113 lines
3.1 KiB
C
113 lines
3.1 KiB
C
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/*
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* ntp_calendar.h - definitions for the calendar time-of-day routine
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*/
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#ifndef NTP_CALENDAR_H
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#define NTP_CALENDAR_H
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#include "ntp_types.h"
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struct calendar {
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u_short year; /* year (A.D.) */
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u_short yearday; /* day of year, 1 = January 1 */
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u_char month; /* month, 1 = January */
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u_char monthday; /* day of month */
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u_char hour; /* hour of day, midnight = 0 */
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u_char minute; /* minute of hour */
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u_char second; /* second of minute */
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};
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/*
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* Days in each month. 30 days hath September...
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*/
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#define JAN 31
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#define FEB 28
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#define FEBLEAP 29
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#define MAR 31
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#define APR 30
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#define MAY 31
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#define JUN 30
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#define JUL 31
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#define AUG 31
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#define SEP 30
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#define OCT 31
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#define NOV 30
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#define DEC 31
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/*
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* We deal in a 4 year cycle starting at March 1, 1900. We assume
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* we will only want to deal with dates since then, and not to exceed
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* the rollover day in 2036.
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*/
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#define SECSPERMIN (60) /* seconds per minute */
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#define MINSPERHR (60) /* minutes per hour */
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#define HRSPERDAY (24) /* hours per day */
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#define DAYSPERYEAR (365) /* days per year */
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#define SECSPERDAY (SECSPERMIN*MINSPERHR*HRSPERDAY)
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#define SECSPERYEAR (365 * SECSPERDAY) /* regular year */
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#define SECSPERLEAPYEAR (366 * SECSPERDAY) /* leap year */
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#define MAR1900 ((JAN+FEB) * SECSPERDAY) /* no leap year in 1900 */
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#define DAYSPERCYCLE (365+365+365+366) /* 3 normal years plus leap */
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#define SECSPERCYCLE (DAYSPERCYCLE*SECSPERDAY)
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#define YEARSPERCYCLE 4
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/*
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* Gross hacks. I have illicit knowlege that there won't be overflows
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* here, the compiler often can't tell this.
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*/
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#define TIMES60(val) ((((val)<<4) - (val))<<2) /* *(16 - 1) * 4 */
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#define TIMES24(val) (((val)<<4) + ((val)<<3)) /* *16 + *8 */
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#define TIMES7(val) (((val)<<3) - (val)) /* *8 - *1 */
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#define TIMESDPERC(val) (((val)<<10) + ((val)<<8) \
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+ ((val)<<7) + ((val)<<5) \
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+ ((val)<<4) + ((val)<<2) + (val)) /* *big* hack */
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/*
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* Another big hack. Cycle 22 started on March 1, 1988. This is
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* STARTCYCLE22 seconds after the start of cycle 0.
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*/
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#define CYCLE22 (22)
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#define STARTCYCLE22 (u_long)(0xa586b500) /* 2777068800 */
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#define MAR1988 (u_long)(STARTCYCLE22 + (u_long)MAR1900)
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/*
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* The length of January + February in leap and non-leap years.
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*/
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#define JANFEBNOLEAP ((JAN+FEB) * SECSPERDAY)
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#define JANFEBLEAP ((JAN+FEBLEAP) * SECSPERDAY)
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extern void caljulian P((u_long, struct calendar *));
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extern u_long caltontp P((const struct calendar *));
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/*
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* Additional support stuff for Ed Rheingold's calendrical calculations
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*/
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/*
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* Start day of NTP time as days past the imaginary date 12/1/1 BC.
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* P((This is the beginning of the Christian Era, or BCE.))
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*/
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#define DAY_NTP_STARTS 693596
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/*
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* The Gregorian calendar is based on a 400 year cycle. This is the number
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* of days in each cycle.
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*/
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#define GREGORIAN_CYCLE_DAYS 146097
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/*
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* Days in a normal 100 year leap year calendar. We lose a leap year day
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* in years evenly divisible by 100 but not by 400.
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*/
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#define GREGORIAN_NORMAL_CENTURY_DAYS 36524
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/*
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* Days in a normal 4 year leap year calendar cycle.
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*/
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#define GREGORIAN_NORMAL_LEAP_CYCLE_DAYS 1461
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#define is_leapyear(y) (y%4 == 0 && !(y%100 == 0 && !(y%400 == 0)))
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#endif
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