1//-----------------------------------------------------------------------------
2// boost variant/detail/element_index.hpp header file
3// See http://www.boost.org for updates, documentation, and revision history.
4//-----------------------------------------------------------------------------
5//
6// Copyright (c) 2014-2023 Antony Polukhin
7//
8// Distributed under the Boost Software License, Version 1.0. (See
9// accompanying file LICENSE_1_0.txt or copy at
10// http://www.boost.org/LICENSE_1_0.txt)
11
12#ifndef BOOST_VARIANT_DETAIL_ELEMENT_INDEX_HPP
13#define BOOST_VARIANT_DETAIL_ELEMENT_INDEX_HPP
14
15#include <boost/config.hpp>
16#include <boost/variant/recursive_wrapper_fwd.hpp>
17#include <boost/variant/variant_fwd.hpp>
18
19#include <boost/type_traits/remove_cv.hpp>
20#include <boost/type_traits/remove_reference.hpp>
21#include <boost/mpl/find_if.hpp>
22
23namespace boost { namespace detail { namespace variant {
24
25template <class VariantElement, class T>
26struct variant_element_functor :
27 boost::mpl::or_<
28 boost::is_same<VariantElement, T>,
29 boost::is_same<VariantElement, boost::recursive_wrapper<T> >,
30 boost::is_same<VariantElement, T& >
31 >
32{};
33
34template <class Types, class T>
35struct element_iterator_impl :
36 boost::mpl::find_if<
37 Types,
38 boost::mpl::or_<
39 variant_element_functor<boost::mpl::_1, T>,
40 variant_element_functor<boost::mpl::_1, typename boost::remove_cv<T>::type >
41 >
42 >
43{};
44
45template <class Variant, class T>
46struct element_iterator :
47 element_iterator_impl< typename Variant::types, typename boost::remove_reference<T>::type >
48{};
49
50template <class Variant, class T>
51struct holds_element :
52 boost::mpl::not_<
53 boost::is_same<
54 typename boost::mpl::end<typename Variant::types>::type,
55 typename element_iterator<Variant, T>::type
56 >
57 >
58{};
59
60
61}}} // namespace boost::detail::variant
62
63#endif // BOOST_VARIANT_DETAIL_ELEMENT_INDEX_HPP
64