System.Text.RegularExpressions.RegexCharClass.AddSet C# (CSharp) Method

        private void AddSet(String set) {
            int i;

            if (_canonical && RangeCount() > 0 && set.Length > 0 && 
                set[0] <= GetRangeAt(RangeCount() - 1)._last)
                _canonical = false;

            for (i = 0; i < set.Length - 1; i += 2) {
                _rangelist.Add(new SingleRange(set[i], (char)(set[i + 1] - 1)));
            }

            if (i < set.Length) {
                _rangelist.Add(new SingleRange(set[i], Lastchar));
            }
        }

        internal RegexFC(String set, bool nullable, bool caseInsensitive)
        {
            _cc = new RegexCharClass();

            _cc.AddSet(set);
            _nullable        = nullable;
            _caseInsensitive = caseInsensitive;
        }