IronRuby.Builtins.RubyFileOps.AppendDirectoryName C# (CSharp) Method

        private static void AppendDirectoryName(MutableString/*!*/ result, MutableString/*!*/ name) {
            int resultLength = result.GetCharCount();

            int i;
            for (i = resultLength - 1; i >= 0; i--) {
                if (!IsDirectorySeparator(result.GetChar(i))) {
                    break;
                }
            }

            if (i == resultLength - 1) {
                if (!IsDirectorySeparator(name.GetFirstChar())) {
                    result.Append(DirectorySeparatorChar);
                }
                result.Append(name);
            } else if (IsDirectorySeparator(name.GetFirstChar())) {
                result.Replace(i + 1, resultLength - i - 1, name);
            } else {
                result.Append(name);
            }
        }