NCrontab.Advanced.CrontabSchedule.GetValue C# (CSharp) Méthode

        private static int GetValue(ref string filter, CrontabFieldKind kind)
        {
            var maxValue = Constants.MaximumDateTimeValues[kind];

            if (string.IsNullOrEmpty(filter))
                throw new CrontabException("Expected number, but filter was empty.");

            int i, value;
            var isDigit = char.IsDigit(filter[0]);
            var isLetter = char.IsLetter(filter[0]);

            // Because this could either numbers, or letters, but not a combination,
            // check each condition separately.
            for (i = 0; i < filter.Length; i++)
                if ((isDigit && !char.IsDigit(filter[i])) || (isLetter && !char.IsLetter(filter[i]))) break;

            var valueToParse = filter.Substring(0, i);
            if (int.TryParse(valueToParse, out value))
            {
                filter = filter.Substring(i);
                var returnValue = value;
                if (returnValue > maxValue)
                    throw new CrontabException(string.Format("Value for {0} filter exceeded maximum value of {1}", Enum.GetName(typeof(CrontabFieldKind), kind), maxValue));
                return returnValue;
            }
            else
            {
                List<KeyValuePair<string, int>> replaceVal = null;

                if (kind == CrontabFieldKind.DayOfWeek)
                    replaceVal = Constants.Days.Where(x => valueToParse.StartsWith(x.Key)).ToList();
                else if (kind == CrontabFieldKind.Month)
                    replaceVal = Constants.Months.Where(x => valueToParse.StartsWith(x.Key)).ToList();

                if (replaceVal != null && replaceVal.Count == 1)
                {
                    // missingFilter addresses when a filter string of "SUNL" is passed in,
                    // which causes the isDigit/isLetter loop above to iterate through the end
                    // of the string.  This catches the edge case, and re-appends L to the end.
                    var missingFilter = "";
                    if (filter.Length == i && filter.EndsWith("L") && kind == CrontabFieldKind.DayOfWeek)
                        missingFilter = "L";

                    filter = filter.Substring(i) + missingFilter;
                    var returnValue = replaceVal.First().Value;
                    if (returnValue > maxValue)
                        throw new CrontabException(string.Format("Value for {0} filter exceeded maximum value of {1}", Enum.GetName(typeof(CrontabFieldKind), kind), maxValue));
                    return returnValue;
                }
            }

            throw new CrontabException("Filter does not contain expected number");
        }