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/*
* [The "BSD license"]
* Copyright (c) 2010 Terence Parr
* 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.analysis;
import org.antlr.misc.IntSet;
import org.antlr.misc.IntervalSet;
import org.antlr.tool.Grammar;
/** An LL(1) lookahead set; contains a set of token types and a "hasEOF"
* condition when the set contains EOF. Since EOF is -1 everywhere and -1
* cannot be stored in my BitSet, I set a condition here. There may be other
* reasons in the future to abstract a LookaheadSet over a raw BitSet.
*/
public class LookaheadSet {
public IntervalSet tokenTypeSet;
public LookaheadSet() {
tokenTypeSet = new IntervalSet();
}
public LookaheadSet(IntSet s) {
this();
tokenTypeSet.addAll(s);
}
public LookaheadSet(int atom) {
tokenTypeSet = IntervalSet.of(atom);
}
public LookaheadSet(LookaheadSet other) {
this();
this.tokenTypeSet.addAll(other.tokenTypeSet);
}
public void orInPlace(LookaheadSet other) {
this.tokenTypeSet.addAll(other.tokenTypeSet);
}
public LookaheadSet or(LookaheadSet other) {
return new LookaheadSet(tokenTypeSet.or(other.tokenTypeSet));
}
public LookaheadSet subtract(LookaheadSet other) {
return new LookaheadSet(this.tokenTypeSet.subtract(other.tokenTypeSet));
}
public boolean member(int a) {
return tokenTypeSet.member(a);
}
public LookaheadSet intersection(LookaheadSet s) {
IntSet i = this.tokenTypeSet.and(s.tokenTypeSet);
LookaheadSet intersection = new LookaheadSet(i);
return intersection;
}
public boolean isNil() {
return tokenTypeSet.isNil();
}
public void remove(int a) {
tokenTypeSet = (IntervalSet)tokenTypeSet.subtract(IntervalSet.of(a));
}
public int hashCode() {
return tokenTypeSet.hashCode();
}
public boolean equals(Object other) {
return tokenTypeSet.equals(((LookaheadSet)other).tokenTypeSet);
}
public String toString(Grammar g) {
if ( tokenTypeSet==null ) {
return "";
}
String r = tokenTypeSet.toString(g);
return r;
}
public String toString() {
return toString(null);
}
}
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