dist/ntp/include/ntp_calendar.h

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