System.DateTimeParse.GetDayOfMNN C# (CSharp) Method

        private static Boolean GetDayOfMNN(ref DateTimeResult result, ref DateTimeRawInfo raw, DateTimeFormatInfo dtfi)
        {
            if ((result.flags & ParseFlags.HaveDate) != 0) {
                // Multiple dates in the input string
                result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null);
                return false;
            }

            int n1 = raw.GetNumber(0);
            int n2 = raw.GetNumber(1);

            int order;
            if (!GetYearMonthDayOrder(dtfi.ShortDatePattern, dtfi, out order)) {
                result.SetFailure(ParseFailureKind.FormatWithParameter, "Format_BadDatePattern", dtfi.ShortDatePattern);
                return false;
            }
            int year;

            if (order == ORDER_MDY)
            {
                if (result.calendar.IsValidDay(year = AdjustYear(ref result, n2), raw.month, n1, result.era))
                {
                    result.SetDate(year, raw.month, n1);      // MDY
                    result.flags |= ParseFlags.HaveDate;
                    return true;
                }
                else if (result.calendar.IsValidDay(year = AdjustYear(ref result, n1), raw.month, n2, result.era))
                {
                    result.SetDate(year, raw.month, n2);      // YMD
                    result.flags |= ParseFlags.HaveDate;
                    return true;
                }
            }
            else if (order == ORDER_YMD)
            {
                if (result.calendar.IsValidDay(year = AdjustYear(ref result, n1), raw.month, n2, result.era))
                {
                    result.SetDate(year, raw.month, n2);      // YMD
                    result.flags |= ParseFlags.HaveDate;
                    return true;
                }
                else if (result.calendar.IsValidDay(year = AdjustYear(ref result, n2), raw.month, n1, result.era))
                {
                    result.SetDate(year, raw.month, n1);      // DMY
                    result.flags |= ParseFlags.HaveDate;
                    return true;
                }
            }
            else if (order == ORDER_DMY)
            {
                if (result.calendar.IsValidDay(year = AdjustYear(ref result, n2), raw.month, n1, result.era))
                {
                    result.SetDate(year, raw.month, n1);      // DMY
                    result.flags |= ParseFlags.HaveDate;
                    return true;
                }
                else if (result.calendar.IsValidDay(year = AdjustYear(ref result, n1), raw.month, n2, result.era))
                {
                    result.SetDate(year, raw.month, n2);      // YMD
                    result.flags |= ParseFlags.HaveDate;
                    return true;
                }
            }

            result.SetFailure(ParseFailureKind.Format, "Format_BadDateTime", null);
            return false;
        }