| /*============================================================================= |
| Copyright (c) 2001-2006 Joel de Guzman |
| Copyright (c) 2005-2006 Dan Marsden |
| |
| Distributed under the Boost Software License, Version 1.0. (See accompanying |
| file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) |
| ==============================================================================*/ |
| #if !defined(BOOST_FUSION_DEQUE_VALUE_AT_IMPL_08122006_0756) |
| #define BOOST_FUSION_DEQUE_VALUE_AT_IMPL_08122006_0756 |
| |
| #include <boost/fusion/container/deque/detail/keyed_element.hpp> |
| |
| #include <boost/mpl/equal_to.hpp> |
| #include <boost/mpl/assert.hpp> |
| |
| namespace boost { namespace fusion { |
| |
| struct deque_tag; |
| |
| namespace extension |
| { |
| template<typename T> |
| struct value_at_impl; |
| |
| template<> |
| struct value_at_impl<deque_tag> |
| { |
| template<typename Sequence, typename N> |
| struct apply |
| { |
| typedef typename Sequence::next_up next_up; |
| typedef typename Sequence::next_down next_down; |
| BOOST_MPL_ASSERT_RELATION(next_down::value, !=, next_up::value); |
| |
| typedef mpl::plus<next_down, mpl::int_<1> > offset; |
| typedef mpl::int_<mpl::plus<N, offset>::value> adjusted_index; |
| typedef typename detail::keyed_element_value_at<Sequence, adjusted_index>::type type; |
| }; |
| }; |
| } |
| }} |
| |
| #endif |