libgps.c

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

/* $Id: libgps.c 4377 2007-06-02 14:52:38Z esr $ */
/* libgps.c -- client interface library for the gpsd daemon */
#include <sys/time.h>
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <stdarg.h>
#ifndef S_SPLINT_S
#include <pthread.h>	/* pacifies OpenBSD's compiler */
#endif
#include <math.h>

#include "gpsd_config.h"
#include "gpsd.h"

#ifdef HAVE_SETLOCALE
#include <locale.h>
#endif

#ifdef S_SPLINT_S
extern char *strtok_r(char *, const char *, char **);
#endif /* S_SPLINT_S */

/* convert double degrees to a static string and return a pointer to it
 *
 * deg_str_type:
 *   	deg_dd     : return DD.dddddd
 *      deg_ddmm   : return DD MM.mmmm'
 *      deg_ddmmss : return DD MM' SS.sss"
 *
 */
/*@observer@*/char *deg_to_str( enum deg_str_type type,  double f) 
{
    static char str[40];
    int dsec, sec, deg, min;
    long frac_deg;
    double fdsec, fsec, fdeg, fmin;

    if ( f < 0 || f > 360 ) {
	(void)strlcpy( str, "nan", 40);
	return str;
    }

    fmin = modf( f, &fdeg);
    deg = (int)fdeg;
    frac_deg = (long)(fmin * 1000000);

    if ( deg_dd == type ) {
	/* DD.dddddd */
	(void)snprintf(str, sizeof(str), "%3d.%06ld", deg,frac_deg);
	return str;
    }
    fsec = modf( fmin * 60, &fmin);
    min = (int)fmin;
    sec = (int)(fsec * 10000.0);

    if ( deg_ddmm == type ) {
	/* DD MM.mmmm */
	(void)snprintf(str,sizeof(str), "%3d %02d.%04d'", deg,min,sec);
	return str;
    }
    /* else DD MM SS.sss */
    fdsec = modf( fsec * 60, &fsec);
    sec = (int)fsec;
    dsec = (int)(fdsec * 1000.0);
    (void)snprintf(str,sizeof(str), "%3d %02d' %02d.%03d\"", deg,min,sec,dsec);

    return str;
}

/* 
 * check the environment to determine proper GPS units
 *
 * clients should only call this if no user preference is specified on 
 * the command line or via X resources.
 *
 * return imperial    - Use miles/feet
 *        nautical    - Use knots/feet
 *        metric      - Use km/meters
 *        unspecified - use compiled default
 * 
 * In order check these environment vars:
 *    GPSD_UNITS one of: 
 *            	imperial   = miles/feet
 *              nautical   = knots/feet
 *              metric     = km/meters
 *    LC_MEASUREMENT
 *		en_US      = miles/feet
 *              C          = miles/feet
 *              POSIX      = miles/feet
 *              [other]    = km/meters
 *    LANG
 *		en_US      = miles/feet
 *              C          = miles/feet
 *              POSIX      = miles/feet
 *              [other]    = km/meters
 *
 * if none found then return compiled in default
 */
enum unit gpsd_units(void)
{
	char *envu = NULL;

#ifdef HAVE_SETLOCALE
	(void)setlocale(LC_NUMERIC, "C");
#endif
  	if ((envu = getenv("GPSD_UNITS")) != NULL && *envu != '\0') {
		if (0 == strcasecmp(envu, "imperial")) {
			return imperial;
		}
		if (0 == strcasecmp(envu, "nautical")) {
			return nautical;
		}
		if (0 == strcasecmp(envu, "metric")) {
			return metric;
		}
		/* unrecognized, ignore it */
	}
 	if (((envu = getenv("LC_MEASUREMENT")) != NULL && *envu != '\0') 
 	    || ((envu = getenv("LANG")) != NULL && *envu != '\0')) {
		if (strcasecmp(envu, "en_US")==0 
		    || strcasecmp(envu, "C")==0
		    || strcasecmp(envu, "POSIX")==0) {
			return imperial;
		}
		/* Other, must be metric */
		return metric;
	}
	/* TODO: allow a compile time default here */
	return unspecified;
}

struct gps_data_t *gps_open(const char *host, const char *port)
/* open a connection to a gpsd daemon */
{
    struct gps_data_t *gpsdata = (struct gps_data_t *)calloc(sizeof(struct gps_data_t), 1);

    /*@ -branchstate @*/
    if (!gpsdata)
	return NULL;
    if (!host)
	host = "127.0.0.1";
    if (!port)
	port = DEFAULT_GPSD_PORT;

    if ((gpsdata->gps_fd = netlib_connectsock(host, port, "tcp")) < 0) {
	errno = gpsdata->gps_fd;
	(void)free(gpsdata);
	return NULL;
    }

    gpsdata->status = STATUS_NO_FIX;
    gps_clear_fix(&gpsdata->fix);
    return gpsdata;
    /*@ +branchstate @*/
}

int gps_close(struct gps_data_t *gpsdata)
/* close a gpsd connection */
{
    int retval = close(gpsdata->gps_fd);
    if (gpsdata->gps_id) {
	(void)free(gpsdata->gps_id);
	gpsdata->gps_id = NULL;
    }
    gpsdata->gps_device[0] = '\0';
    if (gpsdata->devicelist) {
	int i;
	for (i = 0; i < gpsdata->ndevices; i++)
	    /*@i1@*/(void)free(gpsdata->devicelist[i]);
	(void)free(gpsdata->devicelist);
	gpsdata->devicelist = NULL;
	gpsdata->ndevices = -1;
    }    
    /*@i@*/(void)free(gpsdata);
    return retval;
}

void gps_set_raw_hook(struct gps_data_t *gpsdata, 
		      void (*hook)(struct gps_data_t *, char *, size_t len, int level))
{
    gpsdata->raw_hook = hook;
}

/*@ -branchstate -usereleased @*/
static void gps_unpack(char *buf, struct gps_data_t *gpsdata)
/* unpack a daemon response into a status structure */
{
    char *ns, *sp, *tp;
    int i;

    for (ns = buf; ns; ns = strstr(ns+1, "GPSD")) {
	if (/*@i1@*/strncmp(ns, "GPSD", 4) == 0) {
	    /* the following should execute each time we have a good next sp */
	    for (sp = ns + 5; *sp != '\0'; sp = tp+1) {
		tp = sp + strcspn(sp, ",\r\n");
		if (*tp == '\0') tp--;
		else *tp = '\0';

		switch (*sp) {
		case 'A':
		    if (sp[2] == '?') {
			    gpsdata->fix.altitude = NAN;
		    } else {
		        (void)sscanf(sp, "A=%lf", &gpsdata->fix.altitude);
		        gpsdata->set |= ALTITUDE_SET;
		    }
		    break;
		case 'B':
		    if (sp[2] == '?') {
			gpsdata->baudrate = gpsdata->stopbits = 0;
		    } else
			(void)sscanf(sp, "B=%u %*d %*s %u", 
			       &gpsdata->baudrate, &gpsdata->stopbits);
		    break;
		case 'C':
		    if (sp[2] == '?')
			gpsdata->mincycle = gpsdata->cycle = 0;
		    else {
			if (sscanf(sp, "C=%lf %lf", 
				     &gpsdata->cycle,
				   &gpsdata->mincycle) < 2)
			    gpsdata->mincycle = gpsdata->cycle;
		    }
		    break;
		case 'D':
		    if (sp[2] == '?') 
			gpsdata->fix.time = NAN;
		    else {
			gpsdata->fix.time = iso8601_to_unix(sp+2);
			gpsdata->set |= TIME_SET;
		    }
		    break;
		case 'E':
		    gpsdata->epe = gpsdata->fix.eph = gpsdata->fix.epv = NAN;
		    /* epe should always be present if eph or epv is */
		    if (sp[2] != '?') {
			char epe[20], eph[20], epv[20];
		        (void)sscanf(sp, "E=%s %s %s", epe, eph, epv);
#define DEFAULT(val) (val[0] == '?') ? NAN : atof(val)
			    /*@ +floatdouble @*/
			    gpsdata->epe = DEFAULT(epe);
			    gpsdata->fix.eph = DEFAULT(eph);
			    gpsdata->fix.epv = DEFAULT(epv);
			    /*@ -floatdouble @*/
#undef DEFAULT
		    }
		    break;
		case 'F':
		    /*@ -mustfreeonly */
		    if (sp[2] == '?') 
			gpsdata->gps_device[0] = '\0';
		    else {
			/*@ -mayaliasunique @*/
			strncpy(gpsdata->gps_device, sp+2, PATH_MAX);
			/*@ +mayaliasunique @*/
			gpsdata->set |= DEVICE_SET;
		    }
		    /*@ +mustfreeonly */
		    break;
		case 'I':
		    /*@ -mustfreeonly */
		    if (gpsdata->gps_id)
			free(gpsdata->gps_id);
		    if (sp[2] == '?')
			gpsdata->gps_id = NULL;
		    else {
			gpsdata->gps_id = strdup(sp+2);
			gpsdata->set |= DEVICEID_SET;
		    }
		    /*@ +mustfreeonly */
		    break;
		case 'K':
		    if (gpsdata->devicelist) {
			for (i = 0; i < gpsdata->ndevices; i++)
			    /*@i1@*/(void)free(gpsdata->devicelist[i]);
			(void)free(gpsdata->devicelist);
			gpsdata->devicelist = NULL;
			gpsdata->ndevices = -1;
			gpsdata->set |= DEVICELIST_SET;
		    }    
		    if (sp[2] != '?') {
			/*@ -nullderef @*/
			gpsdata->ndevices = (int)strtol(sp+2, &sp, 10);
			gpsdata->devicelist = (char **)calloc(
			    (size_t)gpsdata->ndevices,
			    sizeof(char **));
			/*@ -nullstate -mustfreefresh @*/
			gpsdata->devicelist[i=0] = strdup(strtok_r(sp+1, " \r\n", &ns));
			while ((sp = strtok_r(NULL, " \r\n",  &ns)))
			    gpsdata->devicelist[++i] = strdup(sp);
			/*@ +nullstate +mustfreefresh @*/
			/*@ +nullderef @*/
			gpsdata->set |= DEVICELIST_SET;
		    }
		    break;
		case 'M':
		    if (sp[2] == '?') {
		        gpsdata->fix.mode = MODE_NOT_SEEN;
		    } else {
		        gpsdata->fix.mode = atoi(sp+2);
		        gpsdata->set |= MODE_SET;
		    }
		    break;
		case 'N':
		    if (sp[2] == '?') 
			gpsdata->driver_mode = 0;
		    else
			gpsdata->driver_mode = (unsigned)atoi(sp+2);
		    break;
		case 'O':
		    if (sp[2] == '?') {
			gpsdata->set = MODE_SET | STATUS_SET;
			gpsdata->status = STATUS_NO_FIX;
			gps_clear_fix(&gpsdata->fix);
		    } else {
			struct gps_fix_t nf;
			char tag[MAXTAGLEN+1], alt[20];
			char eph[20], epv[20], track[20],speed[20], climb[20];
			char epd[20], eps[20], epc[20], mode[2];
			char timestr[20], ept[20], lat[20], lon[20];
			int st = sscanf(sp+2, 
			       "%8s %19s %19s %19s %19s %19s %19s %19s %19s %19s %19s %19s %19s %19s %1s",
				tag, timestr, ept, lat, lon,
			        alt, eph, epv, track, speed, climb,
			        epd, eps, epc, mode);
			if (st >= 14) {
#define DEFAULT(val) (val[0] == '?') ? NAN : atof(val)
			    /*@ +floatdouble @*/
			    nf.time = DEFAULT(timestr);
			    nf.latitude = DEFAULT(lat);
			    nf.longitude = DEFAULT(lon);
			    nf.ept = DEFAULT(ept);
			    nf.altitude = DEFAULT(alt);
			    nf.eph = DEFAULT(eph);
			    nf.epv = DEFAULT(epv);
			    nf.track = DEFAULT(track);
			    nf.speed = DEFAULT(speed);
			    nf.climb = DEFAULT(climb);
			    nf.epd = DEFAULT(epd);
			    nf.eps = DEFAULT(eps);
			    nf.epc = DEFAULT(epc);
			    /*@ -floatdouble @*/
#undef DEFAULT
			    if (st >= 15)
				nf.mode = (mode[0] == '?') ? MODE_NOT_SEEN : atoi(mode);
			    else
				nf.mode = (alt[0] == '?') ? MODE_2D : MODE_3D;
			    if (alt[0] != '?')
				gpsdata->set |= ALTITUDE_SET | CLIMB_SET;
			    if (isnan(nf.eph)==0)
				gpsdata->set |= HERR_SET;
			    if (isnan(nf.epv)==0)
				gpsdata->set |= VERR_SET;