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Java > Open Source Codes > org > apache > oro > text > awk > CatNode


1 package org.apache.oro.text.awk;
2
3 /* ====================================================================
4  * The Apache Software License, Version 1.1
5  *
6  * Copyright (c) 2000 The Apache Software Foundation. All rights
7  * reserved.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  *
13  * 1. Redistributions of source code must retain the above copyright
14  * notice, this list of conditions and the following disclaimer.
15  *
16  * 2. Redistributions in binary form must reproduce the above copyright
17  * notice, this list of conditions and the following disclaimer in
18  * the documentation and/or other materials provided with the
19  * distribution.
20  *
21  * 3. The end-user documentation included with the redistribution,
22  * if any, must include the following acknowledgment:
23  * "This product includes software developed by the
24  * Apache Software Foundation (http://www.apache.org/)."
25  * Alternately, this acknowledgment may appear in the software itself,
26  * if and wherever such third-party acknowledgments normally appear.
27  *
28  * 4. The names "Apache" and "Apache Software Foundation", "Jakarta-Oro"
29  * must not be used to endorse or promote products derived from this
30  * software without prior written permission. For written
31  * permission, please contact apache@apache.org.
32  *
33  * 5. Products derived from this software may not be called "Apache"
34  * or "Jakarta-Oro", nor may "Apache" or "Jakarta-Oro" appear in their
35  * name, without prior written permission of the Apache Software Foundation.
36  *
37  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
38  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
39  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
40  * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
41  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
42  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
43  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
44  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
45  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
46  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
47  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
48  * SUCH DAMAGE.
49  * ====================================================================
50  *
51  * This software consists of voluntary contributions made by many
52  * individuals on behalf of the Apache Software Foundation. For more
53  * information on the Apache Software Foundation, please see
54  * <http://www.apache.org/>.
55  *
56  * Portions of this software are based upon software originally written
57  * by Daniel F. Savarese. We appreciate his contributions.
58  */
59
60 import java.util.*;
61
62 /**
63  @author <a HREF="dfs@savarese.org">Daniel F. Savarese</a>
64  @version $Id: CatNode.java,v 1.1.1.1 2000/07/23 23:08:50 jon Exp $
65  */
66 final class CatNode extends SyntaxNode {
67   SyntaxNode _left, _right;
68
69   boolean _nullable() {
70     return (_left._nullable() && _right._nullable());
71   }
72
73   BitSet _firstPosition() {
74     if(_left._nullable()){
75       BitSet ls, rs, bs;
76
77       ls = _left._firstPosition();
78       rs = _right._firstPosition();
79       bs = new BitSet(Math.max(ls.size(), rs.size()));
80       bs.or(rs);
81       bs.or(ls);
82
83       return bs;
84     }
85
86     return _left._firstPosition();
87   }
88
89   BitSet _lastPosition() {
90     if(_right._nullable()) {
91       BitSet ls, rs, bs;
92
93       ls = _left._lastPosition();
94       rs = _right._lastPosition();
95       bs = new BitSet(Math.max(ls.size(), rs.size()));
96       bs.or(rs);
97       bs.or(ls);
98
99       return bs;
100     }
101
102     return _right._lastPosition();
103   }
104
105
106   void _followPosition(BitSet[] follow, SyntaxNode[] nodes) {
107     int size;
108     BitSet leftLast, rightFirst;
109
110     _left._followPosition(follow, nodes);
111     _right._followPosition(follow, nodes);
112
113     leftLast = _left._lastPosition();
114     rightFirst = _right._firstPosition();
115
116     size = leftLast.size();
117     while(0 < size--)
118       if(leftLast.get(size))
119     follow[size].or(rightFirst);
120   }
121
122   SyntaxNode _clone(int pos[]) {
123     CatNode node;
124
125     node = new CatNode();
126     node._left = _left._clone(pos);
127     node._right = _right._clone(pos);
128
129     return node;
130   }
131 }
132
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