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| author | Eric S. Raymond <esr@thyrsus.com> | 2014-08-25 00:00:22 -0400 |
|---|---|---|
| committer | Eric S. Raymond <esr@thyrsus.com> | 2014-08-25 00:00:22 -0400 |
| commit | dbdd6dec471d6a5614379bb6673342873294bc32 (patch) | |
| tree | 4d254ef3945e49f44449cc1a2f8b1b8dc7df72c7 | |
| parent | c0d020644bf925fb1010c86756e5051e50f18e51 (diff) | |
| download | gpsd-dbdd6dec471d6a5614379bb6673342873294bc32.tar.gz | |
Correct computatiojn of build timestamps.
| -rw-r--r-- | TODO | 7 | ||||
| -rwxr-xr-x | leapsecond.py | 12 |
2 files changed, 9 insertions, 10 deletions
@@ -24,13 +24,6 @@ Consider merging the calibration draft into the Time Service HOWTO. Our goal is to be independent of the system clock. -**** Compile the GPS week of the build into the build - -The obvious place tp put this is in timebase.h. Not too expensive; -will typically cause extra work once per seven days. The benefit is that -we can compare received week to the compiled in week and if the latter -is less know that a rollover has occurred. - **** Maybe apply wraparound compensation **** See <http://www.febo.com/pipermail/time-nuts/2013-August/079271.html> diff --git a/leapsecond.py b/leapsecond.py index 5f6d57dc..58ff3fef 100755 --- a/leapsecond.py +++ b/leapsecond.py @@ -76,9 +76,13 @@ __locations = [ GPS_EPOCH = 315964800 # 6 Jan 1981 00:00:00 SECS_PER_WEEK = 60 * 60 * 24 * 7 # Seconds per GPS week +ROLLOVER = 1024 # 10-bit week rollover def gps_week(t): - return (t - GPS_EPOCH)/SECS_PER_WEEK + return ((t - GPS_EPOCH)/SECS_PER_WEEK % ROLLOVER) + +def gps_rollovers(t): + return ((t - GPS_EPOCH)/SECS_PER_WEEK / ROLLOVER) def isotime(s): "Convert timestamps in ISO8661 format to and from Unix time including optional fractional seconds." @@ -191,8 +195,9 @@ def make_leapsecond_include(infile): # which doesn't count substitution through locals() as use. leapjumps = fetch_leapsecs(infile) now = int(time.time()) - _year = time.strftime("%Y", time.gmtime(now)) + _century = time.strftime("%Y", time.gmtime(now))[:2] + "00" _gps_week_now = gps_week(now) + _gps_rollover_now = gps_rollovers(now) _isodate = isotime(now - now % SECS_PER_WEEK) _leapsecs = -1 for leapjump in leapjumps: @@ -204,9 +209,10 @@ def make_leapsecond_include(infile): * * Correct for week beginning %(_isodate)s */ -#define CENTURY_BASE\t%(_year)s00 +#define CENTURY_BASE\t%(_century)s #define LEAPSECOND_NOW\t%(_leapsecs)d #define GPS_WEEK_NOW\t%(_gps_week_now)d +#define GPS_ROLLOVERS_NOW\t%(_gps_rollover_now)d """ % locals() def conditional_leapsecond_fetch(outfile, timeout): |