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

   1 /*!
   2 @file
   3 Defines `boost::hana::greater_equal`.
   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_GREATER_EQUAL_HPP
  11 #define BOOST_HANA_GREATER_EQUAL_HPP
  12
  13 #include <boost/hana/fwd/greater_equal.hpp>
  14
  15 #include <boost/hana/concept/orderable.hpp>
  16 #include <boost/hana/config.hpp>
  17 #include <boost/hana/core/common.hpp>
  18 #include <boost/hana/core/to.hpp>
  19 #include <boost/hana/core/dispatch.hpp>
  20 #include <boost/hana/detail/concepts.hpp>
  21 #include <boost/hana/detail/has_common_embedding.hpp>
  22 #include <boost/hana/detail/nested_than.hpp> // required by fwd decl
  23 #include <boost/hana/if.hpp>
  24 #include <boost/hana/not.hpp>
  25
  26
  27 BOOST_HANA_NAMESPACE_BEGIN
  28     //! @cond
  29     template <typename X, typename Y>
  30     constexpr decltype(auto) greater_equal_t::operator()(X&& x, Y&& y) const {
  31         using T = typename hana::tag_of<X>::type;
  32         using U = typename hana::tag_of<Y>::type;
  33         using GreaterEqual = BOOST_HANA_DISPATCH_IF(
  34             decltype(greater_equal_impl<T, U>{}),
  35             hana::Orderable<T>::value &&
  36             hana::Orderable<U>::value
  37         );
  38
  39     #ifndef BOOST_HANA_CONFIG_DISABLE_CONCEPT_CHECKS
  40         static_assert(hana::Orderable<T>::value,
  41         "hana::greater_equal(x, y) requires 'x' to be Orderable");
  42
  43         static_assert(hana::Orderable<U>::value,
  44         "hana::greater_equal(x, y) requires 'y' to be Orderable");
  45     #endif
  46
  47         return GreaterEqual::apply(static_cast<X&&>(x), static_cast<Y&&>(y));
  48     }
  49     //! @endcond
  50
  51     template <typename T, typename U, bool condition>
  52     struct greater_equal_impl<T, U, when<condition>> : default_ {
  53         template <typename X, typename Y>
  54         static constexpr decltype(auto) apply(X x, Y y) {
  55             return hana::not_(hana::less(static_cast<X&&>(x),
  56                                          static_cast<Y&&>(y)));
  57         }
  58     };
  59
  60     // Cross-type overload
  61     template <typename T, typename U>
  62     struct greater_equal_impl<T, U, when<
  63         detail::has_nontrivial_common_embedding<Orderable, T, U>::value
  64     >> {
  65         using C = typename hana::common<T, U>::type;
  66         template <typename X, typename Y>
  67         static constexpr decltype(auto) apply(X&& x, Y&& y) {
  68             return hana::greater_equal(hana::to<C>(static_cast<X&&>(x)),
  69                                        hana::to<C>(static_cast<Y&&>(y)));
  70         }
  71     };
  72 BOOST_HANA_NAMESPACE_END
  73
  74 #endif // !BOOST_HANA_GREATER_EQUAL_HPP