108 lines
2.4 KiB
C
108 lines
2.4 KiB
C
/*
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* Taken from FreeBSD src / lib / libc / stdtime / localtime.c 1.43 revision.
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* localtime.c 7.78.
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* tzfile.h 1.8
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* adapted to be replacement gmtime_r.
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*/
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#include "config.h"
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#ifdef HAVE_TIME_H
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#include <time.h>
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#endif
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#define MONSPERYEAR 12
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#define DAYSPERNYEAR 365
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#define DAYSPERLYEAR 366
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#define SECSPERMIN 60
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#define SECSPERHOUR (60*60)
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#define SECSPERDAY (24*60*60)
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#define DAYSPERWEEK 7
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#define TM_SUNDAY 0
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#define TM_MONDAY 1
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#define TM_TUESDAY 2
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#define TM_WEDNESDAY 3
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#define TM_THURSDAY 4
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#define TM_FRIDAY 5
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#define TM_SATURDAY 6
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#define TM_YEAR_BASE 1900
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#define EPOCH_YEAR 1970
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#define EPOCH_WDAY TM_THURSDAY
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#define isleap(y) (((y) % 4) == 0 && (((y) % 100) != 0 || ((y) % 400) == 0))
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static const int mon_lengths[2][MONSPERYEAR] = {
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{ 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 },
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{ 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }
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};
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static const int year_lengths[2] = {
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DAYSPERNYEAR, DAYSPERLYEAR
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};
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static void
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timesub(timep, offset, tmp)
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const time_t * const timep;
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const long offset;
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struct tm * const tmp;
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{
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long days;
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long rem;
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long y;
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int yleap;
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const int * ip;
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days = *timep / SECSPERDAY;
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rem = *timep % SECSPERDAY;
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rem += (offset);
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while (rem < 0) {
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rem += SECSPERDAY;
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--days;
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}
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while (rem >= SECSPERDAY) {
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rem -= SECSPERDAY;
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++days;
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}
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tmp->tm_hour = (int) (rem / SECSPERHOUR);
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rem = rem % SECSPERHOUR;
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tmp->tm_min = (int) (rem / SECSPERMIN);
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/*
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** A positive leap second requires a special
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** representation. This uses "... ??:59:60" et seq.
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*/
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tmp->tm_sec = (int) (rem % SECSPERMIN) ;
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tmp->tm_wday = (int) ((EPOCH_WDAY + days) % DAYSPERWEEK);
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if (tmp->tm_wday < 0)
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tmp->tm_wday += DAYSPERWEEK;
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y = EPOCH_YEAR;
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#define LEAPS_THRU_END_OF(y) ((y) / 4 - (y) / 100 + (y) / 400)
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while (days < 0 || days >= (long) year_lengths[yleap = isleap(y)]) {
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long newy;
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newy = y + days / DAYSPERNYEAR;
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if (days < 0)
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--newy;
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days -= (newy - y) * DAYSPERNYEAR +
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LEAPS_THRU_END_OF(newy - 1) -
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LEAPS_THRU_END_OF(y - 1);
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y = newy;
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}
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tmp->tm_year = y - TM_YEAR_BASE;
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tmp->tm_yday = (int) days;
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ip = mon_lengths[yleap];
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for (tmp->tm_mon = 0; days >= (long) ip[tmp->tm_mon]; ++(tmp->tm_mon))
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days = days - (long) ip[tmp->tm_mon];
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tmp->tm_mday = (int) (days + 1);
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tmp->tm_isdst = 0;
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}
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/*
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* Re-entrant version of gmtime.
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*/
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struct tm * gmtime_r(const time_t* timep, struct tm *tm)
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{
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timesub(timep, 0L, tm);
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return tm;
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}
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