1 /*  gnu/regexp/RETokenStart.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 package gnu.java.util.regex;
39 
40 import gnu.java.lang.CPStringBuilder;
41 
42 class RETokenStart extends REToken
43 {
44   private String newline;       // matches after a newline
45   private boolean check_java_line_terminators;
46 
RETokenStart(int subIndex, String newline)47   RETokenStart (int subIndex, String newline)
48   {
49     super (subIndex);
50     this.newline = newline;
51     this.check_java_line_terminators = false;
52   }
53 
RETokenStart(int subIndex, String newline, boolean b)54   RETokenStart (int subIndex, String newline, boolean b)
55   {
56     super (subIndex);
57     this.newline = newline;
58     this.check_java_line_terminators = b;
59   }
60 
61   @Override
getMaximumLength()62     int getMaximumLength ()
63   {
64     return 0;
65   }
66 
67   @Override
matchThis(CharIndexed input, REMatch mymatch)68     REMatch matchThis (CharIndexed input, REMatch mymatch)
69   {
70     // charAt(index-n) may be unknown on a Reader/InputStream. FIXME
71     // Match after a newline if in multiline mode
72 
73     if (check_java_line_terminators)
74       {
75         char ch = input.charAt (mymatch.index - 1);
76         if (ch != CharIndexed.OUT_OF_BOUNDS)
77           {
78             if (ch == '\n')
79               return mymatch;
80             if (ch == '\r')
81               {
82                 char ch1 = input.charAt (mymatch.index);
83                 if (ch1 != '\n')
84                   return mymatch;
85                 return null;
86               }
87             if (ch == '\u0085')
88               return mymatch;   // A next-line character
89             if (ch == '\u2028')
90               return mymatch;   // A line-separator character
91             if (ch == '\u2029')
92               return mymatch;   // A paragraph-separator character
93           }
94       }
95 
96     if (newline != null)
97       {
98         int len = newline.length ();
99         if (mymatch.offset >= len)
100           {
101             boolean found = true;
102             char z;
103             int i = 0;          // position in REToken.newline
104             char ch = input.charAt (mymatch.index - len);
105             do
106               {
107                 z = newline.charAt (i);
108                 if (ch != z)
109                   {
110                     found = false;
111                     break;
112                   }
113                 ++i;
114                 ch = input.charAt (mymatch.index - len + i);
115               }
116             while (i < len);
117 
118             if (found)
119               return mymatch;
120           }
121       }
122 
123     // Don't match at all if REG_NOTBOL is set.
124     if ((mymatch.eflags & RE.REG_NOTBOL) > 0)
125       return null;
126 
127     if ((mymatch.eflags & RE.REG_ANCHORINDEX) > 0)
128       return (mymatch.anchor == mymatch.offset) ? mymatch : null;
129     else
130       return ((mymatch.index == 0) && (mymatch.offset == 0)) ? mymatch : null;
131   }
132 
133   @Override
returnsFixedLengthMatches()134     boolean returnsFixedLengthMatches ()
135   {
136     return true;
137   }
138 
139   @Override
findFixedLengthMatches(CharIndexed input, REMatch mymatch, int max)140     int findFixedLengthMatches (CharIndexed input, REMatch mymatch, int max)
141   {
142     if (matchThis (input, mymatch) != null)
143       return max;
144     else
145       return 0;
146   }
147 
148   @Override
dump(CPStringBuilder os)149     void dump (CPStringBuilder os)
150   {
151     os.append ('^');
152   }
153 }
154