midigen/: MIDI traffic generator

midigen/Makefile

@@ -0,0 +1,9 @@
+CFLAGS = -Wall -g
+LDLIBS = -lasound
+
+.PHONY:		clean
+
+midigen:	midigen.c
+
+clean:
+		rm -f midigen

midigen/midigen.c

@@ -0,0 +1,110 @@
+/*
+ * midigen.c - MIDI traffic generator
+ *
+ * Written 2011 by Werner Almesberger
+ * Copyright 2011 Werner Almesberger
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <sys/time.h>
+#include <alsa/asoundlib.h>
+
+
+#define	NAME "midigen"
+
+
+static void send_cc(snd_seq_t *midi, snd_seq_event_t *ev, int chan)
+{
+	static unsigned v = 0;
+
+	snd_seq_ev_set_controller(ev, chan, (v >> 7) & 127, v & 127);
+	v++;
+	snd_seq_event_output(midi, ev);
+	snd_seq_drain_output(midi);
+}
+
+
+static void generate(snd_seq_t *midi, int port, int chan, int t_s, int t_us)
+{
+	snd_seq_event_t ev;
+	struct timeval next, now;
+	int dt_us;
+
+	snd_seq_ev_clear(&ev);
+	snd_seq_ev_set_source(&ev, port);
+	snd_seq_ev_set_subs(&ev);
+	snd_seq_ev_set_direct(&ev);
+
+	gettimeofday(&next, NULL);
+	while (1) {
+		next.tv_sec += t_s;
+		next.tv_usec += t_us;
+		if (next.tv_usec > 999999) {
+			next.tv_sec++;
+			next.tv_usec -= 1000000;
+		}
+		gettimeofday(&now, NULL);
+		dt_us = (next.tv_sec-now.tv_sec)*1000000+
+		    next.tv_usec-now.tv_usec;
+		if (dt_us > 0)
+			usleep(dt_us);
+		send_cc(midi, &ev, chan);
+	}
+}
+
+static void usage(const char *name)
+{
+	fprintf(stderr, "usage: %s [-c channel] rate_hz\n", name);
+	exit(1);
+}
+
+
+int main(int argc, char **argv)
+{
+	snd_seq_t *midi;
+	int c;
+	int chan = 0, t_us;
+	int port;
+
+	while ((c = getopt(argc, argv, "c:")) != EOF)
+		switch (c) {
+		case 'c':
+			chan = atoi(optarg);
+			break;
+		default:
+			usage(*argv);
+		}
+
+	switch (argc-optind) {
+	case 1:
+		t_us = 1000000/atof(argv[optind]);
+		break;
+	default:
+		usage(*argv);
+	}
+
+	if (snd_seq_open(&midi, "hw", SND_SEQ_OPEN_OUTPUT,0) < 0) {
+		fprintf(stderr, "can't open ALSA sequencer\n");
+		exit(1);
+	}
+	snd_seq_set_client_name(midi, NAME);
+	port = snd_seq_create_simple_port(midi, NAME,
+              SND_SEQ_PORT_CAP_READ | SND_SEQ_PORT_CAP_SUBS_READ,
+              SND_SEQ_PORT_TYPE_APPLICATION);
+	if (port < 0) {
+		fprintf(stderr, "can't create sequencer port\n");
+		exit(1);
+	}
+
+	generate(midi, port, chan, t_us/1000000, t_us % 1000000);
+
+	return 0;
+}