2 * caltontp - convert a date to an NTP time
8 #include "ntp_calendar.h"
9 #include "ntp_stdlib.h"
10 #include "ntp_assert.h"
11 #include "ntp_unixtime.h"
14 * Juergen Perlinger, 2008-11-12
15 * Add support for full calendar calculatios. If the day-of-year is provided
16 * (that is, not zero) it will be used instead of month and day-of-month;
17 * otherwise a full turn through the calendar calculations will be taken.
19 * I know that Harlan Stenn likes to see assertions in production code, and I
20 * agree there, but it would be a tricky thing here. The algorithm is quite
21 * capable of producing sensible answers even to seemingly weird inputs: the
22 * date <any year here>-03-00, the 0.th March of the year, will be automtically
23 * treated as the last day of February, no matter whether the year is a leap
24 * year or not. So adding constraints is merely for the benefit of the callers,
25 * because the only thing we can check for consistency is our input, produced
28 * BTW: A total roundtrip using 'caljulian' would be a quite shaky thing:
29 * Because of the truncation of the NTP time stamp to 32 bits and the epoch
30 * unfolding around the current time done by 'caljulian' the roundtrip does
31 * *not* necessarily reproduce the input, especially if the time spec is more
32 * than 68 years off from the current time...
37 const struct calendar *jt
40 int32_t eraday; /* CE Rata Die number */
41 vint64 ntptime;/* resulting NTP time */
45 REQUIRE(jt->month <= 13); /* permit month 0..13! */
46 REQUIRE(jt->monthday <= 32);
47 REQUIRE(jt->yearday <= 366);
48 REQUIRE(jt->hour <= 24);
49 REQUIRE(jt->minute <= MINSPERHR);
50 REQUIRE(jt->second <= SECSPERMIN);
53 * First convert the date to he corresponding RataDie
54 * number. If yearday is not zero, assume that it contains a
55 * useable value and avoid all calculations involving month
56 * and day-of-month. Do a full evaluation otherwise.
59 eraday = ntpcal_year_to_ystart(jt->year)
62 eraday = ntpcal_date_to_rd(jt);
64 ntptime = ntpcal_dayjoin(eraday - DAY_NTP_STARTS,
65 ntpcal_etime_to_seconds(jt->hour, jt->minute,
67 return ntptime.d_s.lo;