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livetrax/libs/backends/alsa/alsa_midi.cc

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/*
* Copyright (C) 2014-2018 Robin Gareus <robin@gareus.org>
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*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
#include <unistd.h>
#include <glibmm.h>
#include "alsa_midi.h"
#include "pbd/error.h"
#include "pbd/pthread_utils.h"
#include "pbd/i18n.h"
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using namespace ARDOUR;
#ifndef NDEBUG
#define _DEBUGPRINT(STR) fprintf(stderr, STR);
#else
#define _DEBUGPRINT(STR) ;
#endif
AlsaMidiIO::AlsaMidiIO ()
: _state (-1)
, _running (false)
, _pfds (0)
, _sample_length_us (1e6 / 48000.0)
, _period_length_us (1.024e6 / 48000.0)
, _samples_per_period (1024)
, _rb (0)
{
pthread_mutex_init (&_notify_mutex, 0);
pthread_cond_init (&_notify_ready, 0);
// MIDI (hw port) 31.25 kbaud
// worst case here is 8192 SPP and 8KSPS for which we'd need
// 4000 bytes sans MidiEventHeader.
// since we're not always in sync, let's use 4096.
_rb = new PBD::RingBuffer<uint8_t>(4096 + 4096 * sizeof(MidiEventHeader));
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}
AlsaMidiIO::~AlsaMidiIO ()
{
delete _rb;
pthread_mutex_destroy (&_notify_mutex);
pthread_cond_destroy (&_notify_ready);
free (_pfds);
}
static void * pthread_process (void *arg)
{
AlsaMidiIO *d = static_cast<AlsaMidiIO *>(arg);
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pthread_set_name ("AlsaMidiIO");
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d->main_process_thread ();
pthread_exit (0);
return 0;
}
int
AlsaMidiIO::start ()
{
if (pbd_realtime_pthread_create (PBD_SCHED_FIFO, PBD_RT_PRI_MIDI, PBD_RT_STACKSIZE_HELP,
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&_main_thread, pthread_process, this))
{
if (pthread_create (&_main_thread, NULL, pthread_process, this)) {
PBD::error << _("AlsaMidiIO: Failed to create process thread.") << endmsg;
return -1;
} else {
PBD::warning << _("AlsaMidiIO: Cannot acquire realtime permissions.") << endmsg;
}
}
int timeout = 5000;
while (!_running && --timeout > 0) { Glib::usleep (1000); }
if (timeout == 0 || !_running) {
return -1;
}
return 0;
}
int
AlsaMidiIO::stop ()
{
void *status;
if (!_running) {
return 0;
}
_running = false;
pthread_mutex_lock (&_notify_mutex);
pthread_cond_signal (&_notify_ready);
pthread_mutex_unlock (&_notify_mutex);
if (pthread_join (_main_thread, &status)) {
PBD::error << _("AlsaMidiIO: Failed to terminate.") << endmsg;
return -1;
}
return 0;
}
void
AlsaMidiIO::setup_timing (const size_t samples_per_period, const float samplerate)
{
_period_length_us = (double) samples_per_period * 1e6 / samplerate;
_sample_length_us = 1e6 / samplerate;
_samples_per_period = samples_per_period;
}
void
AlsaMidiIO::sync_time (const uint64_t tme)
{
// TODO consider a PLL, if this turns out to be the bottleneck for jitter
// also think about using
// snd_pcm_status_get_tstamp() and snd_rawmidi_status_get_tstamp()
// instead of monotonic clock.
#ifdef DEBUG_TIMING
double tdiff = (_clock_monotonic + _period_length_us - tme) / 1000.0;
if (abs(tdiff) >= .05) {
printf("AlsaMidiIO MJ: %.1f ms\n", tdiff);
}
#endif
_clock_monotonic = tme;
}
///////////////////////////////////////////////////////////////////////////////
AlsaMidiOut::AlsaMidiOut ()
: AlsaMidiIO ()
{
}
int
AlsaMidiOut::send_event (const pframes_t time, const uint8_t *data, const size_t size)
{
const uint32_t buf_size = sizeof (MidiEventHeader) + size;
if (_rb->write_space() < buf_size) {
_DEBUGPRINT("AlsaMidiOut: ring buffer overflow\n");
return -1;
}
struct MidiEventHeader h (_clock_monotonic + time * _sample_length_us, size);
_rb->write ((uint8_t*) &h, sizeof(MidiEventHeader));
_rb->write (data, size);
if (pthread_mutex_trylock (&_notify_mutex) == 0) {
pthread_cond_signal (&_notify_ready);
pthread_mutex_unlock (&_notify_mutex);
}
return 0;
}
///////////////////////////////////////////////////////////////////////////////
AlsaMidiIn::AlsaMidiIn ()
: AlsaMidiIO ()
{
}
size_t
AlsaMidiIn::recv_event (pframes_t &time, uint8_t *data, size_t &size)
{
const uint32_t read_space = _rb->read_space();
struct MidiEventHeader h(0,0);
if (read_space <= sizeof(MidiEventHeader)) {
return 0;
}
PBD::RingBuffer<uint8_t>::rw_vector vector;
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_rb->get_read_vector(&vector);
if (vector.len[0] >= sizeof(MidiEventHeader)) {
memcpy((uint8_t*)&h, vector.buf[0], sizeof(MidiEventHeader));
} else {
if (vector.len[0] > 0) {
memcpy ((uint8_t*)&h, vector.buf[0], vector.len[0]);
}
assert(vector.buf[1]);
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memcpy (((uint8_t*)&h) + vector.len[0], vector.buf[1], sizeof(MidiEventHeader) - vector.len[0]);
}
if (h.time >= _clock_monotonic + _period_length_us ) {
#ifdef DEBUG_TIMING
printf("AlsaMidiIn DEBUG: POSTPONE EVENT TO NEXT CYCLE: %.1f spl\n", ((h.time - _clock_monotonic) / _sample_length_us));
#endif
return 0;
}
_rb->increment_read_idx (sizeof(MidiEventHeader));
assert (h.size > 0);
if (h.size > size) {
_DEBUGPRINT("AlsaMidiIn::recv_event MIDI event too large!\n");
_rb->increment_read_idx (h.size);
return 0;
}
if (_rb->read (&data[0], h.size) != h.size) {
_DEBUGPRINT("AlsaMidiIn::recv_event Garbled MIDI EVENT DATA!!\n");
return 0;
}
if (h.time < _clock_monotonic) {
#ifdef DEBUG_TIMING
printf("AlsaMidiIn DEBUG: MIDI TIME < 0 %.1f spl\n", ((_clock_monotonic - h.time) / -_sample_length_us));
#endif
time = 0;
} else if (h.time >= _clock_monotonic + _period_length_us ) {
#ifdef DEBUG_TIMING
printf("AlsaMidiIn DEBUG: MIDI TIME > PERIOD %.1f spl\n", ((h.time - _clock_monotonic) / _sample_length_us));
#endif
time = _samples_per_period - 1;
} else {
time = floor ((h.time - _clock_monotonic) / _sample_length_us);
}
assert(time < _samples_per_period);
size = h.size;
return h.size;
}
int
AlsaMidiIn::queue_event (const uint64_t time, const uint8_t *data, const size_t size) {
const uint32_t buf_size = sizeof(MidiEventHeader) + size;
if (size == 0) {
return -1;
}
if (_rb->write_space() < buf_size) {
_DEBUGPRINT("AlsaMidiIn: ring buffer overflow\n");
return -1;
}
struct MidiEventHeader h (time, size);
_rb->write ((uint8_t*) &h, sizeof(MidiEventHeader));
_rb->write (data, size);
return 0;
}