common/JackMidiAsyncQueue.cpp

   1 /*
   2 Copyright (C) 2010 Devin Anderson
   3
   4 This program is free software; you can redistribute it and/or modify
   5 it under the terms of the GNU Lesser General Public License as published by
   6 the Free Software Foundation; either version 2.1 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 Lesser General Public License for more details.
  13
  14 You should have received a copy of the GNU Lesser General Public License
  15 along with this program; if not, write to the Free Software
  16 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  17
  18 */
  19
  20 #include <new>
  21
  22 #include "JackMidiAsyncQueue.h"
  23
  24 using Jack::JackMidiAsyncQueue;
  25
  26 JackMidiAsyncQueue::JackMidiAsyncQueue(size_t max_bytes, size_t max_messages)
  27 {
  28     data_buffer = new jack_midi_data_t[max_bytes];
  29     byte_ring = jack_ringbuffer_create((max_bytes * sizeof(jack_midi_data_t)) +
  30                                        1);
  31     if (byte_ring) {
  32         info_ring = jack_ringbuffer_create((max_messages * INFO_SIZE) + 1);
  33         if (info_ring) {
  34             jack_ringbuffer_mlock(byte_ring);
  35             jack_ringbuffer_mlock(info_ring);
  36             this->max_bytes = max_bytes;
  37             return;
  38         }
  39         jack_ringbuffer_free(byte_ring);
  40     }
  41     delete[] data_buffer;
  42     throw std::bad_alloc();
  43 }
  44
  45 JackMidiAsyncQueue::~JackMidiAsyncQueue()
  46 {
  47     jack_ringbuffer_free(byte_ring);
  48     jack_ringbuffer_free(info_ring);
  49     delete[] data_buffer;
  50 }
  51
  52 jack_midi_event_t *
  53 JackMidiAsyncQueue::DequeueEvent()
  54 {
  55     jack_midi_event_t *event = 0;
  56     if (jack_ringbuffer_read_space(info_ring) >= INFO_SIZE) {
  57         size_t size;
  58         event = &dequeue_event;
  59         jack_ringbuffer_read(info_ring, (char *) &(event->time),
  60                              sizeof(jack_nframes_t));
  61         jack_ringbuffer_read(info_ring, (char *) &size,
  62                              sizeof(size_t));
  63         jack_ringbuffer_read(byte_ring, (char *) data_buffer,
  64                              size * sizeof(jack_midi_data_t));
  65         event->buffer = data_buffer;
  66         event->size = size;
  67     }
  68     return event;
  69 }
  70
  71 Jack::JackMidiWriteQueue::EnqueueResult
  72 JackMidiAsyncQueue::EnqueueEvent(jack_nframes_t time, size_t size,
  73                                  jack_midi_data_t *buffer)
  74 {
  75     if (size > max_bytes) {
  76         return BUFFER_TOO_SMALL;
  77     }
  78     if (! ((jack_ringbuffer_write_space(info_ring) >= INFO_SIZE) &&
  79            (jack_ringbuffer_write_space(byte_ring) >=
  80             (size * sizeof(jack_midi_data_t))))) {
  81         return BUFFER_FULL;
  82     }
  83     jack_ringbuffer_write(byte_ring, (const char *) buffer,
  84                           size * sizeof(jack_midi_data_t));
  85     jack_ringbuffer_write(info_ring, (const char *) (&time),
  86                           sizeof(jack_nframes_t));
  87     jack_ringbuffer_write(info_ring, (const char *) (&size), sizeof(size_t));
  88     return OK;
  89 }
  90
  91 size_t
  92 JackMidiAsyncQueue::GetAvailableSpace()
  93 {
  94     return jack_ringbuffer_write_space(info_ring) < INFO_SIZE ? 0 :
  95         max_bytes - jack_ringbuffer_read_space(byte_ring);
  96 }