/*
* mktime.c -- converts a struct tm into a time_t
*
* Copyright (C) 1997 Free Software Foundation, Inc.
*
* This program 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 2, or (at your option) any later
* version.
*
* This program 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
* this program; if not, write to the Free Software Foundation, Inc., 59
* Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
/* Written by Philippe De Muyter <phdm@macqel.be>. */
#include <time.h>
static time_t
mkgmtime(t)
register struct tm *t;
{
register short month, year;
register time_t result;
static int m_to_d[12] =
{0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334};
month = t->tm_mon;
year = t->tm_year + month / 12 + 1900;
month %= 12;
if (month < 0)
{
year -= 1;
month += 12;
}
result = (year - 1970) * 365 + (year - 1969) / 4 + m_to_d[month];
result = (year - 1970) * 365 + m_to_d[month];
if (month <= 1)
year -= 1;
result += (year - 1968) / 4;
result -= (year - 1900) / 100;
result += (year - 1600) / 400;
result += t->tm_mday;
result -= 1;
result *= 24;
result += t->tm_hour;
result *= 60;
result += t->tm_min;
result *= 60;
result += t->tm_sec;
return(result);
}
/*
** mktime -- convert tm struct to time_t
** if tm_isdst >= 0 use it, else compute it
*/
time_t
mktime(t)
struct tm *t;
{
time_t result;
tzset();
result = mkgmtime(t) + timezone;
if (t->tm_isdst > 0
|| (t->tm_isdst < 0 && localtime(&result)->tm_isdst))
result -= 3600;
return(result);
}