ceph/src/boost/boost/hana/insert_range.hpp

   1 /*!
   2 @file
   3 Defines `boost::hana::insert_range`.
   4
   5 @copyright Louis Dionne 2013-2017
   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_INSERT_RANGE_HPP
  11 #define BOOST_HANA_INSERT_RANGE_HPP
  12
  13 #include <boost/hana/fwd/insert_range.hpp>
  14
  15 #include <boost/hana/concat.hpp>
  16 #include <boost/hana/concept/foldable.hpp>
  17 #include <boost/hana/concept/sequence.hpp>
  18 #include <boost/hana/config.hpp>
  19 #include <boost/hana/core/to.hpp>
  20 #include <boost/hana/core/dispatch.hpp>
  21 #include <boost/hana/drop_front.hpp>
  22 #include <boost/hana/take_front.hpp>
  23
  24
  25 namespace boost { namespace hana {
  26     //! @cond
  27     template <typename Xs, typename N, typename Elements>
  28     constexpr auto insert_range_t::operator()(Xs&& xs, N&& n, Elements&& elements) const {
  29         using S = typename hana::tag_of<Xs>::type;
  30         using InsertRange = BOOST_HANA_DISPATCH_IF(insert_range_impl<S>,
  31             hana::Sequence<Xs>::value &&
  32             hana::Foldable<Elements>::value
  33         );
  34
  35     #ifndef BOOST_HANA_CONFIG_DISABLE_CONCEPT_CHECKS
  36         static_assert(hana::Sequence<Xs>::value,
  37         "hana::insert_range(xs, n, elements) requires 'xs' to be a Sequence");
  38
  39         static_assert(hana::Foldable<Elements>::value,
  40         "hana::insert_range(xs, n, elements) requires 'elements' to be a Foldable");
  41     #endif
  42
  43         return InsertRange::apply(static_cast<Xs&&>(xs),
  44                                   static_cast<N&&>(n),
  45                                   static_cast<Elements&&>(elements));
  46     }
  47     //! @endcond
  48
  49     template <typename S, bool condition>
  50     struct insert_range_impl<S, when<condition>> {
  51         template <typename Xs, typename N, typename Elements>
  52         static constexpr auto apply(Xs&& xs, N const& n, Elements&& e) {
  53             return hana::concat(
  54                     hana::concat(
  55                         hana::take_front(xs, n),
  56                         hana::to<S>(static_cast<Elements&&>(e))
  57                     ),
  58                     hana::drop_front(xs, n)
  59                 );
  60         }
  61     };
  62 }} // end namespace boost::hana
  63
  64 #endif // !BOOST_HANA_INSERT_RANGE_HPP