iTextSharp.text.factories.RomanAlphabetFactory.GetString C# (CSharp) Метод

        public static String GetString(int index)
        {
            if (index < 1) throw new FormatException(MessageLocalization.GetComposedMessage("you.can.t.translate.a.negative.number.into.an.alphabetical.value"));

            index--;
            int bytes = 1;
            int start = 0;
            int symbols = 26;
            while (index >= symbols + start) {
                bytes++;
                start += symbols;
                symbols *= 26;
            }

            int c = index - start;
            char[] value = new char[bytes];
            while (bytes > 0) {
                value[--bytes] = (char)( 'a' + (c % 26));
                c /= 26;
            }

            return new String(value);
        }