boost/variant/detail/element_index.hpp
//----------------------------------------------------------------------------- // boost variant/detail/element_index.hpp header file // See http://www.boost.org for updates, documentation, and revision history. //----------------------------------------------------------------------------- // // Copyright (c) 2014-2024 Antony Polukhin // // Distributed under the Boost Software License, Version 1.0. (See // accompanying file LICENSE_1_0.txt or copy at // http://www.boost.org/LICENSE_1_0.txt) #ifndef BOOST_VARIANT_DETAIL_ELEMENT_INDEX_HPP #define BOOST_VARIANT_DETAIL_ELEMENT_INDEX_HPP #include <boost/config.hpp> #include <boost/variant/recursive_wrapper_fwd.hpp> #include <boost/variant/variant_fwd.hpp> #include <boost/type_traits/remove_cv.hpp> #include <boost/type_traits/remove_reference.hpp> #include <boost/mpl/find_if.hpp> namespace boost { namespace detail { namespace variant { template <class VariantElement, class T> struct variant_element_functor : boost::mpl::or_< boost::is_same<VariantElement, T>, boost::is_same<VariantElement, boost::recursive_wrapper<T> >, boost::is_same<VariantElement, T& > > {}; template <class Types, class T> struct element_iterator_impl : boost::mpl::find_if< Types, boost::mpl::or_< variant_element_functor<boost::mpl::_1, T>, variant_element_functor<boost::mpl::_1, typename boost::remove_cv<T>::type > > > {}; template <class Variant, class T> struct element_iterator : element_iterator_impl< typename Variant::types, typename boost::remove_reference<T>::type > {}; template <class Variant, class T> struct holds_element : boost::mpl::not_< boost::is_same< typename boost::mpl::end<typename Variant::types>::type, typename element_iterator<Variant, T>::type > > {}; }}} // namespace boost::detail::variant #endif // BOOST_VARIANT_DETAIL_ELEMENT_INDEX_HPP