freebsd-dev/contrib/ntp/libntp/calyearstart.c
Cy Schubert 2b15cb3d09 MFV ntp 4.2.8p1 (r258945, r275970, r276091, r276092, r276093, r278284)
Thanks to roberto for providing pointers to wedge this into HEAD.

Approved by:	roberto
2015-03-30 13:30:15 +00:00

89 lines
2.1 KiB
C

/*
* calyearstart - determine the NTP time at midnight of January 1 in
* the year of the given date.
*/
#include <config.h>
#include <sys/types.h>
#include "ntp_types.h"
#include "ntp_calendar.h"
#include "ntp_stdlib.h"
#include "ntp_assert.h"
/*
* Juergen Perlinger, 2010-05-02
*
* Redone in terms of the calendar functions. It's rather simple:
* - expand the NTP time stamp
* - split into days and seconds since midnight, dropping the partial day
* - get full number of days before year start in NTP epoch
* - convert to seconds, truncated to 32 bits.
*/
u_int32
calyearstart(u_int32 ntptime, const time_t *pivot)
{
u_int32 ndays; /* elapsed days since NTP starts */
vint64 vlong;
ntpcal_split split;
vlong = ntpcal_ntp_to_ntp(ntptime, pivot);
split = ntpcal_daysplit(&vlong);
ndays = ntpcal_rd_to_ystart(split.hi + DAY_NTP_STARTS)
- DAY_NTP_STARTS;
return (u_int32)(ndays * SECSPERDAY);
}
/*
* calmonthstart - get NTP time at midnight of the first day of the
* current month.
*/
u_int32
calmonthstart(u_int32 ntptime, const time_t *pivot)
{
u_int32 ndays; /* elapsed days since NTP starts */
vint64 vlong;
ntpcal_split split;
vlong = ntpcal_ntp_to_ntp(ntptime, pivot);
split = ntpcal_daysplit(&vlong);
ndays = ntpcal_rd_to_mstart(split.hi + DAY_NTP_STARTS)
- DAY_NTP_STARTS;
return (u_int32)(ndays * SECSPERDAY);
}
/*
* calweekstart - get NTP time at midnight of the last monday on or
* before the current date.
*/
u_int32
calweekstart(u_int32 ntptime, const time_t *pivot)
{
u_int32 ndays; /* elapsed days since NTP starts */
vint64 vlong;
ntpcal_split split;
vlong = ntpcal_ntp_to_ntp(ntptime, pivot);
split = ntpcal_daysplit(&vlong);
ndays = ntpcal_weekday_le(split.hi + DAY_NTP_STARTS, CAL_MONDAY)
- DAY_NTP_STARTS;
return (u_int32)(ndays * SECSPERDAY);
}
/*
* caldaystart - get NTP time at midnight of the current day.
*/
u_int32
caldaystart(u_int32 ntptime, const time_t *pivot)
{
vint64 vlong;
ntpcal_split split;
vlong = ntpcal_ntp_to_ntp(ntptime, pivot);
split = ntpcal_daysplit(&vlong);
return ntptime - split.lo;
}