1 #ifndef BOOST_CLBL_TRTS_PARAMETER_INDEX_HELPER_HPP
2 #define BOOST_CLBL_TRTS_PARAMETER_INDEX_HELPER_HPP
3 
4 #include <boost/callable_traits/detail/config.hpp>
5 
6 namespace boost { namespace callable_traits { namespace detail {
7 
8 template<std::size_t I, typename T, bool IgnoreThisPointer = false,
9     bool AllowPlus1 = false, std::size_t Count = 0>
10 struct parameter_index_helper {
11 
12     using error_t = error_type<T>;
13 
14     using args_tuple = typename std::conditional<IgnoreThisPointer,
15         typename detail::traits<T>::non_invoke_arg_types,
16         typename detail::traits<T>::arg_types>::type;
17 
18     static constexpr bool has_parameter_list =
19         !std::is_same<args_tuple, invalid_type>::value
20         && !std::is_same<args_tuple, reference_error>::value;
21 
22     using temp_tuple = typename std::conditional<has_parameter_list,
23         args_tuple, std::tuple<error_t>>::type;
24 
25     static constexpr std::size_t parameter_list_size =
26         std::tuple_size<temp_tuple>::value;
27 
28     static constexpr bool is_out_of_range = has_parameter_list &&
29         I >= parameter_list_size + static_cast<std::size_t>(AllowPlus1);
30 
31     static constexpr bool is_count_out_of_range = has_parameter_list &&
32         I + Count > parameter_list_size + static_cast<std::size_t>(AllowPlus1);
33 
34     static constexpr std::size_t index =
35         has_parameter_list && !is_out_of_range ? I : 0;
36 
37     static constexpr std::size_t count =
38         has_parameter_list && !is_count_out_of_range ? Count : 0;
39 
40     using permissive_tuple = typename std::conditional<
41         has_parameter_list && !is_out_of_range,
42         args_tuple, std::tuple<error_t>>::type;
43 
44     using permissive_function = typename std::conditional<
45         has_parameter_list && !is_out_of_range,
46         T, error_t(error_t)>::type;
47 };
48 
49 }}} // namespace boost::callable_traits::detail
50 
51 #endif // #ifndef BOOST_CLBL_TRTS_PARAMETER_INDEX_HELPER_HPP
52