/*
* 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.
*/
package org.apache.lucene.util.automaton;
import org.apache.lucene.util.ArrayUtil;
import org.apache.lucene.util.RamUsageEstimator;
import java.util.ArrayList;
import java.util.BitSet;
import java.util.Arrays;
import java.util.Collection;
import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.Set;
/**
* Basic automata operations.
*
* @lucene.experimental
*/
final public class BasicOperations {
private BasicOperations() {}
/**
* Returns an automaton that accepts the concatenation of the languages of the
* given automata.
* <p>
* Complexity: linear in number of states.
*/
static public Automaton concatenate(Automaton a1, Automaton a2) {
if (a1.isSingleton() && a2.isSingleton()) return BasicAutomata
.makeString(a1.singleton + a2.singleton);
// 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.
boolean deterministic = a1.isSingleton() && a2.isDeterministic();
if (a1 == a2) {
a1 = a1.cloneExpanded();
a2 = a2.cloneExpanded();
} else {
a1 = a1.cloneExpandedIfRequired();
a2 = a2.cloneExpandedIfRequired();
}
for (State s : a1.getAcceptStates()) {
s.accept = false;
s.addEpsilon(a2.initial);
}
a1.deterministic = deterministic;
//a1.clearHashCode();
a1.clearNumberedStates();
a1.checkMinimizeAlways();
return a1;
}
/**
* Returns an automaton that accepts the concatenation of the languages of the
* given automata.
* <p>
* Complexity: linear in total number of states.
*/
static public Automaton concatenate(List<Automaton> l) {
if (l.isEmpty()) return BasicAutomata.makeEmptyString();
boolean all_singleton = true;
for (Automaton a : l)
if (!a.isSingleton()) {
all_singleton = false;
break;
}
if (all_singleton) {
StringBuilder b = new StringBuilder();
for (Automaton a : l)
b.append(a.singleton);
return BasicAutomata.makeString(b.toString());
} else {
for (Automaton a : l)
if (BasicOperations.isEmpty(a)) return BasicAutomata.makeEmpty();
Set<Integer> ids = new HashSet<Integer>();
for (Automaton a : l)
ids.add(System.identityHashCode(a));
boolean has_aliases = ids.size() != l.size();
Automaton b = l.get(0);
if (has_aliases) b = b.cloneExpanded();
else b = b.cloneExpandedIfRequired();
Set<State> ac = b.getAcceptStates();
boolean first = true;
for (Automaton a : l)
if (first) first = false;
else {
if (a.isEmptyString()) continue;
Automaton aa = a;
if (has_aliases) aa = aa.cloneExpanded();
else aa = aa.cloneExpandedIfRequired();
Set<State> ns = aa.getAcceptStates();
for (State s : 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;
}
}
/**
* Returns an automaton that accepts the union of the empty string and the
* language of the given automaton.
* <p>
* Complexity: linear in number of states.
*/
static public 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;
}
/**
* Returns an automaton that accepts the Kleene star (zero or more
* concatenated repetitions) of the language of the given automaton. Never
* modifies the input automaton language.
* <p>
* Complexity: linear in number of states.
*/
static public Automaton repeat(Automaton a) {
a = a.cloneExpanded();
State s = new State();
s.accept = true;
s.addEpsilon(a.initial);
for (State p : a.getAcceptStates())
p.addEpsilon(s);
a.initial = s;
a.deterministic = false;
//a.clearHashCode();
a.clearNumberedStates();
a.checkMinimizeAlways();
return a;
}
/**
* Returns an automaton that accepts <code>min</code> or more concatenated
* repetitions of the language of the given automaton.
* <p>
* Complexity: linear in number of states and in <code>min</code>.
*/
static public Automaton repeat(Automaton a, int min) {
if (min == 0) return repeat(a);
List<Automaton> as = new ArrayList<Automaton>();
while (min-- > 0)
as.add(a);
as.add(repeat(a));
return concatenate(as);
}
/**
* Returns an automaton that accepts between <code>min</code> and
* <code>max</code> (including both) concatenated repetitions of the language
* of the given automaton.
* <p>
* Complexity: linear in number of states and in <code>min</code> and
* <code>max</code>.
*/
static public 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 = a.clone();
else {
List<Automaton> as = new ArrayList<Automaton>();
while (min-- > 0)
as.add(a);
b = concatenate(as);
}
if (max > 0) {
Automaton d = a.clone();
while (--max > 0) {
Automaton c = a.clone();
for (State p : c.getAcceptStates())
p.addEpsilon(d.initial);
d = c;
}
for (State p : b.getAcceptStates())
p.addEpsilon(d.initial);
b.deterministic = false;
//b.clearHashCode();
b.clearNumberedStates();
b.checkMinimizeAlways();
}
return b;
}
/**
* Returns a (deterministic) automaton that accepts the complement of the
* language of the given automaton.
* <p>
* Complexity: linear in number of states (if already deterministic).
*/
static public Automaton complement(Automaton a) {
a = a.cloneExpandedIfRequired();
a.determinize();
a.totalize();
for (State p : a.getNumberedStates())
p.accept = !p.accept;
a.removeDeadTransitions();
return a;
}
/**
* Returns a (deterministic) automaton that accepts the intersection of the
* language of <code>a1</code> and the complement of the language of
* <code>a2</code>. As a side-effect, the automata may be determinized, if not
* already deterministic.
* <p>
* Complexity: quadratic in number of states (if already deterministic).
*/
static public Automaton minus(Automaton a1, Automaton a2) {
if (BasicOperations.isEmpty(a1) || a1 == a2) return BasicAutomata
.makeEmpty();
if (BasicOperations.isEmpty(a2)) return a1.cloneIfRequired();
if (a1.isSingleton()) {
if (BasicOperations.run(a2, a1.singleton)) return BasicAutomata.makeEmpty();
else return a1.cloneIfRequired();
}
return intersection(a1, a2.complement());
}
/**
* 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.
*/
static public 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();
LinkedList<StatePair> worklist = new LinkedList<StatePair>();
HashMap<StatePair,StatePair> newstates = new HashMap<StatePair,StatePair>();
StatePair p = new StatePair(c.initial, a1.initial, a2.initial);
worklist.add(p);
newstates.put(p, p);
while (worklist.size() > 0) {
p = 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 < 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);
StatePair r = newstates.get(q);
if (r == null) {
q.s = new State();
worklist.add(q);
newstates.put(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;
}
/** Returns true if these two auotomata accept exactly the
* same language. This is a costly computation! Note
* also that a1 and a2 will be determinized as a side
* effect. */
public static boolean sameLanguage(Automaton a1, Automaton a2) {
if (a1 == a2) {
return true;
}
if (a1.isSingleton() && a2.isSingleton()) {
return a1.singleton.equals(a2.singleton);
} else if (a1.isSingleton()) {
// subsetOf is faster if the first automaton is a singleton
return subsetOf(a1, a2) && subsetOf(a2, a1);
} else {
return subsetOf(a2, a1) && subsetOf(a1, a2);
}
}
/**
* Returns true if the language of <code>a1</code> is a subset of the language
* of <code>a2</code>. As a side-effect, <code>a2</code> is determinized if
* not already marked as deterministic.
* <p>
* Complexity: quadratic in number of states.
*/
public static boolean subsetOf(Automaton a1, Automaton a2) {
if (a1 == a2) return true;
if (a1.isSingleton()) {
if (a2.isSingleton()) return a1.singleton.equals(a2.singleton);
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.add(p);
visited.add(p);
while (worklist.size() > 0) {
p = worklist.removeFirst();
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.add(q);
visited.add(q);
}
}
if (min1 <= max1) {
return false;
}
}
}
return true;
}
/**
* Returns an automaton that accepts the union of the languages of the given
* automata.
* <p>
* Complexity: linear in number of states.
*/
public static Automaton union(Automaton a1, Automaton a2) {
if ((a1.isSingleton() && a2.isSingleton() && a1.singleton
.equals(a2.singleton))
|| 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;
}
/**
* Returns an automaton that accepts the union of the languages of the given
* automata.
* <p>
* Complexity: linear in number of states.
*/
public static Automaton union(Collection<Automaton> l) {
Set<Integer> ids = new HashSet<Integer>();
for (Automaton a : l)
ids.add(System.identityHashCode(a));
boolean has_aliases = ids.size() != l.size();
State s = new State();
for (Automaton b : 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();
a.initial = s;
a.deterministic = false;
//a.clearHashCode();
a.clearNumberedStates();
a.checkMinimizeAlways();
return a;
}
// Simple custom ArrayList<Transition>
private final static class TransitionList {
Transition[] transitions = new Transition[2];
int count;
public void add(Transition t) {
if (transitions.length == count) {
Transition[] newArray = new Transition[ArrayUtil.oversize(1+count, RamUsageEstimator.NUM_BYTES_OBJ_REF)];
System.arraycopy(transitions, 0, newArray, 0, count);
transitions = newArray;
}
transitions[count++] = t;
}
}
// Holds all transitions that start on this int point, or
// end at this point-1
private final static class PointTransitions implements Comparable<PointTransitions> {
int point;
final TransitionList ends = new TransitionList();
final TransitionList starts = new TransitionList();
public int compareTo(PointTransitions other) {
return point - other.point;
}
public void reset(int point) {
this.point = point;
ends.count = 0;
starts.count = 0;
}
public boolean equals(Object other) {
return ((PointTransitions) other).point == point;
}
public int hashCode() {
return point;
}
}
private final static class PointTransitionSet {
int count;
PointTransitions[] points = new PointTransitions[5];
private final static int HASHMAP_CUTOVER = 30;
private final HashMap<Integer,PointTransitions> map = new HashMap<Integer,PointTransitions>();
private boolean useHash = false;
private PointTransitions next(int point) {
// 1st time we are seeing this point
if (count == points.length) {
final PointTransitions[] newArray = new PointTransitions[ArrayUtil.oversize(1+count, RamUsageEstimator.NUM_BYTES_OBJ_REF)];
System.arraycopy(points, 0, newArray, 0, count);
points = newArray;
}
PointTransitions points0 = points[count];
if (points0 == null) {
points0 = points[count] = new PointTransitions();
}
points0.reset(point);
count++;
return points0;
}
private PointTransitions find(int point) {
if (useHash) {
final Integer pi = point;
PointTransitions p = map.get(pi);
if (p == null) {
p = next(point);
map.put(pi, p);
}
return p;
} else {
for(int i=0;i<count;i++) {
if (points[i].point == point) {
return points[i];
}
}
final PointTransitions p = next(point);
if (count == HASHMAP_CUTOVER) {
// switch to HashMap on the fly
assert map.size() == 0;
for(int i=0;i<count;i++) {
map.put(points[i].point, points[i]);
}
useHash = true;
}
return p;
}
}
public void reset() {
if (useHash) {
map.clear();
useHash = false;
}
count = 0;
}
public void sort() {
if (count > 1) {
Arrays.sort(points, 0, count);
}
}
public void add(Transition t) {
find(t.min).starts.add(t);
find(1+t.max).ends.add(t);
}
public String toString() {
StringBuilder s = new StringBuilder();
for(int i=0;i<count;i++) {
if (i > 0) {
s.append(' ');
}
s.append(points[i].point).append(':').append(points[i].starts.count).append(',').append(points[i].ends.count);
}
return s.toString();
}
}
/**
* Determinizes the given automaton.
* <p>
* Worst case complexity: exponential in number of states.
*/
static void determinize(Automaton a) {
if (a.deterministic || a.isSingleton()) {
return;
}
final State[] allStates = a.getNumberedStates();
// subset construction
final boolean initAccept = a.initial.accept;
final int initNumber = a.initial.number;
a.initial = new State();
SortedIntSet.FrozenIntSet initialset = new SortedIntSet.FrozenIntSet(initNumber, a.initial);
LinkedList<SortedIntSet.FrozenIntSet> worklist = new LinkedList<SortedIntSet.FrozenIntSet>();
Map<SortedIntSet.FrozenIntSet,State> newstate = new HashMap<SortedIntSet.FrozenIntSet,State>();
worklist.add(initialset);
a.initial.accept = initAccept;
newstate.put(initialset, a.initial);
int newStateUpto = 0;
State[] newStatesArray = new State[5];
newStatesArray[newStateUpto] = a.initial;
a.initial.number = newStateUpto;
newStateUpto++;
// like Set<Integer,PointTransitions>
final PointTransitionSet points = new PointTransitionSet();
// like SortedMap<Integer,Integer>
final SortedIntSet statesSet = new SortedIntSet(5);
while (worklist.size() > 0) {
SortedIntSet.FrozenIntSet s = worklist.removeFirst();
// Collate all outgoing transitions by min/1+max:
for(int i=0;i<s.values.length;i++) {
final 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;
final State r = s.state;
for(int i=0;i<points.count;i++) {
final int point = points.points[i].point;
if (statesSet.upto > 0) {
assert lastPoint != -1;
statesSet.computeHash();
State q = newstate.get(statesSet);
if (q == null) {
q = new State();
final SortedIntSet.FrozenIntSet p = statesSet.freeze(q);
worklist.add(p);
if (newStateUpto == newStatesArray.length) {
final State[] newArray = new State[ArrayUtil.oversize(1+newStateUpto, RamUsageEstimator.NUM_BYTES_OBJ_REF)];
System.arraycopy(newStatesArray, 0, newArray, 0, newStateUpto);
newStatesArray = newArray;
}
newStatesArray[newStateUpto] = q;
q.number = newStateUpto;
newStateUpto++;
q.accept = accCount > 0;
newstate.put(p, q);
} else {
assert (accCount > 0 ? true:false) == 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++) {
final Transition t = transitions[j];
final Integer 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++) {
final Transition t = transitions[j];
final Integer num = t.to.number;
statesSet.incr(num);
accCount += t.to.accept ? 1:0;
}
lastPoint = point;
points.points[i].starts.count = 0;
}
points.reset();
assert statesSet.upto == 0: "upto=" + statesSet.upto;
}
a.deterministic = true;
a.setNumberedStates(newStatesArray, newStateUpto);
}
/**
* Adds epsilon transitions to the given automaton. This method adds extra
* character interval transitions that are equivalent to the given set of
* epsilon transitions.
*
* @param pairs collection of {@link StatePair} objects representing pairs of
* source/destination states where epsilon transitions should be
* added
*/
public static void addEpsilons(Automaton a, Collection<StatePair> pairs) {
a.expandSingleton();
HashMap<State,HashSet<State>> forward = new HashMap<State,HashSet<State>>();
HashMap<State,HashSet<State>> back = new HashMap<State,HashSet<State>>();
for (StatePair p : pairs) {
HashSet<State> to = forward.get(p.s1);
if (to == null) {
to = new HashSet<State>();
forward.put(p.s1, to);
}
to.add(p.s2);
HashSet<State> from = back.get(p.s2);
if (from == null) {
from = new HashSet<State>();
back.put(p.s2, from);
}
from.add(p.s1);
}
// calculate epsilon closure
LinkedList<StatePair> worklist = new LinkedList<StatePair>(pairs);
HashSet<StatePair> workset = new HashSet<StatePair>(pairs);
while (!worklist.isEmpty()) {
StatePair p = worklist.removeFirst();
workset.remove(p);
HashSet<State> to = forward.get(p.s2);
HashSet<State> from = back.get(p.s1);
if (to != null) {
for (State s : to) {
StatePair pp = new StatePair(p.s1, s);
if (!pairs.contains(pp)) {
pairs.add(pp);
forward.get(p.s1).add(s);
back.get(s).add(p.s1);
worklist.add(pp);
workset.add(pp);
if (from != null) {
for (State q : from) {
StatePair qq = new StatePair(q, p.s1);
if (!workset.contains(qq)) {
worklist.add(qq);
workset.add(qq);
}
}
}
}
}
}
}
// add transitions
for (StatePair p : pairs)
p.s1.addEpsilon(p.s2);
a.deterministic = false;
//a.clearHashCode();
a.clearNumberedStates();
a.checkMinimizeAlways();
}
/**
* Returns true if the given automaton accepts the empty string and nothing
* else.
*/
public static boolean isEmptyString(Automaton a) {
if (a.isSingleton()) return a.singleton.length() == 0;
else return a.initial.accept && a.initial.numTransitions() == 0;
}
/**
* Returns true if the given automaton accepts no strings.
*/
public static boolean isEmpty(Automaton a) {
if (a.isSingleton()) return false;
return !a.initial.accept && a.initial.numTransitions() == 0;
}
/**
* Returns true if the given automaton accepts all strings.
*/
public static boolean isTotal(Automaton a) {
if (a.isSingleton()) return false;
if (a.initial.accept && a.initial.numTransitions() == 1) {
Transition t = a.initial.getTransitions().iterator().next();
return t.to == a.initial && t.min == Character.MIN_CODE_POINT
&& t.max == Character.MAX_CODE_POINT;
}
return false;
}
/**
* 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 {@link RunAutomaton} class.
*/
public static boolean 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 = s.codePointAt(i));
if (q == 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>();
BitSet bb = new BitSet(states.length);
BitSet bb_other = new BitSet(states.length);
pp.add(a.initial);
ArrayList<State> dest = new ArrayList<State>();
boolean accept = a.initial.accept;
for (int i = 0, c = 0; i < s.length(); i += Character.charCount(c)) {
c = s.codePointAt(i);
accept = false;
pp_other.clear();
bb_other.clear();
for (State p : pp) {
dest.clear();
p.step(c, dest);
for (State q : dest) {
if (q.accept) accept = true;
if (!bb_other.get(q.number)) {
bb_other.set(q.number);
pp_other.add(q);
}
}
}
LinkedList<State> tp = pp;
pp = pp_other;
pp_other = tp;
BitSet tb = bb;
bb = bb_other;
bb_other = tb;
}
return accept;
}
}
}