org.antlr.v4.runtime.atn.ATNConfig 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
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*
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* notice, this list of conditions and the following disclaimer in the
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* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
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package org.antlr.v4.runtime.atn;
import org.antlr.v4.runtime.Recognizer;
import org.antlr.v4.runtime.misc.NotNull;
import org.antlr.v4.runtime.misc.Nullable;
import java.util.ArrayDeque;
import java.util.Deque;
import java.util.IdentityHashMap;
import java.util.Map;
/** A tuple: (ATN state, predicted alt, syntactic, semantic context).
* The syntactic context is a graph-structured stack node whose
* path(s) to the root is the rule invocation(s)
* chain used to arrive at the state. The semantic context is
* the tree of semantic predicates encountered before reaching
* an ATN state.
*/
public class ATNConfig {
/** The ATN state associated with this configuration */
@NotNull
private final ATNState state;
private int altAndOuterContextDepth;
/** The stack of invoking states leading to the rule/states associated
* with this config. We track only those contexts pushed during
* execution of the ATN simulator.
*/
@NotNull
private PredictionContext context;
protected ATNConfig(@NotNull ATNState state,
int alt,
@NotNull PredictionContext context)
{
assert (alt & 0xFFFFFF) == alt;
this.state = state;
this.altAndOuterContextDepth = alt & 0x7FFFFFFF;
this.context = context;
}
protected ATNConfig(@NotNull ATNConfig c, @NotNull ATNState state, @NotNull PredictionContext context)
{
this.state = state;
this.altAndOuterContextDepth = c.altAndOuterContextDepth & 0x7FFFFFFF;
this.context = context;
}
public static ATNConfig create(@NotNull ATNState state, int alt, @Nullable PredictionContext context) {
return create(state, alt, context, SemanticContext.NONE, -1);
}
public static ATNConfig create(@NotNull ATNState state, int alt, @Nullable PredictionContext context, @NotNull SemanticContext semanticContext) {
return create(state, alt, context, semanticContext, -1);
}
public static ATNConfig create(@NotNull ATNState state, int alt, @Nullable PredictionContext context, @NotNull SemanticContext semanticContext, int actionIndex) {
if (semanticContext != SemanticContext.NONE) {
if (actionIndex != -1) {
return new ActionSemanticContextATNConfig(actionIndex, semanticContext, state, alt, context);
}
else {
return new SemanticContextATNConfig(semanticContext, state, alt, context);
}
}
else if (actionIndex != -1) {
return new ActionATNConfig(actionIndex, state, alt, context);
}
else {
return new ATNConfig(state, alt, context);
}
}
/** Gets the ATN state associated with this configuration */
@NotNull
public final ATNState getState() {
return state;
}
/** What alt (or lexer rule) is predicted by this configuration */
public final int getAlt() {
return altAndOuterContextDepth & 0x00FFFFFF;
}
public final boolean isHidden() {
return altAndOuterContextDepth < 0;
}
public void setHidden(boolean value) {
if (value) {
altAndOuterContextDepth |= 0x80000000;
} else {
altAndOuterContextDepth &= ~0x80000000;
}
}
@NotNull
public final PredictionContext getContext() {
return context;
}
public void setContext(@NotNull PredictionContext context) {
this.context = context;
}
public final boolean getReachesIntoOuterContext() {
return getOuterContextDepth() != 0;
}
/**
* We cannot execute predicates dependent upon local context unless
* we know for sure we are in the correct context. Because there is
* no way to do this efficiently, we simply cannot evaluate
* dependent predicates unless we are in the rule that initially
* invokes the ATN simulator.
*
* closure() tracks the depth of how far we dip into the
* outer context: depth > 0. Note that it may not be totally
* accurate depth since I don't ever decrement. TODO: make it a boolean then
*/
public final int getOuterContextDepth() {
return (altAndOuterContextDepth >>> 24) & 0x7F;
}
public void setOuterContextDepth(int outerContextDepth) {
assert outerContextDepth >= 0;
// saturate at 0x7F - everything but zero/positive is only used for debug information anyway
outerContextDepth = Math.min(outerContextDepth, 0x7F);
this.altAndOuterContextDepth = (outerContextDepth << 24) | (altAndOuterContextDepth & ~0x7F000000);
}
public int getActionIndex() {
return -1;
}
@NotNull
public SemanticContext getSemanticContext() {
return SemanticContext.NONE;
}
@Override
public final ATNConfig clone() {
return transform(this.getState());
}
public final ATNConfig transform(@NotNull ATNState state) {
return transform(state, this.context, this.getSemanticContext(), this.getActionIndex());
}
public final ATNConfig transform(@NotNull ATNState state, @NotNull SemanticContext semanticContext) {
return transform(state, this.context, semanticContext, this.getActionIndex());
}
public final ATNConfig transform(@NotNull ATNState state, @Nullable PredictionContext context) {
return transform(state, context, this.getSemanticContext(), this.getActionIndex());
}
public final ATNConfig transform(@NotNull ATNState state, int actionIndex) {
return transform(state, context, this.getSemanticContext(), actionIndex);
}
private ATNConfig transform(@NotNull ATNState state, @Nullable PredictionContext context, @NotNull SemanticContext semanticContext, int actionIndex) {
if (semanticContext != SemanticContext.NONE) {
if (actionIndex != -1) {
return new ActionSemanticContextATNConfig(actionIndex, semanticContext, this, state, context);
}
else {
return new SemanticContextATNConfig(semanticContext, this, state, context);
}
}
else if (actionIndex != -1) {
return new ActionATNConfig(actionIndex, this, state, context);
}
else {
return new ATNConfig(this, state, context);
}
}
public ATNConfig appendContext(int context, PredictionContextCache contextCache) {
PredictionContext appendedContext = getContext().appendContext(context, contextCache);
ATNConfig result = transform(getState(), appendedContext);
return result;
}
public ATNConfig appendContext(PredictionContext context, PredictionContextCache contextCache) {
PredictionContext appendedContext = getContext().appendContext(context, contextCache);
ATNConfig result = transform(getState(), appendedContext);
return result;
}
public boolean contains(ATNConfig subconfig) {
if (this.getState().stateNumber != subconfig.getState().stateNumber
|| this.getAlt() != subconfig.getAlt()
|| !this.getSemanticContext().equals(subconfig.getSemanticContext())) {
return false;
}
Deque leftWorkList = new ArrayDeque();
Deque rightWorkList = new ArrayDeque();
leftWorkList.add(getContext());
rightWorkList.add(subconfig.getContext());
while (!leftWorkList.isEmpty()) {
PredictionContext left = leftWorkList.pop();
PredictionContext right = rightWorkList.pop();
if (left == right) {
return true;
}
if (left.size() < right.size()) {
return false;
}
if (right.isEmpty()) {
return left.hasEmpty();
} else {
for (int i = 0; i < right.size(); i++) {
int index = left.findReturnState(right.getReturnState(i));
if (index < 0) {
// assumes invokingStates has no duplicate entries
return false;
}
leftWorkList.push(left.getParent(index));
rightWorkList.push(right.getParent(i));
}
}
}
return false;
}
/** An ATN configuration is equal to another if both have
* the same state, they predict the same alternative, and
* syntactic/semantic contexts are the same.
*/
@Override
public boolean equals(Object o) {
if (!(o instanceof ATNConfig)) {
return false;
}
return this.equals((ATNConfig)o);
}
public boolean equals(ATNConfig other) {
if (this == other) {
return true;
} else if (other == null) {
return false;
}
return this.getState().stateNumber==other.getState().stateNumber
&& this.getAlt()==other.getAlt()
&& this.getReachesIntoOuterContext() == other.getReachesIntoOuterContext()
&& this.getContext().equals(other.getContext())
&& this.getSemanticContext().equals(other.getSemanticContext())
&& this.getActionIndex() == other.getActionIndex();
}
@Override
public int hashCode() {
int hashCode = 7;
hashCode = 5 * hashCode + getState().stateNumber;
hashCode = 5 * hashCode + getAlt();
hashCode = 5 * hashCode + (getReachesIntoOuterContext() ? 1 : 0);
hashCode = 5 * hashCode + (getContext() != null ? getContext().hashCode() : 0);
hashCode = 5 * hashCode + getSemanticContext().hashCode();
return hashCode;
}
public String toDotString() {
StringBuilder builder = new StringBuilder();
builder.append("digraph G {\n");
builder.append("rankdir=LR;\n");
Map visited = new IdentityHashMap();
Deque workList = new ArrayDeque();
workList.add(getContext());
visited.put(getContext(), getContext());
while (!workList.isEmpty()) {
PredictionContext current = workList.pop();
for (int i = 0; i < current.size(); i++) {
builder.append(" s").append(System.identityHashCode(current));
builder.append("->");
builder.append("s").append(System.identityHashCode(current.getParent(i)));
builder.append("[label=\"").append(current.getReturnState(i)).append("\"];\n");
if (visited.put(current.getParent(i), current.getParent(i)) == null) {
workList.push(current.getParent(i));
}
}
}
builder.append("}\n");
return builder.toString();
}
@Override
public String toString() {
return toString(null, true, false);
}
public String toString(@Nullable Recognizer recog, boolean showAlt) {
return toString(recog, showAlt, true);
}
public String toString(@Nullable Recognizer recog, boolean showAlt, boolean showContext) {
StringBuilder buf = new StringBuilder();
// if ( state.ruleIndex>=0 ) {
// if ( recog!=null ) buf.append(recog.getRuleNames()[state.ruleIndex]+":");
// else buf.append(state.ruleIndex+":");
// }
String[] contexts;
if (showContext) {
contexts = getContext().toStrings(recog, this.getState().stateNumber);
}
else {
contexts = new String[] { "?" };
}
boolean first = true;
for (String contextDesc : contexts) {
if ( first ) {
first = false;
}
else {
buf.append(", ");
}
buf.append('(');
buf.append(getState());
if ( showAlt ) {
buf.append(",");
buf.append(getAlt());
}
if ( getContext()!=null ) {
buf.append(",");
buf.append(contextDesc);
}
if ( getSemanticContext()!=null && getSemanticContext() != SemanticContext.NONE ) {
buf.append(",");
buf.append(getSemanticContext());
}
if ( getReachesIntoOuterContext() ) {
buf.append(",up=").append(getOuterContextDepth());
}
buf.append(')');
}
return buf.toString();
}
private static class SemanticContextATNConfig extends ATNConfig {
@NotNull
private final SemanticContext semanticContext;
public SemanticContextATNConfig(SemanticContext semanticContext, @NotNull ATNState state, int alt, @Nullable PredictionContext context) {
super(state, alt, context);
this.semanticContext = semanticContext;
}
public SemanticContextATNConfig(SemanticContext semanticContext, @NotNull ATNConfig c, @NotNull ATNState state, @Nullable PredictionContext context) {
super(c, state, context);
this.semanticContext = semanticContext;
}
@Override
public SemanticContext getSemanticContext() {
return semanticContext;
}
}
private static class ActionATNConfig extends ATNConfig {
private final int actionIndex;
public ActionATNConfig(int actionIndex, @NotNull ATNState state, int alt, @Nullable PredictionContext context) {
super(state, alt, context);
this.actionIndex = actionIndex;
}
protected ActionATNConfig(int actionIndex, @NotNull ATNConfig c, @NotNull ATNState state, @Nullable PredictionContext context) {
super(c, state, context);
if (c.getSemanticContext() != SemanticContext.NONE) {
throw new UnsupportedOperationException();
}
this.actionIndex = actionIndex;
}
@Override
public int getActionIndex() {
return actionIndex;
}
}
private static class ActionSemanticContextATNConfig extends SemanticContextATNConfig {
private final int actionIndex;
public ActionSemanticContextATNConfig(int actionIndex, @NotNull SemanticContext semanticContext, @NotNull ATNState state, int alt, @Nullable PredictionContext context) {
super(semanticContext, state, alt, context);
this.actionIndex = actionIndex;
}
public ActionSemanticContextATNConfig(int actionIndex, @NotNull SemanticContext semanticContext, @NotNull ATNConfig c, @NotNull ATNState state, @Nullable PredictionContext context) {
super(semanticContext, c, state, context);
this.actionIndex = actionIndex;
}
@Override
public int getActionIndex() {
return actionIndex;
}
}
}
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