1 files changed, 124 insertions, 0 deletions
diff --git a/experiments/alsa_midi_controller.c b/experiments/alsa_midi_controller.c
new file mode 100644
index 0000000..3181c29
--- /dev/null
+++ b/experiments/alsa_midi_controller.c
@@ -0,0 +1,124 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <alloca.h>
+#include <signal.h>
+#include <alsa/asoundlib.h>
+
+#define CLIENT_NAME "ttdaw"
+#define MAX_MIDI_PORTS 1
+
+static snd_seq_t *seq_handle;
+static snd_seq_addr_t *ports;
+static int stop = 0;
+
+static void sighandler(int sig ATTRIBUTE_UNUSED) {
+	stop = 1;
+}
+
+int main(void) {
+	fprintf(stdout, "Example: Reading MIDI input\n");
+
+	if (snd_seq_open(&seq_handle, "default", SND_SEQ_OPEN_DUPLEX, 0) < 0) {
+		fprintf(stderr, "Error opening ALSA sequencer.\n");
+		exit(1);
+	}
+
+	if (snd_seq_set_client_name(seq_handle, CLIENT_NAME) < 0) {
+		fprintf(stderr, "Could not set up client name.\n");
+		exit(1);
+	}
+
+	if (snd_seq_create_simple_port(seq_handle, CLIENT_NAME,
+				SND_SEQ_PORT_CAP_WRITE |
+				SND_SEQ_PORT_CAP_SUBS_WRITE,
+				SND_SEQ_PORT_TYPE_MIDI_GENERIC |
+				SND_SEQ_PORT_TYPE_APPLICATION) < 0) {
+		fprintf(stderr, "Error creating sequencer port.\n");
+		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);
+		if (err < 0) {
+			fprintf(stderr, "Cannot connect from port %d:%d - %s", ports[i].client, ports[i].port, snd_strerror(err));
+			exit(1);
+		}
+	}
+
+	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;
+	size_t 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;
+}
+