Description:
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Hi,

I want use Persian calendar in PHP, but not support this feature; In Iran we use 
none standard script for implement this feature and It is not likely...!
If year%33 remaining 1, 5, 9, 13, 17, 22, 26, 30 this year will calling leap 
year.

Persian calendar:
months/abbrevmonths are: Farvardin, Ordibehesht, Khordad, Tir, Mordad, 
Shahrivar, Mehr, Aban, Azar, Dey, Bahman, Esfand
daysname/abbrevdaysname: Yekshanbeh = Sunday, Doshanbeh, Seshhanbeh, 
Chaharshanbeh, Panjshanbeh, Jomeh, Shanbeh
week begin from Shanbeh
days range in month: 29-31

I use below script:
http://www.fourmilab.ch/documents/calendar/

Thanks for cooperation.
Regards

Test script:
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const CAL_PERSIAN = 4;
const PERSIAN_EPOCH = 1948320.5;
function Persian2JD($year, $month, $day) {
	$epbase = $year - (($year >= 0) ? 474 : 473);
	$epyear = 474 + $epbase%2820;
	return $day + (($month <= 7) ? (($month - 1) * 31) : ((($month - 1) * 
30) + 6)) + (int)((($epyear * 682) - 110) / 2816) + ($epyear - 1) * 365 + 
(int)($epbase / 2820) * 1029983 + (PERSIAN_EPOCH - 1);
}
function JD2Persian($jd) { # Calculate Persian date from Julian day
	$jd = (int)$jd + 0.5;

	$depoch = $jd - Persian2JD(475, 1, 1);
	$cycle = (int)($depoch / 1029983);
	$cyear = $depoch%1029983;
	if ($cyear == 1029982)
		$ycycle = 2820;
	else {
		$aux1 = (int)($cyear / 366);
		$aux2 = $cyear%366;
		$ycycle = (int)(((2134 * $aux1) + (2816 * $aux2) + 2815) / 
1028522) + $aux1 + 1;
	}
	$year = $ycycle + (2820 * $cycle) + 474;
	if ($year <= 0)
		$year--;
	$yday = ($jd - Persian2JD($year, 1, 1)) + 1;
	$month = ($yday <= 186) ? ceil($yday / 31) : ceil(($yday - 6) / 30);
	$day = ($jd - Persian2JD($year, $month, 1)) + 1;
	return $year.'-'.str_pad($month, 2, 0, STR_PAD_LEFT).'-'.str_pad($day, 
2, 0, STR_PAD_LEFT);
}