libs/ardour/raw_midi_parser.cc

   1 /*
   2  * Copyright (C) 2014,2017 Robin Gareus <robin@gareus.org>
   3  * Copyright (C) 2010 Devin Anderson
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU General Public License
   7  * as published by the Free Software Foundation; either version 2
   8  * of the License, or (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  18  */
  19
  20 #include "ardour/raw_midi_parser.h"
  21
  22 using namespace ARDOUR;
  23
  24 RawMidiParser::RawMidiParser ()
  25 {
  26         reset ();
  27 }
  28
  29 /* based on AlsaRawMidiIn, some code-dup */
  30 bool
  31 RawMidiParser::process_byte (const uint8_t byte)
  32 {
  33         if (byte >= 0xf8) {
  34                 // Realtime
  35                 if (byte == 0xfd) {
  36                         return false;
  37                 }
  38                 prepare_byte_event (byte);
  39                 return true;
  40         }
  41         if (byte == 0xf7) {
  42                 // Sysex end
  43                 if (_status_byte == 0xf0) {
  44                         record_byte (byte);
  45                         return prepare_buffered_event ();
  46                 }
  47                 _total_bytes = 0;
  48                 _unbuffered_bytes = 0;
  49                 _expected_bytes = 0;
  50                 _status_byte = 0;
  51                 return false;
  52         }
  53         if (byte >= 0x80) {
  54                 // Non-realtime status byte
  55                 if (_total_bytes) {
  56                         _total_bytes = 0;
  57                         _unbuffered_bytes = 0;
  58                 }
  59                 _status_byte = byte;
  60                 switch (byte & 0xf0) {
  61                         case 0x80:
  62                         case 0x90:
  63                         case 0xa0:
  64                         case 0xb0:
  65                         case 0xe0:
  66                                 // Note On, Note Off, Aftertouch, Control Change, Pitch Wheel
  67                                 _expected_bytes = 3;
  68                                 break;
  69                         case 0xc0:
  70                         case 0xd0:
  71                                 // Program Change, Channel Pressure
  72                                 _expected_bytes = 2;
  73                                 break;
  74                         case 0xf0:
  75                                 switch (byte) {
  76                                         case 0xf0:
  77                                                 // Sysex
  78                                                 _expected_bytes = 0;
  79                                                 break;
  80                                         case 0xf1:
  81                                         case 0xf3:
  82                                                 // MTC Quarter Frame, Song Select
  83                                                 _expected_bytes = 2;
  84                                                 break;
  85                                         case 0xf2:
  86                                                 // Song Position
  87                                                 _expected_bytes = 3;
  88                                                 break;
  89                                         case 0xf4:
  90                                         case 0xf5:
  91                                                 // Undefined
  92                                                 _expected_bytes = 0;
  93                                                 _status_byte = 0;
  94                                                 return false;
  95                                         case 0xf6:
  96                                                 // Tune Request
  97                                                 prepare_byte_event (byte);
  98                                                 _expected_bytes = 0;
  99                                                 _status_byte = 0;
 100                                                 return true;
 101                                 }
 102                 }
 103                 record_byte (byte);
 104                 return false;
 105         }
 106         // Data byte
 107         if (!_status_byte) {
 108                 // Data bytes without a status will be discarded.
 109                 _total_bytes++;
 110                 _unbuffered_bytes++;
 111                 return false;
 112         }
 113         if (!_total_bytes) {
 114                 record_byte (_status_byte);
 115         }
 116         record_byte (byte);
 117         return (_total_bytes == _expected_bytes) ? prepare_buffered_event () : false;
 118 }