xref: /freebsd/share/examples/sound/midi.c (revision b64c5a0ace59af62eff52bfe110a521dc73c937b)
1 /*
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 2022 Goran Mekić
5  * Copyright (c) 2024 The FreeBSD Foundation
6  *
7  * Portions of this software were developed by Christos Margiolis
8  * <christos@FreeBSD.org> under sponsorship from the FreeBSD Foundation.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 #include <err.h>
33 #include <fcntl.h>
34 #include <stdio.h>
35 #include <stdlib.h>
36 #include <unistd.h>
37 
38 #define CMD_MASK	0xF0
39 #define CHANNEL_MASK	0x0F
40 #define NOTE_ON		0x90
41 #define NOTE_OFF	0x80
42 #define CTL_CHANGE	0xB0
43 
44 int
45 main(int argc, char *argv[])
46 {
47 	int fd;
48 	unsigned char raw, type, channel, b1, b2;
49 
50 	if ((fd = open("/dev/umidi0.0", O_RDWR)) < 0)
51 		err(1, "Error opening MIDI device");
52 
53 	for (;;) {
54 		if (read(fd, &raw, sizeof(raw)) < sizeof(raw))
55 			err(1, "Error reading command byte");
56 		if (!(raw & 0x80))
57 			continue;
58 
59 		type = raw & CMD_MASK;
60 		channel = raw & CHANNEL_MASK;
61 
62 		if (read(fd, &b1, sizeof(b1)) < sizeof(b1))
63 			err(1, "Error reading byte 1");
64 		if (read(fd, &b2, sizeof(b2)) < sizeof(b2))
65 			err(1, "Error reading byte 2");
66 
67 		switch (type) {
68 		case NOTE_ON:
69 			printf("Channel %d, note on %d, velocity %d\n",
70 			    channel, b1, b2);
71 			break;
72 		case NOTE_OFF:
73 			printf("Channel %d, note off %d, velocity %d\n",
74 			    channel, b1, b2);
75 			break;
76 		case CTL_CHANGE:
77 			printf("Channel %d, controller change %d, value %d\n",
78 			    channel, b1, b2);
79 			break;
80 		default:
81 			printf("Unknown event type %d\n", type);
82 			break;
83 		}
84 	}
85 
86 	close(fd);
87 
88 	return (0);
89 }
90