ntp_calendar.h revision 285612
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 <time.h> 8 9#include "ntp_types.h" 10 11/* gregorian calendar date */ 12struct calendar { 13 uint16_t year; /* year (A.D.) */ 14 uint16_t yearday; /* day of year, 1 = January 1 */ 15 uint8_t month; /* month, 1 = January */ 16 uint8_t monthday; /* day of month */ 17 uint8_t hour; /* hour of day, midnight = 0 */ 18 uint8_t minute; /* minute of hour */ 19 uint8_t second; /* second of minute */ 20 uint8_t weekday; /* 0..7, 0=Sunday */ 21}; 22 23/* ISO week calendar date */ 24struct isodate { 25 uint16_t year; /* year (A.D.) */ 26 uint8_t week; /* 1..53, week in year */ 27 uint8_t weekday; /* 1..7, 1=Monday */ 28 uint8_t hour; /* hour of day, midnight = 0 */ 29 uint8_t minute; /* minute of hour */ 30 uint8_t second; /* second of minute */ 31}; 32 33/* general split representation */ 34typedef struct { 35 int32_t hi; 36 int32_t lo; 37} ntpcal_split; 38 39typedef time_t (*systime_func_ptr)(time_t *); 40 41/* 42 * set the function for getting the system time. This is mostly used for 43 * unit testing to provide a fixed / shifted time stamp. Setting the 44 * value to NULL restores the original function, that is, 'time()', 45 * which is also the automatic default. 46 */ 47extern systime_func_ptr ntpcal_set_timefunc(systime_func_ptr); 48 49/* 50 * days-of-week 51 */ 52#define CAL_SUNDAY 0 53#define CAL_MONDAY 1 54#define CAL_TUESDAY 2 55#define CAL_WEDNESDAY 3 56#define CAL_THURSDAY 4 57#define CAL_FRIDAY 5 58#define CAL_SATURDAY 6 59#define CAL_SUNDAY7 7 /* also sunday */ 60 61/* 62 * Days in each month. 30 days hath September... 63 */ 64#define JAN 31 65#define FEB 28 66#define FEBLEAP 29 67#define MAR 31 68#define APR 30 69#define MAY 31 70#define JUN 30 71#define JUL 31 72#define AUG 31 73#define SEP 30 74#define OCT 31 75#define NOV 30 76#define DEC 31 77 78/* 79 * We deal in a 4 year cycle starting at March 1, 1900. We assume 80 * we will only want to deal with dates since then, and not to exceed 81 * the rollover day in 2036. 82 */ 83#define SECSPERMIN (60) /* seconds per minute */ 84#define MINSPERHR (60) /* minutes per hour */ 85#define HRSPERDAY (24) /* hours per day */ 86#define DAYSPERWEEK (7) /* days per week */ 87#define DAYSPERYEAR (365) /* days per year */ 88 89#define SECSPERHR (SECSPERMIN * MINSPERHR) 90#define SECSPERDAY (SECSPERHR * HRSPERDAY) 91#define SECSPERWEEK (DAYSPERWEEK * SECSPERDAY) 92#define SECSPERYEAR (365 * SECSPERDAY) /* regular year */ 93#define SECSPERLEAPYEAR (366 * SECSPERDAY) /* leap year */ 94#define SECSPERAVGYEAR 31556952 /* mean year length over 400yrs */ 95 96/* 97 * Gross hacks. I have illicit knowlege that there won't be overflows 98 * here, the compiler often can't tell this. 99 */ 100#define TIMES60(val) ((((val)<<4) - (val))<<2) /* *(16 - 1) * 4 */ 101#define TIMES24(val) (((val)<<4) + ((val)<<3)) /* *16 + *8 */ 102#define TIMES7(val) (((val)<<3) - (val)) /* *8 - *1 */ 103#define TIMESDPERC(val) (((val)<<10) + ((val)<<8) \ 104 + ((val)<<7) + ((val)<<5) \ 105 + ((val)<<4) + ((val)<<2) + (val)) /* *big* hack */ 106 107 108extern const char * const months[12]; 109extern const char * const daynames[7]; 110 111extern void caljulian (uint32_t, struct calendar *); 112extern uint32_t caltontp (const struct calendar *); 113 114/* 115 * Convert between 'time_t' and 'vint64' 116 */ 117extern vint64 time_to_vint64(const time_t *); 118extern time_t vint64_to_time(const vint64 *); 119 120/* 121 * Get the build date & time. ATTENTION: The time zone is not specified! 122 * This depends entirely on the C compilers' capabilities to properly 123 * expand the '__TIME__' and '__DATE__' macros, as required by the C 124 * standard. 125 */ 126extern int 127ntpcal_get_build_date(struct calendar * /* jd */); 128 129/* 130 * Convert a timestamp in NTP scale to a time_t value in the UN*X 131 * scale with proper epoch unfolding around a given pivot or the 132 * current system time. 133 */ 134extern vint64 135ntpcal_ntp_to_time(uint32_t /* ntp */, const time_t * /* pivot */); 136 137/* 138 * Convert a timestamp in NTP scale to a 64bit seconds value in the NTP 139 * scale with proper epoch unfolding around a given pivot or the current 140 * system time. 141 * Note: The pivot must be given in UN*X time scale! 142 */ 143extern vint64 144ntpcal_ntp_to_ntp(uint32_t /* ntp */, const time_t * /* pivot */); 145 146/* 147 * Split a time stamp in seconds into elapsed days and elapsed seconds 148 * since midnight. 149 */ 150extern ntpcal_split 151ntpcal_daysplit(const vint64 *); 152 153/* 154 * Merge a number of days and a number of seconds into seconds, 155 * expressed in 64 bits to avoid overflow. 156 */ 157extern vint64 158ntpcal_dayjoin(int32_t /* days */, int32_t /* seconds */); 159 160/* 161 * Convert elapsed years in Era into elapsed days in Era. 162 */ 163extern int32_t 164ntpcal_days_in_years(int32_t /* years */); 165 166/* 167 * Convert a number of elapsed month in a year into elapsed days 168 * in year. 169 * 170 * The month will be normalized, and 'res.hi' will contain the 171 * excessive years that must be considered when converting the years, 172 * while 'res.lo' will contain the days since start of the 173 * year. (Expect the resulting days to be negative, with a positive 174 * excess! But then, we need no leap year flag, either...) 175 */ 176extern ntpcal_split 177ntpcal_days_in_months(int32_t /* months */); 178 179/* 180 * Convert ELAPSED years/months/days of gregorian calendar to elapsed 181 * days in Gregorian epoch. No range checks done here! 182 */ 183extern int32_t 184ntpcal_edate_to_eradays(int32_t /* years */, int32_t /* months */, int32_t /* mdays */); 185 186/* 187 * Convert a time spec to seconds. No range checks done here! 188 */ 189extern int32_t 190ntpcal_etime_to_seconds(int32_t /* hours */, int32_t /* minutes */, int32_t /* seconds */); 191 192/* 193 * Convert ELAPSED years/months/days of gregorian calendar to elapsed 194 * days in year. 195 * 196 * Note: This will give the true difference to the start of the given year, 197 * even if months & days are off-scale. 198 */ 199extern int32_t 200ntpcal_edate_to_yeardays(int32_t /* years */, int32_t /* months */, int32_t /* mdays */); 201 202/* 203 * Convert the date part of a 'struct tm' (that is, year, month, 204 * day-of-month) into the RataDie of that day. 205 */ 206extern int32_t 207ntpcal_tm_to_rd(const struct tm * /* utm */); 208 209/* 210 * Convert the date part of a 'struct calendar' (that is, year, month, 211 * day-of-month) into the RataDie of that day. 212 */ 213extern int32_t 214ntpcal_date_to_rd(const struct calendar * /* jt */); 215 216/* 217 * Given the number of elapsed days in the calendar era, split this 218 * number into the number of elapsed years in 'res.quot' and the 219 * number of elapsed days of that year in 'res.rem'. 220 * 221 * if 'isleapyear' is not NULL, it will receive an integer that is 0 222 * for regular years and a non-zero value for leap years. 223 */ 224extern ntpcal_split 225ntpcal_split_eradays(int32_t /* days */, int/*BOOL*/ * /* isleapyear */); 226 227/* 228 * Given a number of elapsed days in a year and a leap year indicator, 229 * split the number of elapsed days into the number of elapsed months 230 * in 'res.quot' and the number of elapsed days of that month in 231 * 'res.rem'. 232 */ 233extern ntpcal_split 234ntpcal_split_yeardays(int32_t /* eyd */, int/*BOOL*/ /* isleapyear */); 235 236/* 237 * Convert a RataDie number into the date part of a 'struct 238 * calendar'. Return 0 if the year is regular year, !0 if the year is 239 * a leap year. 240 */ 241extern int/*BOOL*/ 242ntpcal_rd_to_date(struct calendar * /* jt */, int32_t /* rd */); 243 244/* 245 * Convert a RataDie number into the date part of a 'struct 246 * tm'. Return 0 if the year is regular year, !0 if the year is a leap 247 * year. 248 */ 249extern int/*BOOL*/ 250ntpcal_rd_to_tm(struct tm * /* utm */, int32_t /* rd */); 251 252/* 253 * Take a value of seconds since midnight and split it into hhmmss in 254 * a 'struct calendar'. Return excessive days. 255 */ 256extern int32_t 257ntpcal_daysec_to_date(struct calendar * /* jt */, int32_t /* secs */); 258 259/* 260 * Take the time part of a 'struct calendar' and return the seconds 261 * since midnight. 262 */ 263extern int32_t 264ntpcal_date_to_daysec(const struct calendar *); 265 266/* 267 * Take a value of seconds since midnight and split it into hhmmss in 268 * a 'struct tm'. Return excessive days. 269 */ 270extern int32_t 271ntpcal_daysec_to_tm(struct tm * /* utm */, int32_t /* secs */); 272 273extern int32_t 274ntpcal_tm_to_daysec(const struct tm * /* utm */); 275 276/* 277 * convert a year number to rata die of year start 278 */ 279extern int32_t 280ntpcal_year_to_ystart(int32_t /* year */); 281 282/* 283 * For a given RataDie, get the RataDie of the associated year start, 284 * that is, the RataDie of the last January,1st on or before that day. 285 */ 286extern int32_t 287ntpcal_rd_to_ystart(int32_t /* rd */); 288 289/* 290 * convert a RataDie to the RataDie of start of the calendar month. 291 */ 292extern int32_t 293ntpcal_rd_to_mstart(int32_t /* year */); 294 295 296extern int 297ntpcal_daysplit_to_date(struct calendar * /* jt */, 298 const ntpcal_split * /* ds */, int32_t /* dof */); 299 300extern int 301ntpcal_daysplit_to_tm(struct tm * /* utm */, const ntpcal_split * /* ds */, 302 int32_t /* dof */); 303 304extern int 305ntpcal_time_to_date(struct calendar * /* jd */, const vint64 * /* ts */); 306 307extern int32_t 308ntpcal_periodic_extend(int32_t /* pivot */, int32_t /* value */, 309 int32_t /* cycle */); 310 311extern int 312ntpcal_ntp64_to_date(struct calendar * /* jd */, const vint64 * /* ntp */); 313 314extern int 315ntpcal_ntp_to_date(struct calendar * /* jd */, uint32_t /* ntp */, 316 const time_t * /* pivot */); 317 318extern vint64 319ntpcal_date_to_ntp64(const struct calendar * /* jd */); 320 321extern uint32_t 322ntpcal_date_to_ntp(const struct calendar * /* jd */); 323 324extern time_t 325ntpcal_date_to_time(const struct calendar * /* jd */); 326 327/* 328 * ISO week-calendar conversions 329 */ 330extern int32_t 331isocal_weeks_in_years(int32_t /* years */); 332 333extern ntpcal_split 334isocal_split_eraweeks(int32_t /* weeks */); 335 336extern int 337isocal_ntp64_to_date(struct isodate * /* id */, const vint64 * /* ntp */); 338 339extern int 340isocal_ntp_to_date(struct isodate * /* id */, uint32_t /* ntp */, 341 const time_t * /* pivot */); 342 343extern vint64 344isocal_date_to_ntp64(const struct isodate * /* id */); 345 346extern uint32_t 347isocal_date_to_ntp(const struct isodate * /* id */); 348 349 350/* 351 * day-of-week calculations 352 * 353 * Given a RataDie and a day-of-week, calculate a RDN that is reater-than, 354 * greater-or equal, closest, less-or-equal or less-than the given RDN 355 * and denotes the given day-of-week 356 */ 357extern int32_t 358ntpcal_weekday_gt(int32_t /* rdn */, int32_t /* dow */); 359 360extern int32_t 361ntpcal_weekday_ge(int32_t /* rdn */, int32_t /* dow */); 362 363extern int32_t 364ntpcal_weekday_close(int32_t /* rdn */, int32_t /* dow */); 365 366extern int32_t 367ntpcal_weekday_le(int32_t /* rdn */, int32_t /* dow */); 368 369extern int32_t 370ntpcal_weekday_lt(int32_t /* rdn */, int32_t /* dow */); 371 372/* 373 * Additional support stuff for Ed Rheingold's calendrical calculations 374 */ 375 376/* 377 * Start day of NTP time as days past the imaginary date 12/1/1 BC. 378 * (This is the beginning of the Christian Era, or BCE.) 379 */ 380#define DAY_NTP_STARTS 693596 381 382/* 383 * Start day of the UNIX epoch. This is the Rata Die of 1970-01-01. 384 */ 385#define DAY_UNIX_STARTS 719163 386 387/* 388 * Difference between UN*X and NTP epoch (25567). 389 */ 390#define NTP_TO_UNIX_DAYS (DAY_UNIX_STARTS - DAY_NTP_STARTS) 391 392/* 393 * Days in a normal 4 year leap year calendar cycle (1461). 394 */ 395#define GREGORIAN_NORMAL_LEAP_CYCLE_DAYS (3 * 365 + 366) 396 397/* 398 * Days in a normal 100 year leap year calendar (36524). We lose a 399 * leap day in years evenly divisible by 100 but not by 400. 400 */ 401#define GREGORIAN_NORMAL_CENTURY_DAYS \ 402 (25 * GREGORIAN_NORMAL_LEAP_CYCLE_DAYS - 1) 403 404/* 405 * The Gregorian calendar is based on a 400 year cycle. This is the 406 * number of days in each cycle (146097). We gain a leap day in years 407 * divisible by 400 relative to the "normal" century. 408 */ 409#define GREGORIAN_CYCLE_DAYS (4 * GREGORIAN_NORMAL_CENTURY_DAYS + 1) 410 411/* 412 * Number of weeks in 400 years (20871). 413 */ 414#define GREGORIAN_CYCLE_WEEKS (GREGORIAN_CYCLE_DAYS / 7) 415 416#define is_leapyear(y) (!((y) % 4) && !(!((y) % 100) && (y) % 400)) 417 418#endif 419