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

   1: /* MidiDataInputStream.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.DataInputStream;
  41: import java.io.IOException;
  42: import java.io.InputStream;
  43: 
  44: /**
  45:  * MidiDataInputStream is simply a DataInputStream with the addition
  46:  * of special variable length int reading as defined by the MIDI spec.
  47:  *
  48:  * @author Anthony Green (green@redhat.com)
  49:  */
  50: public class MidiDataInputStream
  51:     extends DataInputStream
  52: {
  53:   /**
  54:    * Create a MidiDataInputStream.
  55:    */
  56:   public MidiDataInputStream(InputStream is)
  57:   {
  58:     super(is);
  59:   }
  60: 
  61:   /**
  62:    * Read an int encoded in the MIDI-style variable length
  63:    * encoding format.
  64:    *
  65:    * @return an int
  66:    */
  67:   public int readVariableLengthInt()
  68:     throws IOException
  69:   {
  70:     int c, value = readByte();
  71: 
  72:     if ((value & 0x80) != 0)
  73:       {
  74:          value &= 0x7F;
  75:          do
  76:          {
  77:            value = (value << 7) + ((c = readByte()) & 0x7F);
  78:          } while ((c & 0x80) != 0);
  79:       }
  80: 
  81:     return value;
  82:   }
  83: }