aria2/src/timegm.c

81 lines
2.7 KiB
C

/*
* aria2 - The high speed download utility
*
* Copyright (C) 2012 Tatsuhiro Tsujikawa
*
* 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 of the License, 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*
* In addition, as a special exception, the copyright holders give
* permission to link the code of portions of this program with the
* OpenSSL library under certain conditions as described in each
* individual source file, and distribute linked combinations
* including the two.
* You must obey the GNU General Public License in all respects
* for all of the code used other than OpenSSL. If you modify
* file(s) with this exception, you may extend this exception to your
* version of the file(s), but you are not obligated to do so. If you
* do not wish to do so, delete this exception statement from your
* version. If you delete this exception statement from all source
* files in the program, then also delete it here.
*/
/* copyright --> */
#include "timegm.h"
#include <stdint.h>
/* Counter the number of leap year in the range [0, y). The |y| is the
year, including century (e.g., 2012) */
static int count_leap_year(int y)
{
y -= 1;
return y/4-y/100+y/400;
}
/* Returns nonzero if the |y| is the leap year. The |y| is the year,
including century (e.g., 2012) */
static int is_leap_year(int y)
{
return y%4 == 0 && (y%100 != 0 || y%400 == 0);
}
/* The number of days before ith month begins */
static int daysum[] = {
0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334
};
// Based on the algorithm of Python 2.7 calendar.timegm.
time_t timegm(struct tm *tm)
{
int days;
int num_leap_year;
int64_t t;
if(tm->tm_mon > 11) {
return -1;
}
num_leap_year = count_leap_year(tm->tm_year + 1900) - count_leap_year(1970);
days = (tm->tm_year - 70) * 365 +
num_leap_year + daysum[tm->tm_mon] + tm->tm_mday-1;
if(tm->tm_mon >= 2 && is_leap_year(tm->tm_year + 1900)) {
++days;
}
t = ((int64_t)days * 24 + tm->tm_hour) * 3600 + tm->tm_min * 60 + tm->tm_sec;
if(sizeof(time_t) == 4) {
if(t < INT32_MIN || t > INT32_MAX) {
return -1;
}
}
return t;
}