charbufferimpl.java

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/* CharBufferImpl.java -- 
   Copyright (C) 2002 Free Software Foundation, Inc.

This file is part of GNU Classpath.

GNU Classpath is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.

GNU Classpath is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
General Public License for more details.

You should have received a copy of the GNU General Public License
along with GNU Classpath; see the file COPYING.  If not, write to the
Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA.

Linking this library statically or dynamically with other modules is
making a combined work based on this library.  Thus, the terms and
conditions of the GNU General Public License cover the whole
combination.

As a special exception, the copyright holders of this library give you
permission to link this library with independent modules to produce an
executable, regardless of the license terms of these independent
modules, and to copy and distribute the resulting executable under
terms of your choice, provided that you also meet, for each linked
independent module, the terms and conditions of the license of that
module.  An independent module is a module which is not derived from
or based on this library.  If you modify this library, you may extend
this exception to your version of the library, but you are not
obligated to do so.  If you do not wish to do so, delete this
exception statement from your version. */

package gnu.java.nio;

import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.CharBuffer;
import java.nio.ReadOnlyBufferException;

/**
 * This is a Heap memory implementation
 */
public final class CharBufferImpl extends CharBuffer
{
  private boolean readOnly;

  public CharBufferImpl(int cap, int off, int lim)
  {
    super (cap, lim, off, 0);
    this.backing_buffer = new char [cap];
    readOnly = false;
  }
  
  public CharBufferImpl(char[] array, int offset, int length)
  {
    super (array.length, length, offset, 0);
    this.backing_buffer = array;
    readOnly = false;
  }
  
  public CharBufferImpl (CharBufferImpl copy)
  {
    super (copy.capacity (), copy.limit (), copy.position (), 0);
    backing_buffer = copy.backing_buffer;
    readOnly = copy.isReadOnly ();
  }
  
  private static native char[] nio_cast (byte[] copy);

  CharBufferImpl (byte[] copy)
  {
    super (copy.length / 2, copy.length / 2, 0, 0);
    this.backing_buffer = (copy != null ? nio_cast (copy) : null);
    readOnly = false;
  }

  private static native byte nio_get_Byte (CharBufferImpl b, int index, int limit);

  private static native void nio_put_Byte (CharBufferImpl b, int index, int limit, byte value);

  public ByteBuffer asByteBuffer ()
  {
    ByteBufferImpl res = new ByteBufferImpl (backing_buffer);
    res.limit ((limit () * 1) / 2);
    return res;
  }

  
  public boolean isReadOnly()
  {
    return readOnly;
  }
  
  public CharBuffer slice()
  {
    return new CharBufferImpl (this);
  }
  
  public CharBuffer duplicate()
  {
    return new CharBufferImpl(this);
  }
  
  public CharBuffer asReadOnlyBuffer()
  {
    CharBufferImpl result = new CharBufferImpl (this);
    result.readOnly = true;
    return result;
  }
  
  public CharBuffer compact()
  {
    return this;
  }
  
  public boolean isDirect()
  {
    return false;
  }

  final public CharSequence subSequence (int start, int end)
  {
    if (start < 0 ||
        end > length () ||
        start > end)
      throw new IndexOutOfBoundsException ();

    // No support for direct buffers yet.
    // assert array () != null;
    return new CharBufferImpl (array (), position () + start,
                               position () + end);
  }
  
  /**
   * Relative get method. Reads the next character from the buffer.
   */
  final public char get()
  {
    char e = backing_buffer[position()];
    position(position()+1);
    return e;
  }
  
  /**
   * Relative put method. Writes <code>value</code> to the next position
   * in the buffer.
   * 
   * @exception ReadOnlyBufferException If this buffer is read-only.
   */
  final public CharBuffer put(char b)
  {
    if (readOnly)
      throw new ReadOnlyBufferException ();
    
    backing_buffer[position()] = b;
    position(position()+1);
    return this;
  }

  /**
   * Absolute get method. Reads the character at position <code>index</code>.
   *
   * @exception IndexOutOfBoundsException If index is negative or not smaller
   * than the buffer's limit.
   */
  final public char get(int index)
  {
    if (index < 0
        || index >= limit ())
      throw new IndexOutOfBoundsException ();
    
    return backing_buffer[index];
  }
  
  /**
   * Absolute put method. Writes <code>value</value> to position
   * <code>index</code> in the buffer.
   *
   * @exception IndexOutOfBoundsException If index is negative or not smaller
   * than the buffer's limit.
   * @exception ReadOnlyBufferException If this buffer is read-only.
   */
  final public CharBuffer put(int index, char b)
  {
    if (index < 0
        || index >= limit ())
      throw new IndexOutOfBoundsException ();
    
    if (readOnly)
      throw new ReadOnlyBufferException ();
    
    backing_buffer[index] = b;
    return this;
  }


  public final ByteOrder order()
  {
    return ByteOrder.BIG_ENDIAN;
  }
}