unixtime.c
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/* GNU Mailutils -- a suite of utilities for electronic mail
Copyright (C) 1999-2001, 2007, 2009-2012, 2014-2015 Free Software
Foundation, Inc.
GNU Mailutils is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3, or (at your option)
any later version.
GNU Mailutils is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with GNU Mailutils. If not, see <http://www.gnu.org/licenses/>. */
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include <time.h>
#include <mailutils/datetime.h>
#define SECS_PER_DAY 86400
#define JD_OF_EPOCH 2440588
/* Convert struct tm into UTC. */
time_t
mu_datetime_to_utc (struct tm *tm, struct mu_timezone *tz)
{
int jd = mu_datetime_julianday (tm->tm_year + 1900, tm->tm_mon + 1,
tm->tm_mday);
return (jd - JD_OF_EPOCH) * SECS_PER_DAY +
(tm->tm_hour * 60 + tm->tm_min) * 60 + tm->tm_sec
- (tz ? tz->utc_offset : 0);
}