001 /* ShortBuffer.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 /**
045 * @since 1.4
046 */
047 public abstract class ShortBuffer extends Buffer
048 implements Comparable<ShortBuffer>
049 {
050 final int array_offset;
051 final short[] backing_buffer;
052
053 ShortBuffer (int capacity, int limit, int position,
054 int mark, RawData address, short[] backing_buffer,
055 int array_offset)
056 {
057 super (capacity, limit, position, mark, address);
058 this.backing_buffer = backing_buffer;
059 this.array_offset = array_offset;
060 }
061
062 /**
063 * Allocates a new <code>ShortBuffer</code> object with a given capacity.
064 */
065 public static ShortBuffer allocate (int capacity)
066 {
067 return new ShortBufferImpl (capacity);
068 }
069
070 /**
071 * Wraps a <code>short</code> array into a <code>ShortBuffer</code>
072 * object.
073 *
074 * @exception IndexOutOfBoundsException If the preconditions on the offset
075 * and length parameters do not hold
076 */
077 public static final ShortBuffer wrap (short[] array, int offset, int length)
078 {
079 return new ShortBufferImpl (array, 0, array.length, offset + length, offset, -1, false);
080 }
081
082 /**
083 * Wraps a <code>short</code> array into a <code>ShortBuffer</code>
084 * object.
085 */
086 public static final ShortBuffer wrap (short[] array)
087 {
088 return wrap (array, 0, array.length);
089 }
090
091 /**
092 * This method transfers <code>short</code>s from this buffer into the given
093 * destination array. Before the transfer, it checks if there are fewer than
094 * length <code>short</code>s remaining in this buffer.
095 *
096 * @param dst The destination array
097 * @param offset The offset within the array of the first <code>short</code>
098 * to be written; must be non-negative and no larger than dst.length.
099 * @param length The maximum number of bytes to be written to the given array;
100 * must be non-negative and no larger than dst.length - offset.
101 *
102 * @exception BufferUnderflowException If there are fewer than length
103 * <code>short</code>s remaining in this buffer.
104 * @exception IndexOutOfBoundsException If the preconditions on the offset
105 * and length parameters do not hold.
106 */
107 public ShortBuffer get (short[] dst, int offset, int length)
108 {
109 checkArraySize(dst.length, offset, length);
110 checkForUnderflow(length);
111
112 for (int i = offset; i < offset + length; i++)
113 {
114 dst [i] = get ();
115 }
116
117 return this;
118 }
119
120 /**
121 * This method transfers <code>short</code>s from this buffer into the given
122 * destination array.
123 *
124 * @param dst The byte array to write into.
125 *
126 * @exception BufferUnderflowException If there are fewer than dst.length
127 * <code>short</code>s remaining in this buffer.
128 */
129 public ShortBuffer get (short[] dst)
130 {
131 return get (dst, 0, dst.length);
132 }
133
134 /**
135 * Writes the content of the the <code>ShortBUFFER</code> src
136 * into the buffer. Before the transfer, it checks if there is fewer than
137 * <code>src.remaining()</code> space remaining in this buffer.
138 *
139 * @param src The source data.
140 *
141 * @exception BufferOverflowException If there is insufficient space in this
142 * buffer for the remaining <code>short</code>s in the source buffer.
143 * @exception IllegalArgumentException If the source buffer is this buffer.
144 * @exception ReadOnlyBufferException If this buffer is read-only.
145 */
146 public ShortBuffer put (ShortBuffer src)
147 {
148 if (src == this)
149 throw new IllegalArgumentException ();
150
151 checkForOverflow(src.remaining ());
152
153 if (src.remaining () > 0)
154 {
155 short[] toPut = new short [src.remaining ()];
156 src.get (toPut);
157 put (toPut);
158 }
159
160 return this;
161 }
162
163 /**
164 * Writes the content of the the <code>short array</code> src
165 * into the buffer. Before the transfer, it checks if there is fewer than
166 * length space remaining in this buffer.
167 *
168 * @param src The array to copy into the buffer.
169 * @param offset The offset within the array of the first byte to be read;
170 * must be non-negative and no larger than src.length.
171 * @param length The number of bytes to be read from the given array;
172 * must be non-negative and no larger than src.length - offset.
173 *
174 * @exception BufferOverflowException If there is insufficient space in this
175 * buffer for the remaining <code>short</code>s in the source array.
176 * @exception IndexOutOfBoundsException If the preconditions on the offset
177 * and length parameters do not hold
178 * @exception ReadOnlyBufferException If this buffer is read-only.
179 */
180 public ShortBuffer put (short[] src, int offset, int length)
181 {
182 checkArraySize(src.length, offset, length);
183 checkForOverflow(length);
184
185 for (int i = offset; i < offset + length; i++)
186 put (src [i]);
187
188 return this;
189 }
190
191 /**
192 * Writes the content of the the <code>short array</code> src
193 * into the buffer.
194 *
195 * @param src The array to copy into the buffer.
196 *
197 * @exception BufferOverflowException If there is insufficient space in this
198 * buffer for the remaining <code>short</code>s in the source array.
199 * @exception ReadOnlyBufferException If this buffer is read-only.
200 */
201 public final ShortBuffer put (short[] src)
202 {
203 return put (src, 0, src.length);
204 }
205
206 /**
207 * Tells whether ot not this buffer is backed by an accessible
208 * <code>short</code> array.
209 */
210 public final boolean hasArray ()
211 {
212 return (backing_buffer != null
213 && !isReadOnly ());
214 }
215
216 /**
217 * Returns the <code>short</code> array that backs this buffer.
218 *
219 * @exception ReadOnlyBufferException If this buffer is read-only.
220 * @exception UnsupportedOperationException If this buffer is not backed
221 * by an accessible array.
222 */
223 public final short[] array ()
224 {
225 if (backing_buffer == null)
226 throw new UnsupportedOperationException ();
227
228 checkIfReadOnly();
229
230 return backing_buffer;
231 }
232
233 /**
234 * Returns the offset within this buffer's backing array of the first element.
235 *
236 * @exception ReadOnlyBufferException If this buffer is read-only.
237 * @exception UnsupportedOperationException If this buffer is not backed
238 * by an accessible array.
239 */
240 public final int arrayOffset ()
241 {
242 if (backing_buffer == null)
243 throw new UnsupportedOperationException ();
244
245 checkIfReadOnly();
246
247 return array_offset;
248 }
249
250 /**
251 * Calculates a hash code for this buffer.
252 *
253 * This is done with <code>int</code> arithmetic,
254 * where ** represents exponentiation, by this formula:<br>
255 * <code>s[position()] + 31 + (s[position()+1] + 30)*31**1 + ... +
256 * (s[limit()-1]+30)*31**(limit()-1)</code>.
257 * Where s is the buffer data. Note that the hashcode is dependent
258 * on buffer content, and therefore is not useful if the buffer
259 * content may change.
260 *
261 * @return the hash code
262 */
263 public int hashCode ()
264 {
265 int hashCode = get(position()) + 31;
266 int multiplier = 1;
267 for (int i = position() + 1; i < limit(); ++i)
268 {
269 multiplier *= 31;
270 hashCode += (get(i) + 30)*multiplier;
271 }
272 return hashCode;
273 }
274
275 /**
276 * Checks if this buffer is equal to obj.
277 */
278 public boolean equals (Object obj)
279 {
280 if (obj instanceof ShortBuffer)
281 {
282 return compareTo ((ShortBuffer) obj) == 0;
283 }
284
285 return false;
286 }
287
288 /**
289 * Compares two <code>ShortBuffer</code> objects.
290 *
291 * @exception ClassCastException If obj is not an object derived from
292 * <code>ShortBuffer</code>.
293 */
294 public int compareTo (ShortBuffer other)
295 {
296 int num = Math.min(remaining(), other.remaining());
297 int pos_this = position();
298 int pos_other = other.position();
299
300 for (int count = 0; count < num; count++)
301 {
302 short a = get(pos_this++);
303 short b = other.get(pos_other++);
304
305 if (a == b)
306 continue;
307
308 if (a < b)
309 return -1;
310
311 return 1;
312 }
313
314 return remaining() - other.remaining();
315 }
316
317 /**
318 * Returns the byte order of this buffer.
319 */
320 public abstract ByteOrder order ();
321
322 /**
323 * Reads the <code>short</code> at this buffer's current position,
324 * and then increments the position.
325 *
326 * @exception BufferUnderflowException If there are no remaining
327 * <code>short</code>s in this buffer.
328 */
329 public abstract short get ();
330
331 /**
332 * Writes the <code>short</code> at this buffer's current position,
333 * and then increments the position.
334 *
335 * @exception BufferOverflowException If there no remaining
336 * <code>short</code>s in this buffer.
337 * @exception ReadOnlyBufferException If this buffer is read-only.
338 */
339 public abstract ShortBuffer put (short b);
340
341 /**
342 * Absolute get method.
343 *
344 * @exception IndexOutOfBoundsException If index is negative or not smaller
345 * than the buffer's limit.
346 */
347 public abstract short get (int index);
348
349 /**
350 * Absolute put method.
351 *
352 * @exception IndexOutOfBoundsException If index is negative or not smaller
353 * than the buffer's limit.
354 * @exception ReadOnlyBufferException If this buffer is read-only.
355 */
356 public abstract ShortBuffer put (int index, short b);
357
358 /**
359 * Compacts this buffer.
360 *
361 * @exception ReadOnlyBufferException If this buffer is read-only.
362 */
363 public abstract ShortBuffer compact ();
364
365 /**
366 * Tells wether or not this buffer is direct.
367 */
368 public abstract boolean isDirect ();
369
370 /**
371 * Creates a new <code>ShortBuffer</code> whose content is a shared
372 * subsequence of this buffer's content.
373 */
374 public abstract ShortBuffer slice ();
375
376 /**
377 * Creates a new <code>ShortBuffer</code> that shares this buffer's
378 * content.
379 */
380 public abstract ShortBuffer duplicate ();
381
382 /**
383 * Creates a new read-only <code>ShortBuffer</code> that shares this
384 * buffer's content.
385 */
386 public abstract ShortBuffer asReadOnlyBuffer ();
387 }