exp1.ToAutomaton(automata, automaton_provider).Complement();
MinimizationOperations.Minimize(a);
break;
case Kind.REGEXP_CHAR:
a = BasicAutomata.MakeChar(c);
break;
case Kind.REGEXP_CHAR_RANGE:
a = BasicAutomata.MakeCharRange(from, to);
break;
case Kind.REGEXP_ANYCHAR:
a = BasicAutomata.MakeAnyChar();
break;
case Kind.REGEXP_EMPTY:
a = BasicAutomata.MakeEmpty();
break;
case Kind.REGEXP_STRING:
a = BasicAutomata.MakeString(s);
break;
case Kind.REGEXP_ANYSTRING:
a = BasicAutomata.MakeAnyString();
break;
case Kind.REGEXP_AUTOMATON:
Automaton aa = null;
if (automata != null)
{
aa = automata[s];
}
if (aa == null && automaton_provider != null)
{
try
{
aa = automaton_provider.GetAutomaton(s);
}
catch (System.IO.IOException e)
{
throw new System.ArgumentException(e.ToString(), e);
}
}
if (aa == null)
{
throw new System.ArgumentException("'" + s + "' not found");
}
a = (Automaton)aa.Clone(); // always clone here (ignore allow_mutate)
break;
case Kind.REGEXP_INTERVAL:
a = BasicAutomata.MakeInterval(min, max, digits);
break;
}
return(a);
}