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freebsd/contrib/ntp/include/ntp_calendar.h
1999-12-09 13:01:21 +00:00

113 lines
3.1 KiB
C

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