1 /* gnu/regexp/RETokenBackRef.java
2    Copyright (C) 2006 Free Software Foundation, Inc.
3 
4 This file is part of GNU Classpath.
5 
6 GNU Classpath is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2, or (at your option)
9 any later version.
10 
11 GNU Classpath is distributed in the hope that it will be useful, but
12 WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14 General Public License for more details.
15 
16 You should have received a copy of the GNU General Public License
17 along with GNU Classpath; see the file COPYING.  If not, write to the
18 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
19 02110-1301 USA.
20 
21 Linking this library statically or dynamically with other modules is
22 making a combined work based on this library.  Thus, the terms and
23 conditions of the GNU General Public License cover the whole
24 combination.
25 
26 As a special exception, the copyright holders of this library give you
27 permission to link this library with independent modules to produce an
28 executable, regardless of the license terms of these independent
29 modules, and to copy and distribute the resulting executable under
30 terms of your choice, provided that you also meet, for each linked
31 independent module, the terms and conditions of the license of that
32 module.  An independent module is a module which is not derived from
33 or based on this library.  If you modify this library, you may extend
34 this exception to your version of the library, but you are not
35 obligated to do so.  If you do not wish to do so, delete this
36 exception statement from your version. */
37 
38 
39 package gnu.java.util.regex;
40 
41 import gnu.java.lang.CPStringBuilder;
42 
43 final class RETokenBackRef extends REToken
44 {
45   private int num;
46   private boolean insens;
47 
RETokenBackRef(int subIndex, int num, boolean insens)48     RETokenBackRef (int subIndex, int num, boolean insens)
49   {
50     super (subIndex);
51     this.num = num;
52     this.insens = insens;
53   }
54 
55   // should implement getMinimumLength() -- any ideas?
56 
matchThis(CharIndexed input, REMatch mymatch)57   REMatch matchThis (CharIndexed input, REMatch mymatch)
58   {
59     if (num >= mymatch.start.length)
60       return null;
61     if (num >= mymatch.end.length)
62       return null;
63     int b, e;
64     b = mymatch.start[num];
65     e = mymatch.end[num];
66     if ((b == -1) || (e == -1))
67       return null;              // this shouldn't happen, but...
68     if (b < 0)
69       b += 1;
70     if (e < 0)
71       e += 1;
72     for (int i = b; i < e; i++)
73       {
74         char c1 = input.charAt (mymatch.index + i - b);
75         char c2 = input.charAt (i);
76         if (c1 != c2)
77           {
78             if (insens)
79               {
80                 if (c1 != toLowerCase (c2, unicodeAware) &&
81                     c1 != toUpperCase (c2, unicodeAware))
82                   {
83                     return null;
84                   }
85               }
86             else
87               {
88                 return null;
89               }
90           }
91       }
92     mymatch.index += e - b;
93     return mymatch;
94   }
95 
dump(CPStringBuilder os)96   void dump (CPStringBuilder os)
97   {
98     os.append ('\\').append (num);
99   }
100 }
101