Pchp.Library.PerlRegex.RegexParser.ScanCharEscape C# (CSharp) Метод

        internal char ScanCharEscape()
        {
            char ch;

            ch = MoveRightGetChar();

            if (ch >= '0' && ch <= '7')
            {
                MoveLeft();
                return ScanOctal();
            }

            switch (ch)
            {
                case 'x':
                    return ScanHex(2);
                case 'u':
                    return ScanHex(4);
                case 'a':
                    return '\u0007';
                case 'b':
                    return '\b';
                case 'e':
                    return '\u001B';
                case 'f':
                    return '\f';
                case 'n':
                    return '\n';
                case 'r':
                    return '\r';
                case 't':
                    return '\t';
                case 'v':
                    return '\u000B';
                case 'c':
                    return ScanControl();
                default:
                    if (!UseOptionE() && RegexCharClass.IsWordChar(ch))
                        throw MakeException(SR.Format(SR.UnrecognizedEscape, ch.ToString()));
                    return ch;
            }
        }

        /*
         * Escapes all metacharacters (including (,),[,],{,},|,^,$,*,+,?,\, spaces and #)
         */
        internal static string Unescape(string input)
        {
            for (int i = 0; i < input.Length; i++)
            {
                if (input[i] == '\\')
                {
                    var sb = new StringBuilder();
                    RegexParser p = new RegexParser(CultureInfo.InvariantCulture);
                    int lastpos;
                    p.SetPattern(input);

                    sb.Append(input, 0, i);
                    do
                    {
                        i++;
                        p.Textto(i);
                        if (i < input.Length)
                            sb.Append(p.ScanCharEscape());
                        i = p.Textpos();
                        lastpos = i;
                        while (i < input.Length && input[i] != '\\')
                            i++;
                        sb.Append(input, lastpos, i - lastpos);
                    } while (i < input.Length);

                    return sb.ToString();
                }
            }

            return input;
        }