1 /* 2 * ntp_calendar.h - definitions for the calendar time-of-day routine 3 */ 4 #ifndef NTP_CALENDAR_H 5 #define NTP_CALENDAR_H 6 7 #include "ntp_types.h" 8 9 struct calendar { 10 u_short year; /* year (A.D.) */ 11 u_short yearday; /* day of year, 1 = January 1 */ 12 u_char month; /* month, 1 = January */ 13 u_char monthday; /* day of month */ 14 u_char hour; /* hour of day, midnight = 0 */ 15 u_char minute; /* minute of hour */ 16 u_char second; /* second of minute */ 17 }; 18 19 /* 20 * Days in each month. 30 days hath September... 21 */ 22 #define JAN 31 23 #define FEB 28 24 #define FEBLEAP 29 25 #define MAR 31 26 #define APR 30 27 #define MAY 31 28 #define JUN 30 29 #define JUL 31 30 #define AUG 31 31 #define SEP 30 32 #define OCT 31 33 #define NOV 30 34 #define DEC 31 35 36 /* 37 * We deal in a 4 year cycle starting at March 1, 1900. We assume 38 * we will only want to deal with dates since then, and not to exceed 39 * the rollover day in 2036. 40 */ 41 #define SECSPERMIN (60) /* seconds per minute */ 42 #define MINSPERHR (60) /* minutes per hour */ 43 #define HRSPERDAY (24) /* hours per day */ 44 #define DAYSPERYEAR (365) /* days per year */ 45 46 #define SECSPERDAY (SECSPERMIN*MINSPERHR*HRSPERDAY) 47 #define SECSPERYEAR (365 * SECSPERDAY) /* regular year */ 48 #define SECSPERLEAPYEAR (366 * SECSPERDAY) /* leap year */ 49 50 #define MAR1900 ((JAN+FEB) * SECSPERDAY) /* no leap year in 1900 */ 51 #define DAYSPERCYCLE (365+365+365+366) /* 3 normal years plus leap */ 52 #define SECSPERCYCLE (DAYSPERCYCLE*SECSPERDAY) 53 #define YEARSPERCYCLE 4 54 55 /* 56 * Gross hacks. I have illicit knowlege that there won't be overflows 57 * here, the compiler often can't tell this. 58 */ 59 #define TIMES60(val) ((((val)<<4) - (val))<<2) /* *(16 - 1) * 4 */ 60 #define TIMES24(val) (((val)<<4) + ((val)<<3)) /* *16 + *8 */ 61 #define TIMES7(val) (((val)<<3) - (val)) /* *8 - *1 */ 62 #define TIMESDPERC(val) (((val)<<10) + ((val)<<8) \ 63 + ((val)<<7) + ((val)<<5) \ 64 + ((val)<<4) + ((val)<<2) + (val)) /* *big* hack */ 65 66 /* 67 * Another big hack. Cycle 22 started on March 1, 1988. This is 68 * STARTCYCLE22 seconds after the start of cycle 0. 69 */ 70 #define CYCLE22 (22) 71 #define STARTCYCLE22 (u_long)(0xa586b500) /* 2777068800 */ 72 #define MAR1988 (u_long)(STARTCYCLE22 + (u_long)MAR1900) 73 74 /* 75 * The length of January + February in leap and non-leap years. 76 */ 77 #define JANFEBNOLEAP ((JAN+FEB) * SECSPERDAY) 78 #define JANFEBLEAP ((JAN+FEBLEAP) * SECSPERDAY) 79 80 81 extern void caljulian P((u_long, struct calendar *)); 82 extern u_long caltontp P((const struct calendar *)); 83 84 /* 85 * Additional support stuff for Ed Rheingold's calendrical calculations 86 */ 87 88 /* 89 * Start day of NTP time as days past the imaginary date 12/1/1 BC. 90 * P((This is the beginning of the Christian Era, or BCE.)) 91 */ 92 #define DAY_NTP_STARTS 693596 93 /* 94 * The Gregorian calendar is based on a 400 year cycle. This is the number 95 * of days in each cycle. 96 */ 97 #define GREGORIAN_CYCLE_DAYS 146097 98 99 /* 100 * Days in a normal 100 year leap year calendar. We lose a leap year day 101 * in years evenly divisible by 100 but not by 400. 102 */ 103 #define GREGORIAN_NORMAL_CENTURY_DAYS 36524 104 105 /* 106 * Days in a normal 4 year leap year calendar cycle. 107 */ 108 #define GREGORIAN_NORMAL_LEAP_CYCLE_DAYS 1461 109 110 #define is_leapyear(y) (y%4 == 0 && !(y%100 == 0 && !(y%400 == 0))) 111 112 #endif 113