001/* CharBuffer.java -- 
002   Copyright (C) 2002, 2003, 2004, 2005  Free Software Foundation, Inc.
003
004This file is part of GNU Classpath.
005
006GNU Classpath is free software; you can redistribute it and/or modify
007it under the terms of the GNU General Public License as published by
008the Free Software Foundation; either version 2, or (at your option)
009any later version.
010
011GNU Classpath is distributed in the hope that it will be useful, but
012WITHOUT ANY WARRANTY; without even the implied warranty of
013MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014General Public License for more details.
015
016You should have received a copy of the GNU General Public License
017along with GNU Classpath; see the file COPYING.  If not, write to the
018Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
01902110-1301 USA.
020
021Linking this library statically or dynamically with other modules is
022making a combined work based on this library.  Thus, the terms and
023conditions of the GNU General Public License cover the whole
024combination.
025
026As a special exception, the copyright holders of this library give you
027permission to link this library with independent modules to produce an
028executable, regardless of the license terms of these independent
029modules, and to copy and distribute the resulting executable under
030terms of your choice, provided that you also meet, for each linked
031independent module, the terms and conditions of the license of that
032module.  An independent module is a module which is not derived from
033or based on this library.  If you modify this library, you may extend
034this exception to your version of the library, but you are not
035obligated to do so.  If you do not wish to do so, delete this
036exception statement from your version. */
037
038
039package java.nio;
040
041// GCJ LOCAL: Use RawData instead of gnu.classpath.Pointer
042import gnu.gcj.RawData;
043
044import java.io.IOException;
045
046/**
047 * @since 1.4
048 */
049public 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}