1 files changed, 109 insertions, 0 deletions

diff --git a/midi.c b/midi.c
new file mode 100644
index 0000000..3d21f79
--- /dev/null
+++ b/midi.c
@@ -0,0 +1,109 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <alloca.h>
+#include <unistd.h>
+#include <alsa/asoundlib.h>
+
+#include "midi.h"
+
+static snd_seq_t *seq_handle;
+static snd_seq_addr_t *ports;
+
+void *midi(void *arg) {
+        MidiArgs* args = (MidiArgs*)arg;
+
+        while (1) {
+                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.
+                ports = realloc(ports, MAX_MIDI_PORTS * sizeof(snd_seq_addr_t));
+                if (snd_seq_parse_address(seq_handle, &ports[0], args->port_name) < 0) {
+                        fprintf(stderr, "Invalid port %s.\n", args->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);
+                }
+
+
+                // 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);
+                }
+        }
+}
+