/**
* Calculates the day of the year for a given date
*
* @param int $year The year, for example: 2000, -1000, 0
* @param int $month The month, from 1 to 12
* @param float $day The day, from 1 to 31, or with decimals
* @return int The day of the year, for example: 1, 2, 365, 366
*/
function aa_date_to_day_of_year($year, $month, $day)
{
if (aa_is_leap_year($year)) {
$K = 1;
} else {
$K = 2;
}
$day_of_year = aa_int(275 * $month / 9) - $K * aa_int(($month + 9) / 12) + $day - 30;
return $day_of_year;
}
/**
* Calculates the date for a given day in a given year
*
* The calendar in which the year falls is automatically detected.
* This is needed to determine if the year is a leap year.
*
* @param int $year The year, for example: 2000, -1000, 0
* @param int $day_of_year The day of the year, for example: 1, 2, 365, 366
* @return array|bool The date or false on error
* @returns int 0 The year
* @returns int 1 The month
* @returns int 2 The day
*/
function aa_day_of_year_to_date($year, $day_of_year)
{
if (aa_is_leap_year($year)) {
$K = 1;
} else {
$K = 2;
}
if ($day_of_year < 32) {
$month = 1;
} else {
$month = aa_int(($K + $day_of_year) * 9 / 275 + 0.98);
}
$day = $day_of_year - aa_int(275 * $month / 9) + $K * aa_int(($month + 9) / 12) + 30;
return array($year, $month, $day);
}
