xref: /netbsd-src/usr.bin/midiplay/midiplay.c (revision a5847cc334d9a7029f6352b847e9e8d71a0f9e0c)
1 /*	$NetBSD: midiplay.c,v 1.28 2011/08/14 13:26:23 christos Exp $	*/
2 
3 /*
4  * Copyright (c) 1998, 2002 The NetBSD Foundation, Inc.
5  * All rights reserved.
6  *
7  * This code is derived from software contributed to The NetBSD Foundation
8  * by Lennart Augustsson (augustss@NetBSD.org).
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 NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29  * POSSIBILITY OF SUCH DAMAGE.
30  */
31 #include <sys/cdefs.h>
32 
33 #ifndef lint
34 __RCSID("$NetBSD: midiplay.c,v 1.28 2011/08/14 13:26:23 christos Exp $");
35 #endif
36 
37 
38 #include <stdio.h>
39 #include <stdlib.h>
40 #include <fcntl.h>
41 #include <err.h>
42 #include <unistd.h>
43 #include <string.h>
44 #include <sys/types.h>
45 #include <sys/stat.h>
46 #include <sys/ioctl.h>
47 #include <sys/midiio.h>
48 
49 #define DEVMUSIC "/dev/music"
50 
51 struct track {
52 	struct track *indirect; /* for fast swaps in heap code */
53 	u_char *start, *end;
54 	u_long delta;
55 	u_char status;
56 };
57 
58 #define MIDI_META 0xff
59 
60 #define META_SEQNO	0x00
61 #define META_TEXT	0x01
62 #define META_COPYRIGHT	0x02
63 #define META_TRACK	0x03
64 #define META_INSTRUMENT	0x04
65 #define META_LYRIC	0x05
66 #define META_MARKER	0x06
67 #define META_CUE	0x07
68 #define META_CHPREFIX	0x20
69 #define META_EOT	0x2f
70 #define META_SET_TEMPO	0x51
71 #define META_KEY	0x59
72 #define META_SMPTE	0x54
73 #define META_TIMESIGN	0x58
74 
75 static const char *metanames[] = {
76 	"", "Text", "Copyright", "Track", "Instrument",
77 	"Lyric", "Marker", "Cue",
78 };
79 
80 static int midi_lengths[] = { 2, 2, 2, 2, 1, 1, 2, 0 };
81 /* Number of bytes in a MIDI command */
82 #define MIDI_LENGTH(d) (midi_lengths[((d) >> 4) & 7])
83 
84 #define SEQ_MK_SYSEX0(_dev,...) \
85 SEQ_MK_EVENT(sysex, 0x94, .device=(_dev), .buffer={__VA_ARGS__})
86 
87 
88 static void usage(void);
89 static void send_event(seq_event_t *);
90 static void dometa(u_int, u_char *, u_int);
91 #if 0
92 static void midireset(void);
93 #endif
94 static void send_sysex(u_char *, u_int);
95 static u_long getvar(struct track *);
96 static u_long getlen(struct track *);
97 static void playfile(FILE *, const char *);
98 static void playdata(u_char *, u_int, const char *);
99 
100 static void Heapify(struct track *, int, int);
101 static void BuildHeap(struct track *, int);
102 static int ShrinkHeap(struct track *, int);
103 
104 /*
105  * This sample plays at an apparent tempo of 120 bpm when the BASETEMPO is 150
106  * bpm, because the quavers are 5 divisions (4 on 1 off) rather than 4 total.
107  */
108 #define P(c) 1, 0x90, c, 0x7f, 4, 0x80, c, 0
109 #define PL(c) 1, 0x90, c, 0x7f, 8, 0x80, c, 0
110 #define C 0x3c
111 #define D 0x3e
112 #define E 0x40
113 #define F 0x41
114 
115 static u_char sample[] = {
116 	'M', 'T', 'h', 'd',  0, 0, 0, 6,  0, 1,  0, 1,  0, 8,
117 	'M', 'T', 'r', 'k',  0, 0, 0, 4+13*8,
118 	P(C), P(C), P(C), P(E), P(D), P(D), P(D),
119 	P(F), P(E), P(E), P(D), P(D), PL(C),
120 	0, 0xff, 0x2f, 0
121 };
122 #undef P
123 #undef PL
124 #undef C
125 #undef D
126 #undef E
127 #undef F
128 
129 #define MARK_HEADER "MThd"
130 #define MARK_TRACK "MTrk"
131 #define MARK_LEN 4
132 
133 #define	RMID_SIG "RIFF"
134 #define	RMID_MIDI_ID "RMID"
135 #define	RMID_DATA_ID "data"
136 
137 #define SIZE_LEN 4
138 #define HEADER_LEN 6
139 
140 #define GET8(p) ((p)[0])
141 #define GET16(p) (((p)[0] << 8) | (p)[1])
142 #define GET24(p) (((p)[0] << 16) | ((p)[1] << 8) | (p)[2])
143 #define GET32(p) (((p)[0] << 24) | ((p)[1] << 16) | ((p)[2] << 8) | (p)[3])
144 #define GET32_LE(p) (((p)[3] << 24) | ((p)[2] << 16) | ((p)[1] << 8) | (p)[0])
145 
146 static void __attribute__((__noreturn__))
147 usage(void)
148 {
149 	fprintf(stderr, "usage: %s [-d unit] [-f file] [-l] [-m] [-p pgm] [-q] "
150 	       "[-t %%tempo] [-v] [-x] [file ...]\n",
151 		getprogname());
152 	exit(1);
153 }
154 
155 static int showmeta = 0;
156 static int verbose = 0;
157 #define BASETEMPO 400000		/* us/beat(=24 clks or qn) (150 bpm) */
158 static u_int tempo_set = 0;
159 static u_int tempo_abs = 0;
160 static u_int ttempo = 100;
161 static int unit = 0;
162 static int play = 1;
163 static int fd = -1;
164 static int sameprogram = 0;
165 static int insysex = 0;
166 static int svsysex = 0; /* number of sysex bytes saved internally */
167 
168 static void
169 send_event(seq_event_t *ev)
170 {
171 	/*
172 	printf("%02x %02x %02x %02x %02x %02x %02x %02x\n",
173 	       ev->arr[0], ev->arr[1], ev->arr[2], ev->arr[3],
174 	       ev->arr[4], ev->arr[5], ev->arr[6], ev->arr[7]);
175 	*/
176 	if (play)
177 		write(fd, ev, sizeof *ev);
178 }
179 
180 static u_long
181 getvar(struct track *tp)
182 {
183 	u_long r, c;
184 
185 	r = 0;
186 	do {
187 		c = *tp->start++;
188 		r = (r << 7) | (c & 0x7f);
189 	} while ((c & 0x80) && tp->start < tp->end);
190 	return r;
191 }
192 
193 static u_long
194 getlen(struct track *tp)
195 {
196 	u_long len;
197 	len = getvar(tp);
198 	if (tp->start + len > tp->end)
199 		errx(1, "bogus item length exceeds remaining track size");
200 	return len;
201 }
202 
203 static void
204 dometa(u_int meta, u_char *p, u_int len)
205 {
206 	static char const * const keys[] = {
207 	        "Cb", "Gb", "Db", "Ab", "Eb", "Bb", "F",
208 		"C",
209 		"G", "D", "A", "E", "B", "F#", "C#",
210 		"G#", "D#", "A#" /* for minors */
211 	};
212 	seq_event_t ev;
213 	uint32_t usperbeat;
214 
215 	switch (meta) {
216 	case META_TEXT:
217 	case META_COPYRIGHT:
218 	case META_TRACK:
219 	case META_INSTRUMENT:
220 	case META_LYRIC:
221 	case META_MARKER:
222 	case META_CUE:
223 		if (showmeta) {
224 			printf("%s: ", metanames[meta]);
225 			fwrite(p, len, 1, stdout);
226 			printf("\n");
227 		}
228 		break;
229 	case META_SET_TEMPO:
230 		usperbeat = GET24(p);
231 		ev = SEQ_MK_TIMING(TEMPO,
232 		    .bpm=(60000000. / usperbeat) * (ttempo / 100.) + 0.5);
233 		if (showmeta)
234 			printf("Tempo: %u us/'beat'(24 midiclks)"
235 			       " at %u%%; adjusted bpm = %u\n",
236 			       usperbeat, ttempo, ev.t_TEMPO.bpm);
237 		if (tempo_abs)
238 			warnx("tempo event ignored"
239 			      " in absolute-timed MIDI file");
240 		else {
241 			send_event(&ev);
242 			if (!tempo_set) {
243 				tempo_set = 1;
244 				send_event(&SEQ_MK_TIMING(START));
245 			}
246 		}
247 		break;
248 	case META_TIMESIGN:
249 		ev = SEQ_MK_TIMING(TIMESIG,
250 		    .numerator=p[0],      .lg2denom=p[1],
251 		    .clks_per_click=p[2], .dsq_per_24clks=p[3]);
252 		if (showmeta) {
253 			printf("Time signature: %d/%d."
254 			       " Click every %d midiclk%s"
255 			       " (24 midiclks = %d 32nd note%s)\n",
256 			       ev.t_TIMESIG.numerator,
257 			       1 << ev.t_TIMESIG.lg2denom,
258 			       ev.t_TIMESIG.clks_per_click,
259 			       1 == ev.t_TIMESIG.clks_per_click ? "" : "s",
260 			       ev.t_TIMESIG.dsq_per_24clks,
261 			       1 == ev.t_TIMESIG.dsq_per_24clks ? "" : "s");
262 		}
263 		/* send_event(&ev); not implemented in sequencer */
264 		break;
265 	case META_KEY:
266 		if (showmeta)
267 			printf("Key: %s %s\n",
268 			       keys[((char)p[0]) + p[1] ? 10 : 7],
269 			       p[1] ? "minor" : "major");
270 		break;
271 	default:
272 		break;
273 	}
274 }
275 
276 #if 0
277 static void
278 midireset(void)
279 {
280 	/* General MIDI reset sequence */
281 	send_event(&SEQ_MK_SYSEX0(unit, 0x7e, 0x7f, 0x09, 0x01, 0xf7, 0xff));
282 }
283 #endif
284 
285 #define SYSEX_CHUNK 6
286 static void
287 send_sysex(u_char *p, u_int l)
288 {
289 	seq_event_t event;
290 	static u_char bf[6];
291 
292 	if (0 == l) {
293 		warnx("zero-length system-exclusive event");
294 		return;
295 	}
296 
297 	/*
298 	 * This block is needed only to handle the possibility that a sysex
299 	 * message is broken into multiple events in a MIDI file that do not
300 	 * have length six; the /dev/music sequencer assumes a sysex message is
301 	 * finished with the first SYSEX event carrying fewer than six bytes,
302 	 * even if the last is not MIDI_SYSEX_END. So, we need to be careful
303 	 * not to send a short sysex event until we have seen the end byte.
304 	 * Instead, save some straggling bytes in bf, and send when we have a
305 	 * full six (or an end byte). Note bf/saved/insysex should be per-
306 	 * device, if we supported output to more than one device at a time.
307 	 */
308 	if (svsysex > 0) {
309 		if (l > sizeof bf - svsysex) {
310 			memcpy(bf + svsysex, p, sizeof bf - svsysex);
311 			l -= sizeof bf - svsysex;
312 			p += sizeof bf - svsysex;
313 			send_event(&SEQ_MK_SYSEX0(unit,
314 			    bf[0], bf[1], bf[2], bf[3], bf[4], bf[5]));
315 			svsysex = 0;
316 		} else {
317 			memcpy(bf + svsysex, p, l);
318 			svsysex += l;
319 			p += l;
320 			if (MIDI_SYSEX_END == bf[svsysex-1]) {
321 				event = SEQ_MK_SYSEX(unit);
322 				memcpy(event.sysex.buffer, bf, svsysex);
323 				send_event(&event);
324 				svsysex = insysex = 0;
325 			} else
326 				insysex = 1;
327 			return;
328 		}
329 	}
330 
331 	/*
332 	 * l > 0. May as well test now whether we will be left 'insysex'
333 	 * after processing this event.
334 	 */
335 	insysex = (MIDI_SYSEX_END != p[l-1]);
336 
337 	/*
338 	 * If not for multi-event sysexes and chunk-size weirdness, this
339 	 * function could pretty much start here. :)
340 	 */
341 	while (l >= SYSEX_CHUNK) {
342 		send_event(&SEQ_MK_SYSEX0(unit, p[0], p[1], p[2], p[3], p[4], p[5]));
343 		p += SYSEX_CHUNK;
344 		l -= SYSEX_CHUNK;
345 	}
346 	if (l > 0) {
347 		if (insysex) {
348 			memcpy(bf, p, l);
349 			svsysex = l;
350 		} else { /* a <6 byte chunk is ok if it's REALLY the end */
351 			event = SEQ_MK_SYSEX(unit);
352 			memcpy(event.sysex.buffer, p, l);
353 			send_event(&event);
354 		}
355 	}
356 }
357 
358 static void
359 playfile(FILE *f, const char *name)
360 {
361 	u_char *buf, *nbuf;
362 	u_int tot, n, size, nread;
363 
364 	/*
365 	 * We need to read the whole file into memory for easy processing.
366 	 * Using mmap() would be nice, but some file systems do not support
367 	 * it, nor does reading from e.g. a pipe.  The latter also precludes
368 	 * finding out the file size without reading it.
369 	 */
370 	size = 1000;
371 	buf = malloc(size);
372 	if (buf == 0)
373 		errx(1, "malloc() failed");
374 	nread = size;
375 	tot = 0;
376 	for (;;) {
377 		n = fread(buf + tot, 1, nread, f);
378 		tot += n;
379 		if (n < nread)
380 			break;
381 		/* There must be more to read. */
382 		nread = size;
383 		nbuf = realloc(buf, size * 2);
384 		if (nbuf == NULL)
385 			errx(1, "realloc() failed");
386 		buf = nbuf;
387 		size *= 2;
388 	}
389 	playdata(buf, tot, name);
390 	free(buf);
391 }
392 
393 static void
394 playdata(u_char *buf, u_int tot, const char *name)
395 {
396 	int format, ntrks, divfmt, ticks, t;
397 	u_int len, mlen, status, chan;
398 	u_char *p, *end, byte, meta, *msg;
399 	struct track *tracks;
400 	struct track *tp;
401 
402 	end = buf + tot;
403 	if (verbose)
404 		printf("Playing %s (%d bytes) ... \n", name, tot);
405 
406 	if (tot < MARK_LEN + 4) {
407 		warnx("Not a MIDI file, too short");
408 		return;
409 	}
410 
411 	if (memcmp(buf, RMID_SIG, MARK_LEN) == 0) {
412 		u_char *eod;
413 		/* Detected a RMID file, let's just check if it's
414 		 * a MIDI file */
415 		if ((u_int)GET32_LE(buf + MARK_LEN) != tot - 8) {
416 			warnx("Not a RMID file, bad header");
417 			return;
418 		}
419 
420 		buf += MARK_LEN + 4;
421 		if (memcmp(buf, RMID_MIDI_ID, MARK_LEN) != 0) {
422 			warnx("Not a RMID file, bad ID");
423 			return;
424 		}
425 
426 		/* Now look for the 'data' chunk, which contains
427 		 * MIDI data */
428 		buf += MARK_LEN;
429 
430 		/* Test against end-8 since we must have at least 8 bytes
431 		 * left to read */
432 		while(buf < end-8 && memcmp(buf, RMID_DATA_ID, MARK_LEN))
433 			buf += GET32_LE(buf+4) + 8; /* MARK_LEN + 4 */
434 
435 		if (buf >= end-8) {
436 			warnx("Not a valid RMID file, no data chunk");
437 			return;
438 		}
439 
440 		buf += MARK_LEN; /* "data" */
441 		eod = buf + 4 + GET32_LE(buf);
442 		if (eod >= end) {
443 			warnx("Not a valid RMID file, bad data chunk size");
444 			return;
445 		}
446 
447 		end = eod;
448 		buf += 4;
449 	}
450 
451 	if (memcmp(buf, MARK_HEADER, MARK_LEN) != 0) {
452 		warnx("Not a MIDI file, missing header");
453 		return;
454 	}
455 
456 	if (GET32(buf + MARK_LEN) != HEADER_LEN) {
457 		warnx("Not a MIDI file, bad header");
458 		return;
459 	}
460 	format = GET16(buf + MARK_LEN + SIZE_LEN);
461 	ntrks = GET16(buf + MARK_LEN + SIZE_LEN + 2);
462 	divfmt = GET8(buf + MARK_LEN + SIZE_LEN + 4);
463 	ticks = GET8(buf + MARK_LEN + SIZE_LEN + 5);
464 	p = buf + MARK_LEN + SIZE_LEN + HEADER_LEN;
465 	/*
466 	 * Set the timebase (or timebase and tempo, for absolute-timed files).
467 	 * PORTABILITY: some sequencers actually check the timebase against
468 	 * available timing sources and may adjust it accordingly (storing a
469 	 * new value in the ioctl arg) which would require us to compensate
470 	 * somehow. That possibility is ignored for now, as NetBSD's sequencer
471 	 * currently synthesizes all timebases, for better or worse, from the
472 	 * system clock.
473 	 *
474 	 * For a non-absolute file, if timebase is set to the file's divisions
475 	 * value, and tempo set in the obvious way, then the timing deltas in
476 	 * the MTrks require no scaling. A downside to this approach is that
477 	 * the sequencer API wants tempo in (integer) beats per minute, which
478 	 * limits how finely tempo can be specified. That might be got around
479 	 * in some cases by frobbing tempo and timebase more obscurely, but this
480 	 * player is meant to be simple and clear.
481 	 */
482 	if ((divfmt & 0x80) == 0) {
483 		ticks |= divfmt << 8;
484 		if (ioctl(fd, SEQUENCER_TMR_TIMEBASE, &(int){ticks}) < 0)
485 			err(1, "SEQUENCER_TMR_TIMEBASE");
486 	} else {
487 		tempo_abs = tempo_set = 1;
488 		divfmt = -(int8_t)divfmt;
489 		/*
490 		 * divfmt is frames per second; multiplying by 60 to set tempo
491 		 * in frames per minute could exceed sequencer's (arbitrary)
492 		 * tempo limits, so factor 60 as 12*5, set tempo in frames per
493 		 * 12 seconds, and account for the 5 in timebase.
494 		 */
495 		send_event(&SEQ_MK_TIMING(TEMPO,
496 		    .bpm=(12*divfmt) * (ttempo/100.) + 0.5));
497 		if (ioctl(fd, SEQUENCER_TMR_TIMEBASE, &(int){5*ticks}) < 0)
498 			err(1, "SEQUENCER_TMR_TIMEBASE");
499 	}
500 	if (verbose > 1)
501 		printf(tempo_abs ?
502 		       "format=%d ntrks=%d abs fps=%u subdivs=%u\n" :
503 		       "format=%d ntrks=%d divisions=%u\n",
504 		       format, ntrks, tempo_abs ? divfmt : ticks, ticks);
505 	if (format != 0 && format != 1) {
506 		warnx("Cannot play MIDI file of type %d", format);
507 		return;
508 	}
509 	if (ntrks == 0)
510 		return;
511 	tracks = malloc(ntrks * sizeof(struct track));
512 	if (tracks == NULL)
513 		errx(1, "malloc() tracks failed");
514 	for (t = 0; t < ntrks;) {
515 		if (p >= end - MARK_LEN - SIZE_LEN) {
516 			warnx("Cannot find track %d", t);
517 			goto ret;
518 		}
519 		len = GET32(p + MARK_LEN);
520 		if (len > 1000000) { /* a safe guard */
521 			warnx("Crazy track length");
522 			goto ret;
523 		}
524 		if (memcmp(p, MARK_TRACK, MARK_LEN) == 0) {
525 			tracks[t].start = p + MARK_LEN + SIZE_LEN;
526 			tracks[t].end = tracks[t].start + len;
527 			tracks[t].delta = getvar(&tracks[t]);
528 			tracks[t].indirect = &tracks[t]; /* -> self for now */
529 			t++;
530 		}
531 		p += MARK_LEN + SIZE_LEN + len;
532 	}
533 
534 	/*
535 	 * Force every channel to the same patch if requested by the user.
536 	 */
537 	if (sameprogram) {
538 		for(t = 0; t < 16; t++) {
539 			send_event(&SEQ_MK_CHN(PGM_CHANGE, .device=unit,
540 			    .channel=t, .program=sameprogram-1));
541 		}
542 	}
543 	/*
544 	 * Play MIDI events by selecting the track with the lowest
545 	 * delta.  Execute the event, update the delta and repeat.
546 	 *
547 	 * The ticks variable is the number of ticks that make up a beat
548 	 * (beat: 24 MIDI clocks always, a quarter note by usual convention)
549 	 * and is used as a reference value for the delays between
550 	 * the MIDI events.
551 	 */
552 	BuildHeap(tracks, ntrks); /* tracks[0].indirect is always next */
553 	for (;;) {
554 		tp = tracks[0].indirect;
555 		if ((verbose > 2 && tp->delta > 0)  ||  verbose > 3) {
556 			printf("DELAY %4ld TRACK %2td%s",
557 			       tp->delta, tp - tracks, verbose>3?" ":"\n");
558 			fflush(stdout);
559 		}
560 		if (tp->delta > 0) {
561 			if (!tempo_set) {
562 				if (verbose || showmeta)
563 					printf("No initial tempo;"
564 					       " defaulting:\n");
565 				dometa(META_SET_TEMPO, (u_char[]){
566 				    BASETEMPO >> 16,
567 				    (BASETEMPO >> 8) & 0xff,
568 				    BASETEMPO & 0xff},
569 				    3);
570 			}
571 			send_event(&SEQ_MK_TIMING(WAIT_REL,
572 			    .divisions=tp->delta));
573 		}
574 		byte = *tp->start++;
575 		if (byte == MIDI_META) {
576 			meta = *tp->start++;
577 			mlen = getlen(tp);
578 			if (verbose > 3)
579 				printf("META %02x (%d)\n", meta, mlen);
580 			dometa(meta, tp->start, mlen);
581 			tp->start += mlen;
582 		} else {
583 			if (MIDI_IS_STATUS(byte))
584 				tp->status = byte;
585 			else
586 				tp->start--;
587 			mlen = MIDI_LENGTH(tp->status);
588 			msg = tp->start;
589 			if (verbose > 3) {
590 			    if (mlen == 1)
591 				printf("MIDI %02x (%d) %02x\n",
592 				       tp->status, mlen, msg[0]);
593 			    else
594 				printf("MIDI %02x (%d) %02x %02x\n",
595 				       tp->status, mlen, msg[0], msg[1]);
596 			}
597 			if (insysex && tp->status != MIDI_SYSEX_END) {
598 				warnx("incomplete system exclusive message"
599 				      " aborted");
600 				svsysex = insysex = 0;
601 			}
602 			status = MIDI_GET_STATUS(tp->status);
603 			chan = MIDI_GET_CHAN(tp->status);
604 			switch (status) {
605 			case MIDI_NOTEOFF:
606 				send_event(&SEQ_MK_CHN(NOTEOFF, .device=unit,
607 				.channel=chan, .key=msg[0], .velocity=msg[1]));
608 				break;
609 			case MIDI_NOTEON:
610 				send_event(&SEQ_MK_CHN(NOTEON, .device=unit,
611 				.channel=chan, .key=msg[0], .velocity=msg[1]));
612 				break;
613 			case MIDI_KEY_PRESSURE:
614 				send_event(&SEQ_MK_CHN(KEY_PRESSURE,
615 				.device=unit, .channel=chan,
616 				.key=msg[0], .pressure=msg[1]));
617 				break;
618 			case MIDI_CTL_CHANGE:
619 				send_event(&SEQ_MK_CHN(CTL_CHANGE,
620 				.device=unit, .channel=chan,
621 				.controller=msg[0], .value=msg[1]));
622 				break;
623 			case MIDI_PGM_CHANGE:
624 				if (!sameprogram)
625 					send_event(&SEQ_MK_CHN(PGM_CHANGE,
626 					.device=unit, .channel=chan,
627 					.program=msg[0]));
628 				break;
629 			case MIDI_CHN_PRESSURE:
630 				send_event(&SEQ_MK_CHN(CHN_PRESSURE,
631 				.device=unit, .channel=chan, .pressure=msg[0]));
632 				break;
633 			case MIDI_PITCH_BEND:
634 				send_event(&SEQ_MK_CHN(PITCH_BEND,
635 				.device=unit, .channel=chan,
636 				.value=(msg[0] & 0x7f) | ((msg[1] & 0x7f)<<7)));
637 				break;
638 			case MIDI_SYSTEM_PREFIX:
639 				mlen = getlen(tp);
640 				if (tp->status == MIDI_SYSEX_START) {
641 					send_sysex(tp->start, mlen);
642 					break;
643 				} else if (tp->status == MIDI_SYSEX_END) {
644 				/* SMF uses SYSEX_END as CONTINUATION/ESCAPE */
645 					if (insysex) { /* CONTINUATION */
646 						send_sysex(tp->start, mlen);
647 					} else { /* ESCAPE */
648 						for (; mlen > 0 ; -- mlen) {
649 							send_event(
650 							    &SEQ_MK_EVENT(putc,
651 							    SEQOLD_MIDIPUTC,
652 							    .device=unit,
653 							    .byte=*(tp->start++)
654 							   ));
655 						}
656 					}
657 					break;
658 				}
659 				/* Sorry, can't do this yet; FALLTHROUGH */
660 			default:
661 				if (verbose)
662 					printf("MIDI event 0x%02x ignored\n",
663 					       tp->status);
664 			}
665 			tp->start += mlen;
666 		}
667 		if (tp->start >= tp->end) {
668 			ntrks = ShrinkHeap(tracks, ntrks); /* track gone */
669 			if (0 == ntrks)
670 				break;
671 		} else
672 			tp->delta = getvar(tp);
673 		Heapify(tracks, ntrks, 0);
674 	}
675 	if (ioctl(fd, SEQUENCER_SYNC, 0) < 0)
676 		err(1, "SEQUENCER_SYNC");
677 
678  ret:
679 	free(tracks);
680 }
681 
682 int
683 main(int argc, char **argv)
684 {
685 	int ch;
686 	int listdevs = 0;
687 	int example = 0;
688 	int nmidi;
689 	const char *file = DEVMUSIC;
690 	const char *sunit;
691 	struct synth_info info;
692 	FILE *f;
693 
694 	if ((sunit = getenv("MIDIUNIT")))
695 		unit = atoi(sunit);
696 
697 	while ((ch = getopt(argc, argv, "?d:f:lmp:qt:vx")) != -1) {
698 		switch(ch) {
699 		case 'd':
700 			unit = atoi(optarg);
701 			break;
702 		case 'f':
703 			file = optarg;
704 			break;
705 		case 'l':
706 			listdevs++;
707 			break;
708 		case 'm':
709 			showmeta++;
710 			break;
711 		case 'p':
712 			sameprogram = atoi(optarg);
713 			break;
714 		case 'q':
715 			play = 0;
716 			break;
717 		case 't':
718 			ttempo = atoi(optarg);
719 			break;
720 		case 'v':
721 			verbose++;
722 			break;
723 		case 'x':
724 			example++;
725 			break;
726 		case '?':
727 		default:
728 			usage();
729 		}
730 	}
731 	argc -= optind;
732 	argv += optind;
733 
734 	if (!play)
735 		goto output;
736 
737 	fd = open(file, O_WRONLY);
738 	if (fd < 0)
739 		err(1, "%s", file);
740 	if (ioctl(fd, SEQUENCER_NRMIDIS, &nmidi) < 0)
741 		err(1, "ioctl(SEQUENCER_NRMIDIS) failed, ");
742 	if (nmidi == 0)
743 		errx(1, "Sorry, no MIDI devices available");
744 	if (listdevs) {
745 		for (info.device = 0; info.device < nmidi; info.device++) {
746 			if (ioctl(fd, SEQUENCER_INFO, &info) < 0)
747 				err(1, "ioctl(SEQUENCER_INFO) failed, ");
748 			printf("%d: %s\n", info.device, info.name);
749 		}
750 		exit(0);
751 	}
752 
753  output:
754 	if (example)
755 		while (example--)
756 			playdata(sample, sizeof sample, "<Gubben Noa>");
757 	else if (argc == 0)
758 		playfile(stdin, "<stdin>");
759 	else
760 		while (argc--) {
761 			f = fopen(*argv, "r");
762 			if (f == NULL)
763 				err(1, "%s", *argv);
764 			else {
765 				playfile(f, *argv);
766 				fclose(f);
767 			}
768 			argv++;
769 		}
770 
771 	exit(0);
772 }
773 
774 /*
775  * relative-time priority queue (min-heap). Properties:
776  * 1. The delta time at a node is relative to the node's parent's time.
777  * 2. When an event is dequeued from a track, the delta time of the new head
778  *    event is relative to the time of the event just dequeued.
779  * Therefore:
780  * 3. After dequeueing the head event from the track at heap root, the next
781  *    event's time is directly comparable to the root's children.
782  * These properties allow the heap to be maintained with delta times throughout.
783  * Insert is also implementable, but not needed: all the tracks are present
784  * at first; they just go away as they end.
785  */
786 
787 #define PARENT(i) ((i - 1) >> 1)
788 #define LEFT(i)   ((i << 1) + 1)
789 #define RIGHT(i)  ((i + 1) << 1)
790 #define DTIME(i)  (t[i].indirect->delta)
791 #define SWAP(i, j) do { \
792     struct track *_t = t[i].indirect; \
793     t[i].indirect = t[j].indirect; \
794     t[j].indirect = _t; \
795 } while (/*CONSTCOND*/ 0)
796 
797 static void
798 Heapify(struct track *t, int ntrks, int node)
799 {
800 	int lc, rc, mn;
801 
802 	lc = LEFT(node);
803 	rc = RIGHT(node);
804 
805 	if (rc >= ntrks) {			/* no right child */
806 		if (lc >= ntrks)		/* node is a leaf */
807 			return;
808 		if (DTIME(node) > DTIME(lc))
809 			SWAP(node, lc);
810 		DTIME(lc) -= DTIME(node);
811 		return;				/* no rc ==> lc is a leaf */
812 	}
813 
814 	mn = lc;
815 	if (DTIME(lc) > DTIME(rc))
816 		mn = rc;
817 	if (DTIME(node) <= DTIME(mn)) {
818 		DTIME(rc) -= DTIME(node);
819 		DTIME(lc) -= DTIME(node);
820 		return;
821 	}
822 
823 	SWAP(node, mn);
824 	DTIME(rc) -= DTIME(node);
825 	DTIME(lc) -= DTIME(node);
826 	Heapify(t, ntrks, mn); /* gcc groks tail recursion */
827 }
828 
829 static void
830 BuildHeap(struct track *t, int ntrks)
831 {
832 	int node;
833 
834 	for (node = PARENT(ntrks - 1); node --> 0;)
835 		Heapify(t, ntrks, node);
836 }
837 
838 /*
839  * Make the heap 1 item smaller by discarding the track at the root. Move the
840  * rightmost bottom-level leaf to the root and decrement ntrks. It remains to
841  * run Heapify, which the caller is expected to do. Returns the new ntrks.
842  */
843 static int
844 ShrinkHeap(struct track *t, int ntrks)
845 {
846 	int ancest;
847 
848 	--ntrks;
849 	for (ancest = PARENT(ntrks); ancest > 0; ancest = PARENT(ancest))
850 		DTIME(ntrks) += DTIME(ancest);
851 	t[0].indirect = t[ntrks].indirect;
852 	return ntrks;
853 }
854