[latency api] add latent test client for latency api

git-svn-id: svn+ssh://jackaudio.org/trunk/jack@4099 0c269be4-1314-0410-8aa9-9f06e86f4224

example-clients/Makefile.am

@@ -20,6 +20,7 @@ bin_PROGRAMS = jack_simple_client \
 	       jack_showtime \
 	       jack_midisine \
 	       jack_midiseq \
+	       jack_latent_client \
 	       $(JACKREC)
 
 if HAVE_SNDFILE
@@ -62,6 +63,10 @@ jack_midisine_SOURCES = midisine.c
 jack_midisine_LDFLAGS = @OS_LDFLAGS@
 jack_midisine_LDADD = $(top_builddir)/libjack/libjack.la
 
+jack_latent_client_SOURCES = latent_client.c
+jack_latent_client_LDFLAGS = @OS_LDFLAGS@
+jack_latent_client_LDADD = $(top_builddir)/libjack/libjack.la
+
 if HAVE_SNDFILE
 jack_rec_SOURCES = capture_client.c
 jack_rec_LDFLAGS = @SNDFILE_LIBS@ @OS_LDFLAGS@

example-clients/latent_client.c

@@ -0,0 +1,209 @@
+/** @file simple_client.c
+ *
+ * @brief This simple client demonstrates the most basic features of JACK
+ * as they would be used by many applications.
+ */
+
+#include <stdio.h>
+#include <errno.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <jack/jack.h>
+
+jack_port_t *input_port;
+jack_port_t *output_port;
+jack_client_t *client;
+
+jack_default_audio_sample_t *delay_line;
+jack_nframes_t delay_index;
+jack_nframes_t latency = 1024;
+
+/**
+ * The process callback for this JACK application is called in a
+ * special realtime thread once for each audio cycle.
+ *
+ * This client does nothing more than copy data from its input
+ * port to its output port. It will exit when stopped by 
+ * the user (e.g. using Ctrl-C on a unix-ish operating system)
+ */
+int
+process (jack_nframes_t nframes, void *arg)
+{
+	jack_default_audio_sample_t *in, *out;
+	int k;
+	
+	in = jack_port_get_buffer (input_port, nframes);
+	out = jack_port_get_buffer (output_port, nframes);
+
+	for (k=0; k<nframes; k++) {
+		out[k] = delay_line[delay_index];
+		delay_line[delay_index] = in[k];
+		delay_index = (delay_index + 1) % latency;
+	}	
+
+	return 0;      
+}
+
+int
+latency_cb (jack_latency_callback_mode_t mode, void *arg)
+{
+	jack_latency_range_t range;
+	if (mode == JackCaptureLatency) {
+		jack_port_get_latency_range (input_port, mode, &range);
+		range.min += latency;
+		range.max += latency;
+		jack_port_set_latency_range (output_port, mode, &range);
+	} else {
+		jack_port_get_latency_range (output_port, mode, &range);
+		range.min += latency;
+		range.max += latency;
+		jack_port_set_latency_range (input_port, mode, &range);
+	}
+
+	return 0;
+}
+
+/**
+ * JACK calls this shutdown_callback if the server ever shuts down or
+ * decides to disconnect the client.
+ */
+void
+jack_shutdown (void *arg)
+{
+	exit (1);
+}
+
+int
+main (int argc, char *argv[])
+{
+	const char **ports;
+	const char *client_name = "latent";
+	const char *server_name = NULL;
+	jack_options_t options = JackNullOption;
+	jack_status_t status;
+	
+
+	if (argc == 2)
+		latency = atoi(argv[1]);
+
+	delay_line = malloc( latency * sizeof(jack_default_audio_sample_t));
+	if (delay_line == NULL) {
+		fprintf (stderr, "no memory");
+		exit(1);
+	}
+
+	memset (delay_line, 0, latency * sizeof(jack_default_audio_sample_t));
+
+	/* open a client connection to the JACK server */
+
+	client = jack_client_open (client_name, options, &status, server_name);
+	if (client == NULL) {
+		fprintf (stderr, "jack_client_open() failed, "
+			 "status = 0x%2.0x\n", status);
+		if (status & JackServerFailed) {
+			fprintf (stderr, "Unable to connect to JACK server\n");
+		}
+		exit (1);
+	}
+	if (status & JackServerStarted) {
+		fprintf (stderr, "JACK server started\n");
+	}
+	if (status & JackNameNotUnique) {
+		client_name = jack_get_client_name(client);
+		fprintf (stderr, "unique name `%s' assigned\n", client_name);
+	}
+
+	/* tell the JACK server to call `process()' whenever
+	   there is work to be done.
+	*/
+
+	jack_set_process_callback (client, process, 0);
+
+	/* tell the JACK server to call `latency()' whenever
+	   the latency needs to be recalculated.
+	*/
+	jack_set_latency_callback (client, latency_cb, 0);
+
+	/* tell the JACK server to call `jack_shutdown()' if
+	   it ever shuts down, either entirely, or if it
+	   just decides to stop calling us.
+	*/
+
+	jack_on_shutdown (client, jack_shutdown, 0);
+
+	/* display the current sample rate. 
+	 */
+
+	printf ("engine sample rate: %" PRIu32 "\n",
+		jack_get_sample_rate (client));
+
+	/* create two ports */
+
+	input_port = jack_port_register (client, "input",
+					 JACK_DEFAULT_AUDIO_TYPE,
+					 JackPortIsInput, 0);
+	output_port = jack_port_register (client, "output",
+					  JACK_DEFAULT_AUDIO_TYPE,
+					  JackPortIsOutput, 0);
+
+	if ((input_port == NULL) || (output_port == NULL)) {
+		fprintf(stderr, "no more JACK ports available\n");
+		exit (1);
+	}
+
+	/* Tell the JACK server that we are ready to roll.  Our
+	 * process() callback will start running now. */
+
+	if (jack_activate (client)) {
+		fprintf (stderr, "cannot activate client");
+		exit (1);
+	}
+
+	/* Connect the ports.  You can't do this before the client is
+	 * activated, because we can't make connections to clients
+	 * that aren't running.  Note the confusing (but necessary)
+	 * orientation of the driver backend ports: playback ports are
+	 * "input" to the backend, and capture ports are "output" from
+	 * it.
+	 */
+
+	ports = jack_get_ports (client, NULL, NULL,
+				JackPortIsPhysical|JackPortIsOutput);
+	if (ports == NULL) {
+		fprintf(stderr, "no physical capture ports\n");
+		exit (1);
+	}
+
+	if (jack_connect (client, ports[0], jack_port_name (input_port))) {
+		fprintf (stderr, "cannot connect input ports\n");
+	}
+
+	free (ports);
+	
+	ports = jack_get_ports (client, NULL, NULL,
+				JackPortIsPhysical|JackPortIsInput);
+	if (ports == NULL) {
+		fprintf(stderr, "no physical playback ports\n");
+		exit (1);
+	}
+
+	if (jack_connect (client, jack_port_name (output_port), ports[0])) {
+		fprintf (stderr, "cannot connect output ports\n");
+	}
+
+	free (ports);
+
+	/* keep running until stopped by the user */
+
+	sleep (-1);
+
+	/* this is never reached but if the program
+	   had some other way to exit besides being killed,
+	   they would be important to call.
+	*/
+
+	jack_client_close (client);
+	exit (0);
+}