ceph/src/boost/libs/variant/include/boost/variant/detail/element_index.hpp

   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) 2014-2015 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
  23 namespace boost { namespace detail { namespace variant {
  24
  25 template <class VariantElement, class T>
  26 struct 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
  34 template <class Types, class T>
  35 struct 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
  45 template <class Variant, class T>
  46 struct element_iterator :
  47     element_iterator_impl< typename Variant::types, typename boost::remove_reference<T>::type >
  48 {};
  49
  50 template <class Variant, class T>
  51 struct 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