1 /* ShortBuffer.java --
2 Copyright (C) 2002, 2003, 2004 Free Software Foundation, Inc.
3
4 This file is part of GNU Classpath.
5
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)
9 any later version.
10
11 GNU Classpath is distributed in the hope that it will be useful, but
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.
15
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
19 02110-1301 USA.
20
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
24 combination.
25
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. */
37
38
39 package java.nio;
40
41 /**
42 * @since 1.4
43 */
44 public abstract class ShortBuffer extends Buffer
45 implements Comparable
46 {
47 int array_offset;
48 short[] backing_buffer;
49
50 ShortBuffer (int capacity, int limit, int position, int mark)
51 {
52 super (capacity, limit, position, mark);
53 array_offset = 0;
54 }
55
56 /**
57 * Allocates a new <code>ShortBuffer</code> object with a given capacity.
58 */
59 public static ShortBuffer allocate (int capacity)
60 {
61 return new ShortBufferImpl (capacity);
62 }
63
64 /**
65 * Wraps a <code>short</code> array into a <code>ShortBuffer</code>
66 * object.
67 *
68 * @exception IndexOutOfBoundsException If the preconditions on the offset
69 * and length parameters do not hold
70 */
71 public static final ShortBuffer wrap (short[] array, int offset, int length)
72 {
73 return new ShortBufferImpl (array, 0, array.length, offset + length, offset, -1, false);
74 }
75
76 /**
77 * Wraps a <code>short</code> array into a <code>ShortBuffer</code>
78 * object.
79 */
80 public static final ShortBuffer wrap (short[] array)
81 {
82 return wrap (array, 0, array.length);
83 }
84
85 /**
86 * This method transfers <code>short</code>s from this buffer into the given
87 * destination array. Before the transfer, it checks if there are fewer than
88 * length <code>short</code>s remaining in this buffer.
89 *
90 * @param dst The destination array
91 * @param offset The offset within the array of the first <code>short</code>
92 * to be written; must be non-negative and no larger than dst.length.
93 * @param length The maximum number of bytes to be written to the given array;
94 * must be non-negative and no larger than dst.length - offset.
95 *
96 * @exception BufferUnderflowException If there are fewer than length
97 * <code>short</code>s remaining in this buffer.
98 * @exception IndexOutOfBoundsException If the preconditions on the offset
99 * and length parameters do not hold.
100 */
101 public ShortBuffer get (short[] dst, int offset, int length)
102 {
103 checkArraySize(dst.length, offset, length);
104 checkForUnderflow(length);
105
106 for (int i = offset; i < offset + length; i++)
107 {
108 dst [i] = get ();
109 }
110
111 return this;
112 }
113
114 /**
115 * This method transfers <code>short</code>s from this buffer into the given
116 * destination array.
117 *
118 * @param dst The byte array to write into.
119 *
120 * @exception BufferUnderflowException If there are fewer than dst.length
121 * <code>short</code>s remaining in this buffer.
122 */
123 public ShortBuffer get (short[] dst)
124 {
125 return get (dst, 0, dst.length);
126 }
127
128 /**
129 * Writes the content of the the <code>ShortBUFFER</code> src
130 * into the buffer. Before the transfer, it checks if there is fewer than
131 * <code>src.remaining()</code> space remaining in this buffer.
132 *
133 * @param src The source data.
134 *
135 * @exception BufferOverflowException If there is insufficient space in this
136 * buffer for the remaining <code>short</code>s in the source buffer.
137 * @exception IllegalArgumentException If the source buffer is this buffer.
138 * @exception ReadOnlyBufferException If this buffer is read-only.
139 */
140 public ShortBuffer put (ShortBuffer src)
141 {
142 if (src == this)
143 throw new IllegalArgumentException ();
144
145 checkForOverflow(src.remaining ());
146
147 if (src.remaining () > 0)
148 {
149 short[] toPut = new short [src.remaining ()];
150 src.get (toPut);
151 put (toPut);
152 }
153
154 return this;
155 }
156
157 /**
158 * Writes the content of the the <code>short array</code> src
159 * into the buffer. Before the transfer, it checks if there is fewer than
160 * length space remaining in this buffer.
161 *
162 * @param src The array to copy into the buffer.
163 * @param offset The offset within the array of the first byte to be read;
164 * must be non-negative and no larger than src.length.
165 * @param length The number of bytes to be read from the given array;
166 * must be non-negative and no larger than src.length - offset.
167 *
168 * @exception BufferOverflowException If there is insufficient space in this
169 * buffer for the remaining <code>short</code>s in the source array.
170 * @exception IndexOutOfBoundsException If the preconditions on the offset
171 * and length parameters do not hold
172 * @exception ReadOnlyBufferException If this buffer is read-only.
173 */
174 public ShortBuffer put (short[] src, int offset, int length)
175 {
176 checkArraySize(src.length, offset, length);
177 checkForOverflow(length);
178
179 for (int i = offset; i < offset + length; i++)
180 put (src [i]);
181
182 return this;
183 }
184
185 /**
186 * Writes the content of the the <code>short array</code> src
187 * into the buffer.
188 *
189 * @param src The array to copy into the buffer.
190 *
191 * @exception BufferOverflowException If there is insufficient space in this
192 * buffer for the remaining <code>short</code>s in the source array.
193 * @exception ReadOnlyBufferException If this buffer is read-only.
194 */
195 public final ShortBuffer put (short[] src)
196 {
197 return put (src, 0, src.length);
198 }
199
200 /**
201 * Tells whether ot not this buffer is backed by an accessible
202 * <code>short</code> array.
203 */
204 public final boolean hasArray ()
205 {
206 return (backing_buffer != null
207 && !isReadOnly ());
208 }
209
210 /**
211 * Returns the <code>short</code> array that backs this buffer.
212 *
213 * @exception ReadOnlyBufferException If this buffer is read-only.
214 * @exception UnsupportedOperationException If this buffer is not backed
215 * by an accessible array.
216 */
217 public final short[] array ()
218 {
219 if (backing_buffer == null)
220 throw new UnsupportedOperationException ();
221
222 checkIfReadOnly();
223
224 return backing_buffer;
225 }
226
227 /**
228 * Returns the offset within this buffer's backing array of the first element.
229 *
230 * @exception ReadOnlyBufferException If this buffer is read-only.
231 * @exception UnsupportedOperationException If this buffer is not backed
232 * by an accessible array.
233 */
234 public final int arrayOffset ()
235 {
236 if (backing_buffer == null)
237 throw new UnsupportedOperationException ();
238
239 checkIfReadOnly();
240
241 return array_offset;
242 }
243
244 /**
245 * Calculates a hash code for this buffer.
246 *
247 * This is done with <code>int</code> arithmetic,
248 * where ** represents exponentiation, by this formula:<br>
249 * <code>s[position()] + 31 + (s[position()+1] + 30)*31**1 + ... +
250 * (s[limit()-1]+30)*31**(limit()-1)</code>.
251 * Where s is the buffer data. Note that the hashcode is dependent
252 * on buffer content, and therefore is not useful if the buffer
253 * content may change.
254 *
255 * @return the hash code
256 */
257 public int hashCode ()
258 {
259 int hashCode = get(position()) + 31;
260 int multiplier = 1;
261 for (int i = position() + 1; i < limit(); ++i)
262 {
263 multiplier *= 31;
264 hashCode += (get(i) + 30)*multiplier;
265 }
266 return hashCode;
267 }
268
269 /**
270 * Checks if this buffer is equal to obj.
271 */
272 public boolean equals (Object obj)
273 {
274 if (obj instanceof ShortBuffer)
275 {
276 return compareTo (obj) == 0;
277 }
278
279 return false;
280 }
281
282 /**
283 * Compares two <code>ShortBuffer</code> objects.
284 *
285 * @exception ClassCastException If obj is not an object derived from
286 * <code>ShortBuffer</code>.
287 */
288 public int compareTo (Object obj)
289 {
290 ShortBuffer other = (ShortBuffer) obj;
291
292 int num = Math.min(remaining(), other.remaining());
293 int pos_this = position();
294 int pos_other = other.position();
295
296 for (int count = 0; count < num; count++)
297 {
298 short a = get(pos_this++);
299 short b = other.get(pos_other++);
300
301 if (a == b)
302 continue;
303
304 if (a < b)
305 return -1;
306
307 return 1;
308 }
309
310 return remaining() - other.remaining();
311 }
312
313 /**
314 * Returns the byte order of this buffer.
315 */
316 public abstract ByteOrder order ();
317
318 /**
319 * Reads the <code>short</code> at this buffer's current position,
320 * and then increments the position.
321 *
322 * @exception BufferUnderflowException If there are no remaining
323 * <code>short</code>s in this buffer.
324 */
325 public abstract short get ();
326
327 /**
328 * Writes the <code>short</code> at this buffer's current position,
329 * and then increments the position.
330 *
331 * @exception BufferOverflowException If there no remaining
332 * <code>short</code>s in this buffer.
333 * @exception ReadOnlyBufferException If this buffer is read-only.
334 */
335 public abstract ShortBuffer put (short b);
336
337 /**
338 * Absolute get method.
339 *
340 * @exception IndexOutOfBoundsException If index is negative or not smaller
341 * than the buffer's limit.
342 */
343 public abstract short get (int index);
344
345 /**
346 * Absolute put method.
347 *
348 * @exception IndexOutOfBoundsException If index is negative or not smaller
349 * than the buffer's limit.
350 * @exception ReadOnlyBufferException If this buffer is read-only.
351 */
352 public abstract ShortBuffer put (int index, short b);
353
354 /**
355 * Compacts this buffer.
356 *
357 * @exception ReadOnlyBufferException If this buffer is read-only.
358 */
359 public abstract ShortBuffer compact ();
360
361 /**
362 * Tells wether or not this buffer is direct.
363 */
364 public abstract boolean isDirect ();
365
366 /**
367 * Creates a new <code>ShortBuffer</code> whose content is a shared
368 * subsequence of this buffer's content.
369 */
370 public abstract ShortBuffer slice ();
371
372 /**
373 * Creates a new <code>ShortBuffer</code> that shares this buffer's
374 * content.
375 */
376 public abstract ShortBuffer duplicate ();
377
378 /**
379 * Creates a new read-only <code>ShortBuffer</code> that shares this
380 * buffer's content.
381 */
382 public abstract ShortBuffer asReadOnlyBuffer ();
383 }
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