Source for gnu.java.security.util.ByteBufferOutputStream

   1: /* ByteBufferOutputStream.java -- output stream with a growable underlying
   2:                                   byte buffer.
   3:    Copyright (C) 2006  Free Software Foundation, Inc.
   4: 
   5: This file is a part of GNU Classpath.
   6: 
   7: GNU Classpath is free software; you can redistribute it and/or modify
   8: it under the terms of the GNU General Public License as published by
   9: the Free Software Foundation; either version 2 of the License, or (at
  10: your option) any later version.
  11: 
  12: GNU Classpath is distributed in the hope that it will be useful, but
  13: WITHOUT ANY WARRANTY; without even the implied warranty of
  14: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15: General Public License for more details.
  16: 
  17: You should have received a copy of the GNU General Public License
  18: along with GNU Classpath; if not, write to the Free Software
  19: Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301
  20: USA
  21: 
  22: Linking this library statically or dynamically with other modules is
  23: making a combined work based on this library.  Thus, the terms and
  24: conditions of the GNU General Public License cover the whole
  25: combination.
  26: 
  27: As a special exception, the copyright holders of this library give you
  28: permission to link this library with independent modules to produce an
  29: executable, regardless of the license terms of these independent
  30: modules, and to copy and distribute the resulting executable under
  31: terms of your choice, provided that you also meet, for each linked
  32: independent module, the terms and conditions of the license of that
  33: module.  An independent module is a module which is not derived from
  34: or based on this library.  If you modify this library, you may extend
  35: this exception to your version of the library, but you are not
  36: obligated to do so.  If you do not wish to do so, delete this
  37: exception statement from your version. */
  38: 
  39: 
  40: package gnu.java.security.util;
  41: 
  42: import java.io.IOException;
  43: import java.io.OutputStream;
  44: 
  45: import java.nio.ByteBuffer;
  46: 
  47: /**
  48:  * An output stream that writes bytes to a ByteBuffer, which will be resized
  49:  * if more space is needed.
  50:  *
  51:  * @author Casey Marshall (csm@gnu.org)
  52:  */
  53: public class ByteBufferOutputStream extends OutputStream
  54: {
  55:   private ByteBuffer buffer;
  56: 
  57:   public ByteBufferOutputStream()
  58:   {
  59:     this(256);
  60:   }
  61: 
  62:   public ByteBufferOutputStream(int initialCapacity)
  63:   {
  64:     buffer = ByteBuffer.allocate(initialCapacity);
  65:   }
  66: 
  67:   /* (non-Javadoc)
  68:    * @see java.io.OutputStream#write(int)
  69:    */
  70:   public @Override synchronized void write(int b) throws IOException
  71:   {
  72:     if (!buffer.hasRemaining())
  73:       growBuffer();
  74:     buffer.put((byte) b);
  75:   }
  76: 
  77:   public @Override synchronized void write(byte[] b, int offset, int length)
  78:   {
  79:     if (buffer.remaining() < length)
  80:       growBuffer();
  81:     buffer.put(b, offset, length);
  82:   }
  83: 
  84:   public @Override void write(byte[] b)
  85:   {
  86:     write(b, 0, b.length);
  87:   }
  88: 
  89:   /**
  90:    * Get the current state of the buffer. The returned buffer will have
  91:    * its position set to zero, its capacity set to the current limit,
  92:    * and its limit set to its capacity.
  93:    *
  94:    * @return The buffer.
  95:    */
  96:   public ByteBuffer buffer()
  97:   {
  98:     return ((ByteBuffer) buffer.duplicate().flip()).slice();
  99:   }
 100: 
 101:   public String toString()
 102:   {
 103:     return super.toString() + " [ buffer: " + buffer + " ]";
 104:   }
 105: 
 106:   private void growBuffer()
 107:   {
 108:     int newCapacity = buffer.capacity();
 109:     if (newCapacity < 16384) // If the buffer isn't huge yet, double its size
 110:       newCapacity = newCapacity << 1;
 111:     else // Otherwize, increment by a bit.
 112:       newCapacity += 4096;
 113:     ByteBuffer newBuffer = ByteBuffer.allocate(newCapacity);
 114:     buffer.flip();
 115:     newBuffer.put(buffer);
 116:     buffer = newBuffer;
 117:   }
 118: }