vector/detail/at_impl.hpp

0001 /*=============================================================================
0002     Copyright (c) 2001-2011 Joel de Guzman
0003
0004     Distributed under the Boost Software License, Version 1.0. (See accompanying
0005     file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
0006 ==============================================================================*/
0007 #if !defined(FUSION_AT_IMPL_05042005_0741)
0008 #define FUSION_AT_IMPL_05042005_0741
0009
0010 #include <boost/fusion/support/config.hpp>
0011 #include <boost/fusion/support/detail/access.hpp>
0012 #include <boost/fusion/container/vector/detail/value_at_impl.hpp>
0013 #include <boost/static_assert.hpp>
0014
0015 namespace boost { namespace fusion
0016 {
0017     struct vector_tag;
0018
0019     namespace extension
0020     {
0021         template <typename Tag>
0022         struct at_impl;
0023
0024         template <>
0025         struct at_impl<vector_tag>
0026         {
0027             template <typename Sequence, typename N>
0028             struct apply
0029             {
0030                 typedef typename value_at_impl<vector_tag>::template apply<Sequence, N>::type element;
0031                 typedef typename detail::ref_result<element>::type type;
0032
0033                 BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
0034                 static type
0035                 call(Sequence& v)
0036                 {
0037                     BOOST_STATIC_ASSERT((N::value < Sequence::size::value));
0038                     return v.at_impl(N());
0039                 }
0040             };
0041
0042             template <typename Sequence, typename N>
0043             struct apply <Sequence const, N>
0044             {
0045                 typedef typename value_at_impl<vector_tag>::template apply<Sequence, N>::type element;
0046                 typedef typename detail::cref_result<element>::type type;
0047
0048                 BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
0049                 static type
0050                 call(Sequence const& v)
0051                 {
0052                     BOOST_STATIC_ASSERT((N::value < Sequence::size::value));
0053                     return v.at_impl(N());
0054                 }
0055             };
0056         };
0057     }
0058 }}
0059
0060 #endif