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Java > Open Source Codes > gnu > regexp > RETokenStart


1 /*
2  * gnu/regexp/RETokenStart.java
3  * Copyright (C) 1998-2001 Wes Biggs
4  *
5  * This library is free software; you can redistribute it and/or modify
6  * it under the terms of the GNU Lesser General Public License as published
7  * by the Free Software Foundation; either version 2.1 of the License, or
8  * (at your option) any later version.
9  *
10  * This library is distributed in the hope that it will be useful,
11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13  * GNU Lesser General Public License for more details.
14  *
15  * You should have received a copy of the GNU Lesser General Public License
16  * along with this program; if not, write to the Free Software
17  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
18  */
19
20 package gnu.regexp;
21
22 class RETokenStart extends REToken {
23     private String JavaDoc newline; // matches after a newline
24
25     RETokenStart(int subIndex, String JavaDoc newline) {
26     super(subIndex);
27     this.newline = newline;
28     }
29     
30     boolean match(CharIndexed input, REMatch mymatch) {
31     // charAt(index-n) may be unknown on a Reader/InputStream. FIXME
32 // Match after a newline if in multiline mode
33
34     if (newline != null) {
35         int len = newline.length();
36         if (mymatch.offset >= len) {
37         boolean found = true;
38         char z;
39         int i = 0; // position in REToken.newline
40 char ch = input.charAt(mymatch.index - len);
41         do {
42             z = newline.charAt(i);
43             if (ch != z) {
44             found = false;
45             break;
46             }
47             ++i;
48             ch = input.charAt(mymatch.index - len + i);
49         } while (i < len);
50         
51         if (found) return next(input, mymatch);
52         }
53     }
54     
55     // Don't match at all if REG_NOTBOL is set.
56 if ((mymatch.eflags & RE.REG_NOTBOL) > 0) return false;
57     
58     if ((mymatch.eflags & RE.REG_ANCHORINDEX) > 0)
59         return (mymatch.anchor == mymatch.offset) ?
60         next(input, mymatch) : false;
61     else
62         return ((mymatch.index == 0) && (mymatch.offset == 0)) ?
63         next(input, mymatch) : false;
64     }
65     
66     void dump(StringBuffer JavaDoc os) {
67     os.append('^');
68     }
69 }
70
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