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Java > Open Source Codes > org > armedbear > j > FastStringReader


1 /*
2  * FastStringReader.java
3  *
4  * Copyright (C) 2002 Peter Graves
5  * $Id: FastStringReader.java,v 1.2 2002/12/07 10:51:08 piso Exp $
6  *
7  * This program is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU General Public License
9  * as published by the Free Software Foundation; either version 2
10  * of the License, or (at your option) any later version.
11  *
12  * This program is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15  * GNU General Public License for more details.
16  *
17  * You should have received a copy of the GNU General Public License
18  * along with this program; if not, write to the Free Software
19  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
20  */
21
22 package org.armedbear.j;
23
24 import java.io.Reader JavaDoc;
25
26 public final class FastStringReader extends Reader JavaDoc
27 {
28     private final String JavaDoc s;
29     private final int length;
30     private int index;
31     private int mark;
32
33     public FastStringReader(String JavaDoc s)
34     {
35         this.s = s;
36         length = s.length();
37     }
38
39     public final char readChar()
40     {
41         return index < length ? s.charAt(index++) : 0;
42     }
43
44     public final void unreadChar()
45     {
46         Debug.assertTrue(index > 0);
47         if (index > 0)
48             --index;
49     }
50
51     public int read()
52     {
53         return index < length ? s.charAt(index++) : -1;
54     }
55
56     public int read(char array[], int offset, int count)
57     {
58         if (offset < 0 || count < 0 || offset + count > array.length)
59             throw new IndexOutOfBoundsException JavaDoc();
60         if (count == 0)
61             return 0;
62         final int actual = Math.min(count, length - index);
63         s.getChars(index, index + actual, array, offset);
64         index += actual;
65         return actual;
66     }
67
68     // Returns next word (delimited by whitespace) or quoted substring,
69 // without enclosing quotes (if any).
70 public String JavaDoc readToken()
71     {
72         skipWhitespace();
73         if (index == length)
74             return "";
75         char quoteChar = 0;
76         int begin = index;
77         char c = s.charAt(index++);
78         if (c == '"' || c == '\'') {
79             quoteChar = c;
80             ++begin;
81         }
82         while (index < length) {
83             c = s.charAt(index);
84             if (quoteChar != 0 && c == quoteChar) {
85                 // Reached end of pattern.
86 int end = index;
87                 // Skip closing quote.
88 ++index;
89                 return s.substring(begin, end);
90             }
91             if (quoteChar == 0 && Character.isWhitespace(c)) {
92                 // If not quoted, whitespace terminates string.
93 return s.substring(begin, index);
94             } else
95                 ++index;
96         }
97         return s.substring(begin, index);
98     }
99
100     public String JavaDoc readLine()
101     {
102         final int limit = length;
103         if (index >= limit)
104             return null;
105         final int begin = index;
106         do {
107             switch (s.charAt(index)) {
108                 case '\n':
109                     return s.substring(begin, index++);
110                 case '\r': {
111                     final int end = index++;
112                     // Skip following LF if any.
113 if (index < limit && s.charAt(index) == '\n')
114                         ++index;
115                     return s.substring(begin, end);
116                 }
117                 // Fall through...
118 }
119         } while (++index < limit);
120         return s.substring(begin, index);
121     }
122
123     public long skip(long count)
124     {
125         final long actual = Math.min(count, length - index);
126         index += actual;
127         return actual;
128     }
129
130     public boolean ready()
131     {
132         return true;
133     }
134
135     public boolean markSupported()
136     {
137         return true;
138     }
139
140     public void mark(int readAheadLimit)
141     {
142         if (readAheadLimit < 0)
143             throw new IllegalArgumentException JavaDoc("Read-ahead limit < 0");
144         mark = index;
145     }
146
147     public void reset()
148     {
149         index = mark;
150     }
151
152     public void close() {}
153
154     public final String JavaDoc remainder()
155     {
156         return s.substring(index);
157     }
158
159     public final void skipWhitespace()
160     {
161         while (index < length && Character.isWhitespace(s.charAt(index)))
162             ++index;
163     }
164 }
165
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