lv2-midifunctions.h

   1 /****************************************************************************
   2
   3     lv2-midifunctions.h - support file for using MIDI in LV2 plugins
   4
   5     Copyright (C) 2006  Lars Luthman <lars.luthman@gmail.com>
   6
   7     This program is free software; you can redistribute it and/or modify
   8     it under the terms of the GNU Lesser General Public License as published by
   9     the Free Software Foundation; either version 2 of the License, or
  10     (at your option) any later version.
  11
  12     This program is distributed in the hope that it will be useful,
  13     but WITHOUT ANY WARRANTY; without even the implied warranty of
  14     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15     GNU General Public License for more details.
  16
  17     You should have received a copy of the GNU Lesser General Public License
  18     along with this program; if not, write to the Free Software
  19     Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 01222-1307  USA
  20
  21 ****************************************************************************/
  22
  23 #ifndef LV2_MIDIFUNCTIONS
  24 #define LV2_MIDIFUNCTIONS
  25
  26 #include "lv2-miditype.h"
  27
  28
  29 typedef struct {
  30   const LV2_MIDI* midi;
  31   uint32_t frame_count;
  32   uint32_t position;
  33 } LV2_MIDIState;
  34
  35
  36 static double lv2midi_get_event(LV2_MIDIState* state,
  37                                 double* timestamp,
  38                                 uint32_t* size,
  39                                 unsigned char** data) {
  40
  41   if (state->position >= state->midi->size) {
  42     state->position = state->midi->size;
  43     *timestamp = state->frame_count;
  44     *size = 0;
  45     *data = NULL;
  46     return *timestamp;
  47   }
  48
  49   *timestamp = *(double*)(state->midi->data + state->position);
  50   *size = *(size_t*)(state->midi->data + state->position + sizeof(double));
  51   *data = state->midi->data + state->position +
  52     sizeof(double) + sizeof(size_t);
  53   return *timestamp;
  54 }
  55
  56
  57 static double lv2midi_step(LV2_MIDIState* state) {
  58
  59   if (state->position >= state->midi->size) {
  60     state->position = state->midi->size;
  61     return state->frame_count;
  62   }
  63
  64   state->position += sizeof(double);
  65   size_t size = *(size_t*)(state->midi->data + state->position);
  66   state->position += sizeof(size_t);
  67   state->position += size;
  68   return *(double*)(state->midi->data + state->position);
  69 }
  70
  71
  72 #endif
  73