forked from boostorg/fusion
79 lines
2.4 KiB
C++
79 lines
2.4 KiB
C++
/*=============================================================================
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Copyright (c) 2001-2006 Joel de Guzman
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Use, modification and distribution is subject to the Boost Software
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License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
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http://www.boost.org/LICENSE_1_0.txt)
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==============================================================================*/
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#if !defined(FUSION_DISTANCE_09172005_0721)
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#define FUSION_DISTANCE_09172005_0721
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#include <boost/fusion/iterator/detail/distance.hpp>
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#include <boost/fusion/support/category_of.hpp>
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#include <boost/mpl/int.hpp>
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#include <boost/mpl/assert.hpp>
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#include <boost/type_traits/is_same.hpp>
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#include <boost/fusion/support/tag_of.hpp>
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namespace boost { namespace fusion
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{
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struct random_access_traversal_tag;
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// Special tags:
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struct iterator_facade_tag; // iterator facade tag
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struct array_iterator_tag; // boost::array iterator tag
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struct mpl_iterator_tag; // mpl sequence iterator tag
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struct std_pair_iterator_tag; // std::pair iterator tag
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namespace extension
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{
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template <typename Tag>
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struct distance_impl
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{
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// default implementation
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template <typename First, typename Last>
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struct apply : distance_detail::linear_distance<First, Last>
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{
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BOOST_MPL_ASSERT_NOT((traits::is_random_access<First>));
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BOOST_MPL_ASSERT_NOT((traits::is_random_access<Last>));
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};
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};
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template <>
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struct distance_impl<iterator_facade_tag>
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{
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template <typename First, typename Last>
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struct apply : First::template distance<First, Last> {};
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};
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template <>
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struct distance_impl<array_iterator_tag>;
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template <>
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struct distance_impl<mpl_iterator_tag>;
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template <>
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struct distance_impl<std_pair_iterator_tag>;
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}
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namespace result_of
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{
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template <typename First, typename Last>
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struct distance
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: extension::distance_impl<typename detail::tag_of<First>::type>::
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template apply<First, Last>
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{};
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}
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template <typename First, typename Last>
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inline typename result_of::distance<First, Last>::type
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distance(First const& a, Last const& b)
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{
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return result_of::distance<First, Last>::call(a,b);
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}
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}}
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#endif
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