libs/ardour/raw_midi_parser.cc

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