private static void AssertAutomaton(Automaton a)
{
Automaton clone = (Automaton)a.Clone();
// complement(complement(a)) = a
Automaton equivalent = BasicOperations.Complement(BasicOperations.Complement(a));
Assert.IsTrue(BasicOperations.SameLanguage(a, equivalent));
// a union a = a
equivalent = BasicOperations.Union(a, clone);
Assert.IsTrue(BasicOperations.SameLanguage(a, equivalent));
// a intersect a = a
equivalent = BasicOperations.Intersection(a, clone);
Assert.IsTrue(BasicOperations.SameLanguage(a, equivalent));
// a minus a = empty
Automaton empty = BasicOperations.Minus(a, clone);
Assert.IsTrue(BasicOperations.IsEmpty(empty));
// as long as don't accept the empty string
// then optional(a) - empty = a
if (!BasicOperations.Run(a, ""))
{
//System.out.println("test " + a);
Automaton optional = BasicOperations.Optional(a);
//System.out.println("optional " + optional);
equivalent = BasicOperations.Minus(optional, BasicAutomata.MakeEmptyString());
//System.out.println("equiv " + equivalent);
Assert.IsTrue(BasicOperations.SameLanguage(a, equivalent));
}
}
/// <summary>
/// Returns a new (deterministic) automaton that accepts a single codepoint of
/// the given value.
/// </summary>
public static Automaton MakeChar(int c)
{
Automaton a = new Automaton();
a.singleton = new string(Character.ToChars(c));
a.deterministic = true;
return a;
}
public override void SetUp()
{
base.SetUp();
// we generate aweful regexps: good for testing.
// but for preflex codec, the test can be very slow, so use less iterations.
NumIterations = Codec.Default.Name.Equals("Lucene3x") ? 10 * RANDOM_MULTIPLIER : AtLeast(50);
Dir = NewDirectory();
RandomIndexWriter writer = new RandomIndexWriter(Random(), Dir, (IndexWriterConfig)NewIndexWriterConfig(TEST_VERSION_CURRENT, new MockAnalyzer(Random(), MockTokenizer.KEYWORD, false)).SetMaxBufferedDocs(TestUtil.NextInt(Random(), 50, 1000)));
Document doc = new Document();
Field field = NewStringField("field", "", Field.Store.YES);
doc.Add(field);
Terms = new SortedSet<BytesRef>();
int num = AtLeast(200);
for (int i = 0; i < num; i++)
{
string s = TestUtil.RandomUnicodeString(Random());
field.StringValue = s;
Terms.Add(new BytesRef(s));
writer.AddDocument(doc);
}
TermsAutomaton = BasicAutomata.MakeStringUnion(Terms);
Reader = writer.Reader;
Searcher = NewSearcher(Reader);
writer.Dispose();
}
/// <summary>
/// Returns true if the language of this automaton is finite.
/// </summary>
public static bool IsFinite(Automaton a)
{
if (a.IsSingleton)
{
return true;
}
return IsFinite(a.Initial, new BitArray(a.NumberOfStates), new BitArray(a.NumberOfStates));
}
/// <summary>
/// Returns a new (deterministic) automaton that accepts all strings.
/// </summary>
public static Automaton MakeAnyString()
{
Automaton a = new Automaton();
State s = new State();
a.Initial = s;
s.accept = true;
s.AddTransition(new Transition(Character.MIN_CODE_POINT, Character.MAX_CODE_POINT, s));
a.deterministic = true;
return a;
}
/// <summary>
/// Simple, original brics implementation of determinize()
/// </summary>
public static void DeterminizeSimple(Automaton a)
{
if (a.Deterministic || a.Singleton != null)
{
return;
}
HashSet<State> initialset = new HashSet<State>();
initialset.Add(a.InitialState);
DeterminizeSimple(a, initialset);
}
/// <summary>
/// Minimizes (and determinizes if not already deterministic) the given
/// automaton.
/// </summary>
/// <seealso cref= Automaton#setMinimization(int) </seealso>
public static void Minimize(Automaton a)
{
if (!a.IsSingleton)
{
MinimizeHopcroft(a);
}
// recompute hash code
//a.hash_code = 1a.getNumberOfStates() * 3 + a.getNumberOfTransitions() * 2;
//if (a.hash_code == 0) a.hash_code = 1;
}
public override void SetUp()
{
base.SetUp();
// build an automaton matching this jvm's letter definition
State initial = new State();
State accept = new State();
accept.Accept = true;
for (int i = 0; i <= 0x10FFFF; i++)
{
if (Character.IsLetter(i))
{
initial.AddTransition(new Transition(i, i, accept));
}
}
Automaton single = new Automaton(initial);
single.Reduce();
Automaton repeat = BasicOperations.Repeat(single);
jvmLetter = new CharacterRunAutomaton(repeat);
}
private void AssertBruteForceT(string input, Automaton dfa, int distance)
{
CharacterRunAutomaton ra = new CharacterRunAutomaton(dfa);
int maxLen = input.Length + distance + 1;
int maxNum = (int)Math.Pow(2, maxLen);
for (int i = 0; i < maxNum; i++)
{
string encoded = Convert.ToString(i, 2);
bool accepts = ra.Run(encoded);
if (accepts)
{
Assert.IsTrue(GetTDistance(input, encoded) <= distance);
}
else
{
Assert.IsTrue(GetTDistance(input, encoded) > distance);
}
}
}
public void TestRandomRanges()
{
Random r = Random();
int ITERS = AtLeast(10);
int ITERS_PER_DFA = AtLeast(100);
for (int iter = 0; iter < ITERS; iter++)
{
int x1 = GetCodeStart(r);
int x2 = GetCodeStart(r);
int startCode, endCode;
if (x1 < x2)
{
startCode = x1;
endCode = x2;
}
else
{
startCode = x2;
endCode = x1;
}
if (IsSurrogate(startCode) && IsSurrogate(endCode))
{
iter--;
continue;
}
var a = new Automaton();
var end = new State {Accept = true};
a.InitialState.AddTransition(new Transition(startCode, endCode, end));
a.Deterministic = true;
TestOne(r, new ByteRunAutomaton(a), startCode, endCode, ITERS_PER_DFA);
}
}
public RandomAcceptedStrings(Automaton a)
{
this.a = a;
if (!String.IsNullOrEmpty(a.Singleton))
{
LeadsToAccept = null;
return;
}
// must use IdentityHashmap because two Transitions w/
// different start nodes can be considered the same
LeadsToAccept = new IdentityHashMap <Transition, bool?>();
IDictionary <State, IList <ArrivingTransition> > allArriving = new Dictionary <State, IList <ArrivingTransition> >();
LinkedList <State> q = new LinkedList <State>();
HashSet <State> seen = new HashSet <State>();
// reverse map the transitions, so we can quickly look
// up all arriving transitions to a given state
foreach (State s in a.NumberedStates)
{
for (int i = 0; i < s.numTransitions; i++)
{
Transition t = s.TransitionsArray[i];
IList <ArrivingTransition> tl;
allArriving.TryGetValue(t.Dest, out tl);
if (tl == null)
{
tl = new List <ArrivingTransition>();
allArriving[t.Dest] = tl;
}
tl.Add(new ArrivingTransition(s, t));
}
if (s.Accept)
{
q.AddLast(s);
seen.Add(s);
}
}
// Breadth-first search, from accept states,
// backwards:
while (q.Count > 0)
{
State s = q.First.Value;
q.RemoveFirst();
IList <ArrivingTransition> arriving;
allArriving.TryGetValue(s, out arriving);
if (arriving != null)
{
foreach (ArrivingTransition at in arriving)
{
State from = at.From;
if (!seen.Contains(from))
{
q.AddLast(from);
seen.Add(from);
LeadsToAccept[at.t] = true;
}
}
}
}
}
/// <summary>
/// Builds a DFA for some string, and checks all Lev automata
/// up to some maximum distance.
/// </summary>
private void AssertLev(string s, int maxDistance)
{
LevenshteinAutomata builder = new LevenshteinAutomata(s, false);
LevenshteinAutomata tbuilder = new LevenshteinAutomata(s, true);
Automaton[] automata = new Automaton[maxDistance + 1];
Automaton[] tautomata = new Automaton[maxDistance + 1];
for (int n = 0; n < automata.Length; n++)
{
automata[n] = builder.ToAutomaton(n);
tautomata[n] = tbuilder.ToAutomaton(n);
Assert.IsNotNull(automata[n]);
Assert.IsNotNull(tautomata[n]);
Assert.IsTrue(automata[n].Deterministic);
Assert.IsTrue(tautomata[n].Deterministic);
Assert.IsTrue(SpecialOperations.IsFinite(automata[n]));
Assert.IsTrue(SpecialOperations.IsFinite(tautomata[n]));
AutomatonTestUtil.AssertNoDetachedStates(automata[n]);
AutomatonTestUtil.AssertNoDetachedStates(tautomata[n]);
// check that the dfa for n-1 accepts a subset of the dfa for n
if (n > 0)
{
Assert.IsTrue(automata[n - 1].SubsetOf(automata[n]));
Assert.IsTrue(automata[n - 1].SubsetOf(tautomata[n]));
Assert.IsTrue(tautomata[n - 1].SubsetOf(automata[n]));
Assert.IsTrue(tautomata[n - 1].SubsetOf(tautomata[n]));
Assert.AreNotSame(automata[n - 1], automata[n]);
}
// check that Lev(N) is a subset of LevT(N)
Assert.IsTrue(automata[n].SubsetOf(tautomata[n]));
// special checks for specific n
switch (n)
{
case 0:
// easy, matches the string itself
Assert.IsTrue(BasicOperations.SameLanguage(BasicAutomata.MakeString(s), automata[0]));
Assert.IsTrue(BasicOperations.SameLanguage(BasicAutomata.MakeString(s), tautomata[0]));
break;
case 1:
// generate a lev1 naively, and check the accepted lang is the same.
Assert.IsTrue(BasicOperations.SameLanguage(NaiveLev1(s), automata[1]));
Assert.IsTrue(BasicOperations.SameLanguage(NaiveLev1T(s), tautomata[1]));
break;
default:
AssertBruteForce(s, automata[n], n);
AssertBruteForceT(s, tautomata[n], n);
break;
}
}
}
/// <summary>
/// Returns true if the language of <paramref name="a1"/> is a subset of the language
/// of <paramref name="a2"/>. As a side-effect, <paramref name="a2"/> is determinized if
/// not already marked as deterministic.
/// <para/>
/// Complexity: quadratic in number of states.
/// </summary>
public static bool SubsetOf(Automaton a1, Automaton a2)
{
if (a1 == a2)
{
return(true);
}
if (a1.IsSingleton)
{
if (a2.IsSingleton)
{
return(a1.singleton.Equals(a2.singleton, StringComparison.Ordinal));
}
return(BasicOperations.Run(a2, a1.singleton));
}
a2.Determinize();
Transition[][] transitions1 = a1.GetSortedTransitions();
Transition[][] transitions2 = a2.GetSortedTransitions();
Queue <StatePair> worklist = new Queue <StatePair>(); // LUCENENET specific - Queue is much more performant than LinkedList
JCG.HashSet <StatePair> visited = new JCG.HashSet <StatePair>();
StatePair p = new StatePair(a1.initial, a2.initial);
worklist.Enqueue(p);
visited.Add(p);
while (worklist.Count > 0)
{
p = worklist.Dequeue();
if (p.s1.accept && !p.s2.accept)
{
return(false);
}
Transition[] t1 = transitions1[p.s1.number];
Transition[] t2 = transitions2[p.s2.number];
for (int n1 = 0, b2 = 0; n1 < t1.Length; n1++)
{
while (b2 < t2.Length && t2[b2].max < t1[n1].min)
{
b2++;
}
int min1 = t1[n1].min, max1 = t1[n1].max;
for (int n2 = b2; n2 < t2.Length && t1[n1].max >= t2[n2].min; n2++)
{
if (t2[n2].min > min1)
{
return(false);
}
if (t2[n2].max < Character.MaxCodePoint)
{
min1 = t2[n2].max + 1;
}
else
{
min1 = Character.MaxCodePoint;
max1 = Character.MinCodePoint;
}
StatePair q = new StatePair(t1[n1].to, t2[n2].to);
if (!visited.Contains(q))
{
worklist.Enqueue(q);
visited.Add(q);
}
}
if (min1 <= max1)
{
return(false);
}
}
}
return(true);
}
/// <summary>
/// Adds epsilon transitions to the given automaton. This method adds extra
/// character interval transitions that are equivalent to the given set of
/// epsilon transitions.
/// </summary>
/// <param name="a"> Automaton. </param>
/// <param name="pairs"> Collection of <see cref="StatePair"/> objects representing pairs of
/// source/destination states where epsilon transitions should be
/// added. </param>
public static void AddEpsilons(Automaton a, ICollection <StatePair> pairs)
{
a.ExpandSingleton();
Dictionary <State, JCG.HashSet <State> > forward = new Dictionary <State, JCG.HashSet <State> >();
Dictionary <State, JCG.HashSet <State> > back = new Dictionary <State, JCG.HashSet <State> >();
foreach (StatePair p in pairs)
{
if (!forward.TryGetValue(p.s1, out JCG.HashSet <State> to))
{
to = new JCG.HashSet <State>();
forward[p.s1] = to;
}
to.Add(p.s2);
if (!back.TryGetValue(p.s2, out JCG.HashSet <State> from))
{
from = new JCG.HashSet <State>();
back[p.s2] = from;
}
from.Add(p.s1);
}
// calculate epsilon closure
LinkedList <StatePair> worklist = new LinkedList <StatePair>(pairs);
JCG.HashSet <StatePair> workset = new JCG.HashSet <StatePair>(pairs);
while (worklist.Count > 0)
{
StatePair p = worklist.First.Value;
worklist.Remove(p);
workset.Remove(p);
#pragma warning disable IDE0018 // Inline variable declaration
JCG.HashSet <State> from;
#pragma warning restore IDE0018 // Inline variable declaration
if (forward.TryGetValue(p.s2, out JCG.HashSet <State> to))
{
foreach (State s in to)
{
StatePair pp = new StatePair(p.s1, s);
if (!pairs.Contains(pp))
{
pairs.Add(pp);
forward[p.s1].Add(s);
back[s].Add(p.s1);
worklist.AddLast(pp);
workset.Add(pp);
if (back.TryGetValue(p.s1, out from))
{
foreach (State q in from)
{
StatePair qq = new StatePair(q, p.s1);
if (!workset.Contains(qq))
{
worklist.AddLast(qq);
workset.Add(qq);
}
}
}
}
}
}
}
// add transitions
foreach (StatePair p in pairs)
{
p.s1.AddEpsilon(p.s2);
}
a.deterministic = false;
//a.clearHashCode();
a.ClearNumberedStates();
a.CheckMinimizeAlways();
}
/// <summary>
/// Determinizes the given automaton.
/// <para/>
/// Worst case complexity: exponential in number of states.
/// </summary>
public static void Determinize(Automaton a)
{
if (a.IsDeterministic || a.IsSingleton)
{
return;
}
State[] allStates = a.GetNumberedStates();
// subset construction
bool initAccept = a.initial.accept;
int initNumber = a.initial.number;
a.initial = new State();
SortedInt32Set.FrozenInt32Set initialset = new SortedInt32Set.FrozenInt32Set(initNumber, a.initial);
LinkedList <SortedInt32Set.FrozenInt32Set> worklist = new LinkedList <SortedInt32Set.FrozenInt32Set>();
IDictionary <SortedInt32Set.FrozenInt32Set, State> newstate = new Dictionary <SortedInt32Set.FrozenInt32Set, State>();
worklist.AddLast(initialset);
a.initial.accept = initAccept;
newstate[initialset] = a.initial;
int newStateUpto = 0;
State[] newStatesArray = new State[5];
newStatesArray[newStateUpto] = a.initial;
a.initial.number = newStateUpto;
newStateUpto++;
// like Set<Integer,PointTransitions>
PointTransitionSet points = new PointTransitionSet();
// like SortedMap<Integer,Integer>
SortedInt32Set statesSet = new SortedInt32Set(5);
// LUCENENET TODO: THIS IS INFINITE LOOPING
// LUCENENET NOTE: The problem here is almost certainly
// due to the conversion to FrozenIntSet along with its
// differing equality checking.
while (worklist.Count > 0)
{
SortedInt32Set.FrozenInt32Set s = worklist.First.Value;
worklist.Remove(s);
// Collate all outgoing transitions by min/1+max:
for (int i = 0; i < s.values.Length; i++)
{
State s0 = allStates[s.values[i]];
for (int j = 0; j < s0.numTransitions; j++)
{
points.Add(s0.TransitionsArray[j]);
}
}
if (points.count == 0)
{
// No outgoing transitions -- skip it
continue;
}
points.Sort();
int lastPoint = -1;
int accCount = 0;
State r = s.state;
for (int i = 0; i < points.count; i++)
{
int point = points.points[i].point;
if (statesSet.upto > 0)
{
Debug.Assert(lastPoint != -1);
statesSet.ComputeHash();
State q;
if (!newstate.TryGetValue(statesSet.ToFrozenInt32Set(), out q) || q == null)
{
q = new State();
SortedInt32Set.FrozenInt32Set p = statesSet.Freeze(q);
worklist.AddLast(p);
if (newStateUpto == newStatesArray.Length)
{
State[] newArray = new State[ArrayUtil.Oversize(1 + newStateUpto, RamUsageEstimator.NUM_BYTES_OBJECT_REF)];
Array.Copy(newStatesArray, 0, newArray, 0, newStateUpto);
newStatesArray = newArray;
}
newStatesArray[newStateUpto] = q;
q.number = newStateUpto;
newStateUpto++;
q.accept = accCount > 0;
newstate[p] = q;
}
else
{
Debug.Assert((accCount > 0) == q.accept, "accCount=" + accCount + " vs existing accept=" + q.accept + " states=" + statesSet);
}
r.AddTransition(new Transition(lastPoint, point - 1, q));
}
// process transitions that end on this point
// (closes an overlapping interval)
Transition[] transitions = points.points[i].ends.transitions;
int limit = points.points[i].ends.count;
for (int j = 0; j < limit; j++)
{
Transition t = transitions[j];
int num = t.to.number;
statesSet.Decr(num);
accCount -= t.to.accept ? 1 : 0;
}
points.points[i].ends.count = 0;
// process transitions that start on this point
// (opens a new interval)
transitions = points.points[i].starts.transitions;
limit = points.points[i].starts.count;
for (int j = 0; j < limit; j++)
{
Transition t = transitions[j];
int num = t.to.number;
statesSet.Incr(num);
accCount += t.to.accept ? 1 : 0;
}
lastPoint = point;
points.points[i].starts.count = 0;
}
points.Reset();
Debug.Assert(statesSet.upto == 0, "upto=" + statesSet.upto);
}
a.deterministic = true;
a.SetNumberedStates(newStatesArray, newStateUpto);
}
/// <summary>
/// Returns <c>true</c> if the given string is accepted by the automaton.
/// <para/>
/// Complexity: linear in the length of the string.
/// <para/>
/// <b>Note:</b> for full performance, use the <see cref="RunAutomaton"/> class.
/// </summary>
public static bool Run(Automaton a, string s)
{
if (a.IsSingleton)
{
return(s.Equals(a.singleton, StringComparison.Ordinal));
}
if (a.deterministic)
{
State p = a.initial;
int cp; // LUCENENET: Removed unnecessary assignment
for (int i = 0; i < s.Length; i += Character.CharCount(cp))
{
State q = p.Step(cp = Character.CodePointAt(s, i));
if (q is null)
{
return(false);
}
p = q;
}
return(p.accept);
}
else
{
State[] states = a.GetNumberedStates();
LinkedList <State> pp = new LinkedList <State>();
LinkedList <State> pp_other = new LinkedList <State>();
OpenBitSet bb = new OpenBitSet(states.Length);
OpenBitSet bb_other = new OpenBitSet(states.Length);
pp.AddLast(a.initial);
JCG.List <State> dest = new JCG.List <State>();
bool accept = a.initial.accept;
int c; // LUCENENET: Removed unnecessary assignment
for (int i = 0; i < s.Length; i += Character.CharCount(c))
{
c = Character.CodePointAt(s, i);
accept = false;
pp_other.Clear();
bb_other.Clear(0, bb_other.Length - 1);
foreach (State p in pp)
{
dest.Clear();
p.Step(c, dest);
foreach (State q in dest)
{
if (q.accept)
{
accept = true;
}
if (!bb_other.Get(q.number))
{
bb_other.Set(q.number);
pp_other.AddLast(q);
}
}
}
LinkedList <State> tp = pp;
pp = pp_other;
pp_other = tp;
OpenBitSet tb = bb;
bb = bb_other;
bb_other = tb;
}
return(accept);
}
}
protected internal override Automaton ConvertAutomaton(Automaton a)
{
if (unicodeAware)
{
Automaton utf8automaton = (new UTF32ToUTF8()).Convert(a);
BasicOperations.Determinize(utf8automaton);
return utf8automaton;
}
else
{
return a;
}
}
internal Automaton ToLevenshteinAutomata(Automaton automaton)
{
var @ref = SpecialOperations.GetFiniteStrings(automaton, -1);
Automaton[] subs = new Automaton[@ref.Count];
int upto = 0;
foreach (IntsRef path in @ref)
{
if (path.Length <= nonFuzzyPrefix || path.Length < minFuzzyLength)
{
subs[upto] = BasicAutomata.MakeString(path.Ints, path.Offset, path.Length);
upto++;
}
else
{
Automaton prefix = BasicAutomata.MakeString(path.Ints, path.Offset, nonFuzzyPrefix);
int[] ints = new int[path.Length - nonFuzzyPrefix];
Array.Copy(path.Ints, path.Offset + nonFuzzyPrefix, ints, 0, ints.Length);
// TODO: maybe add alphaMin to LevenshteinAutomata,
// and pass 1 instead of 0? We probably don't want
// to allow the trailing dedup bytes to be
// edited... but then 0 byte is "in general" allowed
// on input (but not in UTF8).
LevenshteinAutomata lev = new LevenshteinAutomata(ints, unicodeAware ? char.MAX_CODE_POINT : 255, transpositions);
Automaton levAutomaton = lev.ToAutomaton(maxEdits);
Automaton combined = BasicOperations.Concatenate(Arrays.AsList(prefix, levAutomaton));
combined.Deterministic = true; // its like the special case in concatenate itself, except we cloneExpanded already
subs[upto] = combined;
upto++;
}
}
if (subs.Length == 0)
{
// automaton is empty, there is no accepted paths through it
return BasicAutomata.MakeEmpty(); // matches nothing
}
else if (subs.Length == 1)
{
// no synonyms or anything: just a single path through the tokenstream
return subs[0];
}
else
{
// multiple paths: this is really scary! is it slow?
// maybe we should not do this and throw UOE?
Automaton a = BasicOperations.Union(Arrays.AsList(subs));
// TODO: we could call toLevenshteinAutomata() before det?
// this only happens if you have multiple paths anyway (e.g. synonyms)
BasicOperations.Determinize(a);
return a;
}
}
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();
}
private static void AssertAutomaton(Automaton automaton)
{
var cra = new CharacterRunAutomaton(automaton);
var bra = new ByteRunAutomaton(automaton);
var ras = new AutomatonTestUtil.RandomAcceptedStrings(automaton);
int num = AtLeast(1000);
for (int i = 0; i < num; i++)
{
string s;
if (Random().NextBoolean())
{
// likely not accepted
s = TestUtil.RandomUnicodeString(Random());
}
else
{
// will be accepted
int[] codepoints = ras.GetRandomAcceptedString(Random());
try
{
s = UnicodeUtil.NewString(codepoints, 0, codepoints.Length);
}
catch (Exception e)
{
Console.WriteLine(codepoints.Length + " codepoints:");
for (int j = 0; j < codepoints.Length; j++)
{
Console.WriteLine(" " + codepoints[j].ToString("x"));
}
throw e;
}
}
var bytes = s.GetBytes(Encoding.UTF8);
Assert.AreEqual(cra.Run(s), bra.Run(bytes, 0, bytes.Length));
}
}
public CompiledAutomaton(Automaton automaton)
: this(automaton, null, true)
{
}
/// <summary>
/// Simple, original brics implementation of Determinize()
/// Determinizes the given automaton using the given set of initial states.
/// </summary>
public static void DeterminizeSimple(Automaton a, ISet <State> initialset)
{
int[] points = a.GetStartPoints();
// subset construction
IDictionary <ISet <State>, ISet <State> > sets = new Dictionary <ISet <State>, ISet <State> >();
Queue <ISet <State> > worklist = new Queue <ISet <State> >();// LUCENENET specific - Queue is much more performant than LinkedList
IDictionary <ISet <State>, State> newstate = new Dictionary <ISet <State>, State>();
sets[initialset] = initialset;
worklist.Enqueue(initialset);
a.initial = new State();
newstate[initialset] = a.initial;
while (worklist.Count > 0)
{
ISet <State> s = worklist.Dequeue();
State r = newstate[s];
foreach (State q in s)
{
if (q.accept)
{
r.accept = true;
break;
}
}
for (int n = 0; n < points.Length; n++)
{
ISet <State> p = new JCG.HashSet <State>();
foreach (State q in s)
{
foreach (Transition t in q.GetTransitions())
{
if (t.min <= points[n] && points[n] <= t.max)
{
p.Add(t.to);
}
}
}
if (!sets.ContainsKey(p))
{
sets[p] = p;
worklist.Enqueue(p);
newstate[p] = new State();
}
State q_ = newstate[p];
int min = points[n];
int max;
if (n + 1 < points.Length)
{
max = points[n + 1] - 1;
}
else
{
max = Character.MaxCodePoint;
}
r.AddTransition(new Transition(min, max, q_));
}
}
a.deterministic = true;
a.ClearNumberedStates();
a.RemoveDeadTransitions();
}
public CharacterRunAutomaton(Automaton a)
: base(a, Character.MAX_CODE_POINT, false)
{
}
/// <summary>
/// Returns true if the language of this automaton is finite.
/// <p>
/// WARNING: this method is slow, it will blow up if the automaton is large.
/// this is only used to test the correctness of our faster implementation.
/// </summary>
public static bool IsFiniteSlow(Automaton a)
{
if (!String.IsNullOrEmpty(a.Singleton))
{
return true;
}
return IsFiniteSlow(a.InitialState, new HashSet<State>());
}
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;
}
/// <summary>
/// Checks that an automaton has no detached states that are unreachable
/// from the initial state.
/// </summary>
public static void AssertNoDetachedStates(Automaton a)
{
int numStates = a.NumberOfStates;
a.ClearNumberedStates(); // force recomputation of cached numbered states
Assert.True(numStates == a.NumberOfStates, "automaton has " + (numStates - a.NumberOfStates) + " detached states");
}
protected internal override IList<FSTUtil.Path<Pair<long?, BytesRef>>> GetFullPrefixPaths(IList<FSTUtil.Path<Pair<long?, BytesRef>>> prefixPaths, Automaton lookupAutomaton, FST<Pair<long?, BytesRef>> fst)
{
// TODO: right now there's no penalty for fuzzy/edits,
// ie a completion whose prefix matched exactly what the
// user typed gets no boost over completions that
// required an edit, which get no boost over completions
// requiring two edits. I suspect a multiplicative
// factor is appropriate (eg, say a fuzzy match must be at
// least 2X better weight than the non-fuzzy match to
// "compete") ... in which case I think the wFST needs
// to be log weights or something ...
Automaton levA = convertAutomaton(ToLevenshteinAutomata(lookupAutomaton));
/*
Writer w = new OutputStreamWriter(new FileOutputStream("out.dot"), StandardCharsets.UTF_8);
w.write(levA.toDot());
w.close();
System.out.println("Wrote LevA to out.dot");
*/
return FSTUtil.IntersectPrefixPaths(levA, fst);
}
// TODO: this currently requites a determinized machine,
// but it need not -- we can speed it up by walking the
// NFA instead. it'd still be fail fast.
public static BytesRef GetCommonPrefixBytesRef(Automaton a)
{
if (a.IsSingleton)
{
return new BytesRef(a.singleton);
}
BytesRef @ref = new BytesRef(10);
HashSet<State> visited = new HashSet<State>();
State s = a.Initial;
bool done;
do
{
done = true;
visited.Add(s);
if (!s.accept && s.NumTransitions() == 1)
{
var iter = s.Transitions.GetEnumerator();
iter.MoveNext();
Transition t = iter.Current;
if (t.Min_Renamed == t.Max_Renamed && !visited.Contains(t.To))
{
@ref.Grow([email protected]);
@ref.Bytes[@ref.Length - 1] = (byte)t.Min_Renamed;
s = t.To;
done = false;
}
}
} while (!done);
return @ref;
}
private static Automaton NaiveUnion(IList<BytesRef> strings)
{
Automaton[] eachIndividual = new Automaton[strings.Count];
int i = 0;
foreach (BytesRef bref in strings)
{
eachIndividual[i++] = BasicAutomata.MakeString(bref.Utf8ToString());
}
return BasicOperations.Union(eachIndividual);
}
// TODO: this is a dangerous method ... Automaton could be
// huge ... and it's better in general for caller to
// enumerate & process in a single walk:
/// <summary>
/// Returns the set of accepted strings, assuming that at most
/// <code>limit</code> strings are accepted. If more than <code>limit</code>
/// strings are accepted, the first limit strings found are returned. If <code>limit</code><0, then
/// the limit is infinite.
/// </summary>
public static ISet<IntsRef> GetFiniteStrings(Automaton a, int limit)
{
HashSet<IntsRef> strings = new HashSet<IntsRef>();
if (a.IsSingleton)
{
if (limit > 0)
{
strings.Add(Util.ToUTF32(a.Singleton, new IntsRef()));
}
}
else if (!GetFiniteStrings(a.Initial, new HashSet<State>(), strings, new IntsRef(), limit))
{
return strings;
}
return strings;
}
/// <summary>
/// Compute a DFA that accepts all strings within an edit distance of <paramref name="n"/>.
/// <para>
/// All automata have the following properties:
/// <list type="bullet">
/// <item><description>They are deterministic (DFA).</description></item>
/// <item><description>There are no transitions to dead states.</description></item>
/// <item><description>They are not minimal (some transitions could be combined).</description></item>
/// </list>
/// </para>
/// </summary>
public virtual Automaton ToAutomaton(int n)
{
if (n == 0)
{
return(BasicAutomata.MakeString(word, 0, word.Length));
}
if (n >= descriptions.Length)
{
return(null);
}
int range = 2 * n + 1;
ParametricDescription description = descriptions[n];
// the number of states is based on the length of the word and n
State[] states = new State[description.Count];
// create all states, and mark as accept states if appropriate
for (int i = 0; i < states.Length; i++)
{
states[i] = new State();
states[i].number = i;
states[i].Accept = description.IsAccept(i);
}
// create transitions from state to state
for (int k = 0; k < states.Length; k++)
{
int xpos = description.GetPosition(k);
if (xpos < 0)
{
continue;
}
int end = xpos + Math.Min(word.Length - xpos, range);
for (int x = 0; x < alphabet.Length; x++)
{
int ch = alphabet[x];
// get the characteristic vector at this position wrt ch
int cvec = GetVector(ch, xpos, end);
int dest = description.Transition(k, xpos, cvec);
if (dest >= 0)
{
states[k].AddTransition(new Transition(ch, states[dest]));
}
}
// add transitions for all other chars in unicode
// by definition, their characteristic vectors are always 0,
// because they do not exist in the input string.
int dest_ = description.Transition(k, xpos, 0); // by definition
if (dest_ >= 0)
{
for (int r = 0; r < numRanges; r++)
{
states[k].AddTransition(new Transition(rangeLower[r], rangeUpper[r], states[dest_]));
}
}
}
Automaton a = new Automaton(states[0]);
a.IsDeterministic = true;
// we create some useless unconnected states, and its a net-win overall to remove these,
// as well as to combine any adjacent transitions (it makes later algorithms more efficient).
// so, while we could set our numberedStates here, its actually best not to, and instead to
// force a traversal in reduce, pruning the unconnected states while we combine adjacent transitions.
//a.setNumberedStates(states);
a.Reduce();
// we need not trim transitions to dead states, as they are not created.
//a.restoreInvariant();
return(a);
}
/// <summary>
/// Returns true if the given string is accepted by the automaton.
/// <p>
/// Complexity: linear in the length of the string.
/// <p>
/// <b>Note:</b> for full performance, use the <seealso cref="RunAutomaton"/> class.
/// </summary>
public static bool Run(Automaton a, string s)
{
if (a.IsSingleton)
{
return(s.Equals(a.singleton));
}
if (a.deterministic)
{
State p = a.Initial;
for (int i = 0, cp = 0; i < s.Length; i += Character.CharCount(cp))
{
State q = p.Step(cp = Character.CodePointAt(s, i));
if (q == null)
{
return(false);
}
p = q;
}
return(p.accept);
}
else
{
State[] states = a.NumberedStates;
LinkedList <State> pp = new LinkedList <State>();
LinkedList <State> pp_other = new LinkedList <State>();
BitArray bb = new BitArray(states.Length);
BitArray bb_other = new BitArray(states.Length);
pp.AddLast(a.Initial);
List <State> dest = new List <State>();
bool accept = a.Initial.accept;
for (int i = 0, c = 0; i < s.Length; i += Character.CharCount(c))
{
c = Character.CodePointAt(s, i);
accept = false;
pp_other.Clear();
bb_other.SetAll(false);
foreach (State p in pp)
{
dest.Clear();
p.Step(c, dest);
foreach (State q in dest)
{
if (q.accept)
{
accept = true;
}
if (!bb_other.SafeGet(q.number))
{
bb_other.SafeSet(q.number, true);
pp_other.AddLast(q);
}
}
}
LinkedList <State> tp = pp;
pp = pp_other;
pp_other = tp;
BitArray tb = bb;
bb = bb_other;
bb_other = tb;
}
return(accept);
}
}
/// <summary>
/// See <seealso cref="BasicOperations#concatenate(Automaton, Automaton)"/>.
/// </summary>
public virtual Automaton Concatenate(Automaton a)
{
return(BasicOperations.Concatenate(this, a));
}
/// <summary>
/// Returns an automaton that accepts the intersection of the languages of the
/// given automata. Never modifies the input automata languages.
/// <para/>
/// Complexity: quadratic in number of states.
/// </summary>
public static Automaton Intersection(Automaton a1, Automaton a2)
{
if (a1.IsSingleton)
{
if (BasicOperations.Run(a2, a1.singleton))
{
return(a1.CloneIfRequired());
}
else
{
return(BasicAutomata.MakeEmpty());
}
}
if (a2.IsSingleton)
{
if (BasicOperations.Run(a1, a2.singleton))
{
return(a2.CloneIfRequired());
}
else
{
return(BasicAutomata.MakeEmpty());
}
}
if (a1 == a2)
{
return(a1.CloneIfRequired());
}
Transition[][] transitions1 = a1.GetSortedTransitions();
Transition[][] transitions2 = a2.GetSortedTransitions();
Automaton c = new Automaton();
Queue <StatePair> worklist = new Queue <StatePair>(); // LUCENENET specific - Queue is much more performant than LinkedList
Dictionary <StatePair, StatePair> newstates = new Dictionary <StatePair, StatePair>();
StatePair p = new StatePair(c.initial, a1.initial, a2.initial);
worklist.Enqueue(p);
newstates[p] = p;
while (worklist.Count > 0)
{
p = worklist.Dequeue();
p.s.accept = p.s1.accept && p.s2.accept;
Transition[] t1 = transitions1[p.s1.number];
Transition[] t2 = transitions2[p.s2.number];
for (int n1 = 0, b2 = 0; n1 < t1.Length; n1++)
{
while (b2 < t2.Length && t2[b2].max < t1[n1].min)
{
b2++;
}
for (int n2 = b2; n2 < t2.Length && t1[n1].max >= t2[n2].min; n2++)
{
if (t2[n2].max >= t1[n1].min)
{
StatePair q = new StatePair(t1[n1].to, t2[n2].to);
if (!newstates.TryGetValue(q, out StatePair r) || r is null)
{
q.s = new State();
worklist.Enqueue(q);
newstates[q] = q;
r = q;
}
int min = t1[n1].min > t2[n2].min ? t1[n1].min : t2[n2].min;
int max = t1[n1].max < t2[n2].max ? t1[n1].max : t2[n2].max;
p.s.AddTransition(new Transition(min, max, r.s));
}
}
}
}
c.deterministic = a1.deterministic && a2.deterministic;
c.RemoveDeadTransitions();
c.CheckMinimizeAlways();
return(c);
}
/// <summary>
/// See <seealso cref="BasicOperations#minus(Automaton, Automaton)"/>.
/// </summary>
public virtual Automaton Minus(Automaton a)
{
return(BasicOperations.Minus(this, a));
}
/// <summary>
/// Determinizes the given automaton.
/// <para/>
/// Worst case complexity: exponential in number of states.
/// </summary>
public static void Determinize(Automaton a)
{
if (a.IsDeterministic || a.IsSingleton)
{
return;
}
State[] allStates = a.GetNumberedStates();
// subset construction
bool initAccept = a.initial.accept;
int initNumber = a.initial.number;
a.initial = new State();
SortedInt32Set.FrozenInt32Set initialset = new SortedInt32Set.FrozenInt32Set(initNumber, a.initial);
Queue <SortedInt32Set.FrozenInt32Set> worklist = new Queue <SortedInt32Set.FrozenInt32Set>(); // LUCENENET specific - Queue is much more performant than LinkedList
IDictionary <SortedInt32Set.FrozenInt32Set, State> newstate = new Dictionary <SortedInt32Set.FrozenInt32Set, State>();
worklist.Enqueue(initialset);
a.initial.accept = initAccept;
newstate[initialset] = a.initial;
int newStateUpto = 0;
State[] newStatesArray = new State[5];
newStatesArray[newStateUpto] = a.initial;
a.initial.number = newStateUpto;
newStateUpto++;
// like Set<Integer,PointTransitions>
PointTransitionSet points = new PointTransitionSet();
// like SortedMap<Integer,Integer>
SortedInt32Set statesSet = new SortedInt32Set(5);
while (worklist.Count > 0)
{
SortedInt32Set.FrozenInt32Set s = worklist.Dequeue();
//worklist.Remove(s);
// Collate all outgoing transitions by min/1+max:
for (int i = 0; i < s.values.Length; i++)
{
State s0 = allStates[s.values[i]];
for (int j = 0; j < s0.numTransitions; j++)
{
points.Add(s0.TransitionsArray[j]);
}
}
if (points.count == 0)
{
// No outgoing transitions -- skip it
continue;
}
points.Sort();
int lastPoint = -1;
int accCount = 0;
State r = s.state;
for (int i = 0; i < points.count; i++)
{
int point = points.points[i].point;
if (statesSet.upto > 0)
{
if (Debugging.AssertsEnabled)
{
Debugging.Assert(lastPoint != -1);
}
statesSet.ComputeHash();
if (!newstate.TryGetValue(statesSet.ToFrozenInt32Set(), out State q) || q is null)
{
q = new State();
SortedInt32Set.FrozenInt32Set p = statesSet.Freeze(q);
worklist.Enqueue(p);
if (newStateUpto == newStatesArray.Length)
{
// LUCENENET: Resize rather than copy
Array.Resize(ref newStatesArray, ArrayUtil.Oversize(1 + newStateUpto, RamUsageEstimator.NUM_BYTES_OBJECT_REF));
}
newStatesArray[newStateUpto] = q;
q.number = newStateUpto;
newStateUpto++;
q.accept = accCount > 0;
newstate[p] = q;
}
else
{
if (Debugging.AssertsEnabled)
{
Debugging.Assert((accCount > 0) == q.accept, "accCount={0} vs existing accept={1} states={2}", accCount, q.accept, statesSet);
}
}
r.AddTransition(new Transition(lastPoint, point - 1, q));
}
// process transitions that end on this point
// (closes an overlapping interval)
Transition[] transitions = points.points[i].ends.transitions;
int limit = points.points[i].ends.count;
for (int j = 0; j < limit; j++)
{
Transition t = transitions[j];
int num = t.to.number;
statesSet.Decr(num);
accCount -= t.to.accept ? 1 : 0;
}
points.points[i].ends.count = 0;
// process transitions that start on this point
// (opens a new interval)
transitions = points.points[i].starts.transitions;
limit = points.points[i].starts.count;
for (int j = 0; j < limit; j++)
{
Transition t = transitions[j];
int num = t.to.number;
statesSet.Incr(num);
accCount += t.to.accept ? 1 : 0;
}
lastPoint = point;
points.points[i].starts.count = 0;
}
points.Reset();
if (Debugging.AssertsEnabled)
{
Debugging.Assert(statesSet.upto == 0, "upto={0}", statesSet.upto);
}
}
a.deterministic = true;
a.SetNumberedStates(newStatesArray, newStateUpto);
}
/// <summary>
/// See <seealso cref="BasicOperations#intersection(Automaton, Automaton)"/>.
/// </summary>
public virtual Automaton Intersection(Automaton a)
{
return(BasicOperations.Intersection(this, a));
}
/// <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());
}
}
JCG.HashSet <int> ids = new JCG.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);
}
}
/// <summary>
/// See <seealso cref="BasicOperations#subsetOf(Automaton, Automaton)"/>.
/// </summary>
public virtual bool SubsetOf(Automaton a)
{
return(BasicOperations.SubsetOf(this, a));
}
/// <summary>
/// Simple, original brics implementation of determinize()
/// Determinizes the given automaton using the given set of initial states.
/// </summary>
public static void DeterminizeSimple(Automaton a, ISet <State> initialset)
{
int[] points = a.StartPoints;
// subset construction
IDictionary <ISet <State>, ISet <State> > sets = new Dictionary <ISet <State>, ISet <State> >();
LinkedList <ISet <State> > worklist = new LinkedList <ISet <State> >();
IDictionary <ISet <State>, State> newstate = new Dictionary <ISet <State>, State>();
sets[initialset] = initialset;
worklist.AddLast(initialset);
a.Initial = new State();
newstate[initialset] = a.Initial;
while (worklist.Count > 0)
{
ISet <State> s = worklist.First.Value;
worklist.RemoveFirst();
State r = newstate[s];
foreach (State q in s)
{
if (q.Accept)
{
r.Accept = true;
break;
}
}
for (int n = 0; n < points.Length; n++)
{
ISet <State> p = new ValueHashSet <State>();
foreach (State q in s)
{
foreach (Transition t in q.Transitions)
{
if (t.Min <= points[n] && points[n] <= t.Max)
{
p.Add(t.To);
}
}
}
if (!sets.ContainsKey(p))
{
sets[p] = p;
worklist.AddLast(p);
newstate[p] = new State();
}
State q_ = newstate[p];
int min = points[n];
int max;
if (n + 1 < points.Length)
{
max = points[n + 1] - 1;
}
else
{
max = Character.MAX_CODE_POINT;
}
r.AddTransition(new Transition(min, max, q_));
}
}
a.Deterministic = true;
a.ClearNumberedStates();
a.RemoveDeadTransitions();
}
/// <summary>
/// See <seealso cref="BasicOperations#union(Automaton, Automaton)"/>.
/// </summary>
public virtual Automaton Union(Automaton a)
{
return(BasicOperations.Union(this, a));
}
/// <summary>
/// See <seealso cref="MinimizationOperations#minimize(Automaton)"/>. Returns the
/// automaton being given as argument.
/// </summary>
public static Automaton Minimize(Automaton a)
{
MinimizationOperations.Minimize(a);
return(a);
}
public CharacterRunAutomaton(Automaton a)
: base(a, Character.MaxCodePoint, false)
{
}
/// <summary>
/// below are original, unoptimized implementations of DFA operations for testing.
/// These are from brics automaton, full license (BSD) below:
/// </summary>
/*
* dk.brics.automaton
*
* Copyright (c) 2001-2009 Anders Moeller
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/// <summary>
/// Simple, original brics implementation of Brzozowski minimize()
/// </summary>
public static void MinimizeSimple(Automaton a)
{
if (!String.IsNullOrEmpty(a.Singleton))
{
return;
}
DeterminizeSimple(a, SpecialOperations.Reverse(a));
DeterminizeSimple(a, SpecialOperations.Reverse(a));
}
internal DumbRegexpQuery(Term term, RegExpSyntax flags)
: base(term.Field)
{
RegExp re = new RegExp(term.Text, flags);
automaton = re.ToAutomaton();
}
public RandomAcceptedStrings(Automaton a)
{
this.a = a;
if (!String.IsNullOrEmpty(a.Singleton))
{
LeadsToAccept = null;
return;
}
// must use IdentityHashmap because two Transitions w/
// different start nodes can be considered the same
LeadsToAccept = new IdentityHashMap<Transition, bool?>();
IDictionary<State, IList<ArrivingTransition>> allArriving = new Dictionary<State, IList<ArrivingTransition>>();
LinkedList<State> q = new LinkedList<State>();
HashSet<State> seen = new HashSet<State>();
// reverse map the transitions, so we can quickly look
// up all arriving transitions to a given state
foreach (State s in a.NumberedStates)
{
for (int i = 0; i < s.numTransitions; i++)
{
Transition t = s.TransitionsArray[i];
IList<ArrivingTransition> tl;
allArriving.TryGetValue(t.Dest, out tl);
if (tl == null)
{
tl = new List<ArrivingTransition>();
allArriving[t.Dest] = tl;
}
tl.Add(new ArrivingTransition(s, t));
}
if (s.Accept)
{
q.AddLast(s);
seen.Add(s);
}
}
// Breadth-first search, from accept states,
// backwards:
while (q.Count > 0)
{
State s = q.First.Value;
q.RemoveFirst();
IList<ArrivingTransition> arriving;
allArriving.TryGetValue(s, out arriving);
if (arriving != null)
{
foreach (ArrivingTransition at in arriving)
{
State from = at.From;
if (!seen.Contains(from))
{
q.AddLast(from);
seen.Add(from);
LeadsToAccept[at.t] = true;
}
}
}
}
}
/// <summary>
/// Minimizes the given automaton using Hopcroft's algorithm.
/// </summary>
public static void MinimizeHopcroft(Automaton a)
{
a.Determinize();
if (a.initial.numTransitions == 1)
{
Transition t = a.initial.TransitionsArray[0];
if (t.to == a.initial && t.min == Character.MinCodePoint && t.max == Character.MaxCodePoint)
{
return;
}
}
a.Totalize();
// initialize data structures
int[] sigma = a.GetStartPoints();
State[] states = a.GetNumberedStates();
int sigmaLen = sigma.Length, statesLen = states.Length;
List <State>[,] reverse = new List <State> [statesLen, sigmaLen];
ISet <State>[] partition = new JCG.HashSet <State> [statesLen];
List <State>[] splitblock = new List <State> [statesLen];
int[] block = new int[statesLen];
StateList[,] active = new StateList[statesLen, sigmaLen];
StateListNode[,] active2 = new StateListNode[statesLen, sigmaLen];
LinkedList <Int32Pair> pending = new LinkedList <Int32Pair>();
OpenBitSet pending2 = new OpenBitSet(sigmaLen * statesLen);
OpenBitSet split = new OpenBitSet(statesLen),
refine = new OpenBitSet(statesLen), refine2 = new OpenBitSet(statesLen);
for (int q = 0; q < statesLen; q++)
{
splitblock[q] = new List <State>();
partition[q] = new JCG.HashSet <State>();
for (int x = 0; x < sigmaLen; x++)
{
active[q, x] = new StateList();
}
}
// find initial partition and reverse edges
for (int q = 0; q < statesLen; q++)
{
State qq = states[q];
int j = qq.accept ? 0 : 1;
partition[j].Add(qq);
block[q] = j;
for (int x = 0; x < sigmaLen; x++)
{
//List<State>[] r = reverse[qq.Step(sigma[x]).number];
var r = qq.Step(sigma[x]).number;
if (reverse[r, x] == null)
{
reverse[r, x] = new List <State>();
}
reverse[r, x].Add(qq);
}
}
// initialize active sets
for (int j = 0; j <= 1; j++)
{
for (int x = 0; x < sigmaLen; x++)
{
foreach (State qq in partition[j])
{
if (reverse[qq.number, x] != null)
{
active2[qq.number, x] = active[j, x].Add(qq);
}
}
}
}
// initialize pending
for (int x = 0; x < sigmaLen; x++)
{
int j = (active[0, x].Count <= active[1, x].Count) ? 0 : 1;
pending.AddLast(new Int32Pair(j, x));
pending2.Set(x * statesLen + j);
}
// process pending until fixed point
int k = 2;
while (pending.Count > 0)
{
Int32Pair ip = pending.First.Value;
pending.Remove(ip);
int p = ip.N1;
int x = ip.N2;
pending2.Clear(x * statesLen + p);
// find states that need to be split off their blocks
for (StateListNode m = active[p, x].First; m != null; m = m.Next)
{
List <State> r = reverse[m.Q.number, x];
if (r != null)
{
foreach (State s in r)
{
int i = s.number;
if (!split.Get(i))
{
split.Set(i);
int j = block[i];
splitblock[j].Add(s);
if (!refine2.Get(j))
{
refine2.Set(j);
refine.Set(j);
}
}
}
}
}
// refine blocks
for (int j = refine.NextSetBit(0); j >= 0; j = refine.NextSetBit(j + 1))
{
List <State> sb = splitblock[j];
if (sb.Count < partition[j].Count)
{
ISet <State> b1 = partition[j];
ISet <State> b2 = partition[k];
foreach (State s in sb)
{
b1.Remove(s);
b2.Add(s);
block[s.number] = k;
for (int c = 0; c < sigmaLen; c++)
{
StateListNode sn = active2[s.number, c];
if (sn != null && sn.Sl == active[j, c])
{
sn.Remove();
active2[s.number, c] = active[k, c].Add(s);
}
}
}
// update pending
for (int c = 0; c < sigmaLen; c++)
{
int aj = active[j, c].Count, ak = active[k, c].Count, ofs = c * statesLen;
if (!pending2.Get(ofs + j) && 0 < aj && aj <= ak)
{
pending2.Set(ofs + j);
pending.AddLast(new Int32Pair(j, c));
}
else
{
pending2.Set(ofs + k);
pending.AddLast(new Int32Pair(k, c));
}
}
k++;
}
refine2.Clear(j);
foreach (State s in sb)
{
split.Clear(s.number);
}
sb.Clear();
}
refine.Clear(0, refine.Length - 1);
}
// make a new state for each equivalence class, set initial state
State[] newstates = new State[k];
for (int n = 0; n < newstates.Length; n++)
{
State s = new State();
newstates[n] = s;
foreach (State q in partition[n])
{
if (q == a.initial)
{
a.initial = s;
}
s.accept = q.accept;
s.number = q.number; // select representative
q.number = n;
}
}
// build transitions and set acceptance
for (int n = 0; n < newstates.Length; n++)
{
State s = newstates[n];
s.accept = states[s.number].accept;
foreach (Transition t in states[s.number].GetTransitions())
{
s.AddTransition(new Transition(t.min, t.max, newstates[t.to.number]));
}
}
a.ClearNumberedStates();
a.RemoveDeadTransitions();
}
/// <summary>
/// Simple, original brics implementation of determinize()
/// Determinizes the given automaton using the given set of initial states.
/// </summary>
public static void DeterminizeSimple(Automaton a, ISet<State> initialset)
{
int[] points = a.StartPoints;
// subset construction
IDictionary<ISet<State>, ISet<State>> sets = new Dictionary<ISet<State>, ISet<State>>();
LinkedList<ISet<State>> worklist = new LinkedList<ISet<State>>();
IDictionary<ISet<State>, State> newstate = new Dictionary<ISet<State>, State>();
sets[initialset] = initialset;
worklist.AddLast(initialset);
a.InitialState = new State();
newstate[initialset] = a.InitialState;
while (worklist.Count > 0)
{
ISet<State> s = worklist.First.Value;
worklist.RemoveFirst();
State r = newstate[s];
foreach (State q in s)
{
if (q.Accept)
{
r.Accept = true;
break;
}
}
for (int n = 0; n < points.Length; n++)
{
ISet<State> p = new HashSet<State>();
foreach (State q in s)
{
foreach (Transition t in q.Transitions)
{
if (t.Min <= points[n] && points[n] <= t.Max)
{
p.Add(t.Dest);
}
}
}
if (!sets.ContainsKey(p))
{
sets[p] = p;
worklist.AddLast(p);
newstate[p] = new State();
}
State q_ = newstate[p];
int min = points[n];
int max;
if (n + 1 < points.Length)
{
max = points[n + 1] - 1;
}
else
{
max = Character.MAX_CODE_POINT;
}
r.AddTransition(new Transition(min, max, q_));
}
}
a.Deterministic = true;
a.ClearNumberedStates();
a.RemoveDeadTransitions();
}
/// <summary>
/// Minimizes the given automaton using Hopcroft's algorithm.
/// </summary>
public static void MinimizeHopcroft(Automaton a)
{
a.Determinize();
if (a.Initial.numTransitions == 1)
{
Transition t = a.Initial.TransitionsArray[0];
if (t.To == a.Initial && t.Min_Renamed == Character.MIN_CODE_POINT && t.Max_Renamed == Character.MAX_CODE_POINT)
{
return;
}
}
a.Totalize();
// initialize data structures
int[] sigma = a.StartPoints;
State[] states = a.NumberedStates;
int sigmaLen = sigma.Length, statesLen = states.Length;
List<State>[,] reverse = new List<State>[statesLen, sigmaLen];
HashSet<State>[] partition = new HashSet<State>[statesLen];
List<State>[] splitblock = new List<State>[statesLen];
int[] block = new int[statesLen];
StateList[,] active = new StateList[statesLen, sigmaLen];
StateListNode[,] active2 = new StateListNode[statesLen, sigmaLen];
LinkedList<IntPair> pending = new LinkedList<IntPair>();
BitArray pending2 = new BitArray(sigmaLen * statesLen);
BitArray split = new BitArray(statesLen), refine = new BitArray(statesLen), refine2 = new BitArray(statesLen);
for (int q = 0; q < statesLen; q++)
{
splitblock[q] = new List<State>();
partition[q] = new HashSet<State>();
for (int x = 0; x < sigmaLen; x++)
{
active[q, x] = new StateList();
}
}
// find initial partition and reverse edges
for (int q = 0; q < statesLen; q++)
{
State qq = states[q];
int j = qq.accept ? 0 : 1;
partition[j].Add(qq);
block[q] = j;
for (int x = 0; x < sigmaLen; x++)
{
//List<State>[] r = reverse[qq.Step(sigma[x]).number];
var r = qq.Step(sigma[x]).number;
if (reverse[r, x] == null)
{
reverse[r, x] = new List<State>();
}
reverse[r, x].Add(qq);
}
}
// initialize active sets
for (int j = 0; j <= 1; j++)
{
for (int x = 0; x < sigmaLen; x++)
{
foreach (State qq in partition[j])
{
if (reverse[qq.number, x] != null)
{
active2[qq.number, x] = active[j, x].Add(qq);
}
}
}
}
// initialize pending
for (int x = 0; x < sigmaLen; x++)
{
int j = (active[0, x].Size <= active[1, x].Size) ? 0 : 1;
pending.AddLast(new IntPair(j, x));
pending2.Set(x * statesLen + j, true);
}
// process pending until fixed point
int k = 2;
while (pending.Count > 0)
{
IntPair ip = pending.First.Value;
pending.RemoveFirst();
int p = ip.N1;
int x = ip.N2;
pending2.Set(x * statesLen + p, false);
// find states that need to be split off their blocks
for (StateListNode m = active[p, x].First; m != null; m = m.Next)
{
List<State> r = reverse[m.q.number, x];
if (r != null)
{
foreach (State s in r)
{
int i = s.number;
if (!split.Get(i))
{
split.Set(i, true);
int j = block[i];
splitblock[j].Add(s);
if (!refine2.Get(j))
{
refine2.Set(j, true);
refine.Set(j, true);
}
}
}
}
}
// refine blocks
for (int j = Number.NextSetBit(refine, 0); j >= 0; j = Number.NextSetBit(refine, j + 1))
{
List<State> sb = splitblock[j];
if (sb.Count < partition[j].Count)
{
HashSet<State> b1 = partition[j];
HashSet<State> b2 = partition[k];
foreach (State s in sb)
{
b1.Remove(s);
b2.Add(s);
block[s.number] = k;
for (int c = 0; c < sigmaLen; c++)
{
StateListNode sn = active2[s.number, c];
if (sn != null && sn.Sl == active[j, c])
{
sn.Remove();
active2[s.number, c] = active[k, c].Add(s);
}
}
}
// update pending
for (int c = 0; c < sigmaLen; c++)
{
int aj = active[j, c].Size, ak = active[k, c].Size, ofs = c * statesLen;
if (!pending2.Get(ofs + j) && 0 < aj && aj <= ak)
{
pending2.Set(ofs + j, true);
pending.AddLast(new IntPair(j, c));
}
else
{
pending2.Set(ofs + k, true);
pending.AddLast(new IntPair(k, c));
}
}
k++;
}
refine2.Set(j, false);
foreach (State s in sb)
{
split.Set(s.number, false);
}
sb.Clear();
}
refine.SetAll(false);
}
// make a new state for each equivalence class, set initial state
State[] newstates = new State[k];
for (int n = 0; n < newstates.Length; n++)
{
State s = new State();
newstates[n] = s;
foreach (State q in partition[n])
{
if (q == a.Initial)
{
a.Initial = s;
}
s.accept = q.accept;
s.number = q.number; // select representative
q.number = n;
}
}
// build transitions and set acceptance
for (int n = 0; n < newstates.Length; n++)
{
State s = newstates[n];
s.accept = states[s.number].accept;
foreach (Transition t in states[s.number].Transitions)
{
s.AddTransition(new Transition(t.Min_Renamed, t.Max_Renamed, newstates[t.To.number]));
}
}
a.ClearNumberedStates();
a.RemoveDeadTransitions();
}
/// <summary>
/// Returns the longest string that is a prefix of all accepted strings and
/// visits each state at most once.
/// </summary>
/// <returns> common prefix </returns>
public static string GetCommonPrefix(Automaton a)
{
if (a.IsSingleton)
{
return a.singleton;
}
StringBuilder b = new StringBuilder();
HashSet<State> visited = new HashSet<State>();
State s = a.Initial;
bool done;
do
{
done = true;
visited.Add(s);
if (!s.accept && s.NumTransitions() == 1)
{
var iter = s.Transitions.GetEnumerator();
iter.MoveNext();
Transition t = iter.Current;
if (t.Min_Renamed == t.Max_Renamed && !visited.Contains(t.To))
{
//b.appendCodePoint(t.Min_Renamed);
b.Append(t.Min_Renamed);
s = t.To;
done = false;
}
}
} while (!done);
return b.ToString();
}
/// <summary>
/// Returns an automaton that accepts the intersection of the languages of the
/// given automata. Never modifies the input automata languages.
/// <p>
/// Complexity: quadratic in number of states.
/// </summary>
public static Automaton Intersection(Automaton a1, Automaton a2)
{
if (a1.IsSingleton)
{
if (BasicOperations.Run(a2, a1.singleton))
{
return(a1.CloneIfRequired());
}
else
{
return(BasicAutomata.MakeEmpty());
}
}
if (a2.IsSingleton)
{
if (BasicOperations.Run(a1, a2.singleton))
{
return(a2.CloneIfRequired());
}
else
{
return(BasicAutomata.MakeEmpty());
}
}
if (a1 == a2)
{
return(a1.CloneIfRequired());
}
Transition[][] transitions1 = a1.SortedTransitions;
Transition[][] transitions2 = a2.SortedTransitions;
Automaton c = new Automaton();
LinkedList <StatePair> worklist = new LinkedList <StatePair>();
Dictionary <StatePair, StatePair> newstates = new Dictionary <StatePair, StatePair>();
StatePair p = new StatePair(c.Initial, a1.Initial, a2.Initial);
worklist.AddLast(p);
newstates[p] = p;
while (worklist.Count > 0)
{
p = worklist.First.Value;
worklist.RemoveFirst();
p.s.accept = p.S1.accept && p.S2.accept;
Transition[] t1 = transitions1[p.S1.number];
Transition[] t2 = transitions2[p.S2.number];
for (int n1 = 0, b2 = 0; n1 < t1.Length; n1++)
{
while (b2 < t2.Length && t2[b2].Max_Renamed < t1[n1].Min_Renamed)
{
b2++;
}
for (int n2 = b2; n2 < t2.Length && t1[n1].Max_Renamed >= t2[n2].Min_Renamed; n2++)
{
if (t2[n2].Max_Renamed >= t1[n1].Min_Renamed)
{
StatePair q = new StatePair(t1[n1].To, t2[n2].To);
StatePair r;
newstates.TryGetValue(q, out r);
if (r == null)
{
q.s = new State();
worklist.AddLast(q);
newstates[q] = q;
r = q;
}
int min = t1[n1].Min_Renamed > t2[n2].Min_Renamed ? t1[n1].Min_Renamed : t2[n2].Min_Renamed;
int max = t1[n1].Max_Renamed < t2[n2].Max_Renamed ? t1[n1].Max_Renamed : t2[n2].Max_Renamed;
p.s.AddTransition(new Transition(min, max, r.s));
}
}
}
}
c.deterministic = a1.deterministic && a2.deterministic;
c.RemoveDeadTransitions();
c.CheckMinimizeAlways();
return(c);
}
/// <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();
}
private Automaton ToAutomaton(IDictionary <string, Automaton> automata, AutomatonProvider 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.Message, 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);
}
/// <summary>
/// Reverses the language of the given (non-singleton) automaton while returning
/// the set of new initial states.
/// </summary>
public static ISet<State> Reverse(Automaton a)
{
a.ExpandSingleton();
// reverse all edges
Dictionary<State, HashSet<Transition>> m = new Dictionary<State, HashSet<Transition>>();
State[] states = a.NumberedStates;
HashSet<State> accept = new HashSet<State>();
foreach (State s in states)
{
if (s.Accept)
{
accept.Add(s);
}
}
foreach (State r in states)
{
m[r] = new HashSet<Transition>();
r.accept = false;
}
foreach (State r in states)
{
foreach (Transition t in r.Transitions)
{
m[t.To].Add(new Transition(t.Min_Renamed, t.Max_Renamed, r));
}
}
foreach (State r in states)
{
HashSet<Transition> tr = m[r];
r.Transitions = tr.ToArray(/*new Transition[tr.Count]*/);
}
// make new initial+final states
a.Initial.accept = true;
a.Initial = new State();
foreach (State r in accept)
{
a.Initial.AddEpsilon(r); // ensures that all initial states are reachable
}
a.deterministic = false;
a.ClearNumberedStates();
return accept;
}
/// <summary>
/// Constructs a new <code>RunAutomaton</code> from a deterministic
/// <code>Automaton</code>.
/// </summary>
/// <param name="a"> an automaton </param>
/// <param name="maxInterval"></param>
/// <param name="tableize"></param>
protected RunAutomaton(Automaton a, int maxInterval, bool tableize)
{
this._maxInterval = maxInterval;
a.Determinize();
_points = a.StartPoints;
State[] states = a.NumberedStates;
Initial = a.Initial.Number;
_size = states.Length;
Accept = new bool[_size];
Transitions = new int[_size * _points.Length];
for (int n = 0; n < _size * _points.Length; n++)
{
Transitions[n] = -1;
}
foreach (State s in states)
{
int n = s.number;
Accept[n] = s.accept;
for (int c = 0; c < _points.Length; c++)
{
State q = s.Step(_points[c]);
if (q != null)
{
Transitions[n * _points.Length + c] = q.number;
}
}
}
/*
* Set alphabet table for optimal run performance.
*/
if (tableize)
{
_classmap = new int[maxInterval + 1];
int i = 0;
for (int j = 0; j <= maxInterval; j++)
{
if (i + 1 < _points.Length && j == _points[i + 1])
{
i++;
}
_classmap[j] = i;
}
}
else
{
_classmap = null;
}
}
/// <summary>
/// Compute a DFA that accepts all strings within an edit distance of <code>n</code>.
/// <p>
/// All automata have the following properties:
/// <ul>
/// <li>They are deterministic (DFA).
/// <li>There are no transitions to dead states.
/// <li>They are not minimal (some transitions could be combined).
/// </ul>
/// </p>
/// </summary>
public virtual Automaton ToAutomaton(int n)
{
if (n == 0)
{
return BasicAutomata.MakeString(Word, 0, Word.Length);
}
if (n >= Descriptions.Length)
{
return null;
}
int range = 2 * n + 1;
ParametricDescription description = Descriptions[n];
// the number of states is based on the length of the word and n
State[] states = new State[description.Size()];
// create all states, and mark as accept states if appropriate
for (int i = 0; i < states.Length; i++)
{
states[i] = new State();
states[i].number = i;
states[i].Accept = description.IsAccept(i);
}
// create transitions from state to state
for (int k = 0; k < states.Length; k++)
{
int xpos = description.GetPosition(k);
if (xpos < 0)
{
continue;
}
int end = xpos + Math.Min(Word.Length - xpos, range);
for (int x = 0; x < Alphabet.Length; x++)
{
int ch = Alphabet[x];
// get the characteristic vector at this position wrt ch
int cvec = GetVector(ch, xpos, end);
int dest = description.Transition(k, xpos, cvec);
if (dest >= 0)
{
states[k].AddTransition(new Transition(ch, states[dest]));
}
}
// add transitions for all other chars in unicode
// by definition, their characteristic vectors are always 0,
// because they do not exist in the input string.
int dest_ = description.Transition(k, xpos, 0); // by definition
if (dest_ >= 0)
{
for (int r = 0; r < NumRanges; r++)
{
states[k].AddTransition(new Transition(RangeLower[r], RangeUpper[r], states[dest_]));
}
}
}
Automaton a = new Automaton(states[0]);
a.Deterministic = true;
// we create some useless unconnected states, and its a net-win overall to remove these,
// as well as to combine any adjacent transitions (it makes later algorithms more efficient).
// so, while we could set our numberedStates here, its actually best not to, and instead to
// force a traversal in reduce, pruning the unconnected states while we combine adjacent transitions.
//a.setNumberedStates(states);
a.Reduce();
// we need not trim transitions to dead states, as they are not created.
//a.restoreInvariant();
return a;
}
/// <summary>
/// Returns true if the language of <paramref name="a1"/> is a subset of the language
/// of <paramref name="a2"/>. As a side-effect, <paramref name="a2"/> is determinized if
/// not already marked as deterministic.
/// <para/>
/// Complexity: quadratic in number of states.
/// </summary>
public static bool SubsetOf(Automaton a1, Automaton a2)
{
if (a1 == a2)
{
return(true);
}
if (a1.IsSingleton)
{
if (a2.IsSingleton)
{
return(a1.singleton.Equals(a2.singleton, StringComparison.Ordinal));
}
return(BasicOperations.Run(a2, a1.singleton));
}
a2.Determinize();
Transition[][] transitions1 = a1.GetSortedTransitions();
Transition[][] transitions2 = a2.GetSortedTransitions();
LinkedList <StatePair> worklist = new LinkedList <StatePair>();
HashSet <StatePair> visited = new HashSet <StatePair>();
StatePair p = new StatePair(a1.initial, a2.initial);
worklist.AddLast(p);
visited.Add(p);
while (worklist.Count > 0)
{
p = worklist.First.Value;
worklist.Remove(p);
if (p.S1.accept && !p.S2.accept)
{
return(false);
}
Transition[] t1 = transitions1[p.S1.number];
Transition[] t2 = transitions2[p.S2.number];
for (int n1 = 0, b2 = 0; n1 < t1.Length; n1++)
{
while (b2 < t2.Length && t2[b2].max < t1[n1].min)
{
b2++;
}
int min1 = t1[n1].min, max1 = t1[n1].max;
for (int n2 = b2; n2 < t2.Length && t1[n1].max >= t2[n2].min; n2++)
{
if (t2[n2].min > min1)
{
return(false);
}
if (t2[n2].max < Character.MAX_CODE_POINT)
{
min1 = t2[n2].max + 1;
}
else
{
min1 = Character.MAX_CODE_POINT;
max1 = Character.MIN_CODE_POINT;
}
StatePair q = new StatePair(t1[n1].to, t2[n2].to);
if (!visited.Contains(q))
{
worklist.AddLast(q);
visited.Add(q);
}
}
if (min1 <= max1)
{
return(false);
}
}
}
return(true);
}