Wrapping up example 4 with reading MIDI

1 files changed, 73 insertions, 1 deletions

diff --git a/example4.c b/example4.c
index c14e5bc..a24680e 100644
--- a/example4.c
+++ b/example4.c
@@ -1,13 +1,19 @@
 #include <stdio.h>
 #include <stdlib.h>
+#include <signal.h>
 #include <alsa/asoundlib.h>
 
 #define CLIENT_NAME "ttdaw"
-#define MAX_MIDI_PORTS 4
+#define MAX_MIDI_PORTS 1
 
 static snd_seq_t *seq_handle;
 static snd_seq_addr_t *ports;
 static int rate = 44100;
+static int stop = 0;
+
+static void sighandler(int sig ATTRIBUTE_UNUSED) {
+	stop = 1;
+}
 
 int main(void) {
 	fprintf(stdout, "Example: Reading MIDI input\n");
@@ -33,12 +39,20 @@ int main(void) {
 		exit(1);
 	}
 
+	// Connecting ports.
 	char *port_name = "28:0";
+	ports = realloc(ports, MAX_MIDI_PORTS * sizeof(snd_seq_addr_t));
 	if (snd_seq_parse_address(seq_handle, &ports[0], port_name) < 0) {
 		fprintf(stderr, "Invalid port %s.\n", port_name);
 		exit(1);
 	}
 
+	// Listing assigned ports.
+	fprintf(stdout, "Ports:\n");
+	for (int j = 0; j < MAX_MIDI_PORTS; j++) {
+		fprintf(stdout, " client: %d, port: %d\n", ports[j].client, ports[j].port);
+	}
+
 	// Connecting ports.
 	for (int i = 0; i < MAX_MIDI_PORTS; ++i) {
 		int err = snd_seq_connect_from(seq_handle, 0, ports[i].client, ports[i].port);
@@ -48,6 +62,64 @@ int main(void) {
 		}
 	}
 
+	if (snd_seq_nonblock(seq_handle, 1) < 0) {
+		fprintf(stderr, "Set nonblock mode failed.");
+		exit(1);
+	}
+
+	signal(SIGINT, sighandler);
+	signal(SIGTERM, sighandler);
+
+	// Reading MIDI device.
+	struct pollfd *pfds;
+	int npfds;
+
+	npfds = snd_seq_poll_descriptors_count(seq_handle, POLLIN);
+	pfds = alloca(sizeof(*pfds) * npfds);
+
+	for (;;) {
+		snd_seq_poll_descriptors(seq_handle, pfds, npfds, POLLIN);
+		if (poll(pfds, npfds, -1) < 0) {
+			break;
+		}
+
+		for (;;) {
+			snd_seq_event_t *ev;
+
+			if (snd_seq_event_input(seq_handle, &ev) < 0) {
+				break;
+			}
+
+			if (ev) {
+				switch (ev->type) {
+					case SND_SEQ_EVENT_NOTEON:
+						printf("%3d:%-3dNote on  %2d, note %d, velocity: %3d\n",
+								ev->source.client, ev->source.port,
+								ev->data.note.channel,
+								ev->data.note.note,
+								ev->data.note.velocity);
+						break;
+
+					case SND_SEQ_EVENT_NOTEOFF:
+						printf("%3d:%-3dNote off\t%2d, note %d\n",
+								ev->source.client, ev->source.port,
+								ev->data.note.channel,
+								ev->data.note.note);
+						break;
+
+
+				} 
+			}
+		}
+
+		fflush(stdout);
+
+		if (stop) {
+			break;
+		}
+	}
+
+	fprintf(stdout, "Finishing up\n");
 	snd_seq_close(seq_handle);
 	return 0;
 }