public static GetCommonPrefix ( |
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a | ||
리턴 | string |
/// <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 CompiledAutomaton(Automaton automaton, bool?finite, bool simplify) { if (simplify) { // Test whether the automaton is a "simple" form and // if so, don't create a runAutomaton. Note that on a // large automaton these tests could be costly: if (BasicOperations.IsEmpty(automaton)) { // matches nothing Type = AUTOMATON_TYPE.NONE; Term = null; CommonSuffixRef = null; RunAutomaton = null; sortedTransitions = null; this.Finite = null; return; } else if (BasicOperations.IsTotal(automaton)) { // matches all possible strings Type = AUTOMATON_TYPE.ALL; Term = null; CommonSuffixRef = null; RunAutomaton = null; sortedTransitions = null; this.Finite = null; return; } else { string commonPrefix; string singleton; if (automaton.Singleton == null) { commonPrefix = SpecialOperations.GetCommonPrefix(automaton); if (commonPrefix.Length > 0 && BasicOperations.SameLanguage(automaton, BasicAutomata.MakeString(commonPrefix))) { singleton = commonPrefix; } else { singleton = null; } } else { commonPrefix = null; singleton = automaton.Singleton; } if (singleton != null) { // matches a fixed string in singleton or expanded // representation Type = AUTOMATON_TYPE.SINGLE; Term = new BytesRef(singleton); CommonSuffixRef = null; RunAutomaton = null; sortedTransitions = null; this.Finite = null; return; } else if (BasicOperations.SameLanguage(automaton, BasicOperations.Concatenate(BasicAutomata.MakeString(commonPrefix), BasicAutomata.MakeAnyString()))) { // matches a constant prefix Type = AUTOMATON_TYPE.PREFIX; Term = new BytesRef(commonPrefix); CommonSuffixRef = null; RunAutomaton = null; sortedTransitions = null; this.Finite = null; return; } } } Type = AUTOMATON_TYPE.NORMAL; Term = null; if (finite == null) { this.Finite = SpecialOperations.IsFinite(automaton); } else { this.Finite = finite; } Automaton utf8 = (new UTF32ToUTF8()).Convert(automaton); if (this.Finite == true) { CommonSuffixRef = null; } else { CommonSuffixRef = SpecialOperations.GetCommonSuffixBytesRef(utf8); } RunAutomaton = new ByteRunAutomaton(utf8, true); sortedTransitions = utf8.GetSortedTransitions(); }