45 lines
1.1 KiB
C
45 lines
1.1 KiB
C
/* $NetBSD: caltontp.c,v 1.2 2003/12/04 16:23:36 drochner Exp $ */
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/*
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* caltontp - convert a date to an NTP time
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*/
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#include <sys/types.h>
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#include "ntp_types.h"
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#include "ntp_calendar.h"
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#include "ntp_stdlib.h"
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u_long
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caltontp(
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register const struct calendar *jt
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)
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{
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u_long ace_days; /* absolute Christian Era days */
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u_long ntp_days;
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int prior_years;
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u_long ntp_time;
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/*
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* First convert today's date to absolute days past 12/1/1 BC
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*/
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prior_years = jt->year-1;
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ace_days = jt->yearday /* days this year */
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+(DAYSPERYEAR*prior_years) /* plus days in previous years */
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+(prior_years/4) /* plus prior years's leap days */
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-(prior_years/100) /* minus leapless century years */
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+(prior_years/400); /* plus leapful Gregorian yrs */
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/*
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* Subtract out 1/1/1900, the beginning of the NTP epoch
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*/
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ntp_days = ace_days - DAY_NTP_STARTS;
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/*
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* Do the obvious:
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*/
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ntp_time =
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ntp_days*SECSPERDAY+SECSPERMIN*(MINSPERHR*jt->hour + jt->minute);
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return ntp_time;
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}
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