/*
* [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
* 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.antlr.v4.runtime.atn;
import 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.
*
* <ul>
*
* <li>Solid edges marked with an ε indicate a required
* {@link EpsilonTransition}.</li>
*
* <li>Dashed edges indicate locations where any transition derived from
* {@link Transition} might appear.</li>
*
* <li>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.</li>
*
* <li>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.</li>
*
* </ul>
*
* <h2>Basic Blocks</h2>
*
* <h3>Rule</h3>
*
* <embed src="images/Rule.svg" type="image/svg+xml"/>
*
* <h3>Block of 1 or more alternatives</h3>
*
* <embed src="images/Block.svg" type="image/svg+xml"/>
*
* <h2>Greedy Loops</h2>
*
* <h3>Greedy Closure: {@code (...)*}</h3>
*
* <embed src="images/ClosureGreedy.svg" type="image/svg+xml"/>
*
* <h3>Greedy Positive Closure: {@code (...)+}</h3>
*
* <embed src="images/PositiveClosureGreedy.svg" type="image/svg+xml"/>
*
* <h3>Greedy Optional: {@code (...)?}</h3>
*
* <embed src="images/OptionalGreedy.svg" type="image/svg+xml"/>
*
* <h2>Non-Greedy Loops</h2>
*
* <h3>Non-Greedy Closure: {@code (...)*?}</h3>
*
* <embed src="images/ClosureNonGreedy.svg" type="image/svg+xml"/>
*
* <h3>Non-Greedy Positive Closure: {@code (...)+?}</h3>
*
* <embed src="images/PositiveClosureNonGreedy.svg" type="image/svg+xml"/>
*
* <h3>Non-Greedy Optional: {@code (...)??}</h3>
*
* <embed src="images/OptionalNonGreedy.svg" type="image/svg+xml"/>
*/
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<String> 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<Transition> transitions =
new ArrayList<Transition>(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;
}
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; }
}