ShaderTools.Hlsl.Parser.HlslLexer.ReadOctalValue C# (CSharp) Method

        private long ReadOctalValue(string octal)
        {
            long val = 0;

            for (int i = octal.Length - 1, j = 0; i >= 0; i--, j++)
            {
                int c;

                try
                {
                    c = int.Parse(new string(octal[i], 1), CultureInfo.InvariantCulture);

                    if (c > 7)
                    {
                        _diagnostics.ReportInvalidOctal(CurrentSpan, octal);
                        return 0;
                    }
                }
                catch (FormatException)
                {
                    _diagnostics.ReportInvalidOctal(CurrentSpan, octal);
                    return 0;
                }

                checked
                {
                    val += (long)(c * Math.Pow(8, j));
                }
            }

            return val;
        }