horros / agavi2

        if ($this->fInvertGregorian) {

            $this->fIsGregorian = !$this->fIsGregorian;

        }

        if ($this->fIsGregorian) {

            $isLeap = $isLeap && (($eyear % 100 != 0) || ($eyear % 400 == 0));

            // Add 2 because Gregorian calendar starts 2 days after

            // Julian calendar

            $gregShift = CalendarGrego::gregorianShift($eyear);

            $julianDay += $gregShift;

        }

        // At this point julianDay indicates the day BEFORE the first

        // day of January 1, <eyear> of either the Julian or Gregorian

        $y = $year - 1;

        $julianDay = 365.0 * $y + floor($y / 4) + (DateDefinitions::JAN_1_1_JULIAN_DAY - 3);

        if ($isGregorian) {

            $isLeap = $isLeap && (($year % 100 != 0) || ($year % 400 == 0));

            // Add 2 because Gregorian calendar starts 2 days after Julian calendar

            $julianDay += CalendarGrego::gregorianShift($year);

        }

        return $julianDay;

    }