ceph/src/boost/boost/fusion/view/reverse_view/detail/at_impl.hpp

   1 /*=============================================================================
   2     Copyright (c) 2009 Christopher Schmidt
   3
   4     Distributed under the Boost Software License, Version 1.0. (See accompanying
   5     file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   6 ==============================================================================*/
   7
   8 #ifndef BOOST_FUSION_VIEW_REVERSE_VIEW_DETAIL_AT_IMPL_HPP
   9 #define BOOST_FUSION_VIEW_REVERSE_VIEW_DETAIL_AT_IMPL_HPP
  10
  11 #include <boost/fusion/support/config.hpp>
  12 #include <boost/fusion/sequence/intrinsic/at.hpp>
  13 #include <boost/mpl/minus.hpp>
  14 #include <boost/mpl/int.hpp>
  15
  16 namespace boost { namespace fusion { namespace extension
  17 {
  18     template <typename>
  19     struct at_impl;
  20
  21     template <>
  22     struct at_impl<reverse_view_tag>
  23     {
  24         template <typename Seq, typename N>
  25         struct apply
  26         {
  27             typedef mpl::minus<typename Seq::size, mpl::int_<1>, N> real_n;
  28
  29             typedef typename
  30                 result_of::at<typename Seq::seq_type, real_n>::type
  31             type;
  32
  33             BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
  34             static type
  35             call(Seq& seq)
  36             {
  37                 return fusion::at<real_n>(seq.seq);
  38             }
  39         };
  40     };
  41 }}}
  42
  43 #endif