/* * caltontp - convert a date to an NTP time */ #include #include "ntp_types.h" #include "ntp_calendar.h" #include "ntp_stdlib.h" u_long caltontp( register const struct calendar *jt ) { u_long ace_days; /* absolute Christian Era days */ u_long ntp_days; int prior_years; u_long ntp_time; /* * First convert today's date to absolute days past 12/1/1 BC */ prior_years = jt->year-1; ace_days = jt->yearday /* days this year */ +(DAYSPERYEAR*prior_years) /* plus days in previous years */ +(prior_years/4) /* plus prior years's leap days */ -(prior_years/100) /* minus leapless century years */ +(prior_years/400); /* plus leapful Gregorian yrs */ /* * Subtract out 1/1/1900, the beginning of the NTP epoch */ ntp_days = ace_days - DAY_NTP_STARTS; /* * Do the obvious: */ ntp_time = ntp_days*SECSPERDAY+SECSPERMIN*(MINSPERHR*jt->hour + jt->minute); return ntp_time; }