001    /* FloatBuffer.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: Change gnu.classpath.Pointer to RawData
042    import gnu.gcj.RawData;
043    
044    /**
045     * @since 1.4
046     */
047    public abstract class FloatBuffer extends Buffer
048      implements Comparable<FloatBuffer>
049    {
050      final int array_offset;
051      final float[] backing_buffer;
052    
053      FloatBuffer (int capacity, int limit, int position, int mark,
054                   RawData address, float[] backing_buffer, int array_offset)
055      {
056        super (capacity, limit, position, mark, address);
057        this.backing_buffer = backing_buffer;
058        this.array_offset = array_offset;
059      }
060    
061      /**
062       * Allocates a new <code>FloatBuffer</code> object with a given capacity.
063       */
064      public static FloatBuffer allocate (int capacity)
065      {
066        return new FloatBufferImpl (capacity);
067      }
068    
069      /**
070       * Wraps a <code>float</code> array into a <code>FloatBuffer</code>
071       * object.
072       *
073       * @exception IndexOutOfBoundsException If the preconditions on the offset
074       * and length parameters do not hold
075       */
076      public static final FloatBuffer wrap (float[] array, int offset, int length)
077      {
078        return new FloatBufferImpl (array, 0, array.length, offset + length, offset, -1, false);
079      }
080    
081      /**
082       * Wraps a <code>float</code> array into a <code>FloatBuffer</code>
083       * object.
084       */
085      public static final FloatBuffer wrap (float[] array)
086      {
087        return wrap (array, 0, array.length);
088      }
089    
090      /**
091       * This method transfers <code>float</code>s from this buffer into the given
092       * destination array. Before the transfer, it checks if there are fewer than
093       * length <code>float</code>s remaining in this buffer.
094       *
095       * @param dst The destination array
096       * @param offset The offset within the array of the first <code>float</code>
097       * to be written; must be non-negative and no larger than dst.length.
098       * @param length The maximum number of bytes to be written to the given array;
099       * must be non-negative and no larger than dst.length - offset.
100       *
101       * @exception BufferUnderflowException If there are fewer than length
102       * <code>float</code>s remaining in this buffer.
103       * @exception IndexOutOfBoundsException If the preconditions on the offset
104       * and length parameters do not hold.
105       */
106      public FloatBuffer get (float[] dst, int offset, int length)
107      {
108        checkArraySize(dst.length, offset, length);
109        checkForUnderflow(length);
110    
111        for (int i = offset; i < offset + length; i++)
112          {
113            dst [i] = get ();
114          }
115    
116        return this;
117      }
118    
119      /**
120       * This method transfers <code>float</code>s from this buffer into the given
121       * destination array.
122       *
123       * @param dst The byte array to write into.
124       *
125       * @exception BufferUnderflowException If there are fewer than dst.length
126       * <code>float</code>s remaining in this buffer.
127       */
128      public FloatBuffer get (float[] dst)
129      {
130        return get (dst, 0, dst.length);
131      }
132    
133      /**
134       * Writes the content of the the <code>FloatBUFFER</code> src
135       * into the buffer. Before the transfer, it checks if there is fewer than
136       * <code>src.remaining()</code> space remaining in this buffer.
137       *
138       * @param src The source data.
139       *
140       * @exception BufferOverflowException If there is insufficient space in this
141       * buffer for the remaining <code>float</code>s in the source buffer.
142       * @exception IllegalArgumentException If the source buffer is this buffer.
143       * @exception ReadOnlyBufferException If this buffer is read-only.
144       */
145      public FloatBuffer put (FloatBuffer src)
146      {
147        if (src == this)
148          throw new IllegalArgumentException ();
149    
150        checkForOverflow(src.remaining());
151    
152        if (src.remaining () > 0)
153          {
154            float[] toPut = new float [src.remaining ()];
155            src.get (toPut);
156            put (toPut);
157          }
158    
159        return this;
160      }
161    
162      /**
163       * Writes the content of the the <code>float array</code> src
164       * into the buffer. Before the transfer, it checks if there is fewer than
165       * length space remaining in this buffer.
166       *
167       * @param src The array to copy into the buffer.
168       * @param offset The offset within the array of the first byte to be read;
169       * must be non-negative and no larger than src.length.
170       * @param length The number of bytes to be read from the given array;
171       * must be non-negative and no larger than src.length - offset.
172       *
173       * @exception BufferOverflowException If there is insufficient space in this
174       * buffer for the remaining <code>float</code>s in the source array.
175       * @exception IndexOutOfBoundsException If the preconditions on the offset
176       * and length parameters do not hold
177       * @exception ReadOnlyBufferException If this buffer is read-only.
178       */
179      public FloatBuffer put (float[] src, int offset, int length)
180      {
181        checkArraySize(src.length, offset, length);
182        checkForOverflow(length);
183    
184        for (int i = offset; i < offset + length; i++)
185          put (src [i]);
186    
187        return this;
188      }
189    
190      /**
191       * Writes the content of the the <code>float array</code> src
192       * into the buffer.
193       *
194       * @param src The array to copy into the buffer.
195       *
196       * @exception BufferOverflowException If there is insufficient space in this
197       * buffer for the remaining <code>float</code>s in the source array.
198       * @exception ReadOnlyBufferException If this buffer is read-only.
199       */
200      public final FloatBuffer put (float[] src)
201      {
202        return put (src, 0, src.length);
203      }
204    
205      /**
206       * Tells whether ot not this buffer is backed by an accessible
207       * <code>float</code> array.
208       */
209      public final boolean hasArray ()
210      {
211        return (backing_buffer != null
212                && !isReadOnly ());
213      }
214    
215      /**
216       * Returns the <code>float</code> array that backs this buffer.
217       *
218       * @exception ReadOnlyBufferException If this buffer is read-only.
219       * @exception UnsupportedOperationException If this buffer is not backed
220       * by an accessible array.
221       */
222      public final float[] array ()
223      {
224        if (backing_buffer == null)
225          throw new UnsupportedOperationException ();
226    
227        checkIfReadOnly();
228    
229        return backing_buffer;
230      }
231    
232      /**
233       * Returns the offset within this buffer's backing array of the first element.
234       *
235       * @exception ReadOnlyBufferException If this buffer is read-only.
236       * @exception UnsupportedOperationException If this buffer is not backed
237       * by an accessible array.
238       */
239      public final int arrayOffset ()
240      {
241        if (backing_buffer == null)
242          throw new UnsupportedOperationException ();
243    
244        checkIfReadOnly();
245    
246        return array_offset;
247      }
248    
249      /**
250       * Calculates a hash code for this buffer.
251       *
252       * This is done with <code>int</code> arithmetic,
253       * where ** represents exponentiation, by this formula:<br>
254       * <code>s[position()] + 31 + (s[position()+1] + 30)*31**1 + ... +
255       * (s[limit()-1]+30)*31**(limit()-1)</code>.
256       * Where s is the buffer data, in Float.floatToIntBits() form
257       * Note that the hashcode is dependent on buffer content,
258       * and therefore is not useful if the buffer content may change.
259       *
260       * @return the hash code
261       */
262      public int hashCode ()
263      {
264        int hashCode = Float.floatToIntBits(get(position())) + 31;
265        int multiplier = 1;
266        for (int i = position() + 1; i < limit(); ++i)
267          {
268              multiplier *= 31;
269              hashCode += (Float.floatToIntBits(get(i)) + 30)*multiplier;
270          }
271        return hashCode;
272      }
273    
274      /**
275       * Checks if this buffer is equal to obj.
276       */
277      public boolean equals (Object obj)
278      {
279        if (obj instanceof FloatBuffer)
280          {
281            return compareTo ((FloatBuffer) obj) == 0;
282          }
283    
284        return false;
285      }
286    
287      /**
288       * Compares two <code>FloatBuffer</code> objects.
289       *
290       * @exception ClassCastException If obj is not an object derived from
291       * <code>FloatBuffer</code>.
292       */
293      public int compareTo (FloatBuffer other)
294      {
295        int num = Math.min(remaining(), other.remaining());
296        int pos_this = position();
297        int pos_other = other.position();
298    
299        for (int count = 0; count < num; count++)
300          {
301            float a = get(pos_this++);
302            float b = other.get(pos_other++);
303    
304            if (a == b)
305              continue;
306    
307            if (a < b)
308              return -1;
309    
310            return 1;
311          }
312    
313        return remaining() - other.remaining();
314      }
315    
316      /**
317       * Returns the byte order of this buffer.
318       */
319      public abstract ByteOrder order ();
320    
321      /**
322       * Reads the <code>float</code> at this buffer's current position,
323       * and then increments the position.
324       *
325       * @exception BufferUnderflowException If there are no remaining
326       * <code>float</code>s in this buffer.
327       */
328      public abstract float get ();
329    
330      /**
331       * Writes the <code>float</code> at this buffer's current position,
332       * and then increments the position.
333       *
334       * @exception BufferOverflowException If there no remaining
335       * <code>float</code>s in this buffer.
336       * @exception ReadOnlyBufferException If this buffer is read-only.
337       */
338      public abstract FloatBuffer put (float b);
339    
340      /**
341       * Absolute get method.
342       *
343       * @exception IndexOutOfBoundsException If index is negative or not smaller
344       * than the buffer's limit.
345       */
346      public abstract float get (int index);
347    
348      /**
349       * Absolute put method.
350       *
351       * @exception IndexOutOfBoundsException If index is negative or not smaller
352       * than the buffer's limit.
353       * @exception ReadOnlyBufferException If this buffer is read-only.
354       */
355      public abstract FloatBuffer put (int index, float b);
356    
357      /**
358       * Compacts this buffer.
359       *
360       * @exception ReadOnlyBufferException If this buffer is read-only.
361       */
362      public abstract FloatBuffer compact ();
363    
364      /**
365       * Tells wether or not this buffer is direct.
366       */
367      public abstract boolean isDirect ();
368    
369      /**
370       * Creates a new <code>FloatBuffer</code> whose content is a shared
371       * subsequence of this buffer's content.
372       */
373      public abstract FloatBuffer slice ();
374    
375      /**
376       * Creates a new <code>FloatBuffer</code> that shares this buffer's
377       * content.
378       */
379      public abstract FloatBuffer duplicate ();
380    
381      /**
382       * Creates a new read-only <code>FloatBuffer</code> that shares this
383       * buffer's content.
384       */
385      public abstract FloatBuffer asReadOnlyBuffer ();
386    }