org.antlr.v4.runtime.atn.ATNSimulator Maven / Gradle / Ivy
/*
* [The "BSD license"]
* Copyright (c) 2012 Terence Parr
* Copyright (c) 2012 Sam Harwell
* 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
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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package org.antlr.v4.runtime.atn;
import org.antlr.v4.runtime.Token;
import org.antlr.v4.runtime.dfa.DFA;
import org.antlr.v4.runtime.dfa.DFAState;
import org.antlr.v4.runtime.misc.Interval;
import org.antlr.v4.runtime.misc.IntervalSet;
import org.antlr.v4.runtime.misc.NotNull;
import org.antlr.v4.runtime.misc.Tuple;
import org.antlr.v4.runtime.misc.Tuple2;
import java.io.InvalidClassException;
import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.BitSet;
import java.util.Deque;
import java.util.List;
public abstract class ATNSimulator {
public static final int SERIALIZED_VERSION;
static {
SERIALIZED_VERSION = 5;
}
public static final char RULE_VARIANT_DELIMITER = '$';
public static final String RULE_LF_VARIANT_MARKER = "$lf$";
public static final String RULE_NOLF_VARIANT_MARKER = "$nolf$";
/** Must distinguish between missing edge and edge we know leads nowhere */
@NotNull
public static final DFAState ERROR;
@NotNull
public final ATN atn;
static {
ERROR = new DFAState(new ATNConfigSet(), 0, 0);
ERROR.stateNumber = Integer.MAX_VALUE;
}
public ATNSimulator(@NotNull ATN atn) {
this.atn = atn;
}
public abstract void reset();
public static ATN deserialize(@NotNull char[] data) {
return deserialize(data, true);
}
public static ATN deserialize(@NotNull char[] data, boolean optimize) {
data = data.clone();
// don't adjust the first value since that's the version number
for (int i = 1; i < data.length; i++) {
data[i] = (char)(data[i] - 2);
}
ATN atn = new ATN();
List sets = new ArrayList();
int p = 0;
int version = toInt(data[p++]);
if (version != SERIALIZED_VERSION) {
String reason = String.format("Could not deserialize ATN with version %d (expected %d).", version, SERIALIZED_VERSION);
throw new UnsupportedOperationException(new InvalidClassException(ATN.class.getName(), reason));
}
atn.grammarType = toInt(data[p++]);
atn.maxTokenType = toInt(data[p++]);
//
// STATES
//
List> loopBackStateNumbers = new ArrayList>();
List> endStateNumbers = new ArrayList>();
int nstates = toInt(data[p++]);
for (int i=1; i<=nstates; i++) {
int stype = toInt(data[p++]);
// ignore bad type of states
if ( stype==ATNState.INVALID_TYPE ) {
atn.addState(null);
continue;
}
int ruleIndex = toInt(data[p++]);
ATNState s = stateFactory(stype, ruleIndex);
if ( stype == ATNState.LOOP_END ) { // special case
int loopBackStateNumber = toInt(data[p++]);
loopBackStateNumbers.add(Tuple.create((LoopEndState)s, loopBackStateNumber));
}
else if (s instanceof BlockStartState) {
int endStateNumber = toInt(data[p++]);
endStateNumbers.add(Tuple.create((BlockStartState)s, endStateNumber));
}
atn.addState(s);
}
// delay the assignment of loop back and end states until we know all the state instances have been initialized
for (Tuple2 pair : loopBackStateNumbers) {
pair.getItem1().loopBackState = atn.states.get(pair.getItem2());
}
for (Tuple2 pair : endStateNumbers) {
pair.getItem1().endState = (BlockEndState)atn.states.get(pair.getItem2());
}
int numNonGreedyStates = toInt(data[p++]);
for (int i = 0; i < numNonGreedyStates; i++) {
int stateNumber = toInt(data[p++]);
((DecisionState)atn.states.get(stateNumber)).nonGreedy = true;
}
int numSllDecisions = toInt(data[p++]);
for (int i = 0; i < numSllDecisions; i++) {
int stateNumber = toInt(data[p++]);
((DecisionState)atn.states.get(stateNumber)).sll = true;
}
int numPrecedenceStates = toInt(data[p++]);
for (int i = 0; i < numPrecedenceStates; i++) {
int stateNumber = toInt(data[p++]);
((RuleStartState)atn.states.get(stateNumber)).isPrecedenceRule = true;
}
//
// RULES
//
int nrules = toInt(data[p++]);
if ( atn.grammarType == ATN.LEXER ) {
atn.ruleToTokenType = new int[nrules];
atn.ruleToActionIndex = new int[nrules];
}
atn.ruleToStartState = new RuleStartState[nrules];
for (int i=0; i"+trg+
// " "+Transition.serializationNames[ttype]+
// " "+arg1+","+arg2+","+arg3);
ATNState srcState = atn.states.get(src);
srcState.addTransition(trans);
p += 6;
}
// edges for rule stop states can be derived, so they aren't serialized
for (ATNState state : atn.states) {
boolean returningToLeftFactored = state.ruleIndex >= 0 && atn.ruleToStartState[state.ruleIndex].leftFactored;
for (int i = 0; i < state.getNumberOfTransitions(); i++) {
Transition t = state.transition(i);
if (!(t instanceof RuleTransition)) {
continue;
}
RuleTransition ruleTransition = (RuleTransition)t;
boolean returningFromLeftFactored = atn.ruleToStartState[ruleTransition.target.ruleIndex].leftFactored;
if (!returningFromLeftFactored && returningToLeftFactored) {
continue;
}
atn.ruleToStopState[ruleTransition.target.ruleIndex].addTransition(new EpsilonTransition(ruleTransition.followState));
}
}
for (ATNState state : atn.states) {
if (state instanceof BlockStartState) {
// we need to know the end state to set its start state
if (((BlockStartState)state).endState == null) {
throw new IllegalStateException();
}
// block end states can only be associated to a single block start state
if (((BlockStartState)state).endState.startState != null) {
throw new IllegalStateException();
}
((BlockStartState)state).endState.startState = (BlockStartState)state;
}
if (state instanceof PlusLoopbackState) {
PlusLoopbackState loopbackState = (PlusLoopbackState)state;
for (int i = 0; i < loopbackState.getNumberOfTransitions(); i++) {
ATNState target = loopbackState.transition(i).target;
if (target instanceof PlusBlockStartState) {
((PlusBlockStartState)target).loopBackState = loopbackState;
}
}
}
else if (state instanceof StarLoopbackState) {
StarLoopbackState loopbackState = (StarLoopbackState)state;
for (int i = 0; i < loopbackState.getNumberOfTransitions(); i++) {
ATNState target = loopbackState.transition(i).target;
if (target instanceof StarLoopEntryState) {
((StarLoopEntryState)target).loopBackState = loopbackState;
}
}
}
}
//
// DECISIONS
//
int ndecisions = toInt(data[p++]);
for (int i=1; i<=ndecisions; i++) {
int s = toInt(data[p++]);
DecisionState decState = (DecisionState)atn.states.get(s);
atn.decisionToState.add(decState);
decState.decision = i-1;
}
atn.decisionToDFA = new DFA[ndecisions];
for (int i = 0; i < ndecisions; i++) {
atn.decisionToDFA[i] = new DFA(atn.decisionToState.get(i), i);
}
if (optimize) {
while (true) {
int optimizationCount = 0;
optimizationCount += inlineSetRules(atn);
optimizationCount += combineChainedEpsilons(atn);
boolean preserveOrder = atn.grammarType == ATN.LEXER;
optimizationCount += optimizeSets(atn, preserveOrder);
if (optimizationCount == 0) {
break;
}
}
}
identifyTailCalls(atn);
verifyATN(atn);
return atn;
}
private static void verifyATN(ATN atn) {
// verify assumptions
for (ATNState state : atn.states) {
if (state == null) {
continue;
}
checkCondition(state.onlyHasEpsilonTransitions() || state.getNumberOfTransitions() <= 1);
if (state instanceof PlusBlockStartState) {
checkCondition(((PlusBlockStartState)state).loopBackState != null);
}
if (state instanceof StarLoopEntryState) {
StarLoopEntryState starLoopEntryState = (StarLoopEntryState)state;
checkCondition(starLoopEntryState.loopBackState != null);
checkCondition(starLoopEntryState.getNumberOfTransitions() == 2);
if (starLoopEntryState.transition(0).target instanceof StarBlockStartState) {
checkCondition(starLoopEntryState.transition(1).target instanceof LoopEndState);
checkCondition(!starLoopEntryState.nonGreedy);
}
else if (starLoopEntryState.transition(0).target instanceof LoopEndState) {
checkCondition(starLoopEntryState.transition(1).target instanceof StarBlockStartState);
checkCondition(starLoopEntryState.nonGreedy);
}
else {
throw new IllegalStateException();
}
}
if (state instanceof StarLoopbackState) {
checkCondition(state.getNumberOfTransitions() == 1);
checkCondition(state.transition(0).target instanceof StarLoopEntryState);
}
if (state instanceof LoopEndState) {
checkCondition(((LoopEndState)state).loopBackState != null);
}
if (state instanceof RuleStartState) {
checkCondition(((RuleStartState)state).stopState != null);
}
if (state instanceof BlockStartState) {
checkCondition(((BlockStartState)state).endState != null);
}
if (state instanceof BlockEndState) {
checkCondition(((BlockEndState)state).startState != null);
}
if (state instanceof DecisionState) {
DecisionState decisionState = (DecisionState)state;
checkCondition(decisionState.getNumberOfTransitions() <= 1 || decisionState.decision >= 0);
}
else {
checkCondition(state.getNumberOfTransitions() <= 1 || state instanceof RuleStopState);
}
}
}
public static void checkCondition(boolean condition) {
checkCondition(condition, null);
}
public static void checkCondition(boolean condition, String message) {
if (!condition) {
throw new IllegalStateException(message);
}
}
private static int inlineSetRules(ATN atn) {
int inlinedCalls = 0;
Transition[] ruleToInlineTransition = new Transition[atn.ruleToStartState.length];
for (int i = 0; i < atn.ruleToStartState.length; i++) {
RuleStartState startState = atn.ruleToStartState[i];
ATNState middleState = startState;
while (middleState.onlyHasEpsilonTransitions()
&& middleState.getNumberOfOptimizedTransitions() == 1
&& middleState.getOptimizedTransition(0).getSerializationType() == Transition.EPSILON)
{
middleState = middleState.getOptimizedTransition(0).target;
}
if (middleState.getNumberOfOptimizedTransitions() != 1) {
continue;
}
Transition matchTransition = middleState.getOptimizedTransition(0);
ATNState matchTarget = matchTransition.target;
if (matchTransition.isEpsilon()
|| !matchTarget.onlyHasEpsilonTransitions()
|| matchTarget.getNumberOfOptimizedTransitions() != 1
|| !(matchTarget.getOptimizedTransition(0).target instanceof RuleStopState))
{
continue;
}
switch (matchTransition.getSerializationType()) {
case Transition.ATOM:
case Transition.RANGE:
case Transition.SET:
ruleToInlineTransition[i] = matchTransition;
break;
case Transition.NOT_SET:
case Transition.WILDCARD:
// not implemented yet
continue;
default:
continue;
}
}
for (int stateNumber = 0; stateNumber < atn.states.size(); stateNumber++) {
ATNState state = atn.states.get(stateNumber);
if (state.ruleIndex < 0) {
continue;
}
List optimizedTransitions = null;
for (int i = 0; i < state.getNumberOfOptimizedTransitions(); i++) {
Transition transition = state.getOptimizedTransition(i);
if (!(transition instanceof RuleTransition)) {
if (optimizedTransitions != null) {
optimizedTransitions.add(transition);
}
continue;
}
RuleTransition ruleTransition = (RuleTransition)transition;
Transition effective = ruleToInlineTransition[ruleTransition.target.ruleIndex];
if (effective == null) {
if (optimizedTransitions != null) {
optimizedTransitions.add(transition);
}
continue;
}
if (optimizedTransitions == null) {
optimizedTransitions = new ArrayList();
for (int j = 0; j < i; j++) {
optimizedTransitions.add(state.getOptimizedTransition(i));
}
}
inlinedCalls++;
ATNState target = ruleTransition.followState;
ATNState intermediateState = new BasicState();
intermediateState.setRuleIndex(target.ruleIndex);
atn.addState(intermediateState);
optimizedTransitions.add(new EpsilonTransition(intermediateState));
switch (effective.getSerializationType()) {
case Transition.ATOM:
intermediateState.addTransition(new AtomTransition(target, ((AtomTransition)effective).label));
break;
case Transition.RANGE:
intermediateState.addTransition(new RangeTransition(target, ((RangeTransition)effective).from, ((RangeTransition)effective).to));
break;
case Transition.SET:
intermediateState.addTransition(new SetTransition(target, effective.label()));
break;
default:
throw new UnsupportedOperationException();
}
}
if (optimizedTransitions != null) {
if (state.isOptimized()) {
while (state.getNumberOfOptimizedTransitions() > 0) {
state.removeOptimizedTransition(state.getNumberOfOptimizedTransitions() - 1);
}
}
for (Transition transition : optimizedTransitions) {
state.addOptimizedTransition(transition);
}
}
}
if (ParserATNSimulator.debug) {
System.out.println("ATN runtime optimizer removed " + inlinedCalls + " rule invocations by inlining sets.");
}
return inlinedCalls;
}
private static int combineChainedEpsilons(ATN atn) {
int removedEdges = 0;
nextState:
for (ATNState state : atn.states) {
if (!state.onlyHasEpsilonTransitions() || state instanceof RuleStopState) {
continue;
}
List optimizedTransitions = null;
nextTransition:
for (int i = 0; i < state.getNumberOfOptimizedTransitions(); i++) {
Transition transition = state.getOptimizedTransition(i);
ATNState intermediate = transition.target;
if (transition.getSerializationType() != Transition.EPSILON
|| intermediate.getStateType() != ATNState.BASIC
|| !intermediate.onlyHasEpsilonTransitions())
{
if (optimizedTransitions != null) {
optimizedTransitions.add(transition);
}
continue nextTransition;
}
for (int j = 0; j < intermediate.getNumberOfOptimizedTransitions(); j++) {
if (intermediate.getOptimizedTransition(j).getSerializationType() != Transition.EPSILON) {
if (optimizedTransitions != null) {
optimizedTransitions.add(transition);
}
continue nextTransition;
}
}
removedEdges++;
if (optimizedTransitions == null) {
optimizedTransitions = new ArrayList();
for (int j = 0; j < i; j++) {
optimizedTransitions.add(state.getOptimizedTransition(j));
}
}
for (int j = 0; j < intermediate.getNumberOfOptimizedTransitions(); j++) {
ATNState target = intermediate.getOptimizedTransition(j).target;
optimizedTransitions.add(new EpsilonTransition(target));
}
}
if (optimizedTransitions != null) {
if (state.isOptimized()) {
while (state.getNumberOfOptimizedTransitions() > 0) {
state.removeOptimizedTransition(state.getNumberOfOptimizedTransitions() - 1);
}
}
for (Transition transition : optimizedTransitions) {
state.addOptimizedTransition(transition);
}
}
}
if (ParserATNSimulator.debug) {
System.out.println("ATN runtime optimizer removed " + removedEdges + " transitions by combining chained epsilon transitions.");
}
return removedEdges;
}
private static int optimizeSets(ATN atn, boolean preserveOrder) {
if (preserveOrder) {
// this optimization currently doesn't preserve edge order.
return 0;
}
int removedPaths = 0;
List decisions = atn.decisionToState;
for (DecisionState decision : decisions) {
IntervalSet setTransitions = new IntervalSet();
for (int i = 0; i < decision.getNumberOfOptimizedTransitions(); i++) {
Transition epsTransition = decision.getOptimizedTransition(i);
if (!(epsTransition instanceof EpsilonTransition)) {
continue;
}
if (epsTransition.target.getNumberOfOptimizedTransitions() != 1) {
continue;
}
Transition transition = epsTransition.target.getOptimizedTransition(0);
if (!(transition.target instanceof BlockEndState)) {
continue;
}
if (transition instanceof NotSetTransition) {
// TODO: not yet implemented
continue;
}
if (transition instanceof AtomTransition
|| transition instanceof RangeTransition
|| transition instanceof SetTransition)
{
setTransitions.add(i);
}
}
if (setTransitions.size() <= 1) {
continue;
}
List optimizedTransitions = new ArrayList();
for (int i = 0; i < decision.getNumberOfOptimizedTransitions(); i++) {
if (!setTransitions.contains(i)) {
optimizedTransitions.add(decision.getOptimizedTransition(i));
}
}
ATNState blockEndState = decision.getOptimizedTransition(setTransitions.getMinElement()).target.getOptimizedTransition(0).target;
IntervalSet matchSet = new IntervalSet();
for (int i = 0; i < setTransitions.getIntervals().size(); i++) {
Interval interval = setTransitions.getIntervals().get(i);
for (int j = interval.a; j <= interval.b; j++) {
Transition matchTransition = decision.getOptimizedTransition(j).target.getOptimizedTransition(0);
if (matchTransition instanceof NotSetTransition) {
throw new UnsupportedOperationException("Not yet implemented.");
} else {
matchSet.addAll(matchTransition.label());
}
}
}
Transition newTransition;
if (matchSet.getIntervals().size() == 1) {
if (matchSet.size() == 1) {
newTransition = new AtomTransition(blockEndState, matchSet.getMinElement());
} else {
Interval matchInterval = matchSet.getIntervals().get(0);
newTransition = new RangeTransition(blockEndState, matchInterval.a, matchInterval.b);
}
} else {
newTransition = new SetTransition(blockEndState, matchSet);
}
ATNState setOptimizedState = new BasicState();
setOptimizedState.setRuleIndex(decision.ruleIndex);
atn.addState(setOptimizedState);
setOptimizedState.addTransition(newTransition);
optimizedTransitions.add(new EpsilonTransition(setOptimizedState));
removedPaths += decision.getNumberOfOptimizedTransitions() - optimizedTransitions.size();
if (decision.isOptimized()) {
while (decision.getNumberOfOptimizedTransitions() > 0) {
decision.removeOptimizedTransition(decision.getNumberOfOptimizedTransitions() - 1);
}
}
for (Transition transition : optimizedTransitions) {
decision.addOptimizedTransition(transition);
}
}
if (ParserATNSimulator.debug) {
System.out.println("ATN runtime optimizer removed " + removedPaths + " paths by collapsing sets.");
}
return removedPaths;
}
private static void identifyTailCalls(ATN atn) {
for (ATNState state : atn.states) {
for (Transition transition : state.transitions) {
if (!(transition instanceof RuleTransition)) {
continue;
}
RuleTransition ruleTransition = (RuleTransition)transition;
ruleTransition.tailCall = testTailCall(atn, ruleTransition, false);
ruleTransition.optimizedTailCall = testTailCall(atn, ruleTransition, true);
}
if (!state.isOptimized()) {
continue;
}
for (Transition transition : state.optimizedTransitions) {
if (!(transition instanceof RuleTransition)) {
continue;
}
RuleTransition ruleTransition = (RuleTransition)transition;
ruleTransition.tailCall = testTailCall(atn, ruleTransition, false);
ruleTransition.optimizedTailCall = testTailCall(atn, ruleTransition, true);
}
}
}
private static boolean testTailCall(ATN atn, RuleTransition transition, boolean optimizedPath) {
if (!optimizedPath && transition.tailCall) {
return true;
}
if (optimizedPath && transition.optimizedTailCall) {
return true;
}
BitSet reachable = new BitSet(atn.states.size());
Deque worklist = new ArrayDeque();
worklist.add(transition.followState);
while (!worklist.isEmpty()) {
ATNState state = worklist.pop();
if (reachable.get(state.stateNumber)) {
continue;
}
if (state instanceof RuleStopState) {
continue;
}
if (!state.onlyHasEpsilonTransitions()) {
return false;
}
List transitions = optimizedPath ? state.optimizedTransitions : state.transitions;
for (Transition t : transitions) {
if (t.getSerializationType() != Transition.EPSILON) {
return false;
}
worklist.add(t.target);
}
}
return true;
}
public static int toInt(char c) {
return c==65535 ? -1 : c;
}
@NotNull
public static Transition edgeFactory(@NotNull ATN atn,
int type, int src, int trg,
int arg1, int arg2, int arg3,
List sets)
{
ATNState target = atn.states.get(trg);
switch (type) {
case Transition.EPSILON : return new EpsilonTransition(target);
case Transition.RANGE : return new RangeTransition(target, arg1, arg2);
case Transition.RULE :
RuleTransition rt = new RuleTransition((RuleStartState)atn.states.get(arg1), arg2, arg3, target);
return rt;
case Transition.PREDICATE :
PredicateTransition pt = new PredicateTransition(target, arg1, arg2, arg3 != 0);
return pt;
case Transition.PRECEDENCE:
return new PrecedencePredicateTransition(target, arg1);
case Transition.ATOM : return new AtomTransition(target, arg1);
case Transition.ACTION :
ActionTransition a = new ActionTransition(target, arg1, arg2, arg3 != 0);
return a;
case Transition.SET : return new SetTransition(target, sets.get(arg1));
case Transition.NOT_SET : return new NotSetTransition(target, sets.get(arg1));
case Transition.WILDCARD : return new WildcardTransition(target);
}
throw new IllegalArgumentException("The specified transition type is not valid.");
}
public static ATNState stateFactory(int type, int ruleIndex) {
ATNState s;
switch (type) {
case ATNState.INVALID_TYPE: return null;
case ATNState.BASIC : s = new BasicState(); break;
case ATNState.RULE_START : s = new RuleStartState(); break;
case ATNState.BLOCK_START : s = new BasicBlockStartState(); break;
case ATNState.PLUS_BLOCK_START : s = new PlusBlockStartState(); break;
case ATNState.STAR_BLOCK_START : s = new StarBlockStartState(); break;
case ATNState.TOKEN_START : s = new TokensStartState(); break;
case ATNState.RULE_STOP : s = new RuleStopState(); break;
case ATNState.BLOCK_END : s = new BlockEndState(); break;
case ATNState.STAR_LOOP_BACK : s = new StarLoopbackState(); break;
case ATNState.STAR_LOOP_ENTRY : s = new StarLoopEntryState(); break;
case ATNState.PLUS_LOOP_BACK : s = new PlusLoopbackState(); break;
case ATNState.LOOP_END : s = new LoopEndState(); break;
default :
String message = String.format("The specified state type %d is not valid.", type);
throw new IllegalArgumentException(message);
}
s.ruleIndex = ruleIndex;
return s;
}
/*
public static void dump(DFA dfa, Grammar g) {
DOTGenerator dot = new DOTGenerator(g);
String output = dot.getDOT(dfa, false);
System.out.println(output);
}
public static void dump(DFA dfa) {
dump(dfa, null);
}
*/
}
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