ceph/src/boost/libs/fusion/include/boost/fusion/adapted/boost_tuple/detail/at_impl.hpp

   1 /*=============================================================================
   2     Copyright (c) 2001-2011 Joel de Guzman
   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 #if !defined(BOOST_FUSION_AT_IMPL_09262006_1920)
   8 #define BOOST_FUSION_AT_IMPL_09262006_1920
   9
  10 #include <boost/fusion/support/config.hpp>
  11 #include <boost/tuple/tuple.hpp>
  12 #include <boost/mpl/if.hpp>
  13
  14 namespace boost { namespace fusion
  15 {
  16     struct boost_tuple_tag;
  17
  18     namespace extension
  19     {
  20         template<typename T>
  21         struct at_impl;
  22
  23         template <>
  24         struct at_impl<boost_tuple_tag>
  25         {
  26             template <typename Sequence, typename N>
  27             struct apply
  28             {
  29                 typedef typename
  30                     tuples::element<N::value, Sequence>::type
  31                 element;
  32
  33                 typedef typename
  34                     mpl::if_<
  35                         is_const<Sequence>
  36                       , typename tuples::access_traits<element>::const_type
  37                       , typename tuples::access_traits<element>::non_const_type
  38                     >::type
  39                 type;
  40
  41                 BOOST_FUSION_GPU_ENABLED
  42                 static type
  43                 call(Sequence& seq)
  44                 {
  45                     return tuples::get<N::value>(seq);
  46                 }
  47             };
  48         };
  49     }
  50 }}
  51
  52 #endif