a25439b686
Reviewed by: delphij (suggested MFC) Approved by: roberto Security: CVE-2015-1798, CVE-2015-1799 Security: VuXML ebd84c96-dd7e-11e4-854e-3c970e169bc2 MFC after: 1 month
1626 lines
41 KiB
C
1626 lines
41 KiB
C
/*
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* ntp_calendar.c - calendar and helper functions
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*
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* Written by Juergen Perlinger (perlinger@ntp.org) for the NTP project.
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* The contents of 'html/copyright.html' apply.
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*/
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#include <config.h>
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#include <sys/types.h>
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#include "ntp_types.h"
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#include "ntp_calendar.h"
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#include "ntp_stdlib.h"
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#include "ntp_fp.h"
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#include "ntp_unixtime.h"
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/*
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*---------------------------------------------------------------------
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* replacing the 'time()' function
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* --------------------------------------------------------------------
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*/
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static systime_func_ptr systime_func = &time;
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static inline time_t now(void);
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systime_func_ptr
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ntpcal_set_timefunc(
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systime_func_ptr nfunc
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)
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{
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systime_func_ptr res;
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res = systime_func;
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if (NULL == nfunc)
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nfunc = &time;
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systime_func = nfunc;
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return res;
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}
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static inline time_t
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now(void)
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{
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return (*systime_func)(NULL);
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}
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/*
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*---------------------------------------------------------------------
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* Convert between 'time_t' and 'vint64'
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*---------------------------------------------------------------------
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*/
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vint64
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time_to_vint64(
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const time_t * ptt
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)
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{
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vint64 res;
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time_t tt;
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tt = *ptt;
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#if SIZEOF_TIME_T <= 4
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res.D_s.hi = 0;
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if (tt < 0) {
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res.D_s.lo = (uint32_t)-tt;
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M_NEG(res.D_s.hi, res.D_s.lo);
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} else {
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res.D_s.lo = (uint32_t)tt;
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}
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#elif defined(HAVE_INT64)
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res.q_s = tt;
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#else
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/*
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* shifting negative signed quantities is compiler-dependent, so
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* we better avoid it and do it all manually. And shifting more
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* than the width of a quantity is undefined. Also a don't do!
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*/
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if (tt < 0) {
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tt = -tt;
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res.D_s.lo = (uint32_t)tt;
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res.D_s.hi = (uint32_t)(tt >> 32);
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M_NEG(res.D_s.hi, res.D_s.lo);
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} else {
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res.D_s.lo = (uint32_t)tt;
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res.D_s.hi = (uint32_t)(tt >> 32);
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}
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#endif
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return res;
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}
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time_t
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vint64_to_time(
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const vint64 *tv
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)
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{
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time_t res;
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#if SIZEOF_TIME_T <= 4
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res = (time_t)tv->D_s.lo;
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#elif defined(HAVE_INT64)
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res = (time_t)tv->q_s;
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#else
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res = ((time_t)tv->d_s.hi << 32) | tv->D_s.lo;
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#endif
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return res;
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}
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/*
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*---------------------------------------------------------------------
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* Get the build date & time
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*---------------------------------------------------------------------
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*/
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int
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ntpcal_get_build_date(
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struct calendar * jd
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)
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{
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/* The C standard tells us the format of '__DATE__':
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*
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* __DATE__ The date of translation of the preprocessing
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* translation unit: a character string literal of the form "Mmm
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* dd yyyy", where the names of the months are the same as those
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* generated by the asctime function, and the first character of
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* dd is a space character if the value is less than 10. If the
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* date of translation is not available, an
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* implementation-defined valid date shall be supplied.
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*
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* __TIME__ The time of translation of the preprocessing
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* translation unit: a character string literal of the form
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* "hh:mm:ss" as in the time generated by the asctime
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* function. If the time of translation is not available, an
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* implementation-defined valid time shall be supplied.
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*
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* Note that MSVC declares DATE and TIME to be in the local time
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* zone, while neither the C standard nor the GCC docs make any
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* statement about this. As a result, we may be +/-12hrs off
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* UTC. But for practical purposes, this should not be a
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* problem.
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*
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*/
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#ifdef MKREPRO_DATE
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static const char build[] = MKREPRO_TIME "/" MKREPRO_DATE;
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#else
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static const char build[] = __TIME__ "/" __DATE__;
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#endif
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static const char mlist[] = "JanFebMarAprMayJunJulAugSepOctNovDec";
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char monstr[4];
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const char * cp;
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unsigned short hour, minute, second, day, year;
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/* Note: The above quantities are used for sscanf 'hu' format,
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* so using 'uint16_t' is contra-indicated!
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*/
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#ifdef DEBUG
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static int ignore = 0;
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#endif
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ZERO(*jd);
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jd->year = 1970;
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jd->month = 1;
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jd->monthday = 1;
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#ifdef DEBUG
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/* check environment if build date should be ignored */
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if (0 == ignore) {
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const char * envstr;
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envstr = getenv("NTPD_IGNORE_BUILD_DATE");
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ignore = 1 + (envstr && (!*envstr || !strcasecmp(envstr, "yes")));
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}
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if (ignore > 1)
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return FALSE;
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#endif
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if (6 == sscanf(build, "%hu:%hu:%hu/%3s %hu %hu",
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&hour, &minute, &second, monstr, &day, &year)) {
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cp = strstr(mlist, monstr);
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if (NULL != cp) {
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jd->year = year;
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jd->month = (uint8_t)((cp - mlist) / 3 + 1);
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jd->monthday = (uint8_t)day;
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jd->hour = (uint8_t)hour;
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jd->minute = (uint8_t)minute;
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jd->second = (uint8_t)second;
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return TRUE;
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}
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}
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return FALSE;
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}
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/*
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*---------------------------------------------------------------------
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* basic calendar stuff
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* --------------------------------------------------------------------
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*/
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/* month table for a year starting with March,1st */
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static const uint16_t shift_month_table[13] = {
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0, 31, 61, 92, 122, 153, 184, 214, 245, 275, 306, 337, 366
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};
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/* month tables for years starting with January,1st; regular & leap */
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static const uint16_t real_month_table[2][13] = {
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/* -*- table for regular years -*- */
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{ 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365 },
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/* -*- table for leap years -*- */
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{ 0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335, 366 }
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};
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/*
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* Some notes on the terminology:
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*
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* We use the proleptic Gregorian calendar, which is the Gregorian
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* calendar extended in both directions ad infinitum. This totally
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* disregards the fact that this calendar was invented in 1582, and
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* was adopted at various dates over the world; sometimes even after
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* the start of the NTP epoch.
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*
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* Normally date parts are given as current cycles, while time parts
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* are given as elapsed cycles:
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*
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* 1970-01-01/03:04:05 means 'IN the 1970st. year, IN the first month,
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* ON the first day, with 3hrs, 4minutes and 5 seconds elapsed.
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*
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* The basic calculations for this calendar implementation deal with
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* ELAPSED date units, which is the number of full years, full months
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* and full days before a date: 1970-01-01 would be (1969, 0, 0) in
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* that notation.
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*
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* To ease the numeric computations, month and day values outside the
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* normal range are acceptable: 2001-03-00 will be treated as the day
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* before 2001-03-01, 2000-13-32 will give the same result as
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* 2001-02-01 and so on.
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*
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* 'rd' or 'RD' is used as an abbreviation for the latin 'rata die'
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* (day number). This is the number of days elapsed since 0000-12-31
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* in the proleptic Gregorian calendar. The begin of the Christian Era
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* (0001-01-01) is RD(1).
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*
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*
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* Some notes on the implementation:
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*
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* Calendar algorithms thrive on the division operation, which is one of
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* the slowest numerical operations in any CPU. What saves us here from
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* abysmal performance is the fact that all divisions are divisions by
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* constant numbers, and most compilers can do this by a multiplication
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* operation. But this might not work when using the div/ldiv/lldiv
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* function family, because many compilers are not able to do inline
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* expansion of the code with following optimisation for the
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* constant-divider case.
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*
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* Also div/ldiv/lldiv are defined in terms of int/long/longlong, which
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* are inherently target dependent. Nothing that could not be cured with
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* autoconf, but still a mess...
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*
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* Furthermore, we need floor division while C demands truncation to
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* zero, so additional steps are required to make sure the algorithms
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* work.
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*
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* For all this, all divisions by constant are coded manually, even when
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* there is a joined div/mod operation: The optimiser should sort that
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* out, if possible.
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*
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* Finally, the functions do not check for overflow conditions. This
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* is a sacrifice made for execution speed; since a 32-bit day counter
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* covers +/- 5,879,610 years, this should not pose a problem here.
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*/
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/*
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* ==================================================================
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*
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* General algorithmic stuff
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*
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* ==================================================================
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*/
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/*
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*---------------------------------------------------------------------
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* Do a periodic extension of 'value' around 'pivot' with a period of
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* 'cycle'.
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*
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* The result 'res' is a number that holds to the following properties:
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*
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* 1) res MOD cycle == value MOD cycle
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* 2) pivot <= res < pivot + cycle
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* (replace </<= with >/>= for negative cycles)
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*
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* where 'MOD' denotes the modulo operator for FLOOR DIVISION, which
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* is not the same as the '%' operator in C: C requires division to be
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* a truncated division, where remainder and dividend have the same
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* sign if the remainder is not zero, whereas floor division requires
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* divider and modulus to have the same sign for a non-zero modulus.
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*
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* This function has some useful applications:
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*
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* + let Y be a calendar year and V a truncated 2-digit year: then
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* periodic_extend(Y-50, V, 100)
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* is the closest expansion of the truncated year with respect to
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* the full year, that is a 4-digit year with a difference of less
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* than 50 years to the year Y. ("century unfolding")
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*
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* + let T be a UN*X time stamp and V be seconds-of-day: then
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* perodic_extend(T-43200, V, 86400)
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* is a time stamp that has the same seconds-of-day as the input
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* value, with an absolute difference to T of <= 12hrs. ("day
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* unfolding")
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*
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* + Wherever you have a truncated periodic value and a non-truncated
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* base value and you want to match them somehow...
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*
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* Basically, the function delivers 'pivot + (value - pivot) % cycle',
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* but the implementation takes some pains to avoid internal signed
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* integer overflows in the '(value - pivot) % cycle' part and adheres
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* to the floor division convention.
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*
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* If 64bit scalars where available on all intended platforms, writing a
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* version that uses 64 bit ops would be easy; writing a general
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* division routine for 64bit ops on a platform that can only do
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* 32/16bit divisions and is still performant is a bit more
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* difficult. Since most usecases can be coded in a way that does only
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* require the 32-bit version a 64bit version is NOT provided here.
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* ---------------------------------------------------------------------
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*/
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int32_t
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ntpcal_periodic_extend(
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int32_t pivot,
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int32_t value,
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int32_t cycle
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)
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{
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uint32_t diff;
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char cpl = 0; /* modulo complement flag */
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char neg = 0; /* sign change flag */
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/* make the cycle positive and adjust the flags */
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if (cycle < 0) {
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cycle = - cycle;
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neg ^= 1;
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cpl ^= 1;
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}
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/* guard against div by zero or one */
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if (cycle > 1) {
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/*
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* Get absolute difference as unsigned quantity and
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* the complement flag. This is done by always
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* subtracting the smaller value from the bigger
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* one. This implementation works only on a two's
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* complement machine!
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*/
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if (value >= pivot) {
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diff = (uint32_t)value - (uint32_t)pivot;
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} else {
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diff = (uint32_t)pivot - (uint32_t)value;
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cpl ^= 1;
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}
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diff %= (uint32_t)cycle;
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if (diff) {
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if (cpl)
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diff = cycle - diff;
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if (neg)
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diff = ~diff + 1;
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pivot += diff;
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}
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}
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return pivot;
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}
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/*
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*-------------------------------------------------------------------
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* Convert a timestamp in NTP scale to a 64bit seconds value in the UN*X
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* scale with proper epoch unfolding around a given pivot or the current
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* system time. This function happily accepts negative pivot values as
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* timestamps befor 1970-01-01, so be aware of possible trouble on
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* platforms with 32bit 'time_t'!
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*
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* This is also a periodic extension, but since the cycle is 2^32 and
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* the shift is 2^31, we can do some *very* fast math without explicit
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* divisions.
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*-------------------------------------------------------------------
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*/
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vint64
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ntpcal_ntp_to_time(
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uint32_t ntp,
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const time_t * pivot
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)
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{
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vint64 res;
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#ifdef HAVE_INT64
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res.q_s = (pivot != NULL)
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? *pivot
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: now();
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res.Q_s -= 0x80000000; /* unshift of half range */
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ntp -= (uint32_t)JAN_1970; /* warp into UN*X domain */
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ntp -= res.D_s.lo; /* cycle difference */
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res.Q_s += (uint64_t)ntp; /* get expanded time */
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#else /* no 64bit scalars */
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time_t tmp;
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tmp = (pivot != NULL)
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? *pivot
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: now();
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res = time_to_vint64(&tmp);
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M_SUB(res.D_s.hi, res.D_s.lo, 0, 0x80000000);
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ntp -= (uint32_t)JAN_1970; /* warp into UN*X domain */
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ntp -= res.D_s.lo; /* cycle difference */
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M_ADD(res.D_s.hi, res.D_s.lo, 0, ntp);
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#endif /* no 64bit scalars */
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return res;
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}
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/*
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*-------------------------------------------------------------------
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* Convert a timestamp in NTP scale to a 64bit seconds value in the NTP
|
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* scale with proper epoch unfolding around a given pivot or the current
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* system time.
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*
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* Note: The pivot must be given in the UN*X time domain!
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*
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* This is also a periodic extension, but since the cycle is 2^32 and
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* the shift is 2^31, we can do some *very* fast math without explicit
|
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* divisions.
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*-------------------------------------------------------------------
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*/
|
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vint64
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ntpcal_ntp_to_ntp(
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uint32_t ntp,
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const time_t *pivot
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)
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{
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vint64 res;
|
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|
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#ifdef HAVE_INT64
|
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res.q_s = (pivot)
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? *pivot
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: now();
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res.Q_s -= 0x80000000; /* unshift of half range */
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res.Q_s += (uint32_t)JAN_1970; /* warp into NTP domain */
|
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ntp -= res.D_s.lo; /* cycle difference */
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res.Q_s += (uint64_t)ntp; /* get expanded time */
|
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|
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#else /* no 64bit scalars */
|
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time_t tmp;
|
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tmp = (pivot)
|
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? *pivot
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: now();
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res = time_to_vint64(&tmp);
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M_SUB(res.D_s.hi, res.D_s.lo, 0, 0x80000000u);
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M_ADD(res.D_s.hi, res.D_s.lo, 0, (uint32_t)JAN_1970);/*into NTP */
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ntp -= res.D_s.lo; /* cycle difference */
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M_ADD(res.D_s.hi, res.D_s.lo, 0, ntp);
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|
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#endif /* no 64bit scalars */
|
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|
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return res;
|
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}
|
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|
|
|
|
/*
|
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* ==================================================================
|
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*
|
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* Splitting values to composite entities
|
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*
|
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* ==================================================================
|
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*/
|
|
|
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/*
|
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*-------------------------------------------------------------------
|
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* Split a 64bit seconds value into elapsed days in 'res.hi' and
|
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* elapsed seconds since midnight in 'res.lo' using explicit floor
|
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* division. This function happily accepts negative time values as
|
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* timestamps before the respective epoch start.
|
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* -------------------------------------------------------------------
|
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*/
|
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ntpcal_split
|
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ntpcal_daysplit(
|
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const vint64 *ts
|
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)
|
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{
|
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ntpcal_split res;
|
|
|
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#ifdef HAVE_INT64
|
|
|
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/* manual floor division by SECSPERDAY */
|
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res.hi = (int32_t)(ts->q_s / SECSPERDAY);
|
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res.lo = (int32_t)(ts->q_s % SECSPERDAY);
|
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if (res.lo < 0) {
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res.hi -= 1;
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res.lo += SECSPERDAY;
|
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}
|
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|
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#else
|
|
|
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/*
|
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* since we do not have 64bit ops, we have to this by hand.
|
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* Luckily SECSPERDAY is 86400 is 675*128, so we do the division
|
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* using chained 32/16 bit divisions and shifts.
|
|
*/
|
|
vint64 op;
|
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uint32_t q, r, a;
|
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int isneg;
|
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|
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memcpy(&op, ts, sizeof(op));
|
|
/* fix sign */
|
|
isneg = M_ISNEG(op.D_s.hi);
|
|
if (isneg)
|
|
M_NEG(op.D_s.hi, op.D_s.lo);
|
|
|
|
/* save remainder of DIV 128, shift for divide */
|
|
r = op.D_s.lo & 127; /* save remainder bits */
|
|
op.D_s.lo = (op.D_s.lo >> 7) | (op.D_s.hi << 25);
|
|
op.D_s.hi = (op.D_s.hi >> 7);
|
|
|
|
/* now do a mnual division, trying to remove as many ops as
|
|
* possible -- division is always slow! An since we do not have
|
|
* the advantage of a specific 64/32 bit or even a specific 32/16
|
|
* bit division op, but must use the general 32/32bit division
|
|
* even if we *know* the divider fits into unsigned 16 bits, the
|
|
* exra code pathes should pay off.
|
|
*/
|
|
a = op.D_s.hi;
|
|
if (a > 675u)
|
|
a = a % 675u;
|
|
if (a) {
|
|
a = (a << 16) | op.W_s.lh;
|
|
q = a / 675u;
|
|
a = a % 675u;
|
|
|
|
a = (a << 16) | op.W_s.ll;
|
|
q = (q << 16) | (a / 675u);
|
|
} else {
|
|
a = op.D_s.lo;
|
|
q = a / 675u;
|
|
}
|
|
a = a % 675u;
|
|
|
|
/* assemble remainder */
|
|
r |= a << 7;
|
|
|
|
/* fix sign of result */
|
|
if (isneg) {
|
|
if (r) {
|
|
r = SECSPERDAY - r;
|
|
q = ~q;
|
|
} else
|
|
q = ~q + 1;
|
|
}
|
|
|
|
res.hi = q;
|
|
res.lo = r;
|
|
|
|
#endif
|
|
return res;
|
|
}
|
|
|
|
/*
|
|
*-------------------------------------------------------------------
|
|
* Split a 32bit seconds value into h/m/s and excessive days. This
|
|
* function happily accepts negative time values as timestamps before
|
|
* midnight.
|
|
* -------------------------------------------------------------------
|
|
*/
|
|
static int32_t
|
|
priv_timesplit(
|
|
int32_t split[3],
|
|
int32_t ts
|
|
)
|
|
{
|
|
int32_t days = 0;
|
|
|
|
/* make sure we have a positive offset into a day */
|
|
if (ts < 0 || ts >= SECSPERDAY) {
|
|
days = ts / SECSPERDAY;
|
|
ts = ts % SECSPERDAY;
|
|
if (ts < 0) {
|
|
days -= 1;
|
|
ts += SECSPERDAY;
|
|
}
|
|
}
|
|
|
|
/* get secs, mins, hours */
|
|
split[2] = (uint8_t)(ts % SECSPERMIN);
|
|
ts /= SECSPERMIN;
|
|
split[1] = (uint8_t)(ts % MINSPERHR);
|
|
split[0] = (uint8_t)(ts / MINSPERHR);
|
|
|
|
return days;
|
|
}
|
|
|
|
/*
|
|
* ---------------------------------------------------------------------
|
|
* Given the number of elapsed days in the calendar era, split this
|
|
* number into the number of elapsed years in 'res.hi' and the number
|
|
* of elapsed days of that year in 'res.lo'.
|
|
*
|
|
* if 'isleapyear' is not NULL, it will receive an integer that is 0 for
|
|
* regular years and a non-zero value for leap years.
|
|
*---------------------------------------------------------------------
|
|
*/
|
|
ntpcal_split
|
|
ntpcal_split_eradays(
|
|
int32_t days,
|
|
int *isleapyear
|
|
)
|
|
{
|
|
ntpcal_split res;
|
|
int32_t n400, n100, n004, n001, yday; /* calendar year cycles */
|
|
|
|
/*
|
|
* Split off calendar cycles, using floor division in the first
|
|
* step. After that first step, simple division does it because
|
|
* all operands are positive; alas, we have to be aware of the
|
|
* possibe cycle overflows for 100 years and 1 year, caused by
|
|
* the additional leap day.
|
|
*/
|
|
n400 = days / GREGORIAN_CYCLE_DAYS;
|
|
yday = days % GREGORIAN_CYCLE_DAYS;
|
|
if (yday < 0) {
|
|
n400 -= 1;
|
|
yday += GREGORIAN_CYCLE_DAYS;
|
|
}
|
|
n100 = yday / GREGORIAN_NORMAL_CENTURY_DAYS;
|
|
yday = yday % GREGORIAN_NORMAL_CENTURY_DAYS;
|
|
n004 = yday / GREGORIAN_NORMAL_LEAP_CYCLE_DAYS;
|
|
yday = yday % GREGORIAN_NORMAL_LEAP_CYCLE_DAYS;
|
|
n001 = yday / DAYSPERYEAR;
|
|
yday = yday % DAYSPERYEAR;
|
|
|
|
/*
|
|
* check for leap cycle overflows and calculate the leap flag
|
|
* if needed
|
|
*/
|
|
if ((n001 | n100) > 3) {
|
|
/* hit last day of leap year */
|
|
n001 -= 1;
|
|
yday += DAYSPERYEAR;
|
|
if (isleapyear)
|
|
*isleapyear = 1;
|
|
} else if (isleapyear)
|
|
*isleapyear = (n001 == 3) && ((n004 != 24) || (n100 == 3));
|
|
|
|
/* now merge the cycles to elapsed years, using horner scheme */
|
|
res.hi = ((4*n400 + n100)*25 + n004)*4 + n001;
|
|
res.lo = yday;
|
|
|
|
return res;
|
|
}
|
|
|
|
/*
|
|
*---------------------------------------------------------------------
|
|
* Given a number of elapsed days in a year and a leap year indicator,
|
|
* split the number of elapsed days into the number of elapsed months in
|
|
* 'res.hi' and the number of elapsed days of that month in 'res.lo'.
|
|
*
|
|
* This function will fail and return {-1,-1} if the number of elapsed
|
|
* days is not in the valid range!
|
|
*---------------------------------------------------------------------
|
|
*/
|
|
ntpcal_split
|
|
ntpcal_split_yeardays(
|
|
int32_t eyd,
|
|
int isleapyear
|
|
)
|
|
{
|
|
ntpcal_split res;
|
|
const uint16_t *lt; /* month length table */
|
|
|
|
/* check leap year flag and select proper table */
|
|
lt = real_month_table[(isleapyear != 0)];
|
|
if (0 <= eyd && eyd < lt[12]) {
|
|
/* get zero-based month by approximation & correction step */
|
|
res.hi = eyd >> 5; /* approx month; might be 1 too low */
|
|
if (lt[res.hi + 1] <= eyd) /* fixup approximative month value */
|
|
res.hi += 1;
|
|
res.lo = eyd - lt[res.hi];
|
|
} else {
|
|
res.lo = res.hi = -1;
|
|
}
|
|
|
|
return res;
|
|
}
|
|
|
|
/*
|
|
*---------------------------------------------------------------------
|
|
* Convert a RD into the date part of a 'struct calendar'.
|
|
*---------------------------------------------------------------------
|
|
*/
|
|
int
|
|
ntpcal_rd_to_date(
|
|
struct calendar *jd,
|
|
int32_t rd
|
|
)
|
|
{
|
|
ntpcal_split split;
|
|
int leaps;
|
|
int retv;
|
|
|
|
leaps = 0;
|
|
retv = 0;
|
|
/* Get day-of-week first. Since rd is signed, the remainder can
|
|
* be in the range [-6..+6], but the assignment to an unsigned
|
|
* variable maps the negative values to positive values >=7.
|
|
* This makes the sign correction look strange, but adding 7
|
|
* causes the needed wrap-around into the desired value range of
|
|
* zero to six, both inclusive.
|
|
*/
|
|
jd->weekday = rd % 7;
|
|
if (jd->weekday >= 7) /* unsigned! */
|
|
jd->weekday += 7;
|
|
|
|
split = ntpcal_split_eradays(rd - 1, &leaps);
|
|
retv = leaps;
|
|
/* get year and day-of-year */
|
|
jd->year = (uint16_t)split.hi + 1;
|
|
if (jd->year != split.hi + 1) {
|
|
jd->year = 0;
|
|
retv = -1; /* bletch. overflow trouble. */
|
|
}
|
|
jd->yearday = (uint16_t)split.lo + 1;
|
|
|
|
/* convert to month and mday */
|
|
split = ntpcal_split_yeardays(split.lo, leaps);
|
|
jd->month = (uint8_t)split.hi + 1;
|
|
jd->monthday = (uint8_t)split.lo + 1;
|
|
|
|
return retv ? retv : leaps;
|
|
}
|
|
|
|
/*
|
|
*---------------------------------------------------------------------
|
|
* Convert a RD into the date part of a 'struct tm'.
|
|
*---------------------------------------------------------------------
|
|
*/
|
|
int
|
|
ntpcal_rd_to_tm(
|
|
struct tm *utm,
|
|
int32_t rd
|
|
)
|
|
{
|
|
ntpcal_split split;
|
|
int leaps;
|
|
|
|
leaps = 0;
|
|
/* get day-of-week first */
|
|
utm->tm_wday = rd % 7;
|
|
if (utm->tm_wday < 0)
|
|
utm->tm_wday += 7;
|
|
|
|
/* get year and day-of-year */
|
|
split = ntpcal_split_eradays(rd - 1, &leaps);
|
|
utm->tm_year = split.hi - 1899;
|
|
utm->tm_yday = split.lo; /* 0-based */
|
|
|
|
/* convert to month and mday */
|
|
split = ntpcal_split_yeardays(split.lo, leaps);
|
|
utm->tm_mon = split.hi; /* 0-based */
|
|
utm->tm_mday = split.lo + 1; /* 1-based */
|
|
|
|
return leaps;
|
|
}
|
|
|
|
/*
|
|
*---------------------------------------------------------------------
|
|
* Take a value of seconds since midnight and split it into hhmmss in a
|
|
* 'struct calendar'.
|
|
*---------------------------------------------------------------------
|
|
*/
|
|
int32_t
|
|
ntpcal_daysec_to_date(
|
|
struct calendar *jd,
|
|
int32_t sec
|
|
)
|
|
{
|
|
int32_t days;
|
|
int ts[3];
|
|
|
|
days = priv_timesplit(ts, sec);
|
|
jd->hour = (uint8_t)ts[0];
|
|
jd->minute = (uint8_t)ts[1];
|
|
jd->second = (uint8_t)ts[2];
|
|
|
|
return days;
|
|
}
|
|
|
|
/*
|
|
*---------------------------------------------------------------------
|
|
* Take a value of seconds since midnight and split it into hhmmss in a
|
|
* 'struct tm'.
|
|
*---------------------------------------------------------------------
|
|
*/
|
|
int32_t
|
|
ntpcal_daysec_to_tm(
|
|
struct tm *utm,
|
|
int32_t sec
|
|
)
|
|
{
|
|
int32_t days;
|
|
int32_t ts[3];
|
|
|
|
days = priv_timesplit(ts, sec);
|
|
utm->tm_hour = ts[0];
|
|
utm->tm_min = ts[1];
|
|
utm->tm_sec = ts[2];
|
|
|
|
return days;
|
|
}
|
|
|
|
/*
|
|
*---------------------------------------------------------------------
|
|
* take a split representation for day/second-of-day and day offset
|
|
* and convert it to a 'struct calendar'. The seconds will be normalised
|
|
* into the range of a day, and the day will be adjusted accordingly.
|
|
*
|
|
* returns >0 if the result is in a leap year, 0 if in a regular
|
|
* year and <0 if the result did not fit into the calendar struct.
|
|
*---------------------------------------------------------------------
|
|
*/
|
|
int
|
|
ntpcal_daysplit_to_date(
|
|
struct calendar *jd,
|
|
const ntpcal_split *ds,
|
|
int32_t dof
|
|
)
|
|
{
|
|
dof += ntpcal_daysec_to_date(jd, ds->lo);
|
|
return ntpcal_rd_to_date(jd, ds->hi + dof);
|
|
}
|
|
|
|
/*
|
|
*---------------------------------------------------------------------
|
|
* take a split representation for day/second-of-day and day offset
|
|
* and convert it to a 'struct tm'. The seconds will be normalised
|
|
* into the range of a day, and the day will be adjusted accordingly.
|
|
*
|
|
* returns 1 if the result is in a leap year and zero if in a regular
|
|
* year.
|
|
*---------------------------------------------------------------------
|
|
*/
|
|
int
|
|
ntpcal_daysplit_to_tm(
|
|
struct tm *utm,
|
|
const ntpcal_split *ds ,
|
|
int32_t dof
|
|
)
|
|
{
|
|
dof += ntpcal_daysec_to_tm(utm, ds->lo);
|
|
|
|
return ntpcal_rd_to_tm(utm, ds->hi + dof);
|
|
}
|
|
|
|
/*
|
|
*---------------------------------------------------------------------
|
|
* Take a UN*X time and convert to a calendar structure.
|
|
*---------------------------------------------------------------------
|
|
*/
|
|
int
|
|
ntpcal_time_to_date(
|
|
struct calendar *jd,
|
|
const vint64 *ts
|
|
)
|
|
{
|
|
ntpcal_split ds;
|
|
|
|
ds = ntpcal_daysplit(ts);
|
|
ds.hi += ntpcal_daysec_to_date(jd, ds.lo);
|
|
ds.hi += DAY_UNIX_STARTS;
|
|
|
|
return ntpcal_rd_to_date(jd, ds.hi);
|
|
}
|
|
|
|
|
|
/*
|
|
* ==================================================================
|
|
*
|
|
* merging composite entities
|
|
*
|
|
* ==================================================================
|
|
*/
|
|
|
|
/*
|
|
*---------------------------------------------------------------------
|
|
* Merge a number of days and a number of seconds into seconds,
|
|
* expressed in 64 bits to avoid overflow.
|
|
*---------------------------------------------------------------------
|
|
*/
|
|
vint64
|
|
ntpcal_dayjoin(
|
|
int32_t days,
|
|
int32_t secs
|
|
)
|
|
{
|
|
vint64 res;
|
|
|
|
#ifdef HAVE_INT64
|
|
|
|
res.q_s = days;
|
|
res.q_s *= SECSPERDAY;
|
|
res.q_s += secs;
|
|
|
|
#else
|
|
|
|
uint32_t p1, p2;
|
|
int isneg;
|
|
|
|
/*
|
|
* res = days *86400 + secs, using manual 16/32 bit
|
|
* multiplications and shifts.
|
|
*/
|
|
isneg = (days < 0);
|
|
if (isneg)
|
|
days = -days;
|
|
|
|
/* assemble days * 675 */
|
|
res.D_s.lo = (days & 0xFFFF) * 675u;
|
|
res.D_s.hi = 0;
|
|
p1 = (days >> 16) * 675u;
|
|
p2 = p1 >> 16;
|
|
p1 = p1 << 16;
|
|
M_ADD(res.D_s.hi, res.D_s.lo, p2, p1);
|
|
|
|
/* mul by 128, using shift */
|
|
res.D_s.hi = (res.D_s.hi << 7) | (res.D_s.lo >> 25);
|
|
res.D_s.lo = (res.D_s.lo << 7);
|
|
|
|
/* fix sign */
|
|
if (isneg)
|
|
M_NEG(res.D_s.hi, res.D_s.lo);
|
|
|
|
/* properly add seconds */
|
|
p2 = 0;
|
|
if (secs < 0) {
|
|
p1 = (uint32_t)-secs;
|
|
M_NEG(p2, p1);
|
|
} else {
|
|
p1 = (uint32_t)secs;
|
|
}
|
|
M_ADD(res.D_s.hi, res.D_s.lo, p2, p1);
|
|
|
|
#endif
|
|
|
|
return res;
|
|
}
|
|
|
|
/*
|
|
*---------------------------------------------------------------------
|
|
* Convert elapsed years in Era into elapsed days in Era.
|
|
*
|
|
* To accomodate for negative values of years, floor division would be
|
|
* required for all division operations. This can be eased by first
|
|
* splitting the years into full 400-year cycles and years in the
|
|
* cycle. Only this operation must be coded as a full floor division; as
|
|
* the years in the cycle is a non-negative number, all other divisions
|
|
* can be regular truncated divisions.
|
|
*---------------------------------------------------------------------
|
|
*/
|
|
int32_t
|
|
ntpcal_days_in_years(
|
|
int32_t years
|
|
)
|
|
{
|
|
int32_t cycle; /* full gregorian cycle */
|
|
|
|
/* split off full calendar cycles, using floor division */
|
|
cycle = years / 400;
|
|
years = years % 400;
|
|
if (years < 0) {
|
|
cycle -= 1;
|
|
years += 400;
|
|
}
|
|
|
|
/*
|
|
* Calculate days in cycle. years now is a non-negative number,
|
|
* holding the number of years in the 400-year cycle.
|
|
*/
|
|
return cycle * GREGORIAN_CYCLE_DAYS
|
|
+ years * DAYSPERYEAR /* days inregular years */
|
|
+ years / 4 /* 4 year leap rule */
|
|
- years / 100; /* 100 year leap rule */
|
|
/* the 400-year rule does not apply due to full-cycle split-off */
|
|
}
|
|
|
|
/*
|
|
*---------------------------------------------------------------------
|
|
* Convert a number of elapsed month in a year into elapsed days in year.
|
|
*
|
|
* The month will be normalized, and 'res.hi' will contain the
|
|
* excessive years that must be considered when converting the years,
|
|
* while 'res.lo' will contain the number of elapsed days since start
|
|
* of the year.
|
|
*
|
|
* This code uses the shifted-month-approach to convert month to days,
|
|
* because then there is no need to have explicit leap year
|
|
* information. The slight disadvantage is that for most month values
|
|
* the result is a negative value, and the year excess is one; the
|
|
* conversion is then simply based on the start of the following year.
|
|
*---------------------------------------------------------------------
|
|
*/
|
|
ntpcal_split
|
|
ntpcal_days_in_months(
|
|
int32_t m
|
|
)
|
|
{
|
|
ntpcal_split res;
|
|
|
|
/* normalize month into range */
|
|
res.hi = 0;
|
|
res.lo = m;
|
|
if (res.lo < 0 || res.lo >= 12) {
|
|
res.hi = res.lo / 12;
|
|
res.lo = res.lo % 12;
|
|
if (res.lo < 0) {
|
|
res.hi -= 1;
|
|
res.lo += 12;
|
|
}
|
|
}
|
|
|
|
/* add 10 month for year starting with march */
|
|
if (res.lo < 2)
|
|
res.lo += 10;
|
|
else {
|
|
res.hi += 1;
|
|
res.lo -= 2;
|
|
}
|
|
|
|
/* get cummulated days in year with unshift */
|
|
res.lo = shift_month_table[res.lo] - 306;
|
|
|
|
return res;
|
|
}
|
|
|
|
/*
|
|
*---------------------------------------------------------------------
|
|
* Convert ELAPSED years/months/days of gregorian calendar to elapsed
|
|
* days in Gregorian epoch.
|
|
*
|
|
* If you want to convert years and days-of-year, just give a month of
|
|
* zero.
|
|
*---------------------------------------------------------------------
|
|
*/
|
|
int32_t
|
|
ntpcal_edate_to_eradays(
|
|
int32_t years,
|
|
int32_t mons,
|
|
int32_t mdays
|
|
)
|
|
{
|
|
ntpcal_split tmp;
|
|
int32_t res;
|
|
|
|
if (mons) {
|
|
tmp = ntpcal_days_in_months(mons);
|
|
res = ntpcal_days_in_years(years + tmp.hi) + tmp.lo;
|
|
} else
|
|
res = ntpcal_days_in_years(years);
|
|
res += mdays;
|
|
|
|
return res;
|
|
}
|
|
|
|
/*
|
|
*---------------------------------------------------------------------
|
|
* Convert ELAPSED years/months/days of gregorian calendar to elapsed
|
|
* days in year.
|
|
*
|
|
* Note: This will give the true difference to the start of the given year,
|
|
* even if months & days are off-scale.
|
|
*---------------------------------------------------------------------
|
|
*/
|
|
int32_t
|
|
ntpcal_edate_to_yeardays(
|
|
int32_t years,
|
|
int32_t mons,
|
|
int32_t mdays
|
|
)
|
|
{
|
|
ntpcal_split tmp;
|
|
|
|
if (0 <= mons && mons < 12) {
|
|
years += 1;
|
|
mdays += real_month_table[is_leapyear(years)][mons];
|
|
} else {
|
|
tmp = ntpcal_days_in_months(mons);
|
|
mdays += tmp.lo
|
|
+ ntpcal_days_in_years(years + tmp.hi)
|
|
- ntpcal_days_in_years(years);
|
|
}
|
|
|
|
return mdays;
|
|
}
|
|
|
|
/*
|
|
*---------------------------------------------------------------------
|
|
* Convert elapsed days and the hour/minute/second information into
|
|
* total seconds.
|
|
*
|
|
* If 'isvalid' is not NULL, do a range check on the time specification
|
|
* and tell if the time input is in the normal range, permitting for a
|
|
* single leapsecond.
|
|
*---------------------------------------------------------------------
|
|
*/
|
|
int32_t
|
|
ntpcal_etime_to_seconds(
|
|
int32_t hours,
|
|
int32_t minutes,
|
|
int32_t seconds
|
|
)
|
|
{
|
|
int32_t res;
|
|
|
|
res = (hours * MINSPERHR + minutes) * SECSPERMIN + seconds;
|
|
|
|
return res;
|
|
}
|
|
|
|
/*
|
|
*---------------------------------------------------------------------
|
|
* Convert the date part of a 'struct tm' (that is, year, month,
|
|
* day-of-month) into the RD of that day.
|
|
*---------------------------------------------------------------------
|
|
*/
|
|
int32_t
|
|
ntpcal_tm_to_rd(
|
|
const struct tm *utm
|
|
)
|
|
{
|
|
return ntpcal_edate_to_eradays(utm->tm_year + 1899,
|
|
utm->tm_mon,
|
|
utm->tm_mday - 1) + 1;
|
|
}
|
|
|
|
/*
|
|
*---------------------------------------------------------------------
|
|
* Convert the date part of a 'struct calendar' (that is, year, month,
|
|
* day-of-month) into the RD of that day.
|
|
*---------------------------------------------------------------------
|
|
*/
|
|
int32_t
|
|
ntpcal_date_to_rd(
|
|
const struct calendar *jd
|
|
)
|
|
{
|
|
return ntpcal_edate_to_eradays((int32_t)jd->year - 1,
|
|
(int32_t)jd->month - 1,
|
|
(int32_t)jd->monthday - 1) + 1;
|
|
}
|
|
|
|
/*
|
|
*---------------------------------------------------------------------
|
|
* convert a year number to rata die of year start
|
|
*---------------------------------------------------------------------
|
|
*/
|
|
int32_t
|
|
ntpcal_year_to_ystart(
|
|
int32_t year
|
|
)
|
|
{
|
|
return ntpcal_days_in_years(year - 1) + 1;
|
|
}
|
|
|
|
/*
|
|
*---------------------------------------------------------------------
|
|
* For a given RD, get the RD of the associated year start,
|
|
* that is, the RD of the last January,1st on or before that day.
|
|
*---------------------------------------------------------------------
|
|
*/
|
|
int32_t
|
|
ntpcal_rd_to_ystart(
|
|
int32_t rd
|
|
)
|
|
{
|
|
/*
|
|
* Rather simple exercise: split the day number into elapsed
|
|
* years and elapsed days, then remove the elapsed days from the
|
|
* input value. Nice'n sweet...
|
|
*/
|
|
return rd - ntpcal_split_eradays(rd - 1, NULL).lo;
|
|
}
|
|
|
|
/*
|
|
*---------------------------------------------------------------------
|
|
* For a given RD, get the RD of the associated month start.
|
|
*---------------------------------------------------------------------
|
|
*/
|
|
int32_t
|
|
ntpcal_rd_to_mstart(
|
|
int32_t rd
|
|
)
|
|
{
|
|
ntpcal_split split;
|
|
int leaps;
|
|
|
|
split = ntpcal_split_eradays(rd - 1, &leaps);
|
|
split = ntpcal_split_yeardays(split.lo, leaps);
|
|
|
|
return rd - split.lo;
|
|
}
|
|
|
|
/*
|
|
*---------------------------------------------------------------------
|
|
* take a 'struct calendar' and get the seconds-of-day from it.
|
|
*---------------------------------------------------------------------
|
|
*/
|
|
int32_t
|
|
ntpcal_date_to_daysec(
|
|
const struct calendar *jd
|
|
)
|
|
{
|
|
return ntpcal_etime_to_seconds(jd->hour, jd->minute,
|
|
jd->second);
|
|
}
|
|
|
|
/*
|
|
*---------------------------------------------------------------------
|
|
* take a 'struct tm' and get the seconds-of-day from it.
|
|
*---------------------------------------------------------------------
|
|
*/
|
|
int32_t
|
|
ntpcal_tm_to_daysec(
|
|
const struct tm *utm
|
|
)
|
|
{
|
|
return ntpcal_etime_to_seconds(utm->tm_hour, utm->tm_min,
|
|
utm->tm_sec);
|
|
}
|
|
|
|
/*
|
|
*---------------------------------------------------------------------
|
|
* take a 'struct calendar' and convert it to a 'time_t'
|
|
*---------------------------------------------------------------------
|
|
*/
|
|
time_t
|
|
ntpcal_date_to_time(
|
|
const struct calendar *jd
|
|
)
|
|
{
|
|
vint64 join;
|
|
int32_t days, secs;
|
|
|
|
days = ntpcal_date_to_rd(jd) - DAY_UNIX_STARTS;
|
|
secs = ntpcal_date_to_daysec(jd);
|
|
join = ntpcal_dayjoin(days, secs);
|
|
|
|
return vint64_to_time(&join);
|
|
}
|
|
|
|
|
|
/*
|
|
* ==================================================================
|
|
*
|
|
* extended and unchecked variants of caljulian/caltontp
|
|
*
|
|
* ==================================================================
|
|
*/
|
|
int
|
|
ntpcal_ntp64_to_date(
|
|
struct calendar *jd,
|
|
const vint64 *ntp
|
|
)
|
|
{
|
|
ntpcal_split ds;
|
|
|
|
ds = ntpcal_daysplit(ntp);
|
|
ds.hi += ntpcal_daysec_to_date(jd, ds.lo);
|
|
|
|
return ntpcal_rd_to_date(jd, ds.hi + DAY_NTP_STARTS);
|
|
}
|
|
|
|
int
|
|
ntpcal_ntp_to_date(
|
|
struct calendar *jd,
|
|
uint32_t ntp,
|
|
const time_t *piv
|
|
)
|
|
{
|
|
vint64 ntp64;
|
|
|
|
/*
|
|
* Unfold ntp time around current time into NTP domain. Split
|
|
* into days and seconds, shift days into CE domain and
|
|
* process the parts.
|
|
*/
|
|
ntp64 = ntpcal_ntp_to_ntp(ntp, piv);
|
|
return ntpcal_ntp64_to_date(jd, &ntp64);
|
|
}
|
|
|
|
|
|
vint64
|
|
ntpcal_date_to_ntp64(
|
|
const struct calendar *jd
|
|
)
|
|
{
|
|
/*
|
|
* Convert date to NTP. Ignore yearday, use d/m/y only.
|
|
*/
|
|
return ntpcal_dayjoin(ntpcal_date_to_rd(jd) - DAY_NTP_STARTS,
|
|
ntpcal_date_to_daysec(jd));
|
|
}
|
|
|
|
|
|
uint32_t
|
|
ntpcal_date_to_ntp(
|
|
const struct calendar *jd
|
|
)
|
|
{
|
|
/*
|
|
* Get lower half of 64-bit NTP timestamp from date/time.
|
|
*/
|
|
return ntpcal_date_to_ntp64(jd).d_s.lo;
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
* ==================================================================
|
|
*
|
|
* day-of-week calculations
|
|
*
|
|
* ==================================================================
|
|
*/
|
|
/*
|
|
* Given a RataDie and a day-of-week, calculate a RDN that is reater-than,
|
|
* greater-or equal, closest, less-or-equal or less-than the given RDN
|
|
* and denotes the given day-of-week
|
|
*/
|
|
int32_t
|
|
ntpcal_weekday_gt(
|
|
int32_t rdn,
|
|
int32_t dow
|
|
)
|
|
{
|
|
return ntpcal_periodic_extend(rdn+1, dow, 7);
|
|
}
|
|
|
|
int32_t
|
|
ntpcal_weekday_ge(
|
|
int32_t rdn,
|
|
int32_t dow
|
|
)
|
|
{
|
|
return ntpcal_periodic_extend(rdn, dow, 7);
|
|
}
|
|
|
|
int32_t
|
|
ntpcal_weekday_close(
|
|
int32_t rdn,
|
|
int32_t dow
|
|
)
|
|
{
|
|
return ntpcal_periodic_extend(rdn-3, dow, 7);
|
|
}
|
|
|
|
int32_t
|
|
ntpcal_weekday_le(
|
|
int32_t rdn,
|
|
int32_t dow
|
|
)
|
|
{
|
|
return ntpcal_periodic_extend(rdn, dow, -7);
|
|
}
|
|
|
|
int32_t
|
|
ntpcal_weekday_lt(
|
|
int32_t rdn,
|
|
int32_t dow
|
|
)
|
|
{
|
|
return ntpcal_periodic_extend(rdn-1, dow, -7);
|
|
}
|
|
|
|
/*
|
|
* ==================================================================
|
|
*
|
|
* ISO week-calendar conversions
|
|
*
|
|
* The ISO8601 calendar defines a calendar of years, weeks and weekdays.
|
|
* It is related to the Gregorian calendar, and a ISO year starts at the
|
|
* Monday closest to Jan,1st of the corresponding Gregorian year. A ISO
|
|
* calendar year has always 52 or 53 weeks, and like the Grogrian
|
|
* calendar the ISO8601 calendar repeats itself every 400 years, or
|
|
* 146097 days, or 20871 weeks.
|
|
*
|
|
* While it is possible to write ISO calendar functions based on the
|
|
* Gregorian calendar functions, the following implementation takes a
|
|
* different approach, based directly on years and weeks.
|
|
*
|
|
* Analysis of the tabulated data shows that it is not possible to
|
|
* interpolate from years to weeks over a full 400 year range; cyclic
|
|
* shifts over 400 years do not provide a solution here. But it *is*
|
|
* possible to interpolate over every single century of the 400-year
|
|
* cycle. (The centennial leap year rule seems to be the culprit here.)
|
|
*
|
|
* It can be shown that a conversion from years to weeks can be done
|
|
* using a linear transformation of the form
|
|
*
|
|
* w = floor( y * a + b )
|
|
*
|
|
* where the slope a must hold to
|
|
*
|
|
* 52.1780821918 <= a < 52.1791044776
|
|
*
|
|
* and b must be chosen according to the selected slope and the number
|
|
* of the century in a 400-year period.
|
|
*
|
|
* The inverse calculation can also be done in this way. Careful scaling
|
|
* provides an unlimited set of integer coefficients a,k,b that enable
|
|
* us to write the calulation in the form
|
|
*
|
|
* w = (y * a + b ) / k
|
|
* y = (w * a' + b') / k'
|
|
*
|
|
* In this implementation the values of k and k' are chosen to be
|
|
* smallest possible powers of two, so the division can be implemented
|
|
* as shifts if the optimiser chooses to do so.
|
|
*
|
|
* ==================================================================
|
|
*/
|
|
|
|
/*
|
|
* Given a number of elapsed (ISO-)years since the begin of the
|
|
* christian era, return the number of elapsed weeks corresponding to
|
|
* the number of years.
|
|
*/
|
|
int32_t
|
|
isocal_weeks_in_years(
|
|
int32_t years
|
|
)
|
|
{
|
|
/*
|
|
* use: w = (y * 53431 + b[c]) / 1024 as interpolation
|
|
*/
|
|
static const int32_t bctab[4] = { 449, 157, 889, 597 };
|
|
int32_t cycle; /* full gregorian cycle */
|
|
int32_t cents; /* full centuries */
|
|
int32_t weeks; /* accumulated weeks */
|
|
|
|
/* split off full calendar cycles, using floor division */
|
|
cycle = years / 400;
|
|
years = years % 400;
|
|
if (years < 0) {
|
|
cycle -= 1;
|
|
years += 400;
|
|
}
|
|
|
|
/* split off full centuries */
|
|
cents = years / 100;
|
|
years = years % 100;
|
|
|
|
/*
|
|
* calculate elapsed weeks, taking into account that the
|
|
* first, third and fourth century have 5218 weeks but the
|
|
* second century falls short by one week.
|
|
*/
|
|
weeks = (years * 53431 + bctab[cents]) / 1024;
|
|
|
|
return cycle * GREGORIAN_CYCLE_WEEKS
|
|
+ cents * 5218 - (cents > 1)
|
|
+ weeks;
|
|
}
|
|
|
|
/*
|
|
* Given a number of elapsed weeks since the begin of the christian
|
|
* era, split this number into the number of elapsed years in res.hi
|
|
* and the excessive number of weeks in res.lo. (That is, res.lo is
|
|
* the number of elapsed weeks in the remaining partial year.)
|
|
*/
|
|
ntpcal_split
|
|
isocal_split_eraweeks(
|
|
int32_t weeks
|
|
)
|
|
{
|
|
/*
|
|
* use: y = (w * 157 + b[c]) / 8192 as interpolation
|
|
*/
|
|
static const int32_t bctab[4] = { 85, 131, 17, 62 };
|
|
ntpcal_split res;
|
|
int32_t cents;
|
|
|
|
/*
|
|
* split off 400-year cycles, using the fact that a 400-year
|
|
* cycle has 146097 days, which is exactly 20871 weeks.
|
|
*/
|
|
res.hi = weeks / GREGORIAN_CYCLE_WEEKS;
|
|
res.lo = weeks % GREGORIAN_CYCLE_WEEKS;
|
|
if (res.lo < 0) {
|
|
res.hi -= 1;
|
|
res.lo += GREGORIAN_CYCLE_WEEKS;
|
|
}
|
|
res.hi *= 400;
|
|
|
|
/*
|
|
* split off centuries, taking into account that the first,
|
|
* third and fourth century have 5218 weeks but that the
|
|
* second century falls short by one week.
|
|
*/
|
|
res.lo += (res.lo >= 10435);
|
|
cents = res.lo / 5218;
|
|
res.lo %= 5218; /* res.lo is weeks in century now */
|
|
|
|
/* convert elapsed weeks in century to elapsed years and weeks */
|
|
res.lo = res.lo * 157 + bctab[cents];
|
|
res.hi += cents * 100 + res.lo / 8192;
|
|
res.lo = (res.lo % 8192) / 157;
|
|
|
|
return res;
|
|
}
|
|
|
|
/*
|
|
* Given a second in the NTP time scale and a pivot, expand the NTP
|
|
* time stamp around the pivot and convert into an ISO calendar time
|
|
* stamp.
|
|
*/
|
|
int
|
|
isocal_ntp64_to_date(
|
|
struct isodate *id,
|
|
const vint64 *ntp
|
|
)
|
|
{
|
|
ntpcal_split ds;
|
|
int32_t ts[3];
|
|
|
|
/*
|
|
* Split NTP time into days and seconds, shift days into CE
|
|
* domain and process the parts.
|
|
*/
|
|
ds = ntpcal_daysplit(ntp);
|
|
|
|
/* split time part */
|
|
ds.hi += priv_timesplit(ts, ds.lo);
|
|
id->hour = (uint8_t)ts[0];
|
|
id->minute = (uint8_t)ts[1];
|
|
id->second = (uint8_t)ts[2];
|
|
|
|
/* split date part */
|
|
ds.lo = ds.hi + DAY_NTP_STARTS - 1; /* elapsed era days */
|
|
ds.hi = ds.lo / 7; /* elapsed era weeks */
|
|
ds.lo = ds.lo % 7; /* elapsed week days */
|
|
if (ds.lo < 0) { /* floor division! */
|
|
ds.hi -= 1;
|
|
ds.lo += 7;
|
|
}
|
|
id->weekday = (uint8_t)ds.lo + 1; /* weekday result */
|
|
|
|
ds = isocal_split_eraweeks(ds.hi); /* elapsed years&week*/
|
|
id->year = (uint16_t)ds.hi + 1; /* shift to current */
|
|
id->week = (uint8_t )ds.lo + 1;
|
|
|
|
return (ds.hi >= 0 && ds.hi < 0x0000FFFF);
|
|
}
|
|
|
|
int
|
|
isocal_ntp_to_date(
|
|
struct isodate *id,
|
|
uint32_t ntp,
|
|
const time_t *piv
|
|
)
|
|
{
|
|
vint64 ntp64;
|
|
|
|
/*
|
|
* Unfold ntp time around current time into NTP domain, then
|
|
* convert the full time stamp.
|
|
*/
|
|
ntp64 = ntpcal_ntp_to_ntp(ntp, piv);
|
|
return isocal_ntp64_to_date(id, &ntp64);
|
|
}
|
|
|
|
/*
|
|
* Convert a ISO date spec into a second in the NTP time scale,
|
|
* properly truncated to 32 bit.
|
|
*/
|
|
vint64
|
|
isocal_date_to_ntp64(
|
|
const struct isodate *id
|
|
)
|
|
{
|
|
int32_t weeks, days, secs;
|
|
|
|
weeks = isocal_weeks_in_years((int32_t)id->year - 1)
|
|
+ (int32_t)id->week - 1;
|
|
days = weeks * 7 + (int32_t)id->weekday;
|
|
/* days is RDN of ISO date now */
|
|
secs = ntpcal_etime_to_seconds(id->hour, id->minute, id->second);
|
|
|
|
return ntpcal_dayjoin(days - DAY_NTP_STARTS, secs);
|
|
}
|
|
|
|
uint32_t
|
|
isocal_date_to_ntp(
|
|
const struct isodate *id
|
|
)
|
|
{
|
|
/*
|
|
* Get lower half of 64-bit NTP timestamp from date/time.
|
|
*/
|
|
return isocal_date_to_ntp64(id).d_s.lo;
|
|
}
|
|
|
|
/* -*-EOF-*- */
|