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+/*=============================================================================
+ Copyright (c) 2005-2011 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