common/JackMidiPort.h

   1 /*
   2 Copyright (C) 2007 Dmitry Baikov
   3 Original JACK MIDI API implementation Copyright (C) 2004 Ian Esten
   4
   5 This program is free software; you can redistribute it and/or modify
   6 it under the terms of the GNU Lesser General Public License as published by
   7 the Free Software Foundation; either version 2.1 of the License, or
   8 (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 Lesser General Public License for more details.
  14
  15 You should have received a copy of the GNU Lesser General Public License
  16 along with this program; if not, write to the Free Software
  17 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  18
  19 */
  20
  21 #ifndef __JackMidiPort__
  22 #define __JackMidiPort__
  23
  24 #include "types.h"
  25 #include "JackConstants.h"
  26 #include "JackPlatformPlug.h"
  27 #include <stddef.h>
  28
  29 /** Type for raw event data contained in @ref jack_midi_event_t. */
  30 typedef unsigned char jack_midi_data_t;
  31
  32 /** A Jack MIDI event. */
  33 struct jack_midi_event_t
  34 {
  35     jack_nframes_t    time;   /**< Sample index at which event is valid */
  36     size_t            size;   /**< Number of bytes of data in \a buffer */
  37     jack_midi_data_t *buffer; /**< Raw MIDI data */
  38 };
  39
  40 /** A Jack MIDI port type. */
  41 #define JACK_DEFAULT_MIDI_TYPE "8 bit raw midi"
  42
  43 namespace Jack
  44 {
  45
  46 struct SERVER_EXPORT JackMidiEvent
  47 {
  48     // Most MIDI events are < 4 bytes in size, so we can save a lot, storing them inplace.
  49     enum { INLINE_SIZE_MAX = sizeof(jack_shmsize_t) };
  50
  51     uint32_t time;
  52     jack_shmsize_t size;
  53     union {
  54         jack_shmsize_t offset;
  55         jack_midi_data_t data[INLINE_SIZE_MAX];
  56     };
  57
  58     jack_midi_data_t* GetData(void* buffer)
  59     {
  60         if (size <= INLINE_SIZE_MAX) {
  61             return data;
  62         } else {
  63             return (jack_midi_data_t*)buffer + offset;
  64         }
  65     }
  66 };
  67
  68 /*
  69  * To store events with arbitrarily sized payload, but still have O(1) indexed access
  70  * we use a trick here:
  71  * Events are stored in an linear array from the beginning of the buffer,
  72  * but their data (if not inlined) is stored from the end of the same buffer.
  73  */
  74
  75 struct SERVER_EXPORT JackMidiBuffer
  76 {
  77     enum { MAGIC = 0x900df00d };
  78
  79     uint32_t magic;
  80     jack_shmsize_t buffer_size;
  81     jack_nframes_t nframes;
  82     jack_shmsize_t write_pos; //!< data write position from the end of the buffer.
  83     uint32_t event_count;
  84     uint32_t lost_events;
  85
  86     JackMidiEvent events[1]; // Using 0 size does not compile with older GCC versions, so use 1 here.
  87
  88     int IsValid() const
  89     {
  90         return magic == MAGIC;
  91     }
  92     void Reset(jack_nframes_t nframes);
  93     jack_shmsize_t MaxEventSize() const;
  94
  95     // checks only size constraints.
  96     jack_midi_data_t* ReserveEvent(jack_nframes_t time, jack_shmsize_t size);
  97 };
  98
  99 void MidiBufferInit(void* buffer, size_t buffer_size, jack_nframes_t nframes);
 100
 101 } // namespace Jack
 102
 103 #endif