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/*
 * Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
 * Use of this file is governed by the BSD 3-clause license that
 * can be found in the LICENSE.txt file in the project root.
 */

package com.hazelcast.org.antlr.v4.runtime.atn;

import com.hazelcast.org.antlr.v4.runtime.misc.IntervalSet;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import java.util.Locale;

/**
 * The following images show the relation of states and
 * {@link ATNState#transitions} for various grammar constructs.
 *
 * 
    * *
  • Solid edges marked with an ε indicate a required * {@link EpsilonTransition}.
  • * *
  • Dashed edges indicate locations where any transition derived from * {@link Transition} might appear.
  • * *
  • Dashed nodes are place holders for either a sequence of linked * {@link BasicState} states or the inclusion of a block representing a nested * construct in one of the forms below.
  • * *
  • Nodes showing multiple outgoing alternatives with a {@code ...} support * any number of alternatives (one or more). Nodes without the {@code ...} only * support the exact number of alternatives shown in the diagram.
  • * *
* *

Basic Blocks

* *

Rule

* * * *

Block of 1 or more alternatives

* * * *

Greedy Loops

* *

Greedy Closure: {@code (...)*}

* * * *

Greedy Positive Closure: {@code (...)+}

* * * *

Greedy Optional: {@code (...)?}

* * * *

Non-Greedy Loops

* *

Non-Greedy Closure: {@code (...)*?}

* * * *

Non-Greedy Positive Closure: {@code (...)+?}

* * * *

Non-Greedy Optional: {@code (...)??}

* * */ public abstract class ATNState { public static final int INITIAL_NUM_TRANSITIONS = 4; // constants for serialization public static final int INVALID_TYPE = 0; public static final int BASIC = 1; public static final int RULE_START = 2; public static final int BLOCK_START = 3; public static final int PLUS_BLOCK_START = 4; public static final int STAR_BLOCK_START = 5; public static final int TOKEN_START = 6; public static final int RULE_STOP = 7; public static final int BLOCK_END = 8; public static final int STAR_LOOP_BACK = 9; public static final int STAR_LOOP_ENTRY = 10; public static final int PLUS_LOOP_BACK = 11; public static final int LOOP_END = 12; public static final List serializationNames = Collections.unmodifiableList(Arrays.asList( "INVALID", "BASIC", "RULE_START", "BLOCK_START", "PLUS_BLOCK_START", "STAR_BLOCK_START", "TOKEN_START", "RULE_STOP", "BLOCK_END", "STAR_LOOP_BACK", "STAR_LOOP_ENTRY", "PLUS_LOOP_BACK", "LOOP_END" )); public static final int INVALID_STATE_NUMBER = -1; /** Which ATN are we in? */ public ATN atn = null; public int stateNumber = INVALID_STATE_NUMBER; public int ruleIndex; // at runtime, we don't have Rule objects public boolean epsilonOnlyTransitions = false; /** Track the transitions emanating from this ATN state. */ protected final List transitions = new ArrayList(INITIAL_NUM_TRANSITIONS); /** Used to cache lookahead during parsing, not used during construction */ public IntervalSet nextTokenWithinRule; @Override public int hashCode() { return stateNumber; } @Override public boolean equals(Object o) { // are these states same object? if ( o instanceof ATNState ) return stateNumber==((ATNState)o).stateNumber; return false; } public boolean isNonGreedyExitState() { return false; } @Override public String toString() { return String.valueOf(stateNumber); } public Transition[] getTransitions() { return transitions.toArray(new Transition[transitions.size()]); } public int getNumberOfTransitions() { return transitions.size(); } public void addTransition(Transition e) { addTransition(transitions.size(), e); } public void addTransition(int index, Transition e) { if (transitions.isEmpty()) { epsilonOnlyTransitions = e.isEpsilon(); } else if (epsilonOnlyTransitions != e.isEpsilon()) { System.err.format(Locale.getDefault(), "ATN state %d has both epsilon and non-epsilon transitions.\n", stateNumber); epsilonOnlyTransitions = false; } boolean alreadyPresent = false; for (Transition t : transitions) { if ( t.target.stateNumber == e.target.stateNumber ) { if ( t.label()!=null && e.label()!=null && t.label().equals(e.label()) ) { // System.err.println("Repeated transition upon "+e.label()+" from "+stateNumber+"->"+t.target.stateNumber); alreadyPresent = true; break; } else if ( t.isEpsilon() && e.isEpsilon() ) { // System.err.println("Repeated epsilon transition from "+stateNumber+"->"+t.target.stateNumber); alreadyPresent = true; break; } } } if ( !alreadyPresent ) { transitions.add(index, e); } } public Transition transition(int i) { return transitions.get(i); } public void setTransition(int i, Transition e) { transitions.set(i, e); } public Transition removeTransition(int index) { return transitions.remove(index); } public abstract int getStateType(); public final boolean onlyHasEpsilonTransitions() { return epsilonOnlyTransitions; } public void setRuleIndex(int ruleIndex) { this.ruleIndex = ruleIndex; } }




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