/interpreter/tags/at2dist130208/src/edu/vub/util/regexp/RETokenStart.java

 1/*  gnu/regexp/RETokenStart.java
 2    Copyright (C) 1998-2001, 2004 Free Software Foundation, Inc.
 3
 4This file is part of GNU Classpath.
 5
 6GNU Classpath is free software; you can redistribute it and/or modify
 7it under the terms of the GNU General Public License as published by
 8the Free Software Foundation; either version 2, or (at your option)
 9any later version.
10
11GNU Classpath is distributed in the hope that it will be useful, but
12WITHOUT ANY WARRANTY; without even the implied warranty of
13MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14General Public License for more details.
15
16You should have received a copy of the GNU General Public License
17along with GNU Classpath; see the file COPYING.  If not, write to the
18Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
1902110-1301 USA.
20
21Linking this library statically or dynamically with other modules is
22making a combined work based on this library.  Thus, the terms and
23conditions of the GNU General Public License cover the whole
24combination.
25
26As a special exception, the copyright holders of this library give you
27permission to link this library with independent modules to produce an
28executable, regardless of the license terms of these independent
29modules, and to copy and distribute the resulting executable under
30terms of your choice, provided that you also meet, for each linked
31independent module, the terms and conditions of the license of that
32module.  An independent module is a module which is not derived from
33or based on this library.  If you modify this library, you may extend
34this exception to your version of the library, but you are not
35obligated to do so.  If you do not wish to do so, delete this
36exception statement from your version. */
37
38package edu.vub.util.regexp;
39
40class RETokenStart extends REToken {
41    private String newline; // matches after a newline
42    
43    RETokenStart(int subIndex, String newline) {
44	super(subIndex);
45	this.newline = newline;
46    }
47
48    int getMaximumLength() {
49        return 0;
50    }
51    
52    boolean match(CharIndexed input, REMatch mymatch) {
53	// charAt(index-n) may be unknown on a Reader/InputStream. FIXME
54	// Match after a newline if in multiline mode
55	
56	if (newline != null) {
57	    int len = newline.length();
58	    if (mymatch.offset >= len) {
59		boolean found = true;
60		char z;
61		int i = 0; // position in REToken.newline
62		char ch = input.charAt(mymatch.index - len);
63		do {
64		    z = newline.charAt(i);
65		    if (ch != z) {
66			found = false;
67			break;
68		    }
69		    ++i;
70		    ch = input.charAt(mymatch.index - len + i);
71		} while (i < len);
72	    
73		if (found) return next(input, mymatch);
74	    }
75	}
76	
77	// Don't match at all if REG_NOTBOL is set.
78	if ((mymatch.eflags & RE.REG_NOTBOL) > 0) return false;
79	
80	if ((mymatch.eflags & RE.REG_ANCHORINDEX) > 0)
81	    return (mymatch.anchor == mymatch.offset) ? 
82		next(input, mymatch) : false;
83	else
84	    return ((mymatch.index == 0) && (mymatch.offset == 0)) ?
85		next(input, mymatch) : false;
86    }
87    
88    void dump(StringBuffer os) {
89	os.append('^');
90    }
91}