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/*
* Copyright (C) 1995. Bill Brown <brown@gis.uiuc.edu> & Michael Shapiro
*
* This program is free software under the GPL (>=v2)
* Read the file GPL.TXT coming with GRASS for details.
*/
#include "datetime.h"
/*!
* \brief
*
* \param year
* \param ad
* \return int
*/
int
datetime_is_leap_year (int year, int ad)
{
if (year == 0)
return datetime_error (-1, "datetime_is_leap_year(): illegal year");
if (!ad) return 0; /* BC */
if (year < 0) return 0; /* ?? */
return((year%4 == 0 && year%100 != 0) || year%400 == 0);
}
/*!
* \brief
*
* \param year
* \param ad
* \return int
*/
int
datetime_days_in_year (int year, int ad)
{
if (year == 0)
return datetime_error (-1, "datetime_days_in_year(): illegal year");
if(datetime_is_leap_year(year,ad))
return 366;
else
return 365;
}
/*!
* \brief
*
* \param month
* \param year
* \return int
*/
int
datetime_days_in_month (int year, int month, int ad)
{
static int days[12] = {31,28,31,30,31,30,31,31,30,31,30,31};
if (month < 1 || month > 12)
return datetime_error (-1, "datetime_days_in_month(): illegal month");
if(month == 2 && datetime_is_leap_year(year,ad))
return(29);
return(days[month - 1]);
}
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