1 /* LineNumberReader.java -- A character input stream which counts line numbers
2 Copyright (C) 1998, 1999, 2001, 2003, 2005 Free Software Foundation, Inc.
4 This file is part of GNU Classpath.
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)
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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.
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
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
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. */
41 * This class functions like a standard <code>Reader</code> except that it
42 * counts line numbers, and canonicalizes newline characters. As data
43 * is read, whenever the char sequences "\r", "\n", or "\r\n" are encountered,
44 * the running line count is incremeted by one. Additionally, the whatever
45 * line termination sequence was encountered will be converted to a "\n"
46 * char. Note that this class numbers lines from 0. When the first
47 * line terminator is encountered, the line number is incremented to 1, and
48 * so on. Also note that actual "\r" and "\n" characters are looked for.
49 * The system dependent line separator sequence is ignored.
51 * This class counts only line termination characters. If the last line
52 * read from the stream does not end in a line termination sequence, it
53 * will not be counted as a line.
55 * @author Per Bothner (bothner@cygnus.com)
56 * @author Aaron M. Renn (arenn@urbanophile.com)
57 * @author Guilhem Lavaux (guilhem@kaffe.org)
58 * @date December 28, 2003.
60 /* Written using "Java Class Libraries", 2nd edition, plus online
61 * API docs for JDK 1.2 beta from http://www.javasoft.com.
62 * Status: Believed complete and correct.
64 * This implementation has the feature that if '\r' is read, it
65 * does not look for a '\n', but immediately returns '\n'.
66 * On the next read(), if a '\n' is read, it is skipped.
67 * This has the advantage that we do not read (and hang) unnecessarily.
69 * This implementation is also minimal in the number of fields it uses.
71 public class LineNumberReader
extends BufferedReader
73 /** The current line number. */
74 private int lineNumber
;
75 /** Whether we already found a new line in the former call. */
76 private boolean matchedNewLine
;
77 /** The saved line number when calling mark() */
78 private int savedLineNumber
;
81 * Create a new <code>LineNumberReader</code> that reads from the
82 * specified subordinate <code>Reader</code>. A default 8K char sized
83 * buffer will be used for reads.
85 * @param in The subordinate <code>Reader</code> to read from
87 public LineNumberReader(Reader in
)
89 super(in
, DEFAULT_BUFFER_SIZE
);
93 * This method initializes a new <code>LineNumberReader</code> to read
94 * from the specified subordinate <code>Reader</code> using the specified
97 * @param in The subordinate <code>Reader</code> to read from
98 * @param size The buffer size to use for reading
100 public LineNumberReader(Reader in
, int size
)
106 * This method returns the current line number
108 * @return The current line number
110 public int getLineNumber()
116 * This method sets the current line number to the specified value.
118 * @param lineNumber The new line number
120 public void setLineNumber(int lineNumber
)
122 this.lineNumber
= lineNumber
;
126 * This method marks a position in the input to which the stream can be
127 * "reset" char calling the <code>reset()</code> method. The parameter
128 * <code>readlimit</code> is the number of chars that can be read from the
129 * stream after setting the mark before the mark becomes invalid. For
130 * example, if <code>mark()</code> is called with a read limit of 10,
132 * 11 chars of data are read from the stream before the <code>reset()</code>
133 * method is called, then the mark is invalid and the stream object
134 * instance is not required to remember the mark.
136 * In this class, this method will remember the current line number as well
137 * as the current position in the stream. When the <code>reset()</code>
139 * is called, the line number will be restored to the saved line number in
140 * addition to the stream position.
142 * @param readLimit The number of chars that can be read before the
143 * mark becomes invalid
145 * @exception IOException If an error occurs
147 public void mark(int readLimit
) throws IOException
150 throw new IllegalArgumentException("Read-ahead limit is negative");
154 // This is basically the same as BufferedReader.mark.
155 // However, if the previous character was a '\r', we need to
156 // save that 'r', in case the next character is a '\n'.
157 if (pos
+ readLimit
> limit
)
159 int saveCR
= matchedNewLine ?
1 : 0;
160 char[] old_buffer
= buffer
;
161 if (readLimit
> limit
)
162 buffer
= new char[saveCR
+ readLimit
];
163 int copy_start
= pos
- saveCR
;
164 savedLineNumber
= lineNumber
;
166 System
.arraycopy(old_buffer
, copy_start
, buffer
, 0, limit
);
174 * This method resets a stream to the point where the <code>mark()</code>
176 * was called. Any chars that were read after the mark point was set will
177 * be re-read during subsequent reads.
179 * In this class, this method will also restore the line number that was
180 * current when the <code>mark()</code> method was called.
182 * @exception IOException If an error occurs
184 public void reset() throws IOException
189 throw new IOException("mark never set or invalidated");
190 lineNumber
= savedLineNumber
;
192 matchedNewLine
= (markPos
> 0 && buffer
[markPos
-1] == '\r');
197 * This private method fills the input buffer whatever pos is.
198 * Consequently pos should be checked before calling this method.
200 * @return the number of bytes actually read from the input stream or
201 * -1 if end of stream.
202 * @exception IOException If an error occurs.
204 private int fill() throws IOException
206 if (markPos
>= 0 && limit
== buffer
.length
)
210 int count
= in
.read(buffer
, limit
, buffer
.length
- limit
);
219 * This method reads an unsigned char from the input stream and returns it
220 * as an int in the range of 0-65535. This method will return -1 if the
221 * end of the stream has been reached.
223 * Note that if a line termination sequence is encountered (ie, "\r",
224 * "\n", or "\r\n") then that line termination sequence is converted to
225 * a single "\n" value which is returned from this method. This means
226 * that it is possible this method reads two chars from the subordinate
227 * stream instead of just one.
229 * Note that this method will block until a char of data is available
232 * @return The char read or -1 if end of stream
234 * @exception IOException If an error occurs
236 public int read() throws IOException
241 if (pos
>= limit
&& fill() < 0)
243 char ch
= buffer
[pos
++];
245 if ((matchedNewLine
= (ch
== '\r')) || ch
== '\n')
250 matchedNewLine
= false;
256 * This method reads chars from a stream and stores them into a caller
257 * supplied buffer. It starts storing data at index <code>offset</code> into
258 * the buffer and attemps to read <code>len</code> chars. This method can
259 * return before reading the number of chars requested. The actual number
260 * of chars read is returned as an int. A -1 is returned to indicated the
263 * This method will block until some data can be read.
265 * Note that if a line termination sequence is encountered (ie, "\r",
266 * "\n", or "\r\n") then that line termination sequence is converted to
267 * a single "\n" value which is stored in the buffer. Only a single
268 * char is counted towards the number of chars read in this case.
270 * @param buf The array into which the chars read should be stored
271 * @param offset The offset into the array to start storing chars
272 * @param count The requested number of chars to read
274 * @return The actual number of chars read, or -1 if end of stream
276 * @exception IOException If an error occurs.
277 * @exception NullPointerException If buf is null (in any case).
278 * @exception IndexOutOfBoundsException If buffer parameters (offset and
279 * count) lies outside of the buffer capacity.
281 public int read(char[] buf
, int offset
, int count
) throws IOException
284 throw new NullPointerException();
286 if (offset
+ count
> buf
.length
|| offset
< 0)
287 throw new IndexOutOfBoundsException();
292 throw new IndexOutOfBoundsException();
298 if (pos
>= limit
&& fill() < 0)
301 int start_offset
= offset
;
302 boolean matched
= matchedNewLine
;
304 while (count
-- > 0 && pos
< limit
)
306 char ch
= buffer
[pos
++];
312 else if (ch
== '\n' && !matched
)
320 matchedNewLine
= matched
;
321 return offset
- start_offset
;
325 private void skipRedundantLF() throws IOException
327 if (pos
> 0 && matchedNewLine
)
331 if (buffer
[pos
] == '\n')
335 { // check whether the next buffer begins with '\n'.
336 // in that case kill the '\n'.
339 if (buffer
[pos
] == '\n')
342 matchedNewLine
= true;
347 * This method reads a line of text from the input stream and returns
348 * it as a <code>String</code>. A line is considered to be terminated
349 * by a "\r", "\n", or "\r\n" sequence, not by the system dependent line
352 * @return The line read as a <code>String</code> or <code>null</code>
355 * @exception IOException If an error occurs
357 public String
readLine() throws IOException
359 // BufferedReader.readLine already does this. Shouldn't need to keep
360 // track of newlines (since the read method deals with this for us).
361 // But if the buffer is large, we may not call the read method at all
362 // and super.readLine can't increment lineNumber itself.
363 // Though it may seem kludgy, the safest thing to do is to save off
364 // lineNumber and increment it explicitly when we're done (iff we
365 // ended with a '\n' or '\r' as opposed to EOF).
367 // Also, we need to undo the special casing done by BufferedReader.readLine
368 // when a '\r' is the last char in the buffer. That situation is marked
370 int tmpLineNumber
= lineNumber
;
372 String str
= super.readLine();
376 // The only case where you mustn't increment the line number is you are
379 lineNumber
= tmpLineNumber
+ 1;
385 * This method skips over characters in the stream. This method will
386 * skip the specified number of characters if possible, but is not required
387 * to skip them all. The actual number of characters skipped is returned.
388 * This method returns 0 if the specified number of chars is less than 1.
390 * @param count The specified number of chars to skip.
392 * @return The actual number of chars skipped.
394 * @exception IOException If an error occurs
396 public long skip (long count
) throws IOException
399 throw new IllegalArgumentException("skip() value is negative");
404 char[] buf
= new char[1];
406 for (skipped
= 0; skipped
< count
; skipped
++)
408 int ch
= read(buf
, 0, 1);