jdkmidi class library documentation
Copyright © 2004 J.D. Koftinoff Software, Ltd.
Released under the GNU General Public License (GPL)

---

src/jdkmidi_file.cpp

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/*
 *  libjdkmidi-2004 C++ Class Library for MIDI
 *
 *  Copyright (C) 2004  J.D. Koftinoff Software, Ltd.
 *  www.jdkoftinoff.com
 *  jeffk@jdkoftinoff.com
 *
 *  *** RELEASED UNDER THE GNU GENERAL PUBLIC LICENSE (GPL) April 27, 2004 ***
 *
 *  This program 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 of the License, or
 *  (at your option) any later version.
 *
 *  This program 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 this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/
/*
**  Copyright 1986 to 1998 By J.D. Koftinoff Software, Ltd.
**
**  All rights reserved.
**
**  No one may duplicate this source code in any form for any reason
**  without the written permission given by J.D. Koftinoff Software, Ltd.
**
*/

#include "jdkmidi/world.h"

#include "jdkmidi/file.h"

#if DEBUG_MDFILE
# undef DBG
# define DBG(a) a
#endif

namespace jdkmidi
{
  
  
  MIDIFile::MIDIFile()  
  {
  } 
  
  MIDIFile::~MIDIFile() 
  {
  } 
  
  unsigned long MIDIFile::ConvertTempoToFreq(
    short division,
    MIDITempo &tempo
    ) 
  {
    if( division>0 )
    {
      long clocks_per_beat = (long)division*1000;
      long micro_sec_per_beat = tempo.GetMIDIFileTempo()/1000;
      
      return (unsigned long) clocks_per_beat/micro_sec_per_beat;
    }
    else
    {
      // TO DO: handle smpte frame rate references
      return 120;
    }
  } 
  
  
  unsigned long MIDIFile::ReadVariableLengthNumber( unsigned char **in )  
  {
    unsigned long num=0;
    unsigned char *t=*in;
    
    do
    {
      num <<= 7;
      num |= (*t);
    } while( (*t++)&0x80 );
    
    *in=t;
    return num;
  } 
  
  unsigned char * MIDIFile::WriteVariableLengthNumber( unsigned long num, unsigned char *out )  
  {
    register unsigned long buffer;
    
    buffer = num & 0x7f;
    while( (num >>=7 )>0 )
    {
      buffer <<= 8;
      buffer |=0x80;
      buffer += (num & 0x7f);
    }
    
    do
    {
      *out++ = (unsigned char)buffer;
      if( buffer & 0x80 )
        buffer >>=8;
      else
        break;            
    } while( true );
    
    return out;
  } 
  
}