| /* |
| * [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); |
| } |
| } |