gomp-20050608-branch/libjava/classpath/java/awt/image/DataBufferByte.java

   1 /* Copyright (C) 2000, 2002  Free Software Foundation
   2
   3 This file is part of GNU Classpath.
   4
   5 GNU Classpath is free software; you can redistribute it and/or modify
   6 it under the terms of the GNU General Public License as published by
   7 the Free Software Foundation; either version 2, or (at your option)
   8 any later version.
   9
  10 GNU Classpath is distributed in the hope that it will be useful, but
  11 WITHOUT ANY WARRANTY; without even the implied warranty of
  12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13 General Public License for more details.
  14
  15 You should have received a copy of the GNU General Public License
  16 along with GNU Classpath; see the file COPYING.  If not, write to the
  17 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  18 02110-1301 USA.
  19
  20 Linking this library statically or dynamically with other modules is
  21 making a combined work based on this library.  Thus, the terms and
  22 conditions of the GNU General Public License cover the whole
  23 combination.
  24
  25 As a special exception, the copyright holders of this library give you
  26 permission to link this library with independent modules to produce an
  27 executable, regardless of the license terms of these independent
  28 modules, and to copy and distribute the resulting executable under
  29 terms of your choice, provided that you also meet, for each linked
  30 independent module, the terms and conditions of the license of that
  31 module.  An independent module is a module which is not derived from
  32 or based on this library.  If you modify this library, you may extend
  33 this exception to your version of the library, but you are not
  34 obligated to do so.  If you do not wish to do so, delete this
  35 exception statement from your version. */
  36
  37 package java.awt.image;
  38
  39 /* This is one of several classes that are nearly identical. Maybe we
  40    should have a central template and generate all these files. This
  41    is one of the cases where templates or macros would have been
  42    useful to have in Java.
  43
  44    This file has been created using search-replace. My only fear is
  45    that these classes will grow out-of-sync as of a result of changes
  46    that are not propagated to the other files. As always, mirroring
  47    code is a maintenance nightmare.  */
  48
  49 /**
  50  * A {@link DataBuffer} that uses an array of <code>byte</code> primitives
  51  * to represent each of its banks.
  52  *
  53  * @author Rolf W. Rasmussen (rolfwr@ii.uib.no)
  54  */
  55 public final class DataBufferByte extends DataBuffer
  56 {
  57   private byte[] data;
  58   private byte[][] bankData;
  59
  60   /**
  61    * Creates a new data buffer with a single data bank containing the
  62    * specified number of <code>byte</code> elements.
  63    *
  64    * @param size the number of elements in the data bank.
  65    */
  66   public DataBufferByte(int size)
  67   {
  68     super(TYPE_BYTE, size, 1, 0);
  69     bankData = new byte[1][];
  70     data = new byte[size];
  71     bankData[0] = data;
  72   }
  73
  74   /**
  75    * Creates a new data buffer with the specified number of data banks,
  76    * each containing the specified number of <code>byte</code> elements.
  77    *
  78    * @param size the number of elements in the data bank.
  79    * @param numBanks the number of data banks.
  80    */
  81   public DataBufferByte(int size, int numBanks)
  82   {
  83     super(TYPE_BYTE, size, numBanks);
  84     bankData = new byte[numBanks][size];
  85     data = bankData[0];
  86   }
  87
  88   /**
  89    * Creates a new data buffer backed by the specified data bank.
  90    * <p>
  91    * Note: there is no exception when <code>dataArray</code> is
  92    * <code>null</code>, but in that case an exception will be thrown
  93    * later if you attempt to access the data buffer.
  94    *
  95    * @param dataArray the data bank.
  96    * @param size the number of elements in the data bank.
  97    */
  98   public DataBufferByte(byte[] dataArray, int size)
  99   {
 100     super(TYPE_BYTE, size, 1, 0);
 101     bankData = new byte[1][];
 102     data = dataArray;
 103     bankData[0] = data;
 104   }
 105
 106   /**
 107    * Creates a new data buffer backed by the specified data bank, with
 108    * the specified offset to the first element.
 109    * <p>
 110    * Note: there is no exception when <code>dataArray</code> is
 111    * <code>null</code>, but in that case an exception will be thrown
 112    * later if you attempt to access the data buffer.
 113    *
 114    * @param dataArray the data bank.
 115    * @param size the number of elements in the data bank.
 116    * @param offset the offset to the first element in the array.
 117    */
 118   public DataBufferByte(byte[] dataArray, int size, int offset)
 119   {
 120     super(TYPE_BYTE, size, 1, offset);
 121     bankData = new byte[1][];
 122     data = dataArray;
 123     bankData[0] = data;
 124   }
 125
 126   /**
 127    * Creates a new data buffer backed by the specified data banks.
 128    *
 129    * @param dataArray the data banks.
 130    * @param size the number of elements in the data bank.
 131    *
 132    * @throws NullPointerException if <code>dataArray</code> is
 133    *         <code>null</code>.
 134    */
 135   public DataBufferByte(byte[][] dataArray, int size)
 136   {
 137     super(TYPE_BYTE, size, dataArray.length);
 138     bankData = dataArray;
 139     data = bankData[0];
 140   }
 141
 142   /**
 143    * Creates a new data buffer backed by the specified data banks, with
 144    * the specified offsets to the first element in each bank.
 145    *
 146    * @param dataArray the data banks.
 147    * @param size the number of elements in the data bank.
 148    * @param offsets the offsets to the first element in each data bank.
 149    *
 150    * @throws NullPointerException if <code>dataArray</code> is
 151    *         <code>null</code>.
 152    */
 153   public DataBufferByte(byte[][] dataArray, int size, int[] offsets)
 154   {
 155     super(TYPE_BYTE, size, dataArray.length, offsets);
 156     bankData = dataArray;
 157     data = bankData[0];
 158   }
 159
 160   /**
 161    * Returns the first data bank.
 162    *
 163    * @return The first data bank.
 164    */
 165   public byte[] getData()
 166   {
 167     return data;
 168   }
 169
 170   /**
 171    * Returns a data bank.
 172    *
 173    * @param bank the bank index.
 174    * @return A data bank.
 175    */
 176   public byte[] getData(int bank)
 177   {
 178     return bankData[bank];
 179   }
 180
 181   /**
 182    * Returns the array underlying this <code>DataBuffer</code>.
 183    *
 184    * @return The data banks.
 185    */
 186   public byte[][] getBankData()
 187   {
 188     return bankData;
 189   }
 190
 191   /**
 192    * Returns an element from the first data bank.  The offset (specified in
 193    * the constructor) is added to <code>i</code> before accessing the
 194    * underlying data array.
 195    *
 196    * @param i the element index.
 197    * @return The element.
 198    */
 199   public int getElem(int i)
 200   {
 201     return data[i+offset] & 0xff; // get unsigned byte as int
 202   }
 203
 204   /**
 205    * Returns an element from a particular data bank.  The offset (specified in
 206    * the constructor) is added to <code>i</code> before accessing the
 207    * underlying data array.
 208    *
 209    * @param bank the bank index.
 210    * @param i the element index.
 211    * @return The element.
 212    */
 213   public int getElem(int bank, int i)
 214   {
 215     // get unsigned byte as int
 216     return bankData[bank][i+offsets[bank]] & 0xff;
 217   }
 218
 219   /**
 220    * Sets an element in the first data bank.  The offset (specified in the
 221    * constructor) is added to <code>i</code> before updating the underlying
 222    * data array.
 223    *
 224    * @param i the element index.
 225    * @param val the new element value.
 226    */
 227   public void setElem(int i, int val)
 228   {
 229     data[i+offset] = (byte) val;
 230   }
 231
 232   /**
 233    * Sets an element in a particular data bank.  The offset (specified in the
 234    * constructor) is added to <code>i</code> before updating the underlying
 235    * data array.
 236    *
 237    * @param bank the data bank index.
 238    * @param i the element index.
 239    * @param val the new element value.
 240    */
 241   public void setElem(int bank, int i, int val)
 242   {
 243     bankData[bank][i+offsets[bank]] = (byte) val;
 244   }
 245 }