tm.c
2.48 KB
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/*
* Copyright (C) 2014 René Kijewski <rene.kijewski@fu-berlin.de>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file
* @author René Kijewski <rene.kijewski@fu-berlin.de>
*/
#include "tm.h"
#include <stdint.h>
const int8_t TM_MON_DAYS[12] = {
31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
};
const int16_t TM_MON_DAYS_ACCU[12] = {
0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334
};
int tm_is_leap_year(unsigned year)
{
return ((year & 3) == 0) && ((year % 400 == 0) || (year % 100 != 0));
}
int tm_doomsday(int year)
{
int result;
result = TM_WDAY_TUE;
result += year;
result += year >>= 2;
result -= year /= 25;
result += year >>= 2;
return result;
}
void tm_get_wyday(int year, int mon, int mday, int *wday, int *yday)
{
int is_leap_year = tm_is_leap_year(year);
*yday = TM_MON_DAYS_ACCU[mon] + mday + (mon <= TM_MON_FEB ? 0 : is_leap_year) - 1;
int jan1 = tm_doomsday(year) - 2 - is_leap_year;
*wday = (jan1 + *yday) % 7;
}
void tm_fill_derived_values(struct tm *tm)
{
tm_get_wyday(tm->tm_year + 1900, tm->tm_mon, tm->tm_mday, &tm->tm_wday, &tm->tm_yday);
}
int tm_is_valid_date(int year, int mon, int mday)
{
if ((mon < TM_MON_JAN) || (mon > TM_MON_DEC)) {
return 0;
}
if ((mday <= 0) || (mday > TM_MON_DAYS[mon])) {
if ((mday != 29) || (mon != TM_MON_FEB) || !tm_is_leap_year(year)) {
return 0;
}
}
if (year <= 1582) {
if (year < 1582) {
return 0;
}
if ((mon < TM_MON_OCT) || ((mon == TM_MON_OCT) && (mday < 15))) {
return 0;
}
}
return 1;
}
int tm_is_valid_time(int hour, int min, int sec)
{
return (hour >= 0) && (hour < 24) &&
(min >= 0) && (min < 60) &&
(sec >= 0) && (sec <= 60);
}