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#include "../buffer/audio.h"
#include "mixer.h"
#include "audio.h"
// Should an initial read from within start() be marked as silence or not.
#define MIXER_WANT_INITIAL_SILENCE 1
// Number of silent frames to append before signaling MIXER_EMPTY.
#define MIXER_TRAILING_SILENCE 12
static s32 data_callback(void *userdata, u8 *data, s32 frame_count, bool *silence)
{
struct camu_mixer *mixer = (struct camu_mixer *)userdata;
ptrdiff_t req = (ptrdiff_t)camu_audio_format_samples_to_bytes(&mixer->fmt.req, (size_t)frame_count);
#ifdef CAMU_MIXER_THREADED_START_STOP
if (UNLIKELY(atomic_load(bool)(&mixer->paused, AL_ATOMIC_RELAXED))) {
al_memset(data, 0, req);
*silence = MIXER_WANT_INITIAL_SILENCE;
} else {
#endif
#ifdef CAMU_MIXER_THREADED
if (atomic_load(bool)(&mixer->queued, AL_ATOMIC_RELAXED)) {
camu_mixer_run_queue(mixer);
}
#endif
if (UNLIKELY(mixer->empty_after > 0)) {
if (--mixer->empty_after == 0) {
mixer->callback(mixer->userdata, CAMU_MIXER_EMPTY);
}
*silence = false;
} else {
*silence = true;
}
struct camu_audio_buffer *buf;
// Read from all current buffers on each callback to
// emulate the behavior of an actual mixer.
al_array_foreach(mixer->buffers, i, buf) {
if (i < mixer->buffers.count - 1) {
camu_audio_buffer_read(buf, data, req);
}
}
struct camu_audio_buffer *probed_for_swap = NULL;
for (;;) {
if (!mixer->buffers.count) {
al_memset(data, 0, req);
} else {
buf = al_array_last(mixer->buffers);
*silence = false;
ptrdiff_t signal;
if ((signal = camu_audio_buffer_read(buf, data, req)) < req) {
// In the case of a swap, two successive buffers cannot share
// the same pointer.
if (buf == probed_for_swap) {
al_memset(data, 0, req);
break;
}
#ifdef CAMU_MIXER_THREADED
if (atomic_load(bool)(&mixer->queued, AL_ATOMIC_RELAXED)) {
camu_mixer_run_queue(mixer);
}
#endif
data += signal;
req = req - signal;
probed_for_swap = buf;
continue;
}
}
break;
}
#ifdef CAMU_MIXER_THREADED_START_STOP
}
#endif
return frame_count;
}
bool camu_mixer_init(struct camu_mixer *mixer, struct camu_audio *audio)
{
mixer->audio = audio;
mixer->audio->data_callback = data_callback;
mixer->audio->userdata = mixer;
mixer->audio->init(mixer->audio, &al_str_c("cmv"));
mixer->volume = 1.f;
atomic_store(bool)(&mixer->paused, true, AL_ATOMIC_RELAXED);
mixer->empty_after = 0;
al_array_init(mixer->buffers);
#ifdef CAMU_MIXER_THREADED
al_array_init(mixer->add_queue);
al_array_init(mixer->rem_queue);
atomic_store(bool)(&mixer->queued, false, AL_ATOMIC_RELAXED);
nn_mutex_init(&mixer->mutex);
#endif
return true;
}
void camu_mixer_pick_format(struct camu_mixer *mixer, struct camu_resampler_format *fmt)
{
mixer->audio->pick_format(mixer->audio, fmt);
}
void camu_mixer_set_volume(struct camu_mixer *mixer, f32 volume)
{
#ifdef CAMU_MIXER_THREADED
nn_mutex_lock(&mixer->mutex);
#endif
mixer->volume = volume;
struct camu_audio_buffer *buf;
al_array_foreach(mixer->buffers, i, buf) {
camu_audio_buffer_set_volume(buf, mixer->volume);
}
#ifdef CAMU_MIXER_THREADED
nn_mutex_unlock(&mixer->mutex);
#endif
}
f32 camu_mixer_offset_volume(struct camu_mixer *mixer, f32 amount)
{
#ifdef CAMU_MIXER_THREADED
nn_mutex_lock(&mixer->mutex);
#endif
if (FLT_MAX - mixer->volume < amount) {
mixer->volume = FLT_MAX;
} else {
mixer->volume = MAX(0.f, mixer->volume + amount);
}
f32 volume = mixer->volume;
struct camu_audio_buffer *buf;
al_array_foreach(mixer->buffers, i, buf) {
camu_audio_buffer_set_volume(buf, mixer->volume);
}
#ifdef CAMU_MIXER_THREADED
nn_mutex_unlock(&mixer->mutex);
#endif
return volume;
}
f64 camu_mixer_get_latency(struct camu_mixer *mixer)
{
return mixer->audio->get_latency(mixer->audio) / 1000000.0;
}
static void add_buffer_internal(struct camu_mixer *mixer, struct camu_audio_buffer *buf)
{
struct camu_audio_buffer *active;
al_array_foreach(mixer->buffers, i, active) {
al_assert(active != buf);
}
camu_audio_buffer_set_volume(buf, mixer->volume);
#ifdef CAMU_MIXER_THREADED
atomic_store(bool)(&buf->ref, true, AL_ATOMIC_RELAXED);
#endif
al_array_push(mixer->buffers, buf);
}
static void remove_buffer_internal(struct camu_mixer *mixer, struct camu_audio_buffer *buf)
{
struct camu_audio_buffer *added;
al_array_foreach(mixer->buffers, i, added) {
if (added == buf) {
#ifdef CAMU_MIXER_THREADED
atomic_store(bool)(&buf->ref, false, AL_ATOMIC_RELAXED);
#endif
al_array_remove_at(mixer->buffers, i);
break;
}
}
}
#ifdef CAMU_MIXER_THREADED
static void run_queue_internal(struct camu_mixer *mixer)
{
struct camu_audio_buffer *buf;
if (mixer->rem_queue.count > 0) {
al_array_foreach(mixer->rem_queue, i, buf) {
remove_buffer_internal(mixer, buf);
}
mixer->rem_queue.count = 0;
}
if (mixer->add_queue.count > 0) {
al_array_reserve(mixer->buffers, mixer->buffers.count + mixer->add_queue.count);
al_array_foreach(mixer->add_queue, i, buf) {
add_buffer_internal(mixer, buf);
}
mixer->add_queue.count = 0;
}
atomic_store(bool)(&mixer->queued, false, AL_ATOMIC_RELAXED);
if (!mixer->buffers.count) {
mixer->empty_after = MIXER_TRAILING_SILENCE;
} else {
mixer->empty_after = 0;
}
}
#endif
void camu_mixer_add_buffer(struct camu_mixer *mixer, struct camu_audio_buffer *buf)
{
#ifdef CAMU_MIXER_THREADED
nn_mutex_lock(&mixer->mutex);
struct camu_audio_buffer *queued;
al_array_foreach(mixer->add_queue, i, queued) {
if (queued == buf) {
nn_mutex_unlock(&mixer->mutex);
al_assert_and_return();
}
}
al_array_foreach_rev(mixer->rem_queue, i, queued) {
if (queued == buf) {
al_array_remove_at(mixer->rem_queue, i);
bool queue_empty = mixer->add_queue.count + mixer->rem_queue.count == 0;
if (queue_empty) {
atomic_store(bool)(&mixer->queued, false, AL_ATOMIC_RELAXED);
}
nn_mutex_unlock(&mixer->mutex);
return;
}
}
al_array_push(mixer->add_queue, buf);
atomic_store(bool)(&mixer->queued, true, AL_ATOMIC_RELAXED);
nn_mutex_unlock(&mixer->mutex);
#else
add_buffer_internal(mixer, buf);
mixer->empty_after = 0;
#endif
}
void camu_mixer_remove_buffer(struct camu_mixer *mixer, struct camu_audio_buffer *buf)
{
#ifdef CAMU_MIXER_THREADED
nn_mutex_lock(&mixer->mutex);
struct camu_audio_buffer *queued;
al_array_foreach(mixer->rem_queue, i, queued) {
if (queued == buf) {
nn_mutex_unlock(&mixer->mutex);
return;
}
}
al_array_foreach_rev(mixer->add_queue, i, queued) {
if (queued == buf) {
al_array_remove_at(mixer->add_queue, i);
bool queue_empty = mixer->add_queue.count + mixer->rem_queue.count == 0;
if (queue_empty) {
atomic_store(bool)(&mixer->queued, false, AL_ATOMIC_RELAXED);
}
nn_mutex_unlock(&mixer->mutex);
return;
}
}
al_array_push(mixer->rem_queue, buf);
atomic_store(bool)(&mixer->queued, true, AL_ATOMIC_RELAXED);
if (atomic_load(bool)(&mixer->paused, AL_ATOMIC_RELAXED)) {
run_queue_internal(mixer);
}
nn_mutex_unlock(&mixer->mutex);
#else
remove_buffer_internal(mixer, buf);
if (!mixer->buffers.count) {
mixer->empty_after = MIXER_TRAILING_SILENCE;
}
#endif
}
#ifdef CAMU_MIXER_THREADED
void camu_mixer_run_queue(struct camu_mixer *mixer)
{
nn_mutex_lock(&mixer->mutex);
run_queue_internal(mixer);
nn_mutex_unlock(&mixer->mutex);
}
void camu_mixer_clear(struct camu_mixer *mixer)
{
struct camu_audio_buffer *buf;
al_array_foreach(mixer->buffers, i, buf) {
atomic_store(bool)(&buf->ref, false, AL_ATOMIC_RELAXED);
}
}
#endif
void camu_mixer_pause(struct camu_mixer *mixer)
{
#ifdef CAMU_MIXER_THREADED_START_STOP
nn_mutex_lock(&mixer->mutex);
#endif
if (!atomic_load(bool)(&mixer->paused, AL_ATOMIC_ACQUIRE)) {
mixer->audio->stop(mixer->audio);
atomic_store(bool)(&mixer->paused, true, AL_ATOMIC_RELEASE);
}
#ifdef CAMU_MIXER_THREADED
// This requires that stop() blocks until the output actually stops.
run_queue_internal(mixer);
#endif
#ifdef CAMU_MIXER_THREADED_START_STOP
nn_mutex_unlock(&mixer->mutex);
#endif
}
void camu_mixer_resume(struct camu_mixer *mixer)
{
#ifdef CAMU_MIXER_THREADED_START_STOP
nn_mutex_lock(&mixer->mutex);
#endif
if (atomic_load(bool)(&mixer->paused, AL_ATOMIC_ACQUIRE)) {
// audio->start() can internally call data_callback() or possibly start a thread which
// can call data_callback() before we have a chance to set paused to false.
// MIXER_THREADED_START_STOP: If paused is true in data_callback(), immediately return silence.
// This will avoid a deadlock in the first case described above.
mixer->audio->start(mixer->audio);
atomic_store(bool)(&mixer->paused, false, AL_ATOMIC_RELEASE);
}
#ifdef CAMU_MIXER_THREADED_START_STOP
nn_mutex_unlock(&mixer->mutex);
#endif
}
void camu_mixer_close(struct camu_mixer *mixer)
{
al_array_free(mixer->buffers);
#ifdef CAMU_MIXER_THREADED
al_array_free(mixer->add_queue);
al_array_free(mixer->rem_queue);
nn_mutex_destroy(&mixer->mutex);
#endif
if (mixer->audio) {
mixer->audio->free(&mixer->audio);
}
}
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