123 lines
3.2 KiB
C
123 lines
3.2 KiB
C
/* Convert `time_t' to `struct tm' in local time zone.
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Copyright (C) 1991, 92, 93, 95, 96, 97 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If not,
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write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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#include <errno.h>
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#include <time.h>
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#include <libc-lock.h>
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/* The C Standard says that localtime and gmtime return the same pointer. */
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struct tm _tmbuf;
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/* Prototype for the internal function to get information based on TZ. */
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extern void __tzset_internal __P ((int always));
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extern int __tz_compute __P ((time_t timer, struct tm *tp));
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extern int __tzfile_compute __P ((time_t timer,
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long int *leap_correct, int *leap_hit));
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extern int __use_tzfile;
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/* This lock is defined in tzset.c and locks all the data defined there
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and in tzfile.c; the internal functions do no locking themselves.
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This lock is only taken here and in `tzset'. */
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__libc_lock_define (extern, __tzset_lock)
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/* Return the `struct tm' representation of *TIMER in the local timezone. */
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static struct tm *
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localtime_internal (const time_t *timer, struct tm *tp)
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{
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long int leap_correction;
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int leap_extra_secs;
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if (timer == NULL)
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{
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__set_errno (EINVAL);
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return NULL;
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}
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if (__use_tzfile)
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{
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if (! __tzfile_compute (*timer, &leap_correction, &leap_extra_secs))
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tp = NULL;
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}
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else
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{
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tp = __gmtime_r (timer, tp);
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if (tp && ! __tz_compute (*timer, tp))
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tp = NULL;
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leap_correction = 0L;
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leap_extra_secs = 0;
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}
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if (tp)
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{
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__offtime (timer, __timezone - leap_correction, tp);
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tp->tm_sec += leap_extra_secs;
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tp->tm_isdst = __daylight;
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tp->tm_gmtoff = __timezone;
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tp->tm_zone = __tzname[__daylight];
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}
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return tp;
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}
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/* POSIX.1 8.3.7.2 says that localtime_r is not required to set
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tzname. This is a good idea since this allows at least a bit more
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parallelism. */
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struct tm *
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localtime (timer)
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const time_t *timer;
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{
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struct tm *result;
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__libc_lock_lock (__tzset_lock);
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/* Update internal database according to current TZ setting. */
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__tzset_internal (1);
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result = localtime_internal (timer, &_tmbuf);
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__libc_lock_unlock (__tzset_lock);
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return result;
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}
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struct tm *
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__localtime_r (timer, tp)
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const time_t *timer;
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struct tm *tp;
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{
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struct tm *result;
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__libc_lock_lock (__tzset_lock);
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/* Make sure the database is initialized. */
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__tzset_internal (0);
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result = localtime_internal (timer, tp);
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__libc_lock_unlock (__tzset_lock);
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return result;
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}
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weak_alias (__localtime_r, localtime_r)
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