libgps.c

来自「gpsd, a popular GPS daemon.」· C语言 代码 · 共 712 行 · 第 1/2 页

			    if (isnan(nf.track)==0)
				gpsdata->set |= TRACK_SET | SPEED_SET;
			    if (isnan(nf.eps)==0)
				gpsdata->set |= SPEEDERR_SET;
			    if (isnan(nf.epc)==0)
				gpsdata->set |= CLIMBERR_SET;
			    gpsdata->fix = nf;
			    (void)strlcpy(gpsdata->tag, tag, MAXTAGLEN+1);
			    gpsdata->set |= TIME_SET|TIMERR_SET|LATLON_SET|MODE_SET;
			    gpsdata->status = STATUS_FIX;
			    gpsdata->set |= STATUS_SET;
			}
		    }
		    break;
		case 'P':
		    if (sp[2] == '?') {
			   gpsdata->fix.latitude = NAN;
			   gpsdata->fix.longitude = NAN;
		    } else {
		        (void)sscanf(sp, "P=%lf %lf",
			   &gpsdata->fix.latitude, &gpsdata->fix.longitude);
		        gpsdata->set |= LATLON_SET;
		    }
		    break;
		case 'Q':
		    if (sp[2] == '?') {
			   gpsdata->satellites_used = 0;
			   gpsdata->pdop = 0;
			   gpsdata->hdop = 0;
			   gpsdata->vdop = 0;
		    } else {
		        (void)sscanf(sp, "Q=%d %lf %lf %lf %lf %lf",
			       &gpsdata->satellites_used,
			       &gpsdata->pdop,
			       &gpsdata->hdop,
			       &gpsdata->vdop,
			       &gpsdata->tdop,
			       &gpsdata->gdop);
		        gpsdata->set |= HDOP_SET | VDOP_SET | PDOP_SET;
		    }
		    break;
		case 'S':
		    if (sp[2] == '?') {
		        gpsdata->status = -1;
		    } else {
		        gpsdata->status = atoi(sp+2);
		        gpsdata->set |= STATUS_SET;
		    }
		    break;
		case 'T':
		    if (sp[2] == '?') {
		        gpsdata->fix.track = NAN;
		    } else {
		        (void)sscanf(sp, "T=%lf", &gpsdata->fix.track);
		        gpsdata->set |= TRACK_SET;
		    }
		    break;
		case 'U':
		    if (sp[2] == '?') {
		        gpsdata->fix.climb = NAN;
		    } else {
		        (void)sscanf(sp, "U=%lf", &gpsdata->fix.climb);
		        gpsdata->set |= CLIMB_SET;
		    }
		    break;
		case 'V':
		    if (sp[2] == '?') {
		        gpsdata->fix.speed = NAN;
		    } else {
		        (void)sscanf(sp, "V=%lf", &gpsdata->fix.speed);
			/* V reply is in kt, fix.speed is in metres/sec */
			gpsdata->fix.speed = gpsdata->fix.speed / MPS_TO_KNOTS;
		        gpsdata->set |= SPEED_SET;
		    }
		    break;
		case 'X':
		    if (sp[2] == '?') 
			gpsdata->online = -1;
		    else {
			(void)sscanf(sp, "X=%lf", &gpsdata->online);
			gpsdata->set |= ONLINE_SET;
		    }
		    break;
		case 'Y':
		    if (sp[2] == '?') {
			gpsdata->satellites = 0;
		    } else {
			int j, i1, i2, i3, i4, i5;
			int PRN[MAXCHANNELS];
			int elevation[MAXCHANNELS], azimuth[MAXCHANNELS];
			int ss[MAXCHANNELS], used[MAXCHANNELS];
			char tag[MAXTAGLEN+1], timestamp[21];

			(void)sscanf(sp, "Y=%8s %20s %d ", 
			       tag, timestamp, &gpsdata->satellites);
			(void)strncpy(gpsdata->tag, tag, MAXTAGLEN);
			if (timestamp[0] != '?') {
			    gpsdata->sentence_time = atof(timestamp);
			    gpsdata->set |= TIME_SET;
			}
			for (j = 0; j < gpsdata->satellites; j++) {
			    PRN[j]=elevation[j]=azimuth[j]=ss[j]=used[j]=0;
			}
			for (j = 0, gpsdata->satellites_used = 0; j < gpsdata->satellites; j++) {
			    if ((sp != NULL) && ((sp = strchr(sp, ':')) != NULL)) {
				sp++;
				(void)sscanf(sp, "%d %d %d %d %d", &i1, &i2, &i3, &i4, &i5);
				PRN[j] = i1;
				elevation[j] = i2; azimuth[j] = i3;
				ss[j] = i4; used[j] = i5;
				if (i5 == 1)
				    gpsdata->satellites_used++;
			    }
			}
			/*@ -compdef @*/
			memcpy(gpsdata->PRN, PRN, sizeof(PRN));
			memcpy(gpsdata->elevation, elevation, sizeof(elevation));
			memcpy(gpsdata->azimuth, azimuth,sizeof(azimuth));
			memcpy(gpsdata->ss, ss, sizeof(ss));
			memcpy(gpsdata->used, used, sizeof(used));
			/*@ +compdef @*/
		    }
		    gpsdata->set |= SATELLITE_SET;
		    break;
		case 'Z':
		    gpsdata->profiling = (sp[2] == '1');
		    break;
		case '$':
		    if (gpsdata->profiling != true)
			break;
		    /*@ +matchanyintegral -formatcode @*/
		    (void)sscanf(sp, "$=%8s %zd %lf %lf %lf %lf %lf %lf", 
			   gpsdata->tag,
			   &gpsdata->sentence_length,
			   &gpsdata->fix.time, 
			   &gpsdata->d_xmit_time, 
			   &gpsdata->d_recv_time, 
			   &gpsdata->d_decode_time, 
			   &gpsdata->poll_time, 
			   &gpsdata->emit_time);
		    /*@ -matchanyintegral +formatcode @*/
		    break;
		}
	    }
	}
    }

/*@ -nullstate -compdef @*/
    if (gpsdata->raw_hook)
	gpsdata->raw_hook(gpsdata, buf, strlen(buf),  1);
    if (gpsdata->thread_hook)
	gpsdata->thread_hook(gpsdata, buf, strlen(buf), 1);
}
/*@ +nullstate +compdef @*/
/*@ -branchstate +usereleased @*/

/*
 * return: 0, success
 *        -1, read error
 */

int gps_poll(struct gps_data_t *gpsdata)
/* wait for and read data being streamed from the daemon */ 
{
    char	buf[BUFSIZ];
    ssize_t	n;
    double received = 0;

    /* the daemon makes sure that every read is NUL-terminated */
    n = read(gpsdata->gps_fd, buf, sizeof(buf)-1);
    if (n <= 0) {
	 /* error or nothing read */    
	return -1;
    }
    buf[n] = '\0';

    received = gpsdata->online = timestamp();
    gps_unpack(buf, gpsdata);
    if (gpsdata->profiling)
    {
	gpsdata->c_decode_time = received - gpsdata->fix.time;
	gpsdata->c_recv_time = timestamp() - gpsdata->fix.time;
    }
    return 0;
}

int gps_query(struct gps_data_t *gpsdata, const char *fmt, ... )
/* query a gpsd instance for new data */
{
    char buf[BUFSIZ];
    va_list ap;

    va_start(ap, fmt);
    (void)vsnprintf(buf, sizeof(buf)-2, fmt, ap);
    va_end(ap);
    if (buf[strlen(buf)-1] != '\n')
	(void)strlcat(buf, "\n", BUFSIZ);
    if (write(gpsdata->gps_fd, buf, strlen(buf)) <= 0)
	return -1;
    return gps_poll(gpsdata);
}

#ifdef HAVE_LIBPTHREAD
static void *poll_gpsd(void *args) 
/* helper for the thread launcher */
{
    int oldtype, oldstate;
    int res;
    struct gps_data_t *gpsdata;

    /* set thread parameters */
    /*@ -compdef @*/
    /*@ -unrecog (splint has no pthread declarations as yet) @*/
    (void)pthread_setcancelstate(PTHREAD_CANCEL_ENABLE,&oldstate);
    (void)pthread_setcanceltype(PTHREAD_CANCEL_ASYNCHRONOUS,&oldtype); /* we want to be canceled also when blocked on gps_poll() */
    /*@ +unrecog @*/
    /*@ +compdef @*/
    gpsdata = (struct gps_data_t *) args;
    do {
	res = gps_poll(gpsdata); /* this is not actually polling */
    } while 
	(res == 0);
    /* if we are here an error occured with gpsd */
    return NULL;
}

int gps_set_callback(struct gps_data_t *gpsdata, 
		     void (*callback)(struct gps_data_t *sentence, char *buf, size_t len, int level),
		     pthread_t *handler) 
/* set an asynchronous callback and launch a thread for it */
{
    (void)gps_query(gpsdata,"w+\n");	/* ensure gpsd is in watcher mode, so we'll have data to read */
    if (gpsdata->thread_hook != NULL) {
	gpsdata->thread_hook = callback;
	return 0;
    }
    gpsdata->thread_hook = callback;

    /* start the thread which will read data from gpsd */
    /*@ -unrecog (splint has no pthread declarations as yet */
    return pthread_create(handler,NULL,poll_gpsd,(void*)gpsdata);
    /*@ +unrecog @*/
}

int gps_del_callback(struct gps_data_t *gpsdata, pthread_t *handler)
/* delete asynchronous callback and kill its thread */
{
    int res;
    /*@i@*/res = pthread_cancel(*handler);	/* we cancel the whole thread */
    gpsdata->thread_hook = NULL;	/* finally we cancel the callback */
    if (res == 0) 			/* tell gpsd to stop sending data */
	(void)gps_query(gpsdata,"w-\n");	/* disable watcher mode */
    return res;
}
#endif /* HAVE_LIBPTHREAD */

#ifdef TESTMAIN
/*
 * A simple command-line exerciser for the library.
 * Not really useful for anything but debugging.
 */
static void data_dump(struct gps_data_t *collect, time_t now)
{
    char *status_values[] = {"NO_FIX", "FIX", "DGPS_FIX"};
    char *mode_values[] = {"", "NO_FIX", "MODE_2D", "MODE_3D"};

    if (collect->set & ONLINE_SET)
	printf("online: %lf\n", collect->online);
    if (collect->set & LATLON_SET)
	printf("P: lat/lon: %lf %lf\n", collect->fix.latitude, collect->fix.longitude);
    if (collect->set & ALTITUDE_SET)
	printf("A: altitude: %lf  U: climb: %lf\n", 
	       collect->fix.altitude, collect->fix.climb);
    if (!isnan(collect->fix.track))
	printf("T: track: %lf  V: speed: %lf\n", 
	       collect->fix.track, collect->fix.speed);
    if (collect->set & STATUS_SET)
	printf("S: status: %d (%s)\n", 
	       collect->status, status_values[collect->status]);
    if (collect->fix.mode & MODE_SET)
	printf("M: mode: %d (%s)\n", 
	   collect->fix.mode, mode_values[collect->fix.mode]);
    if (collect->fix.mode & (HDOP_SET | VDOP_SET | PDOP_SET))
	printf("Q: satellites %d, pdop=%lf, hdop=%lf, vdop=%lf\n",
	   collect->satellites_used, 
	   collect->pdop, collect->hdop, collect->vdop);

    if (collect->set & SATELLITE_SET) {
	int i;

	printf("Y: satellites in view: %d\n", collect->satellites);
	for (i = 0; i < collect->satellites; i++) {
	    printf("    %2.2d: %2.2d %3.3d %3.3d %c\n", collect->PRN[i], collect->elevation[i], collect->azimuth[i], collect->ss[i], collect->used[i]? 'Y' : 'N');
	}
    }
    if (collect->set & DEVICE_SET)
	printf("Device is %s\n", collect->gps_device);
    if (collect->set & DEVICEID_SET)
	printf("GPSD ID is %s\n", collect->gps_id);
    if (collect->set & DEVICELIST_SET) {
	int i;
	printf("%d devices:\n", collect->ndevices);
	for (i = 0; i < collect->ndevices; i++) {
	    printf("%d: %s\n", collect->ndevices, collect->devicelist[i]);
	}
    }
	
}

static void dumpline(struct gps_data_t *ud UNUSED, char *buf,
		     size_t ulen UNUSED, int level UNUSED)
{
    puts(buf);
}

#include <getopt.h>

int main(int argc, char *argv[])
{
    struct gps_data_t *collect;
    char buf[BUFSIZ];

    collect = gps_open(NULL, 0);
    gps_set_raw_hook(collect, dumpline);
    if (optind < argc) {
	strlcpy(buf, argv[optind], BUFSIZ);
	strlcat(buf,"\n", BUFSIZ);
	gps_query(collect, buf);
	data_dump(collect, time(NULL));
    } else {
	int	tty = isatty(0);

	if (tty)
	    (void)fputs("This is the gpsd exerciser.\n", stdout);
	for (;;) {
	    if (tty)
		(void)fputs("> ", stdout);
	    if (fgets(buf, sizeof(buf), stdin) == NULL) {
		if (tty)
		    putchar('\n');
		break;
	    }
	    collect->set = 0;
	    gps_query(collect, buf);
	    data_dump(collect, time(NULL));
	}
    }

    (void)gps_close(collect);
    return 0;
}

#endif /* TESTMAIN */