Jalali date (Persian) for simple date picker

function check(&$field,&$value,$oldvalue){
		$value = JFactory::getDate()->format($value);
		return true;
	}

function showfield($viewObj, $namekey, $row) {
		if( isset( $row->$namekey)) {
			$date_format = !empty( $this->field_options['format']) ? $this->field_options['format'] : '%Y-%m-%d %H:%M:%S';
			return hikashop_getDate( $row->$namekey, $date_format);
		}
		return '';
	}

function check(&$field,&$value,$oldvalue){
		$date = explode('/',$value);
		$value = implode('/',$this->gregorian_to_jalali($date[0],$date[1],$date[2]));
		return true;
	}
function div($a,$b) { 
    return (int) ($a / $b); 
} 
 
function gregorian_to_jalali ($g_y, $g_m, $g_d,$str=false) 
{ 
    $g_days_in_month = array(31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31); 
    $j_days_in_month = array(31, 31, 31, 31, 31, 31, 30, 30, 30, 30, 30, 29); 
 
  
   $gy = $g_y-1600; 
   $gm = $g_m-1; 
   $gd = $g_d-1; 
 
   $g_day_no = 365*$gy+$this->div($gy+3,4)-$this->div($gy+99,100)+$this->div($gy+399,400); 
 
   for ($i=0; $i < $gm; ++$i) 
      $g_day_no += $g_days_in_month[$i]; 
   if ($gm>1 && (($gy%4==0 && $gy%100!=0) || ($gy%400==0))) 
      /* leap and after Feb */ 
      $g_day_no++; 
   $g_day_no += $gd; 
 
   $j_day_no = $g_day_no-79; 
 
   $j_np = $this->div($j_day_no, 12053); /* 12053 = 365*33 + 32/4 */ 
   $j_day_no = $j_day_no % 12053; 
 
   $jy = 979+33*$j_np+4*$this->div($j_day_no,1461); /* 1461 = 365*4 + 4/4 */ 
 
   $j_day_no %= 1461; 
 
   if ($j_day_no >= 366) { 
      $jy += $this->div($j_day_no-1, 365); 
      $j_day_no = ($j_day_no-1)%365; 
   } 
 
   for ($i = 0; $i < 11 && $j_day_no >= $j_days_in_month[$i]; ++$i) 
      $j_day_no -= $j_days_in_month[$i]; 
   $jm = $i+1; 
   $jd = $j_day_no+1; 
 if($str) return $jy.'/'.$jm.'/'.$jd ;
   return array($jy, $jm, $jd); 
}