libjava/java/nio/CharViewBufferImpl.java

   1 /* CharViewBufferImpl.java --
   2    Copyright (C) 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., 59 Temple Place, Suite 330, Boston, MA
  19 02111-1307 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 class CharViewBufferImpl extends CharBuffer
  42 {
  43   /** Position in bb (i.e. a byte offset) where this buffer starts. */
  44   private int offset;
  45   private ByteBuffer bb;
  46   private boolean readOnly;
  47   private ByteOrder endian;
  48
  49   CharViewBufferImpl (ByteBuffer bb, int capacity)
  50   {
  51     super (capacity, capacity, 0, -1);
  52     this.bb = bb;
  53     this.offset = bb.position();
  54     this.readOnly = bb.isReadOnly();
  55     this.endian = bb.order();
  56     if (bb.isDirect())
  57       this.address = VMDirectByteBuffer.adjustAddress(bb.address, offset);
  58   }
  59
  60   public CharViewBufferImpl (ByteBuffer bb, int offset, int capacity,
  61                              int limit, int position, int mark,
  62                              boolean readOnly, ByteOrder endian)
  63   {
  64     super (capacity, limit, position, mark);
  65     this.bb = bb;
  66     this.offset = offset;
  67     this.readOnly = readOnly;
  68     this.endian = endian;
  69     if (bb.isDirect())
  70       this.address = VMDirectByteBuffer.adjustAddress(bb.address, offset);
  71   }
  72
  73   /**
  74    * Reads the <code>char</code> at this buffer's current position,
  75    * and then increments the position.
  76    *
  77    * @exception BufferUnderflowException If there are no remaining
  78    * <code>char</code>s in this buffer.
  79    */
  80   public char get ()
  81   {
  82     int p = position();
  83     char result = ByteBufferHelper.getChar(bb, (p << 1) + offset, endian);
  84     position(p + 1);
  85     return result;
  86   }
  87
  88   /**
  89    * Absolute get method. Reads the <code>char</code> at position
  90    * <code>index</code>.
  91    *
  92    * @param index Position to read the <code>char</code> from.
  93    *
  94    * @exception IndexOutOfBoundsException If index is negative or not smaller
  95    * than the buffer's limit.
  96    */
  97   public char get (int index)
  98   {
  99     return ByteBufferHelper.getChar(bb, (index << 1) + offset, endian);
 100   }
 101
 102   public CharBuffer put (char value)
 103   {
 104     int p = position();
 105     ByteBufferHelper.putChar(bb, (p << 1) + offset, value, endian);
 106     position(p + 1);
 107     return this;
 108   }
 109
 110   public CharBuffer put (int index, char value)
 111   {
 112     ByteBufferHelper.putChar(bb, (index << 1) + offset, value, endian);
 113     return this;
 114   }
 115
 116   public CharBuffer compact ()
 117   {
 118     if (position () > 0)
 119       {
 120         int count = limit () - position ();
 121         bb.shiftDown(offset, offset + 2 * position(), 2 * count);
 122         position (count);
 123         limit (capacity ());
 124       }
 125     else
 126       {
 127         position(limit());
 128         limit(capacity());
 129       }
 130     return this;
 131   }
 132
 133   public CharBuffer slice ()
 134   {
 135     // Create a sliced copy of this object that shares its content.
 136     return new CharViewBufferImpl (bb, (position () >> 1) + offset,
 137                                    remaining (), remaining (), 0, -1,
 138                                    isReadOnly (), endian);
 139   }
 140
 141   CharBuffer duplicate (boolean readOnly)
 142   {
 143     int pos = position();
 144     reset();
 145     int mark = position();
 146     position(pos);
 147     return new CharViewBufferImpl (bb, offset, capacity(), limit(),
 148                                      pos, mark, readOnly, endian);
 149   }
 150
 151   public CharBuffer duplicate ()
 152   {
 153     return duplicate(readOnly);
 154   }
 155
 156   public CharBuffer asReadOnlyBuffer ()
 157   {
 158     return duplicate(true);
 159   }
 160
 161   public CharSequence subSequence (int start, int end)
 162   {
 163     if (start < 0
 164         || end < start
 165         || end > length ())
 166       throw new IndexOutOfBoundsException ();
 167
 168     return new CharViewBufferImpl (bb, array_offset, capacity (),
 169                                    position () + end, position () + start,
 170                                    -1, isReadOnly (), endian);
 171   }
 172
 173   public boolean isReadOnly ()
 174   {
 175     return readOnly;
 176   }
 177
 178   public boolean isDirect ()
 179   {
 180     return bb.isDirect ();
 181   }
 182
 183   public ByteOrder order ()
 184   {
 185     return endian;
 186   }
 187 }