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 /** 042 * @since 1.4 043 */ 044 public abstract class FloatBuffer extends Buffer 045 implements Comparable<FloatBuffer> 046 { 047 int array_offset; 048 float[] backing_buffer; 049 050 FloatBuffer (int capacity, int limit, int position, int mark) 051 { 052 super (capacity, limit, position, mark); 053 array_offset = 0; 054 } 055 056 /** 057 * Allocates a new <code>FloatBuffer</code> object with a given capacity. 058 */ 059 public static FloatBuffer allocate (int capacity) 060 { 061 return new FloatBufferImpl (capacity); 062 } 063 064 /** 065 * Wraps a <code>float</code> array into a <code>FloatBuffer</code> 066 * object. 067 * 068 * @exception IndexOutOfBoundsException If the preconditions on the offset 069 * and length parameters do not hold 070 */ 071 public static final FloatBuffer wrap (float[] array, int offset, int length) 072 { 073 return new FloatBufferImpl (array, 0, array.length, offset + length, offset, -1, false); 074 } 075 076 /** 077 * Wraps a <code>float</code> array into a <code>FloatBuffer</code> 078 * object. 079 */ 080 public static final FloatBuffer wrap (float[] array) 081 { 082 return wrap (array, 0, array.length); 083 } 084 085 /** 086 * This method transfers <code>float</code>s from this buffer into the given 087 * destination array. Before the transfer, it checks if there are fewer than 088 * length <code>float</code>s remaining in this buffer. 089 * 090 * @param dst The destination array 091 * @param offset The offset within the array of the first <code>float</code> 092 * to be written; must be non-negative and no larger than dst.length. 093 * @param length The maximum number of bytes to be written to the given array; 094 * must be non-negative and no larger than dst.length - offset. 095 * 096 * @exception BufferUnderflowException If there are fewer than length 097 * <code>float</code>s remaining in this buffer. 098 * @exception IndexOutOfBoundsException If the preconditions on the offset 099 * and length parameters do not hold. 100 */ 101 public FloatBuffer get (float[] 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>float</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>float</code>s remaining in this buffer. 122 */ 123 public FloatBuffer get (float[] dst) 124 { 125 return get (dst, 0, dst.length); 126 } 127 128 /** 129 * Writes the content of the the <code>FloatBUFFER</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>float</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 FloatBuffer put (FloatBuffer src) 141 { 142 if (src == this) 143 throw new IllegalArgumentException (); 144 145 checkForOverflow(src.remaining()); 146 147 if (src.remaining () > 0) 148 { 149 float[] toPut = new float [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>float 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>float</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 FloatBuffer put (float[] 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>float 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>float</code>s in the source array. 193 * @exception ReadOnlyBufferException If this buffer is read-only. 194 */ 195 public final FloatBuffer put (float[] 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>float</code> array. 203 */ 204 public final boolean hasArray () 205 { 206 return (backing_buffer != null 207 && !isReadOnly ()); 208 } 209 210 /** 211 * Returns the <code>float</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 float[] 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, in Float.floatToIntBits() form 252 * Note that the hashcode is dependent on buffer content, 253 * and therefore is not useful if the buffer content may change. 254 * 255 * @return the hash code 256 */ 257 public int hashCode () 258 { 259 int hashCode = Float.floatToIntBits(get(position())) + 31; 260 int multiplier = 1; 261 for (int i = position() + 1; i < limit(); ++i) 262 { 263 multiplier *= 31; 264 hashCode += (Float.floatToIntBits(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 FloatBuffer) 275 { 276 return compareTo ((FloatBuffer) obj) == 0; 277 } 278 279 return false; 280 } 281 282 /** 283 * Compares two <code>FloatBuffer</code> objects. 284 * 285 * @exception ClassCastException If obj is not an object derived from 286 * <code>FloatBuffer</code>. 287 */ 288 public int compareTo (FloatBuffer other) 289 { 290 int num = Math.min(remaining(), other.remaining()); 291 int pos_this = position(); 292 int pos_other = other.position(); 293 294 for (int count = 0; count < num; count++) 295 { 296 float a = get(pos_this++); 297 float b = other.get(pos_other++); 298 299 if (a == b) 300 continue; 301 302 if (a < b) 303 return -1; 304 305 return 1; 306 } 307 308 return remaining() - other.remaining(); 309 } 310 311 /** 312 * Returns the byte order of this buffer. 313 */ 314 public abstract ByteOrder order (); 315 316 /** 317 * Reads the <code>float</code> at this buffer's current position, 318 * and then increments the position. 319 * 320 * @exception BufferUnderflowException If there are no remaining 321 * <code>float</code>s in this buffer. 322 */ 323 public abstract float get (); 324 325 /** 326 * Writes the <code>float</code> at this buffer's current position, 327 * and then increments the position. 328 * 329 * @exception BufferOverflowException If there no remaining 330 * <code>float</code>s in this buffer. 331 * @exception ReadOnlyBufferException If this buffer is read-only. 332 */ 333 public abstract FloatBuffer put (float b); 334 335 /** 336 * Absolute get method. 337 * 338 * @exception IndexOutOfBoundsException If index is negative or not smaller 339 * than the buffer's limit. 340 */ 341 public abstract float get (int index); 342 343 /** 344 * Absolute put method. 345 * 346 * @exception IndexOutOfBoundsException If index is negative or not smaller 347 * than the buffer's limit. 348 * @exception ReadOnlyBufferException If this buffer is read-only. 349 */ 350 public abstract FloatBuffer put (int index, float b); 351 352 /** 353 * Compacts this buffer. 354 * 355 * @exception ReadOnlyBufferException If this buffer is read-only. 356 */ 357 public abstract FloatBuffer compact (); 358 359 /** 360 * Tells wether or not this buffer is direct. 361 */ 362 public abstract boolean isDirect (); 363 364 /** 365 * Creates a new <code>FloatBuffer</code> whose content is a shared 366 * subsequence of this buffer's content. 367 */ 368 public abstract FloatBuffer slice (); 369 370 /** 371 * Creates a new <code>FloatBuffer</code> that shares this buffer's 372 * content. 373 */ 374 public abstract FloatBuffer duplicate (); 375 376 /** 377 * Creates a new read-only <code>FloatBuffer</code> that shares this 378 * buffer's content. 379 */ 380 public abstract FloatBuffer asReadOnlyBuffer (); 381 }