Source for gnu.CORBA.CDR.AligningOutput

   1: /* AligningOutput.java --
   2:    Copyright (C) 2005 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., 51 Franklin Street, Fifth Floor, Boston, MA
  19: 02110-1301 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 gnu.CORBA.CDR;
  40: 
  41: import java.io.ByteArrayOutputStream;
  42: 
  43: import org.omg.CORBA.BAD_PARAM;
  44: 
  45: /**
  46:  * The input stream with the possibility to align on the
  47:  * word (arbitrary size) boundary.
  48:  *
  49:  * @author Audrius Meskauskas (AudriusA@Bioinformatics.org)
  50:  */
  51: public class AligningOutput
  52:   extends ByteArrayOutputStream
  53: {
  54:   /**
  55:    * The alignment offset.
  56:    */
  57:   private int offset = 0;
  58: 
  59:   /**
  60:    * Create a stream with the default intial buffer size.
  61:    */
  62:   public AligningOutput()
  63:   {
  64:   }
  65: 
  66:   /**
  67:    * Create a stream with the given intial buffer size.
  68:    */
  69:   public AligningOutput(int initial_size)
  70:   {
  71:     super(initial_size);
  72:   }
  73: 
  74:   /**
  75:    * Set the alignment offset, if the index of the first byte in the
  76:    * stream is different from 0.
  77:    */
  78:   public void setOffset(int an_offset)
  79:   {
  80:     offset = an_offset;
  81:   }
  82: 
  83:   /**
  84:    * Skip several bytes, aligning the internal pointer on the
  85:    * selected boundary.
  86:    *
  87:    * @throws BAD_PARAM, minor code 0, the alignment is not possible,
  88:    * usually due the wrong parameter value.
  89:    */
  90:   public void align(int alignment)
  91:   {
  92:     try
  93:       {
  94:         int d = (count + offset) % alignment;
  95:         if (d > 0)
  96:           {
  97:             skip(alignment - d);
  98:           }
  99:       }
 100:     catch (Exception ex)
 101:       {
 102:         BAD_PARAM p = new BAD_PARAM("Unable to align at " + alignment);
 103:         p.initCause(ex);
 104:         throw p;
 105:       }
 106:   }
 107: 
 108:   /**
 109:    * Write the specified number of zero bytes.
 110:    *
 111:    * @param bytes the number of zero bytes to write.
 112:    */
 113:   public void skip(int bytes)
 114:   {
 115:     for (int i = 0; i < bytes; i++)
 116:       {
 117:         write(0);
 118:       }
 119:   }
 120: 
 121:   /**
 122:    * Get the current position in the buffer.
 123:    *
 124:    * @return The position in the buffer, taking offset into consideration.
 125:    */
 126:   public int getPosition()
 127:   {
 128:     return size()+offset;
 129:   }
 130: 
 131:   /**
 132:    * Seek to the given position (not in use).
 133:    */
 134:   public void seek(int position)
 135:   {
 136:     count = position - offset;
 137:   }
 138: 
 139:   /**
 140:    * Get the buffer without copying it. Use with care.
 141:    */
 142:   public byte[] getBuffer()
 143:   {
 144:     return buf;
 145:   }
 146: 
 147: 
 148: }