diff options
Diffstat (limited to 'libntp/ntp_calendar.c')
| -rw-r--r-- | libntp/ntp_calendar.c | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/libntp/ntp_calendar.c b/libntp/ntp_calendar.c index f8b7db4ea501..79742688a2bd 100644 --- a/libntp/ntp_calendar.c +++ b/libntp/ntp_calendar.c @@ -1832,6 +1832,7 @@ isocal_date_to_ntp( */ static int32_t s_baseday = NTP_TO_UNIX_DAYS; +static int32_t s_gpsweek = 0; int32_t basedate_eval_buildstamp(void) @@ -1901,6 +1902,7 @@ basedate_set_day( struct calendar jd; int32_t retv; + /* set NTP base date for NTP era unfolding */ if (day < NTP_TO_UNIX_DAYS) { msyslog(LOG_WARNING, "baseday_set_day: invalid day (%lu), UNIX epoch substituted", @@ -1912,6 +1914,17 @@ basedate_set_day( ntpcal_rd_to_date(&jd, day + DAY_NTP_STARTS); msyslog(LOG_INFO, "basedate set to %04hu-%02hu-%02hu", jd.year, (u_short)jd.month, (u_short)jd.monthday); + + /* set GPS base week for GPS week unfolding */ + day = ntpcal_weekday_ge(day + DAY_NTP_STARTS, CAL_SUNDAY) + - DAY_NTP_STARTS; + if (day < NTP_TO_GPS_DAYS) + day = NTP_TO_GPS_DAYS; + s_gpsweek = (day - NTP_TO_GPS_DAYS) / DAYSPERWEEK; + ntpcal_rd_to_date(&jd, day + DAY_NTP_STARTS); + msyslog(LOG_INFO, "gps base set to %04hu-%02hu-%02hu (week %d)", + jd.year, (u_short)jd.month, (u_short)jd.monthday, s_gpsweek); + return retv; } @@ -1934,4 +1947,29 @@ basedate_get_erabase(void) return retv; } +uint32_t +basedate_get_gpsweek(void) +{ + return s_gpsweek; +} + +uint32_t +basedate_expand_gpsweek( + unsigned short weekno + ) +{ + /* We do a fast modulus expansion here. Since all quantities are + * unsigned and we cannot go before the start of the GPS epoch + * anyway, and since the truncated GPS week number is 10 bit, the + * expansion becomes a simple sub/and/add sequence. + */ + #if GPSWEEKS != 1024 + # error GPSWEEKS defined wrong -- should be 1024! + #endif + + uint32_t diff; + diff = ((uint32_t)weekno - s_gpsweek) & (GPSWEEKS - 1); + return s_gpsweek + diff; +} + /* -*-EOF-*- */ |