aplaymidi.c

ALSA驱动的一些调试测试工具

/*
 * aplaymidi.c - play Standard MIDI Files to sequencer port(s)
 *
 * Copyright (c) 2004-2006 Clemens Ladisch <[e-mail]>
 *
 *
 *  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.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 */

/* TODO: sequencer queue timer selection */

#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <string.h>
#include <getopt.h>
#include <unistd.h>
#include <alsa/asoundlib.h>
#include "aconfig.h"
#include "version.h"

#define MIDI_BYTES_PER_SEC 3125

/*
 * A MIDI event after being parsed/loaded from the file.
 * There could be made a case for using snd_seq_event_t instead.
 */
struct event {
	struct event *next;		/* linked list */

	unsigned char type;		/* SND_SEQ_EVENT_xxx */
	unsigned char port;		/* port index */
	unsigned int tick;
	union {
		unsigned char d[3];	/* channel and data bytes */
		int tempo;
		unsigned int length;	/* length of sysex data */
	} data;
	unsigned char sysex[0];
};

struct track {
	struct event *first_event;	/* list of all events in this track */
	int end_tick;			/* length of this track */

	struct event *current_event;	/* used while loading and playing */
};

static snd_seq_t *seq;
static int client;
static int port_count;
static snd_seq_addr_t *ports;
static int queue;
static int end_delay = 2;
static const char *file_name;
static FILE *file;
static int file_offset;		/* current offset in input file */
static int num_tracks;
static struct track *tracks;
static int smpte_timing;

/* prints an error message to stderr */
static void errormsg(const char *msg, ...)
{
	va_list ap;

	va_start(ap, msg);
	vfprintf(stderr, msg, ap);
	va_end(ap);
	fputc('\n', stderr);
}

/* prints an error message to stderr, and dies */
static void fatal(const char *msg, ...)
{
	va_list ap;

	va_start(ap, msg);
	vfprintf(stderr, msg, ap);
	va_end(ap);
	fputc('\n', stderr);
	exit(EXIT_FAILURE);
}

/* memory allocation error handling */
static void check_mem(void *p)
{
	if (!p)
		fatal("Out of memory");
}

/* error handling for ALSA functions */
static void check_snd(const char *operation, int err)
{
	if (err < 0)
		fatal("Cannot %s - %s", operation, snd_strerror(err));
}

static void init_seq(void)
{
	int err;

	/* open sequencer */
	err = snd_seq_open(&seq, "default", SND_SEQ_OPEN_DUPLEX, 0);
	check_snd("open sequencer", err);

	/* set our name (otherwise it's "Client-xxx") */
	err = snd_seq_set_client_name(seq, "aplaymidi");
	check_snd("set client name", err);

	/* find out who we actually are */
	client = snd_seq_client_id(seq);
	check_snd("get client id", client);
}

/* parses one or more port addresses from the string */
static void parse_ports(const char *arg)
{
	char *buf, *s, *port_name;
	int err;

	/* make a copy of the string because we're going to modify it */
	buf = strdup(arg);
	check_mem(buf);

	for (port_name = s = buf; s; port_name = s + 1) {
		/* Assume that ports are separated by commas.  We don't use
		 * spaces because those are valid in client names. */
		s = strchr(port_name, ',');
		if (s)
			*s = '\0';

		++port_count;
		ports = realloc(ports, port_count * sizeof(snd_seq_addr_t));
		check_mem(ports);

		err = snd_seq_parse_address(seq, &ports[port_count - 1], port_name);
		if (err < 0)
			fatal("Invalid port %s - %s", port_name, snd_strerror(err));
	}

	free(buf);
}

static void create_source_port(void)
{
	snd_seq_port_info_t *pinfo;
	int err;

	snd_seq_port_info_alloca(&pinfo);

	/* the first created port is 0 anyway, but let's make sure ... */
	snd_seq_port_info_set_port(pinfo, 0);
	snd_seq_port_info_set_port_specified(pinfo, 1);

	snd_seq_port_info_set_name(pinfo, "aplaymidi");

	snd_seq_port_info_set_capability(pinfo, 0); /* sic */
	snd_seq_port_info_set_type(pinfo,
				   SND_SEQ_PORT_TYPE_MIDI_GENERIC |
				   SND_SEQ_PORT_TYPE_APPLICATION);

	err = snd_seq_create_port(seq, pinfo);
	check_snd("create port", err);
}

static void create_queue(void)
{
	queue = snd_seq_alloc_named_queue(seq, "aplaymidi");
	check_snd("create queue", queue);
	/* the queue is now locked, which is just fine */
}

static void connect_ports(void)
{
	int i, err;

	/*
	 * We send MIDI events with explicit destination addresses, so we don't
	 * need any connections to the playback ports.  But we connect to those
	 * anyway to force any underlying RawMIDI ports to remain open while
	 * we're playing - otherwise, ALSA would reset the port after every
	 * event.
	 */
	for (i = 0; i < port_count; ++i) {
		err = snd_seq_connect_to(seq, 0, ports[i].client, ports[i].port);
		if (err < 0)
			fatal("Cannot connect to port %d:%d - %s",
			      ports[i].client, ports[i].port, snd_strerror(err));
	}
}

static int read_byte(void)
{
	++file_offset;
	return getc(file);
}

/* reads a little-endian 32-bit integer */
static int read_32_le(void)
{
	int value;
	value = read_byte();
	value |= read_byte() << 8;
	value |= read_byte() << 16;
	value |= read_byte() << 24;
	return !feof(file) ? value : -1;
}

/* reads a 4-character identifier */
static int read_id(void)
{
	return read_32_le();
}
#define MAKE_ID(c1, c2, c3, c4) ((c1) | ((c2) << 8) | ((c3) << 16) | ((c4) << 24))

/* reads a fixed-size big-endian number */
static int read_int(int bytes)
{
	int c, value = 0;

	do {
		c = read_byte();
		if (c == EOF)
			return -1;
		value = (value << 8) | c;
	} while (--bytes);
	return value;
}

/* reads a variable-length number */
static int read_var(void)
{
	int value, c;

	c = read_byte();
	value = c & 0x7f;
	if (c & 0x80) {
		c = read_byte();
		value = (value << 7) | (c & 0x7f);
		if (c & 0x80) {
			c = read_byte();
			value = (value << 7) | (c & 0x7f);
			if (c & 0x80) {
				c = read_byte();
				value = (value << 7) | c;
				if (c & 0x80)
					return -1;
			}
		}
	}
	return !feof(file) ? value : -1;
}

/* allocates a new event */
static struct event *new_event(struct track *track, int sysex_length)
{
	struct event *event;

	event = malloc(sizeof(struct event) + sysex_length);
	check_mem(event);

	event->next = NULL;

	/* append at the end of the track's linked list */
	if (track->current_event)
		track->current_event->next = event;
	else
		track->first_event = event;
	track->current_event = event;

	return event;
}

static void skip(int bytes)
{
	while (bytes > 0)
		read_byte(), --bytes;
}

/* reads one complete track from the file */
static int read_track(struct track *track, int track_end)
{
	int tick = 0;
	unsigned char last_cmd = 0;
	unsigned char port = 0;

	/* the current file position is after the track ID and length */
	while (file_offset < track_end) {
		unsigned char cmd;
		struct event *event;
		int delta_ticks, len, c;

		delta_ticks = read_var();
		if (delta_ticks < 0)
			break;
		tick += delta_ticks;

		c = read_byte();
		if (c < 0)
			break;

		if (c & 0x80) {
			/* have command */
			cmd = c;
			if (cmd < 0xf0)
				last_cmd = cmd;
		} else {
			/* running status */
			ungetc(c, file);
			file_offset--;
			cmd = last_cmd;
			if (!cmd)
				goto _error;
		}

		switch (cmd >> 4) {
			/* maps SMF events to ALSA sequencer events */
			static const unsigned char cmd_type[] = {
				[0x8] = SND_SEQ_EVENT_NOTEOFF,
				[0x9] = SND_SEQ_EVENT_NOTEON,
				[0xa] = SND_SEQ_EVENT_KEYPRESS,
				[0xb] = SND_SEQ_EVENT_CONTROLLER,
				[0xc] = SND_SEQ_EVENT_PGMCHANGE,
				[0xd] = SND_SEQ_EVENT_CHANPRESS,
				[0xe] = SND_SEQ_EVENT_PITCHBEND
			};

		case 0x8: /* channel msg with 2 parameter bytes */
		case 0x9:
		case 0xa:
		case 0xb:
		case 0xe:
			event = new_event(track, 0);
			event->type = cmd_type[cmd >> 4];
			event->port = port;
			event->tick = tick;
			event->data.d[0] = cmd & 0x0f;
			event->data.d[1] = read_byte() & 0x7f;
			event->data.d[2] = read_byte() & 0x7f;
			break;

		case 0xc: /* channel msg with 1 parameter byte */
		case 0xd:
			event = new_event(track, 0);
			event->type = cmd_type[cmd >> 4];
			event->port = port;
			event->tick = tick;
			event->data.d[0] = cmd & 0x0f;
			event->data.d[1] = read_byte() & 0x7f;
			break;

		case 0xf:
			switch (cmd) {
			case 0xf0: /* sysex */
			case 0xf7: /* continued sysex, or escaped commands */
				len = read_var();
				if (len < 0)
					goto _error;
				if (cmd == 0xf0)
					++len;
				event = new_event(track, len);
				event->type = SND_SEQ_EVENT_SYSEX;
				event->port = port;
				event->tick = tick;
				event->data.length = len;
				if (cmd == 0xf0) {
					event->sysex[0] = 0xf0;
					c = 1;
				} else {
					c = 0;
				}
				for (; c < len; ++c)
					event->sysex[c] = read_byte();
				break;

			case 0xff: /* meta event */
				c = read_byte();
				len = read_var();
				if (len < 0)
					goto _error;

				switch (c) {
				case 0x21: /* port number */
					if (len < 1)
						goto _error;
					port = read_byte() % port_count;
					skip(len - 1);
					break;

				case 0x2f: /* end of track */
					track->end_tick = tick;
					skip(track_end - file_offset);
					return 1;

				case 0x51: /* tempo */
					if (len < 3)
						goto _error;
					if (smpte_timing) {
						/* SMPTE timing doesn't change */
						skip(len);
					} else {
						event = new_event(track, 0);
						event->type = SND_SEQ_EVENT_TEMPO;
						event->port = port;
						event->tick = tick;
						event->data.tempo = read_byte() << 16;
						event->data.tempo |= read_byte() << 8;
						event->data.tempo |= read_byte();
						skip(len - 3);
					}
					break;

				default: /* ignore all other meta events */
					skip(len);
					break;
				}
				break;

			default: /* invalid Fx command */
				goto _error;
			}
			break;

		default: /* cannot happen */
			goto _error;
		}
	}
_error:
	errormsg("%s: invalid MIDI data (offset %#x)", file_name, file_offset);
	return 0;
}

/* reads an entire MIDI file */
static int read_smf(void)
{
	int header_len, type, time_division, i, err;
	snd_seq_queue_tempo_t *queue_tempo;

	/* the curren position is immediately after the "MThd" id */
	header_len = read_int(4);
	if (header_len < 6) {
invalid_format:
		errormsg("%s: invalid file format", file_name);
		return 0;
	}

	type = read_int(2);
	if (type != 0 && type != 1) {
		errormsg("%s: type %d format is not supported", file_name, type);
		return 0;
	}