001: /*
002: * $Id: CatNode.java,v 1.7 2003/11/07 20:16:24 dfs Exp $
003: *
004: * ====================================================================
005: * The Apache Software License, Version 1.1
006: *
007: * Copyright (c) 2000 The Apache Software Foundation. All rights
008: * reserved.
009: *
010: * Redistribution and use in source and binary forms, with or without
011: * modification, are permitted provided that the following conditions
012: * are met:
013: *
014: * 1. Redistributions of source code must retain the above copyright
015: * notice, this list of conditions and the following disclaimer.
016: *
017: * 2. Redistributions in binary form must reproduce the above copyright
018: * notice, this list of conditions and the following disclaimer in
019: * the documentation and/or other materials provided with the
020: * distribution.
021: *
022: * 3. The end-user documentation included with the redistribution,
023: * if any, must include the following acknowledgment:
024: * "This product includes software developed by the
025: * Apache Software Foundation (http://www.apache.org/)."
026: * Alternately, this acknowledgment may appear in the software itself,
027: * if and wherever such third-party acknowledgments normally appear.
028: *
029: * 4. The names "Apache" and "Apache Software Foundation", "Jakarta-Oro"
030: * must not be used to endorse or promote products derived from this
031: * software without prior written permission. For written
032: * permission, please contact apache@apache.org.
033: *
034: * 5. Products derived from this software may not be called "Apache"
035: * or "Jakarta-Oro", nor may "Apache" or "Jakarta-Oro" appear in their
036: * name, without prior written permission of the Apache Software Foundation.
037: *
038: * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
039: * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
040: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
041: * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
042: * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
043: * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
044: * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
045: * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
046: * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
047: * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
048: * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
049: * SUCH DAMAGE.
050: * ====================================================================
051: *
052: * This software consists of voluntary contributions made by many
053: * individuals on behalf of the Apache Software Foundation. For more
054: * information on the Apache Software Foundation, please see
055: * <http://www.apache.org/>.
056: */
057:
058: package org.apache.oro.text.awk;
059:
060: import java.util.*;
061:
062: /**
063: * @version @version@
064: * @since 1.0
065: */
066: final class CatNode extends SyntaxNode {
067: SyntaxNode _left, _right;
068:
069: boolean _nullable() {
070: return (_left._nullable() && _right._nullable());
071: }
072:
073: BitSet _firstPosition() {
074: if (_left._nullable()) {
075: BitSet ls, rs, bs;
076:
077: ls = _left._firstPosition();
078: rs = _right._firstPosition();
079: bs = new BitSet(Math.max(ls.size(), rs.size()));
080: bs.or(rs);
081: bs.or(ls);
082:
083: return bs;
084: }
085:
086: return _left._firstPosition();
087: }
088:
089: BitSet _lastPosition() {
090: if (_right._nullable()) {
091: BitSet ls, rs, bs;
092:
093: ls = _left._lastPosition();
094: rs = _right._lastPosition();
095: bs = new BitSet(Math.max(ls.size(), rs.size()));
096: bs.or(rs);
097: bs.or(ls);
098:
099: return bs;
100: }
101:
102: return _right._lastPosition();
103: }
104:
105: void _followPosition(BitSet[] follow, SyntaxNode[] nodes) {
106: int size;
107: BitSet leftLast, rightFirst;
108:
109: _left._followPosition(follow, nodes);
110: _right._followPosition(follow, nodes);
111:
112: leftLast = _left._lastPosition();
113: rightFirst = _right._firstPosition();
114:
115: size = leftLast.size();
116: while (0 < size--)
117: if (leftLast.get(size))
118: follow[size].or(rightFirst);
119: }
120:
121: SyntaxNode _clone(int pos[]) {
122: CatNode node;
123:
124: node = new CatNode();
125: node._left = _left._clone(pos);
126: node._right = _right._clone(pos);
127:
128: return node;
129: }
130: }
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