alsaseq_c.c

MIDI解码程序(用VC编写)

/*
    TiMidity++ -- MIDI to WAVE converter and player
    Copyright (C) 1999-2004 Masanao Izumo <[e-mail]>
    Copyright (C) 1995 Tuukka Toivonen <[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

    alsaseq_c.c - ALSA sequencer server interface
        Copyright (c) 2000  Takashi Iwai <[e-mail]>

    This interface provides an ALSA sequencer client which receives
    events and plays it in real-time.  On this mode, TiMidity works
    as a software (quasi-)real-time MIDI synth engine.

    See doc/C/README.alsaseq for more details.
*/

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif /* HAVE_CONFIG_H */

#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <unistd.h>
#include <sched.h>
#include <sys/types.h>
#include <sys/time.h>
#ifndef NO_STRING_H
#include <string.h>
#else
#include <strings.h>
#endif
#include <math.h>
#include <signal.h>

#if HAVE_ALSA_ASOUNDLIB_H
#include <alsa/asoundlib.h>
#else
#include <sys/asoundlib.h>
#endif

#include "timidity.h"
#include "common.h"
#include "controls.h"
#include "instrum.h"
#include "playmidi.h"
#include "readmidi.h"
#include "recache.h"
#include "output.h"
#include "aq.h"
#include "timer.h"


void readmidi_read_init(void);

#define MAX_PORTS	16

#define TICKTIME_HZ	100

struct seq_context {
	snd_seq_t *handle;	/* The snd_seq handle to /dev/snd/seq */
	int client;		/* The client associated with this context */
	int num_ports;		/* number of ports */
	int port[MAX_PORTS];	/* created sequencer ports */
	int fd;			/* The file descriptor */
	int used;		/* number of current connection */
	int active;		/* */
	int queue;
	snd_seq_queue_status_t *q_status;
};

static struct seq_context alsactx;

#if SND_LIB_MAJOR > 0 || SND_LIB_MINOR >= 6
/* !! this is a dirty hack.  not sure to work in future !! */
static int snd_seq_file_descriptor(snd_seq_t *handle)
{
	int pfds = snd_seq_poll_descriptors_count(handle, POLLIN);
	if (pfds > 0) {
		struct pollfd pfd;
		if (snd_seq_poll_descriptors(handle, &pfd, 1, POLLIN) >= 0)
			return pfd.fd;
	}
	return -ENXIO;
}

static int alsa_seq_open(snd_seq_t **seqp)
{
	return snd_seq_open(seqp, "hw", SND_SEQ_OPEN_DUPLEX, 0);
}

static int alsa_create_port(snd_seq_t *seq, int index)
{
	char name[32];
	int port;

	sprintf(name, "TiMidity port %d", index);
	port = snd_seq_create_simple_port(seq, name,
					  SND_SEQ_PORT_CAP_WRITE|SND_SEQ_PORT_CAP_SUBS_WRITE,
					  SND_SEQ_PORT_TYPE_MIDI_GENERIC);
	if (port < 0) {
		fprintf(stderr, "error in snd_seq_create_simple_port\n");
		return -1;
	}

	return port;
}

#else
static int alsa_seq_open(snd_seq_t **seqp)
{
	return snd_seq_open(seqp, SND_SEQ_OPEN_IN);
}

static int alsa_create_port(snd_seq_t *seq, int index)
{
	snd_seq_port_info_t pinfo;

	memset(&pinfo, 0, sizeof(pinfo));
	sprintf(pinfo.name, "TiMidity port %d", index);
	pinfo.capability = SND_SEQ_PORT_CAP_WRITE|SND_SEQ_PORT_CAP_SUBS_WRITE;
	pinfo.type = SND_SEQ_PORT_TYPE_MIDI_GENERIC;
	strcpy(pinfo.group, SND_SEQ_GROUP_DEVICE);
	if (snd_seq_create_port(alsactx.handle, &pinfo) < 0) {
		fprintf(stderr, "error in snd_seq_create_simple_port\n");
		return -1;
	}
	return pinfo.port;
}

#endif

static void alsa_set_timestamping(struct seq_context *ctxp, int port)
{
#if HAVE_SND_SEQ_PORT_INFO_SET_TIMESTAMPING
	int q = 0;
	snd_seq_port_info_t *pinfo;

	if (ctxp->queue < 0) {
		q = snd_seq_alloc_queue(ctxp->handle);
		ctxp->queue = q;
		if (q < 0)
			return;
		if (snd_seq_queue_status_malloc(&ctxp->q_status) < 0) {
			fprintf(stderr, "no memory!\n");
			exit(1);
		}
	}

	snd_seq_port_info_alloca(&pinfo);
	if (snd_seq_get_port_info(ctxp->handle, port, pinfo) < 0)
		return;
	snd_seq_port_info_set_timestamping(pinfo, 1);
	snd_seq_port_info_set_timestamp_real(pinfo, 1);
	snd_seq_port_info_set_timestamp_queue(pinfo, q);
	if (snd_seq_set_port_info(ctxp->handle, port, pinfo) < 0)
		return;
#endif
}


static int ctl_open(int using_stdin, int using_stdout);
static void ctl_close(void);
static int ctl_read(int32 *valp);
static int cmsg(int type, int verbosity_level, char *fmt, ...);
static void ctl_event(CtlEvent *e);
static void ctl_pass_playing_list(int n, char *args[]);

/**********************************/
/* export the interface functions */

#define ctl alsaseq_control_mode

ControlMode ctl=
{
    "ALSA sequencer interface", 'A',
    1,0,0,
    0,
    ctl_open,
    ctl_close,
    ctl_pass_playing_list,
    ctl_read,
    cmsg,
    ctl_event
};

/* options */
int opt_realtime_priority = 0;
int opt_sequencer_ports = 4;

static int buffer_time_advance;
static long buffer_time_offset;
static long start_time_base;
static long cur_time_offset;
static long last_queue_offset;
static double rate_frac, rate_frac_nsec;
static FILE *outfp;

/*ARGSUSED*/
static int ctl_open(int using_stdin, int using_stdout)
{
	ctl.opened = 1;
	ctl.flags &= ~(CTLF_LIST_RANDOM|CTLF_LIST_SORT);
	if (using_stdout)
		outfp = stderr;
	else
		outfp = stdout;
	return 0;
}

static void ctl_close(void)
{
	if (!ctl.opened)
		return;
}

static int ctl_read(int32 *valp)
{
    return RC_NONE;
}

static int cmsg(int type, int verbosity_level, char *fmt, ...)
{
    va_list ap;

    if((type==CMSG_TEXT || type==CMSG_INFO || type==CMSG_WARNING) &&
       ctl.verbosity < verbosity_level)
	return 0;

    if(outfp == NULL)
	outfp = stderr;

    va_start(ap, fmt);
    vfprintf(outfp, fmt, ap);
    fputs(NLS, outfp);
    fflush(outfp);
    va_end(ap);

    return 0;
}

static void ctl_event(CtlEvent *e)
{
}

static RETSIGTYPE sig_timeout(int sig)
{
    signal(SIGALRM, sig_timeout); /* For SysV base */
    /* Expect EINTR */
}

static void doit(struct seq_context *ctxp);
static int do_sequencer(struct seq_context *ctxp);
static int start_sequencer(struct seq_context *ctxp);
static void stop_sequencer(struct seq_context *ctxp);
static void server_reset(void);

/* reset all when SIGHUP is received */
static RETSIGTYPE sig_reset(int sig)
{
	if (alsactx.active) {
		stop_sequencer(&alsactx);
		server_reset();
	}
	signal(SIGHUP, sig_reset);
}

/*
 * set the process to realtime privs
 */
static int set_realtime_priority(void)
{
	struct sched_param schp;
	int max_prio;

	if (opt_realtime_priority <= 0)
		return 0;

        memset(&schp, 0, sizeof(schp));
	max_prio = sched_get_priority_max(SCHED_FIFO);
	if (max_prio < opt_realtime_priority)
		opt_realtime_priority = max_prio;

	schp.sched_priority = opt_realtime_priority;
        if (sched_setscheduler(0, SCHED_FIFO, &schp) != 0) {
		printf("can't set sched_setscheduler - using normal priority\n");
                return -1;
        }
	/* drop root priv. */
	if (! geteuid() && getuid() != geteuid()) {
		if (setuid(getuid()))
			perror("dropping root priv");
	}
	printf("set SCHED_FIFO(%d)\n", opt_realtime_priority);
        return 0;
}

static void ctl_pass_playing_list(int n, char *args[])
{
	double btime;
	int i, j;

#ifdef SIGPIPE
	signal(SIGPIPE, SIG_IGN);    /* Handle broken pipe */
#endif /* SIGPIPE */

	printf("TiMidity starting in ALSA server mode\n");

	set_realtime_priority();

	if (alsa_seq_open(&alsactx.handle) < 0) {
		fprintf(stderr, "error in snd_seq_open\n");
		return;
	}
	alsactx.queue = -1;
	alsactx.client = snd_seq_client_id(alsactx.handle);
	alsactx.fd = snd_seq_file_descriptor(alsactx.handle);
	snd_seq_set_client_name(alsactx.handle, "TiMidity");
	snd_seq_set_client_pool_input(alsactx.handle, 1000); /* enough? */
	if (opt_sequencer_ports < 1)
		alsactx.num_ports = 1;
	else if (opt_sequencer_ports > MAX_PORTS)
		alsactx.num_ports = MAX_PORTS;
	else
		alsactx.num_ports = opt_sequencer_ports;

	printf("Opening sequencer port:");
	for (i = 0; i < alsactx.num_ports; i++) {
		int port;
		port = alsa_create_port(alsactx.handle, i);
		if (port < 0)
			return;
		alsactx.port[i] = port;
		alsa_set_timestamping(&alsactx, port);
		printf(" %d:%d", alsactx.client, alsactx.port[i]);
	}
	printf("\n");

	alsactx.used = 0;
	alsactx.active = 0;

	opt_realtime_playing = 1; /* Enable loading patch while playing */
	allocate_cache_size = 0; /* Don't use pre-calclated samples */
	current_keysig = (opt_init_keysig == 8) ? 0 : opt_init_keysig;
	note_key_offset = key_adjust;

	if (IS_STREAM_TRACE) {
		/* set the audio queue size as minimum as possible, since
		 * we don't have to use audio queue..
		 */
		play_mode->acntl(PM_REQ_GETFRAGSIZ, &buffer_time_advance);
		if (!(play_mode->encoding & PE_MONO))
			buffer_time_advance >>= 1;
		if (play_mode->encoding & PE_16BIT)
			buffer_time_advance >>= 1;

		btime = (double)buffer_time_advance / play_mode->rate;
		btime *= 1.01; /* to be sure */
		aq_set_soft_queue(btime, 0.0);
	} else {
		buffer_time_advance = 0;
	}
	rate_frac = (double)play_mode->rate / 1000000.0;
	rate_frac_nsec = (double)play_mode->rate / 1000000000.0;

	alarm(0);
	signal(SIGALRM, sig_timeout);
	signal(SIGINT, safe_exit);
	signal(SIGTERM, safe_exit);
	signal(SIGHUP, sig_reset);

	i = current_keysig + ((current_keysig < 8) ? 7 : -9), j = 0;
	while (i != 7)
		i += (i < 7) ? 5 : -7, j++;
	j += note_key_offset, j -= floor(j / 12.0) * 12;
	current_freq_table = j;

	play_mode->close_output();

	if (ctl.flags & CTLF_DAEMONIZE)
	{
		int pid = fork();
		FILE *pidf;
		switch (pid)
		{
			case 0:			// child is the daemon
				break;
			case -1:		// error status return
				exit(7);
			default:		// no error, doing well
				if ((pidf = fopen( "/var/run/timidity.pid", "w" )) != NULL )