ceph/src/boost/libs/hana/include/boost/hana/is_subset.hpp

   1 /*!
   2 @file
   3 Defines `boost::hana::is_subset`.
   4
   5 @copyright Louis Dionne 2013-2016
   6 Distributed under the Boost Software License, Version 1.0.
   7 (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
   8  */
   9
  10 #ifndef BOOST_HANA_IS_SUBSET_HPP
  11 #define BOOST_HANA_IS_SUBSET_HPP
  12
  13 #include <boost/hana/fwd/is_subset.hpp>
  14
  15 #include <boost/hana/all_of.hpp>
  16 #include <boost/hana/concept/searchable.hpp>
  17 #include <boost/hana/config.hpp>
  18 #include <boost/hana/contains.hpp>
  19 #include <boost/hana/core/common.hpp>
  20 #include <boost/hana/core/to.hpp>
  21 #include <boost/hana/core/dispatch.hpp>
  22 #include <boost/hana/detail/has_common_embedding.hpp>
  23 #include <boost/hana/functional/partial.hpp>
  24
  25
  26 BOOST_HANA_NAMESPACE_BEGIN
  27     //! @cond
  28     template <typename Xs, typename Ys>
  29     constexpr auto is_subset_t::operator()(Xs&& xs, Ys&& ys) const {
  30         using S1 = typename hana::tag_of<Xs>::type;
  31         using S2 = typename hana::tag_of<Ys>::type;
  32         using IsSubset = BOOST_HANA_DISPATCH_IF(
  33             decltype(is_subset_impl<S1, S2>{}),
  34             hana::Searchable<S1>::value &&
  35             hana::Searchable<S2>::value &&
  36             !is_default<is_subset_impl<S1, S2>>::value
  37         );
  38
  39     #ifndef BOOST_HANA_CONFIG_DISABLE_CONCEPT_CHECKS
  40         static_assert(hana::Searchable<S1>::value,
  41         "hana::is_subset(xs, ys) requires 'xs' to be Searchable");
  42
  43         static_assert(hana::Searchable<S2>::value,
  44         "hana::is_subset(xs, ys) requires 'ys' to be Searchable");
  45
  46         static_assert(!is_default<is_subset_impl<S1, S2>>::value,
  47         "hana::is_subset(xs, ys) requires 'xs' and 'ys' to be embeddable "
  48         "in a common Searchable");
  49     #endif
  50
  51         return IsSubset::apply(static_cast<Xs&&>(xs), static_cast<Ys&&>(ys));
  52     }
  53     //! @endcond
  54
  55     template <typename S1, typename S2, bool condition>
  56     struct is_subset_impl<S1, S2, when<condition>> : default_ {
  57         template <typename ...Args>
  58         static constexpr auto apply(Args&& ...) = delete;
  59     };
  60
  61     template <typename S, bool condition>
  62     struct is_subset_impl<S, S, when<condition>> {
  63         template <typename Xs, typename Ys>
  64         static constexpr decltype(auto) apply(Xs&& xs, Ys&& ys) {
  65             return hana::all_of(static_cast<Xs&&>(xs),
  66                     hana::partial(hana::contains, static_cast<Ys&&>(ys)));
  67         }
  68     };
  69
  70     // Cross-type overload
  71     template <typename S1, typename S2>
  72     struct is_subset_impl<S1, S2, when<
  73         detail::has_nontrivial_common_embedding<Searchable, S1, S2>::value
  74     >> {
  75         using C = typename common<S1, S2>::type;
  76         template <typename Xs, typename Ys>
  77         static constexpr decltype(auto) apply(Xs&& xs, Ys&& ys) {
  78             return hana::is_subset(hana::to<C>(static_cast<Xs&&>(xs)),
  79                                    hana::to<C>(static_cast<Ys&&>(ys)));
  80         }
  81     };
  82 BOOST_HANA_NAMESPACE_END
  83
  84 #endif // !BOOST_HANA_IS_SUBSET_HPP