System.Globalization.PersianCalendar.DaysUpToPersianYear C# (CSharp) Method

        long DaysUpToPersianYear(int PersianYear) {

            long NumDays;          // number of absolute days
            int NumCycles;         // number of 33 year cycles
            int NumYearsLeft;      // number of years into 33 year cycle

            //
            //  Compute the number of 33 years cycles.
            //
            NumCycles = (PersianYear - 1) / DateCycle;

            //
            //  Compute the number of years left.  This is the number of years
            //  into the 33 year cycle for the given year.
            //
            NumYearsLeft = (PersianYear-1) % DateCycle;

            //
            //  Compute the number of absolute days up to the given year.
            //
            NumDays = NumCycles * DaysPerCycle + GregorianOffset;
            while (NumYearsLeft > 0) {
                NumDays += 365;
                // Common year is 365 days, and leap year is 366 days.
                if(IsLeapYear(NumYearsLeft, CurrentEra)) {
                    NumDays++;
                }
                NumYearsLeft--;
            }

            //
            //  Return the number of absolute days.
            //
            return (NumDays);
        }