79 lines
2.0 KiB
C++
79 lines
2.0 KiB
C++
// Boost.Geometry
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// Copyright (c) 2017 Adam Wulkiewicz, Lodz, Poland.
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// Use, modification and distribution is subject to the Boost Software License,
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// 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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#ifndef BOOST_GEOMETRY_UTIL_SELECT_SEQUENCE_ELEMENT
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#define BOOST_GEOMETRY_UTIL_SELECT_SEQUENCE_ELEMENT
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#include <boost/mpl/if.hpp>
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#include <boost/mpl/int.hpp>
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#include <boost/mpl/at.hpp>
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#include <boost/mpl/size.hpp>
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#include <boost/type_traits/is_same.hpp>
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#include <boost/geometry/core/coordinate_type.hpp>
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#include <boost/geometry/util/select_most_precise.hpp>
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namespace boost { namespace geometry
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{
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namespace util
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{
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template <typename Curr, typename Next>
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struct pred_more_precise_coordinate_type
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{
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typedef typename geometry::coordinate_type<Curr>::type curr_coord_t;
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typedef typename geometry::coordinate_type<Next>::type next_coord_t;
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typedef typename boost::mpl::if_c
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<
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boost::is_same
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<
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curr_coord_t,
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typename select_most_precise
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<
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curr_coord_t,
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next_coord_t
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>::type
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>::value,
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Curr,
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Next
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>::type type;
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};
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template
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<
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typename Seq,
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template<typename, typename> class Pred = pred_more_precise_coordinate_type,
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int I = 0,
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int N = boost::mpl::size<Seq>::value
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>
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struct select_sequence_element
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{
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typedef typename boost::mpl::at<Seq, boost::mpl::int_<I> >::type curr_t;
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typedef typename select_sequence_element<Seq, Pred, I+1, N>::type next_t;
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typedef typename Pred<curr_t, next_t>::type type;
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};
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template <typename Seq, template<typename, typename> class Pred, int N>
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struct select_sequence_element<Seq, Pred, N, N>
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{
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typedef typename boost::mpl::at<Seq, boost::mpl::int_<N-1> >::type type;
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};
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} // namespace util
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}} // namespace boost::geometry
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#endif // BOOST_GEOMETRY_UTIL_SELECT_SEQUENCE_ELEMENT
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