Source for java.nio.ShortBuffer

   1: /* ShortBuffer.java --
   2:    Copyright (C) 2002, 2003, 2004, 2005  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: // GCJ LOCAL: Use RawData instead of gnu.classpath.Pointer
  42: import gnu.gcj.RawData;
  43: 
  44: /**
  45:  * @since 1.4
  46:  */
  47: public abstract class ShortBuffer extends Buffer
  48:   implements Comparable<ShortBuffer>
  49: {
  50:   final int array_offset;
  51:   final short[] backing_buffer;
  52: 
  53:   ShortBuffer (int capacity, int limit, int position,
  54:                int mark, RawData address, short[] backing_buffer,
  55:                int array_offset)
  56:   {
  57:     super (capacity, limit, position, mark, address);
  58:     this.backing_buffer = backing_buffer;
  59:     this.array_offset = array_offset;
  60:   }
  61: 
  62:   /**
  63:    * Allocates a new <code>ShortBuffer</code> object with a given capacity.
  64:    */
  65:   public static ShortBuffer allocate (int capacity)
  66:   {
  67:     return new ShortBufferImpl (capacity);
  68:   }
  69: 
  70:   /**
  71:    * Wraps a <code>short</code> array into a <code>ShortBuffer</code>
  72:    * object.
  73:    *
  74:    * @exception IndexOutOfBoundsException If the preconditions on the offset
  75:    * and length parameters do not hold
  76:    */
  77:   public static final ShortBuffer wrap (short[] array, int offset, int length)
  78:   {
  79:     return new ShortBufferImpl (array, 0, array.length, offset + length, offset, -1, false);
  80:   }
  81: 
  82:   /**
  83:    * Wraps a <code>short</code> array into a <code>ShortBuffer</code>
  84:    * object.
  85:    */
  86:   public static final ShortBuffer wrap (short[] array)
  87:   {
  88:     return wrap (array, 0, array.length);
  89:   }
  90: 
  91:   /**
  92:    * This method transfers <code>short</code>s from this buffer into the given
  93:    * destination array. Before the transfer, it checks if there are fewer than
  94:    * length <code>short</code>s remaining in this buffer.
  95:    *
  96:    * @param dst The destination array
  97:    * @param offset The offset within the array of the first <code>short</code>
  98:    * to be written; must be non-negative and no larger than dst.length.
  99:    * @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: }