/src/ntp-dev/include/ntp_calgps.h

Source
/*
 * ntp_calgps.h - calendar for GPS/GNSS based clocks
 *
 * Written by Juergen Perlinger (perlinger@ntp.org) for the NTP project.
 * The contents of 'html/copyright.html' apply.
 *
 * --------------------------------------------------------------------
 *
 * This module implements stuff often used with GPS/GNSS receivers
 */
#ifndef NTP_CALGPS_H
#define NTP_CALGPS_H

#include <time.h>

#include "ntp_types.h"
#include "ntp_fp.h"
#include "ntp_calendar.h"

/* GPS week calendar (extended weeks)
 * We use weeks based on 1899-31-12, which was the last Sunday before
 * the begin of the NTP epoch. (Which is equivalent to saying 1900-01-01
 * was a Monday...)
 *
 * We simply pre-calculate the offsets and cycle shifts for the real GPS
 * calendar, which starts at 1980-01-06, to simplyfy some expressions.
 *
 * This has a fringe benefit that should not be overlooked: Since week zero
 * is around 1900, and we should never have to deal with dates before
 * 1970 or 1980, a week number of zero can be easily used to indicate
 * an invalid week time stamp.
 */
#define GPSNTP_WSHIFT 4175  /* weeks 1899-31-12 --> 1980-01-06 */
#define GPSNTP_WCYCLE   79  /* above, modulo 1024 */
#define GPSNTP_DSHIFT    1  /* day number of 1900-01-01 in week */

struct gpsdatum {
  uint32_t weeks;   /* weeks since GPS epoch  */
  int32_t  wsecs;   /* seconds since week start */
  uint32_t frac;    /* fractional seconds   */
};
typedef struct gpsdatum TGpsDatum;
typedef struct gpsdatum const TcGpsDatum;

/* NTP date/time in split representation */
struct ntpdatum {
  uint32_t days;    /* since NTP epoch    */
  int32_t  secs;    /* since midnight, denorm is ok */
  uint32_t frac;    /* fractional seconds   */
};
typedef struct ntpdatum TNtpDatum;
typedef struct ntpdatum const TcNtpDatum;

/*
 * GPS week/sec calendar functions
 *
 * see the implementation for details, especially the
 * 'gpscal_from_weektime{1,2}()'
 */

extern TGpsDatum
gpscal_fix_gps_era(TcGpsDatum *);

extern void
gpscal_add_offset(TGpsDatum *datum, l_fp offset);

extern TGpsDatum
gpscal_from_calendar_ex(TcCivilDate*, l_fp fofs, int/*BOOL*/ warp);

static inline TGpsDatum
gpscal_from_calendar(TcCivilDate *pCiv, l_fp fofs) {
    return gpscal_from_calendar_ex(pCiv, fofs, TRUE);
}

extern TGpsDatum  /* see source for semantic of the 'fofs' value! */
gpscal_from_gpsweek(uint16_t w, int32_t s, l_fp fofs);

extern TGpsDatum
gpscal_from_weektime1(int32_t wsecs, l_fp fofs, l_fp pivot);

extern TGpsDatum
gpscal_from_weektime2(int32_t wsecs, l_fp fofs, TcGpsDatum *pivot);

extern void
gpscal_to_calendar(TCivilDate*, TcGpsDatum*);

extern TGpsDatum
gpscal_from_gpsntp(TcNtpDatum*);

extern l_fp
ntpfp_from_gpsdatum(TcGpsDatum *);

/*
 * NTP day/sec calendar functions
 *
 * see the implementation for details, especially the
 * 'gpscal_from_daytime{1,2}()'
 */
extern TNtpDatum
gpsntp_fix_gps_era(TcNtpDatum *);

extern void
gpsntp_add_offset(TNtpDatum *datum, l_fp offset);

extern TNtpDatum
gpsntp_from_calendar_ex(TcCivilDate*, l_fp fofs, int/*BOOL*/ warp);

static inline TNtpDatum
gpsntp_from_calendar(TcCivilDate * pCiv, l_fp fofs) {
  return gpsntp_from_calendar_ex(pCiv, fofs, TRUE);
}

extern TNtpDatum
gpsntp_from_daytime1_ex(TcCivilDate *dt, l_fp fofs, l_fp pivot, int/*BOOL*/ warp);

static inline TNtpDatum
gpsntp_from_daytime1(TcCivilDate *dt, l_fp fofs, l_fp pivot) {
  return gpsntp_from_daytime1_ex(dt, fofs, pivot, TRUE);
}

extern TNtpDatum
gpsntp_from_daytime2_ex(TcCivilDate *dt, l_fp fofs, TcNtpDatum *pivot, int/*BOOL*/ warp);

static inline TNtpDatum
gpsntp_from_daytime2(TcCivilDate *dt, l_fp fofs, TcNtpDatum *pivot) {
  return gpsntp_from_daytime2_ex(dt, fofs, pivot, TRUE);
}

extern TNtpDatum
gpsntp_from_gpscal_ex(TcGpsDatum*, int/*BOOL*/ warp);

static inline TNtpDatum
gpsntp_from_gpscal(TcGpsDatum *wd) {
  return gpsntp_from_gpscal_ex(wd, FALSE);
}

extern void
gpsntp_to_calendar(TCivilDate*, TcNtpDatum*);

extern l_fp
ntpfp_from_ntpdatum(TcNtpDatum*);

/*
 * Some helpers
 */

/* apply fudge to time stamp: *SUBTRACT* the given offset from an l_fp*/
extern l_fp
ntpfp_with_fudge(l_fp lfp, double ofs);

#endif /*!defined(NTP_CALGPS_H)*/

Coverage Report

Created: 2026-02-26 06:20

Line	Count	Source
1		/*
2		* ntp_calgps.h - calendar for GPS/GNSS based clocks
3		*
4		* Written by Juergen Perlinger (perlinger@ntp.org) for the NTP project.
5		* The contents of 'html/copyright.html' apply.
6		*
7		* --------------------------------------------------------------------
8		*
9		* This module implements stuff often used with GPS/GNSS receivers
10		*/
11		#ifndef NTP_CALGPS_H
12		#define NTP_CALGPS_H
13
14		#include <time.h>
15
16		#include "ntp_types.h"
17		#include "ntp_fp.h"
18		#include "ntp_calendar.h"
19
20		/* GPS week calendar (extended weeks)
21		* We use weeks based on 1899-31-12, which was the last Sunday before
22		* the begin of the NTP epoch. (Which is equivalent to saying 1900-01-01
23		* was a Monday...)
24		*
25		* We simply pre-calculate the offsets and cycle shifts for the real GPS
26		* calendar, which starts at 1980-01-06, to simplyfy some expressions.
27		*
28		* This has a fringe benefit that should not be overlooked: Since week zero
29		* is around 1900, and we should never have to deal with dates before
30		* 1970 or 1980, a week number of zero can be easily used to indicate
31		* an invalid week time stamp.
32		*/
33	0	#define GPSNTP_WSHIFT 4175 /* weeks 1899-31-12 --> 1980-01-06 */
34		#define GPSNTP_WCYCLE 79 /* above, modulo 1024 */
35	0	#define GPSNTP_DSHIFT 1 /* day number of 1900-01-01 in week */
36
37		struct gpsdatum {
38		uint32_t weeks; /* weeks since GPS epoch */
39		int32_t wsecs; /* seconds since week start */
40		uint32_t frac; /* fractional seconds */
41		};
42		typedef struct gpsdatum TGpsDatum;
43		typedef struct gpsdatum const TcGpsDatum;
44
45		/* NTP date/time in split representation */
46		struct ntpdatum {
47		uint32_t days; /* since NTP epoch */
48		int32_t secs; /* since midnight, denorm is ok */
49		uint32_t frac; /* fractional seconds */
50		};
51		typedef struct ntpdatum TNtpDatum;
52		typedef struct ntpdatum const TcNtpDatum;
53
54		/*
55		* GPS week/sec calendar functions
56		*
57		* see the implementation for details, especially the
58		* 'gpscal_from_weektime{1,2}()'
59		*/
60
61		extern TGpsDatum
62		gpscal_fix_gps_era(TcGpsDatum *);
63
64		extern void
65		gpscal_add_offset(TGpsDatum *datum, l_fp offset);
66
67		extern TGpsDatum
68		gpscal_from_calendar_ex(TcCivilDate, l_fp fofs, int/BOOL*/ warp);
69
70		static inline TGpsDatum
71	0	gpscal_from_calendar(TcCivilDate *pCiv, l_fp fofs) {
72	0	return gpscal_from_calendar_ex(pCiv, fofs, TRUE);
73	0	} Unexecuted instantiation: refclock_nmea.c:gpscal_from_calendar Unexecuted instantiation: refclock_palisade.c:gpscal_from_calendar Unexecuted instantiation: refclock_zyfer.c:gpscal_from_calendar Unexecuted instantiation: ntp_calgps.c:gpscal_from_calendar
74
75		extern TGpsDatum /* see source for semantic of the 'fofs' value! */
76		gpscal_from_gpsweek(uint16_t w, int32_t s, l_fp fofs);
77
78		extern TGpsDatum
79		gpscal_from_weektime1(int32_t wsecs, l_fp fofs, l_fp pivot);
80
81		extern TGpsDatum
82		gpscal_from_weektime2(int32_t wsecs, l_fp fofs, TcGpsDatum *pivot);
83
84		extern void
85		gpscal_to_calendar(TCivilDate, TcGpsDatum);
86
87		extern TGpsDatum
88		gpscal_from_gpsntp(TcNtpDatum*);
89
90		extern l_fp
91		ntpfp_from_gpsdatum(TcGpsDatum *);
92
93		/*
94		* NTP day/sec calendar functions
95		*
96		* see the implementation for details, especially the
97		* 'gpscal_from_daytime{1,2}()'
98		*/
99		extern TNtpDatum
100		gpsntp_fix_gps_era(TcNtpDatum *);
101
102		extern void
103		gpsntp_add_offset(TNtpDatum *datum, l_fp offset);
104
105		extern TNtpDatum
106		gpsntp_from_calendar_ex(TcCivilDate, l_fp fofs, int/BOOL*/ warp);
107
108		static inline TNtpDatum
109	0	gpsntp_from_calendar(TcCivilDate * pCiv, l_fp fofs) {
110	0	return gpsntp_from_calendar_ex(pCiv, fofs, TRUE);
111	0	} Unexecuted instantiation: refclock_nmea.c:gpsntp_from_calendar Unexecuted instantiation: refclock_palisade.c:gpsntp_from_calendar Unexecuted instantiation: refclock_zyfer.c:gpsntp_from_calendar Unexecuted instantiation: ntp_calgps.c:gpsntp_from_calendar
112
113		extern TNtpDatum
114		gpsntp_from_daytime1_ex(TcCivilDate dt, l_fp fofs, l_fp pivot, int/BOOL*/ warp);
115
116		static inline TNtpDatum
117	0	gpsntp_from_daytime1(TcCivilDate *dt, l_fp fofs, l_fp pivot) {
118	0	return gpsntp_from_daytime1_ex(dt, fofs, pivot, TRUE);
119	0	} Unexecuted instantiation: refclock_nmea.c:gpsntp_from_daytime1 Unexecuted instantiation: refclock_palisade.c:gpsntp_from_daytime1 Unexecuted instantiation: refclock_zyfer.c:gpsntp_from_daytime1 Unexecuted instantiation: ntp_calgps.c:gpsntp_from_daytime1
120
121		extern TNtpDatum
122		gpsntp_from_daytime2_ex(TcCivilDate dt, l_fp fofs, TcNtpDatum pivot, int/BOOL/ warp);
123
124		static inline TNtpDatum
125	0	gpsntp_from_daytime2(TcCivilDate dt, l_fp fofs, TcNtpDatum pivot) {
126	0	return gpsntp_from_daytime2_ex(dt, fofs, pivot, TRUE);
127	0	} Unexecuted instantiation: refclock_nmea.c:gpsntp_from_daytime2 Unexecuted instantiation: refclock_palisade.c:gpsntp_from_daytime2 Unexecuted instantiation: refclock_zyfer.c:gpsntp_from_daytime2 Unexecuted instantiation: ntp_calgps.c:gpsntp_from_daytime2
128
129		extern TNtpDatum
130		gpsntp_from_gpscal_ex(TcGpsDatum, int/BOOL*/ warp);
131
132		static inline TNtpDatum
133	0	gpsntp_from_gpscal(TcGpsDatum *wd) {
134	0	return gpsntp_from_gpscal_ex(wd, FALSE);
135	0	} Unexecuted instantiation: refclock_nmea.c:gpsntp_from_gpscal Unexecuted instantiation: refclock_palisade.c:gpsntp_from_gpscal Unexecuted instantiation: refclock_zyfer.c:gpsntp_from_gpscal Unexecuted instantiation: ntp_calgps.c:gpsntp_from_gpscal
136
137		extern void
138		gpsntp_to_calendar(TCivilDate, TcNtpDatum);
139
140		extern l_fp
141		ntpfp_from_ntpdatum(TcNtpDatum*);
142
143		/*
144		* Some helpers
145		*/
146
147		/* apply fudge to time stamp: SUBTRACT the given offset from an l_fp*/
148		extern l_fp
149		ntpfp_with_fudge(l_fp lfp, double ofs);
150
151		#endif /!defined(NTP_CALGPS_H)/