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

        internal static String CharDescription(char ch) {
            StringBuilder sb = new StringBuilder();
            int shift;

            if (ch == '\\')
                return "\\\\";

            if (ch >= ' ' && ch <= '~') {
                sb.Append(ch);
                return sb.ToString();
            }

            if (ch < 256) {
                sb.Append("\\x");
                shift = 8;
            }
            else {
                sb.Append("\\u");
                shift = 16;
            }

            while (shift > 0) {
                shift -= 4;
                sb.Append(Hex[(ch >> shift) & 0xF]);
            }

            return sb.ToString();
        }

        internal virtual String TextposDescription()
        {
            StringBuilder Sb = new StringBuilder();
            int           remaining;

            Sb.Append(_runtextpos);

            if (Sb.Length < 8)
            {
                Sb.Append(' ', 8 - Sb.Length);
            }

            if (_runtextpos > _runtextbeg)
            {
                Sb.Append(RegexCharClass.CharDescription(_runtext[_runtextpos - 1]));
            }
            else
            {
                Sb.Append('^');
            }

            Sb.Append('>');

            remaining = _runtextend - _runtextpos;

            for (int i = _runtextpos; i < _runtextend; i++)
            {
                Sb.Append(RegexCharClass.CharDescription(_runtext[i]));
            }
            if (Sb.Length >= 64)
            {
                Sb.Length = 61;
                Sb.Append("...");
            }
            else
            {
                Sb.Append('$');
            }

            return(Sb.ToString());
        }