Source for gnu.javax.sound.midi.file.MidiDataOutputStream

   1: /* MidiDataOutputStream.java -- adds variable length MIDI ints
   2:    Copyright (C) 2006 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: package gnu.javax.sound.midi.file;
  39: 
  40: import java.io.DataOutputStream;
  41: import java.io.IOException;
  42: import java.io.OutputStream;
  43: 
  44: /**
  45:  * MidiDataOutputStream is simply a DataOutputStream with the addition
  46:  * of special variable length int writing as defined by the MIDI spec.
  47:  *
  48:  * @author Anthony Green (green@redhat.com)
  49:  */
  50: public class MidiDataOutputStream
  51:     extends DataOutputStream
  52: {
  53:   /**
  54:    * Create a MidiDataOutputStream.
  55:    */
  56:   public MidiDataOutputStream(OutputStream os)
  57:   {
  58:     super(os);
  59:   }
  60: 
  61:   /**
  62:    * Return the length of a variable length encoded int without
  63:    * writing it out.
  64:    *
  65:    * @return the length of the encoding
  66:    */
  67:   public int variableLengthIntLength (int value)
  68:   {
  69:     int length = 0;
  70:     int buffer = value & 0x7F;
  71: 
  72:     while ((value >>= 7) != 0)
  73:       {
  74:         buffer <<= 8;
  75:         buffer |= ((value & 0x7F) | 0x80);
  76:       }
  77: 
  78:     while (true)
  79:       {
  80:         length++;
  81:         if ((buffer & 0x80) != 0)
  82:           buffer >>>= 8;
  83:         else
  84:           break;
  85:       }
  86: 
  87:     return length;
  88:   }
  89: 
  90:   /**
  91:    * Write an int encoded in the MIDI-style variable length
  92:    * encoding format.
  93:    */
  94:   public synchronized void writeVariableLengthInt (int value)
  95:     throws IOException
  96:   {
  97:     int buffer = value & 0x7F;
  98: 
  99:     while ((value >>= 7) != 0)
 100:       {
 101:         buffer <<= 8;
 102:         buffer |= ((value & 0x7F) | 0x80);
 103:       }
 104: 
 105:     while (true)
 106:       {
 107:         writeByte(buffer & 0xff);
 108:         if ((buffer & 0x80) != 0)
 109:           buffer >>>= 8;
 110:         else
 111:           break;
 112:       }
 113:   }
 114: }