1// Copyright (c) 2016-2024 Antony Polukhin
2//
3// Distributed under the Boost Software License, Version 1.0. (See accompanying
4// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
5
6#ifndef BOOST_PFR_DETAIL_FOR_EACH_FIELD_IMPL_HPP
7#define BOOST_PFR_DETAIL_FOR_EACH_FIELD_IMPL_HPP
8#pragma once
9
10#include <boost/pfr/detail/config.hpp>
11
12#include <utility> // metaprogramming stuff
13
14#include <boost/pfr/detail/sequence_tuple.hpp>
15#include <boost/pfr/detail/rvalue_t.hpp>
16
17namespace boost { namespace pfr { namespace detail {
18
19template <std::size_t Index>
20using size_t_ = std::integral_constant<std::size_t, Index >;
21
22template <class T, class F, class I, class = decltype(std::declval<F>()(std::declval<T>(), I{}))>
23constexpr void for_each_field_impl_apply(T&& v, F&& f, I i, long) {
24 std::forward<F>(f)(std::forward<T>(v), i);
25}
26
27template <class T, class F, class I>
28constexpr void for_each_field_impl_apply(T&& v, F&& f, I /*i*/, int) {
29 std::forward<F>(f)(std::forward<T>(v));
30}
31
32#if !defined(__cpp_fold_expressions) || __cpp_fold_expressions < 201603
33template <class T, class F, std::size_t... I>
34constexpr void for_each_field_impl(T& t, F&& f, std::index_sequence<I...>, std::false_type /*move_values*/) {
35 const int v[] = {0, (
36 detail::for_each_field_impl_apply(sequence_tuple::get<I>(t), std::forward<F>(f), size_t_<I>{}, 1L),
37 0
38 )...};
39 (void)v;
40}
41
42
43template <class T, class F, std::size_t... I>
44constexpr void for_each_field_impl(T& t, F&& f, std::index_sequence<I...>, std::true_type /*move_values*/) {
45 const int v[] = {0, (
46 detail::for_each_field_impl_apply(sequence_tuple::get<I>(std::move(t)), std::forward<F>(f), size_t_<I>{}, 1L),
47 0
48 )...};
49 (void)v;
50}
51#else
52template <class T, class F, std::size_t... I>
53constexpr void for_each_field_impl(T& t, F&& f, std::index_sequence<I...>, std::false_type /*move_values*/) {
54 (detail::for_each_field_impl_apply(sequence_tuple::get<I>(t), std::forward<F>(f), size_t_<I>{}, 1L), ...);
55}
56
57template <class T, class F, std::size_t... I>
58constexpr void for_each_field_impl(T& t, F&& f, std::index_sequence<I...>, std::true_type /*move_values*/) {
59 (detail::for_each_field_impl_apply(sequence_tuple::get<I>(std::move(t)), std::forward<F>(f), size_t_<I>{}, 1L), ...);
60}
61#endif
62
63}}} // namespace boost::pfr::detail
64
65
66#endif // BOOST_PFR_DETAIL_FOR_EACH_FIELD_IMPL_HPP
67

source code of boost/libs/pfr/include/boost/pfr/detail/for_each_field_impl.hpp