001 /* CharBuffer.java --
002 Copyright (C) 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
003
004 This file is part of GNU Classpath.
005
006 GNU Classpath is free software; you can redistribute it and/or modify
007 it under the terms of the GNU General Public License as published by
008 the Free Software Foundation; either version 2, or (at your option)
009 any later version.
010
011 GNU Classpath is distributed in the hope that it will be useful, but
012 WITHOUT ANY WARRANTY; without even the implied warranty of
013 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
014 General Public License for more details.
015
016 You should have received a copy of the GNU General Public License
017 along with GNU Classpath; see the file COPYING. If not, write to the
018 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
019 02110-1301 USA.
020
021 Linking this library statically or dynamically with other modules is
022 making a combined work based on this library. Thus, the terms and
023 conditions of the GNU General Public License cover the whole
024 combination.
025
026 As a special exception, the copyright holders of this library give you
027 permission to link this library with independent modules to produce an
028 executable, regardless of the license terms of these independent
029 modules, and to copy and distribute the resulting executable under
030 terms of your choice, provided that you also meet, for each linked
031 independent module, the terms and conditions of the license of that
032 module. An independent module is a module which is not derived from
033 or based on this library. If you modify this library, you may extend
034 this exception to your version of the library, but you are not
035 obligated to do so. If you do not wish to do so, delete this
036 exception statement from your version. */
037
038
039 package java.nio;
040
041 // GCJ LOCAL: Use RawData instead of gnu.classpath.Pointer
042 import gnu.gcj.RawData;
043
044 import java.io.IOException;
045
046 /**
047 * @since 1.4
048 */
049 public abstract class CharBuffer extends Buffer
050 implements Comparable<CharBuffer>, CharSequence, Readable, Appendable
051 {
052 final int array_offset;
053 final char[] backing_buffer;
054
055 CharBuffer (int capacity, int limit, int position, int mark,
056 RawData address, char[] backing_buffer, int array_offset)
057 {
058 super (capacity, limit, position, mark, address);
059 this.backing_buffer = backing_buffer;
060 this.array_offset = array_offset;
061 }
062
063 /**
064 * Allocates a new <code>CharBuffer</code> object with a given capacity.
065 */
066 public static CharBuffer allocate (int capacity)
067 {
068 return new CharBufferImpl (capacity);
069 }
070
071 /**
072 * Wraps a <code>char</code> array into a <code>CharBuffer</code>
073 * object.
074 *
075 * @param array the array to wrap
076 * @param offset the offset of the region in the array to wrap
077 * @param length the length of the region in the array to wrap
078 *
079 * @return a new <code>CharBuffer</code> object
080 *
081 * @exception IndexOutOfBoundsException If the preconditions on the offset
082 * and length parameters do not hold
083 */
084 public static final CharBuffer wrap(char[] array, int offset, int length)
085 {
086 return new CharBufferImpl(array, 0, array.length, offset + length, offset,
087 -1, false);
088 }
089
090 /**
091 * Wraps a character sequence into a <code>CharBuffer</code> object.
092 *
093 * @param seq the sequence to wrap
094 *
095 * @return a new <code>CharBuffer</code> object
096 */
097 public static final CharBuffer wrap(CharSequence seq)
098 {
099 return wrap(seq, 0, seq.length());
100 }
101
102 /**
103 * Wraps a character sequence into a <code>CharBuffer</code> object.
104 *
105 * @param seq the sequence to wrap
106 * @param start the index of the first character to wrap
107 * @param end the index of the first character not to wrap
108 *
109 * @return a new <code>CharBuffer</code> object
110 *
111 * @exception IndexOutOfBoundsException If the preconditions on the offset
112 * and length parameters do not hold
113 */
114 public static final CharBuffer wrap(CharSequence seq, int start, int end)
115 {
116 return new CharSequenceBuffer(seq, start, end);
117 }
118
119 /**
120 * Wraps a <code>char</code> array into a <code>CharBuffer</code>
121 * object.
122 *
123 * @param array the array to wrap
124 *
125 * @return a new <code>CharBuffer</code> object
126 */
127 public static final CharBuffer wrap(char[] array)
128 {
129 return wrap(array, 0, array.length);
130 }
131
132 /**
133 * This method transfers <code>char</code>s from this buffer into the given
134 * destination array. Before the transfer, it checks if there are fewer than
135 * length <code>char</code>s remaining in this buffer.
136 *
137 * @param dst The destination array
138 * @param offset The offset within the array of the first <code>char</code>
139 * to be written; must be non-negative and no larger than dst.length.
140 * @param length The maximum number of bytes to be written to the given array;
141 * must be non-negative and no larger than dst.length - offset.
142 *
143 * @exception BufferUnderflowException If there are fewer than length
144 * <code>char</code>s remaining in this buffer.
145 * @exception IndexOutOfBoundsException If the preconditions on the offset
146 * and length parameters do not hold.
147 */
148 public CharBuffer get (char[] dst, int offset, int length)
149 {
150 checkArraySize(dst.length, offset, length);
151 checkForUnderflow(length);
152
153 for (int i = offset; i < offset + length; i++)
154 {
155 dst [i] = get ();
156 }
157
158 return this;
159 }
160
161 /** @since 1.5 */
162 public int read(CharBuffer buffer) throws IOException
163 {
164 // We want to call put(), so we don't manipulate the CharBuffer
165 // directly.
166 int rem = Math.min(buffer.remaining(), remaining());
167 char[] buf = new char[rem];
168 get(buf);
169 buffer.put(buf);
170 return rem;
171 }
172
173 /**
174 * This method transfers <code>char</code>s from this buffer into the given
175 * destination array.
176 *
177 * @param dst The byte array to write into.
178 *
179 * @exception BufferUnderflowException If there are fewer than dst.length
180 * <code>char</code>s remaining in this buffer.
181 */
182 public CharBuffer get (char[] dst)
183 {
184 return get (dst, 0, dst.length);
185 }
186
187 /**
188 * Writes the content of the the <code>CharBUFFER</code> src
189 * into the buffer. Before the transfer, it checks if there is fewer than
190 * <code>src.remaining()</code> space remaining in this buffer.
191 *
192 * @param src The source data.
193 *
194 * @exception BufferOverflowException If there is insufficient space in this
195 * buffer for the remaining <code>char</code>s in the source buffer.
196 * @exception IllegalArgumentException If the source buffer is this buffer.
197 * @exception ReadOnlyBufferException If this buffer is read-only.
198 */
199 public CharBuffer put (CharBuffer src)
200 {
201 if (src == this)
202 throw new IllegalArgumentException ();
203
204 checkForOverflow(src.remaining());
205
206 if (src.remaining () > 0)
207 {
208 char[] toPut = new char [src.remaining ()];
209 src.get (toPut);
210 put (toPut);
211 }
212
213 return this;
214 }
215
216 /**
217 * Writes the content of the the <code>char array</code> src
218 * into the buffer. Before the transfer, it checks if there is fewer than
219 * length space remaining in this buffer.
220 *
221 * @param src The array to copy into the buffer.
222 * @param offset The offset within the array of the first byte to be read;
223 * must be non-negative and no larger than src.length.
224 * @param length The number of bytes to be read from the given array;
225 * must be non-negative and no larger than src.length - offset.
226 *
227 * @exception BufferOverflowException If there is insufficient space in this
228 * buffer for the remaining <code>char</code>s in the source array.
229 * @exception IndexOutOfBoundsException If the preconditions on the offset
230 * and length parameters do not hold
231 * @exception ReadOnlyBufferException If this buffer is read-only.
232 */
233 public CharBuffer put (char[] src, int offset, int length)
234 {
235 checkArraySize(src.length, offset, length);
236 checkForOverflow(length);
237
238 for (int i = offset; i < offset + length; i++)
239 put (src [i]);
240
241 return this;
242 }
243
244 /**
245 * Writes the content of the the <code>char array</code> src
246 * into the buffer.
247 *
248 * @param src The array to copy into the buffer.
249 *
250 * @exception BufferOverflowException If there is insufficient space in this
251 * buffer for the remaining <code>char</code>s in the source array.
252 * @exception ReadOnlyBufferException If this buffer is read-only.
253 */
254 public final CharBuffer put (char[] src)
255 {
256 return put (src, 0, src.length);
257 }
258
259 /**
260 * Tells whether ot not this buffer is backed by an accessible
261 * <code>char</code> array.
262 */
263 public final boolean hasArray ()
264 {
265 return (backing_buffer != null
266 && !isReadOnly ());
267 }
268
269 /**
270 * Returns the <code>char</code> array that backs this buffer.
271 *
272 * @exception ReadOnlyBufferException If this buffer is read-only.
273 * @exception UnsupportedOperationException If this buffer is not backed
274 * by an accessible array.
275 */
276 public final char[] array ()
277 {
278 if (backing_buffer == null)
279 throw new UnsupportedOperationException ();
280
281 checkIfReadOnly();
282
283 return backing_buffer;
284 }
285
286 /**
287 * Returns the offset within this buffer's backing array of the first element.
288 *
289 * @exception ReadOnlyBufferException If this buffer is read-only.
290 * @exception UnsupportedOperationException If this buffer is not backed
291 * by an accessible array.
292 */
293 public final int arrayOffset ()
294 {
295 if (backing_buffer == null)
296 throw new UnsupportedOperationException ();
297
298 checkIfReadOnly();
299
300 return array_offset;
301 }
302
303 /**
304 * Calculates a hash code for this buffer.
305 *
306 * This is done with int arithmetic,
307 * where ** represents exponentiation, by this formula:<br>
308 * <code>s[position()] + 31 + (s[position()+1] + 30)*31**1 + ... +
309 * (s[limit()-1]+30)*31**(limit()-1)</code>.
310 * Where s is the buffer data. Note that the hashcode is dependent
311 * on buffer content, and therefore is not useful if the buffer
312 * content may change.
313 */
314 public int hashCode ()
315 {
316 int hashCode = get(position()) + 31;
317 int multiplier = 1;
318 for (int i = position() + 1; i < limit(); ++i)
319 {
320 multiplier *= 31;
321 hashCode += (get(i) + 30)*multiplier;
322 }
323 return hashCode;
324 }
325
326 /**
327 * Checks if this buffer is equal to obj.
328 */
329 public boolean equals (Object obj)
330 {
331 if (obj instanceof CharBuffer)
332 {
333 return compareTo ((CharBuffer) obj) == 0;
334 }
335
336 return false;
337 }
338
339 /**
340 * Compares two <code>CharBuffer</code> objects.
341 *
342 * @exception ClassCastException If obj is not an object derived from
343 * <code>CharBuffer</code>.
344 */
345 public int compareTo (CharBuffer other)
346 {
347 int num = Math.min(remaining(), other.remaining());
348 int pos_this = position();
349 int pos_other = other.position();
350
351 for (int count = 0; count < num; count++)
352 {
353 char a = get(pos_this++);
354 char b = other.get(pos_other++);
355
356 if (a == b)
357 continue;
358
359 if (a < b)
360 return -1;
361
362 return 1;
363 }
364
365 return remaining() - other.remaining();
366 }
367
368 /**
369 * Returns the byte order of this buffer.
370 */
371 public abstract ByteOrder order ();
372
373 /**
374 * Reads the <code>char</code> at this buffer's current position,
375 * and then increments the position.
376 *
377 * @exception BufferUnderflowException If there are no remaining
378 * <code>char</code>s in this buffer.
379 */
380 public abstract char get ();
381
382 /**
383 * Writes the <code>char</code> at this buffer's current position,
384 * and then increments the position.
385 *
386 * @exception BufferOverflowException If there no remaining
387 * <code>char</code>s in this buffer.
388 * @exception ReadOnlyBufferException If this buffer is read-only.
389 */
390 public abstract CharBuffer put (char b);
391
392 /**
393 * Absolute get method.
394 *
395 * @exception IndexOutOfBoundsException If index is negative or not smaller
396 * than the buffer's limit.
397 */
398 public abstract char get (int index);
399
400 /**
401 * Absolute put method.
402 *
403 * @exception IndexOutOfBoundsException If index is negative or not smaller
404 * than the buffer's limit.
405 * @exception ReadOnlyBufferException If this buffer is read-only.
406 */
407 public abstract CharBuffer put (int index, char b);
408
409 /**
410 * Compacts this buffer.
411 *
412 * @exception ReadOnlyBufferException If this buffer is read-only.
413 */
414 public abstract CharBuffer compact ();
415
416 /**
417 * Tells wether or not this buffer is direct.
418 */
419 public abstract boolean isDirect ();
420
421 /**
422 * Creates a new <code>CharBuffer</code> whose content is a shared
423 * subsequence of this buffer's content.
424 */
425 public abstract CharBuffer slice ();
426
427 /**
428 * Creates a new <code>CharBuffer</code> that shares this buffer's
429 * content.
430 */
431 public abstract CharBuffer duplicate ();
432
433 /**
434 * Creates a new read-only <code>CharBuffer</code> that shares this
435 * buffer's content.
436 */
437 public abstract CharBuffer asReadOnlyBuffer ();
438
439 /**
440 * Returns the remaining content of the buffer as a string.
441 */
442 public String toString ()
443 {
444 if (hasArray ())
445 return new String (array (), position (), length ());
446
447 char[] buf = new char [length ()];
448 int pos = position ();
449 get (buf, 0, buf.length);
450 position (pos);
451 return new String (buf);
452 }
453
454 /**
455 * Returns the length of the remaining chars in this buffer.
456 */
457 public final int length ()
458 {
459 return remaining ();
460 }
461
462 /**
463 * Creates a new character buffer that represents the specified subsequence
464 * of this buffer, relative to the current position.
465 *
466 * @exception IndexOutOfBoundsException If the preconditions on start and
467 * end do not hold.
468 */
469 public abstract CharSequence subSequence (int start, int length);
470
471 /**
472 * Relative put method.
473 *
474 * @exception BufferOverflowException If there is insufficient space in this
475 * buffer.
476 * @exception IndexOutOfBoundsException If the preconditions on the start
477 * and end parameters do not hold.
478 * @exception ReadOnlyBufferException If this buffer is read-only.
479 */
480 public CharBuffer put (String str, int start, int length)
481 {
482 return put (str.toCharArray (), start, length);
483 }
484
485 /**
486 * Relative put method.
487 *
488 * @exception BufferOverflowException If there is insufficient space in this
489 * buffer.
490 * @exception ReadOnlyBufferException If this buffer is read-only.
491 */
492 public final CharBuffer put (String str)
493 {
494 return put (str.toCharArray (), 0, str.length ());
495 }
496
497 /**
498 * Returns the character at <code>position() + index</code>.
499 *
500 * @exception IndexOutOfBoundsException If index is negative not smaller than
501 * <code>remaining()</code>.
502 */
503 public final char charAt (int index)
504 {
505 if (index < 0
506 || index >= remaining ())
507 throw new IndexOutOfBoundsException ();
508
509 return get (position () + index);
510 }
511
512 /** @since 1.5 */
513 public CharBuffer append(char c)
514 {
515 put(c);
516 return this;
517 }
518
519 /** @since 1.5 */
520 public CharBuffer append(CharSequence cs)
521 {
522 put(cs == null ? "null" : cs.toString());
523 return this;
524 }
525
526 /** @since 1.5 */
527 public CharBuffer append(CharSequence cs, int start, int end)
528 {
529 put(cs == null ? "null" : cs.subSequence(start, end).toString());
530 return this;
531 }
532 }