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- /*=============================================================================
- Copyright (c) 2001-2011 Joel de Guzman
- Copyright (c) 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(FUSION_DISTANCE_IMPL_20060124_2033)
- #define FUSION_DISTANCE_IMPL_20060124_2033
- #include <boost/fusion/support/config.hpp>
- #include <boost/mpl/eval_if.hpp>
- #include <boost/mpl/placeholders.hpp>
- #include <boost/mpl/assert.hpp>
- #include <boost/fusion/iterator/distance.hpp>
- #include <boost/fusion/support/category_of.hpp>
- #include <boost/fusion/algorithm/query/find_if.hpp>
- #include <boost/fusion/sequence/intrinsic/end.hpp>
- #include <boost/fusion/sequence/intrinsic/value_at.hpp>
- #include <boost/type_traits/is_same.hpp>
- namespace boost { namespace fusion {
- struct zip_view_iterator_tag;
- struct random_access_iterator_tag;
- namespace detail
- {
- template<typename FoundIt, typename SearchIt>
- struct best_distance
- {
- typedef typename result_of::find_if<
- typename SearchIt::iterators, is_same<traits::category_of<mpl::_>, random_access_iterator_tag> > finder;
- BOOST_MPL_ASSERT_NOT((is_same<typename finder::type, result_of::end<typename SearchIt::iterators> >));
- typedef typename result_of::distance<FoundIt, typename finder::type>::type type;
- };
- template<typename It1, typename It2>
- struct default_distance
- : result_of::distance<
- typename result_of::value_at_c<typename It1::iterators, 0>::type,
- typename result_of::value_at_c<typename It2::iterators, 0>::type>
- {};
- template<typename It1, typename It2>
- struct zip_view_iterator_distance
- {
- typedef typename result_of::find_if<
- typename It1::iterators, is_same<traits::category_of<mpl::_>, random_access_iterator_tag> > finder;
-
- typedef typename mpl::eval_if<
- is_same<typename finder::type, typename result_of::end<typename It1::iterators>::type>,
- detail::default_distance<It1, It2> ,
- detail::best_distance<typename finder::type, It2> >::type type;
- };
- }
- namespace extension
- {
- template<typename Tag>
- struct distance_impl;
- template<>
- struct distance_impl<zip_view_iterator_tag>
- {
- template<typename It1, typename It2>
- struct apply
- : detail::zip_view_iterator_distance<It1, It2>::type
- {
- BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
- static typename detail::zip_view_iterator_distance<It1, It2>::type
- call(It1 const& /*it1*/, It2 const& /*it2*/)
- {
- return typename detail::zip_view_iterator_distance<It1, It2>::type();
- }
- };
- };
- }
- }}
- #endif
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