implement samples_since cycle start.

libs/backends/coreaudio/coreaudio_backend.cc

@@ -90,6 +90,7 @@ CoreAudioBackend::CoreAudioBackend (AudioEngine& e, AudioBackendInfo& info)
 	, _freewheel_ack (false)
 	, _reinit_thread_callback (false)
 	, _measure_latency (false)
+	, _last_process_start (0)
 	, _audio_device("")
 	, _midi_driver_option(_("None"))
 	, _samplerate (48000)
@@ -416,10 +417,10 @@ static void * pthread_freewheel (void *arg)
 	return 0;
 }
 
-static int process_callback_ptr (void *arg)
+static int process_callback_ptr (void *arg, const uint32_t n_samples, const uint64_t host_time)
 {
 	CoreAudioBackend *d = static_cast<CoreAudioBackend*> (arg);
-	return d->process_callback();
+	return d->process_callback(n_samples, host_time);
 }
 
 int
@@ -452,6 +453,7 @@ CoreAudioBackend::_start (bool for_latency_measurement)
 
 	_freewheel_ack = false;
 	_reinit_thread_callback = true;
+	_last_process_start = 0;
 
 	_pcmio->set_error_callback (error_callback_ptr, this);
 	_pcmio->set_buffer_size_callback (buffer_size_callback_ptr, this);
@@ -648,8 +650,17 @@ CoreAudioBackend::sample_time_at_cycle_start ()
 pframes_t
 CoreAudioBackend::samples_since_cycle_start ()
 {
+	if (!_active_ca || !_run || _freewheeling || _freewheel) {
 		return 0;
 	}
+	if (_last_process_start == 0) {
+		return 0;
+	}
+
+	const uint64_t now = AudioGetCurrentHostTime ();
+	const int64_t elapsed_time_ns = AudioConvertHostTimeToNanos(now - _last_process_start);
+	return std::max((pframes_t)0, (pframes_t)rint(1e-9 * elapsed_time_ns * _samplerate));
+}
 
 uint32_t
 CoreAudioBackend::name_to_id(std::string device_name) const {
@@ -1503,6 +1514,7 @@ CoreAudioBackend::freewheel_thread ()
 			static_cast<CoreMidiBuffer*>((*it)->get_buffer(0))->clear ();
 		}
 
+		_last_process_start = 0;
 		if (engine.process_callback (_samples_per_period)) {
 			pthread_mutex_unlock (&_process_callback_mutex);
 			break;
@@ -1525,7 +1537,7 @@ CoreAudioBackend::freewheel_thread ()
 }
 
 int
-CoreAudioBackend::process_callback ()
+CoreAudioBackend::process_callback (const uint32_t n_samples, const uint64_t host_time)
 {
 	uint32_t i = 0;
 	uint64_t clock1, clock2;
@@ -1548,6 +1560,10 @@ CoreAudioBackend::process_callback ()
 
 	if (pthread_mutex_trylock (&_process_callback_mutex)) {
 		// block while devices are added/removed
+#ifndef NDEBUG
+		printf("Xrun due to device change\n");
+#endif
+		engine.Xrun();
 		return 1;
 	}
 
@@ -1560,8 +1576,6 @@ CoreAudioBackend::process_callback ()
 	/* port-connection change */
 	pre_process();
 
-	const uint32_t n_samples = _pcmio->n_samples();
-
 	// cycle-length in usec
 	const int64_t nominal_time = 1e6 * n_samples / _samplerate;
 
@@ -1595,6 +1609,7 @@ CoreAudioBackend::process_callback ()
 	}
 
 	_midiio->start_cycle();
+	_last_process_start = host_time;
 
 	if (engine.process_callback (n_samples)) {
 		fprintf(stderr, "ENGINE PROCESS ERROR\n");

libs/backends/coreaudio/coreaudio_backend.h

@@ -215,7 +215,7 @@ class CoreAudioBackend : public AudioBackend {
 		bool midi_device_enabled (std::string const) const;
 
 		// really private, but needing static access:
-		int process_callback();
+		int process_callback(uint32_t, uint64_t);
 		void error_callback();
 		void xrun_callback();
 		void buffer_size_callback();
@@ -322,6 +322,8 @@ class CoreAudioBackend : public AudioBackend {
 		bool  _reinit_thread_callback;
 		bool  _measure_latency;
 
+		uint64_t _last_process_start;
+
 		pthread_mutex_t _process_callback_mutex;
 
 		pthread_mutex_t _freewheel_mutex;

libs/backends/coreaudio/coreaudio_pcmio.cc

@@ -765,7 +765,7 @@ int
 CoreAudioPCM::pcm_start (
 		uint32_t device_id_in, uint32_t device_id_out,
 		uint32_t sample_rate, uint32_t samples_per_period,
-		int (process_callback (void*)), void *process_arg)
+		int (process_callback (void*, const uint32_t, const uint64_t)), void *process_arg)
 {
 
 	assert(_device_ids);
@@ -1095,9 +1095,9 @@ CoreAudioPCM::render_callback (
 
 	assert(_playback_channels == 0 || ioData->mNumberBuffers == _playback_channels);
 
+	UInt64 cur_cycle_start = AudioGetCurrentHostTime ();
 	_cur_samples_per_period = inNumberFrames;
 
-
 	if (_capture_channels > 0) {
 		_input_audio_buffer_list->mNumberBuffers = _capture_channels;
 		for (uint32_t i = 0; i < _capture_channels; ++i) {
@@ -1127,7 +1127,7 @@ CoreAudioPCM::render_callback (
 	int rv = -1;
 
 	if (_process_callback) {
-		rv = _process_callback(_process_arg);
+		rv = _process_callback(_process_arg, inNumberFrames, cur_cycle_start);
 	}
 
 	_in_process = false;

libs/backends/coreaudio/coreaudio_pcmio.h

@@ -65,7 +65,7 @@ public:
 			uint32_t output_device,
 			uint32_t sample_rate,
 			uint32_t samples_per_period,
-			int (process_callback (void*)),
+			int (process_callback (void*, const uint32_t, const uint64_t)),
 			void * process_arg
 			);
 
@@ -160,7 +160,7 @@ private:
 	bool     _in_process;
 	size_t   _n_devices;
 
-	int (* _process_callback) (void*);
+	int (* _process_callback) (void*, const uint32_t, const uint64_t);
 	void * _process_arg;
 
 	void (* _error_callback) (void*);