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Diffstat (limited to 'boost/fusion/container/deque/detail/at_impl.hpp')
-rw-r--r-- | boost/fusion/container/deque/detail/at_impl.hpp | 59 |
1 files changed, 59 insertions, 0 deletions
diff --git a/boost/fusion/container/deque/detail/at_impl.hpp b/boost/fusion/container/deque/detail/at_impl.hpp new file mode 100644 index 0000000000..dc09d31b7c --- /dev/null +++ b/boost/fusion/container/deque/detail/at_impl.hpp @@ -0,0 +1,59 @@ +/*============================================================================= + 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_AT_IMPL_09122006_2017) +#define BOOST_FUSION_DEQUE_AT_IMPL_09122006_2017 + +#include <boost/fusion/container/deque/detail/keyed_element.hpp> + +#include <boost/mpl/eval_if.hpp> +#include <boost/mpl/equal_to.hpp> +#include <boost/mpl/assert.hpp> +#include <boost/mpl/identity.hpp> + +#include <boost/type_traits/is_const.hpp> +#include <boost/type_traits/add_const.hpp> +#include <boost/type_traits/add_reference.hpp> + +namespace boost { namespace fusion { + + struct deque_tag; + + namespace extension + { + template<typename T> + struct at_impl; + + template<> + struct 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 element_type; + typedef typename add_reference< + typename mpl::eval_if< + is_const<Sequence>, + add_const<element_type>, + mpl::identity<element_type> >::type>::type type; + + static type call(Sequence& seq) + { + return seq.get(adjusted_index()); + } + }; + }; + } +}} + +#endif |