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- // Boost.Geometry (aka GGL, Generic Geometry Library)
- // Copyright (c) 2014, Oracle and/or its affiliates.
- // Contributed and/or modified by Menelaos Karavelas, on behalf of Oracle
- // Licensed under the Boost Software License version 1.0.
- // http://www.boost.org/users/license.html
- #ifndef BOOST_GEOMETRY_ALGORITHMS_DETAIL_CLOSEST_FEATURE_GEOMETRY_TO_RANGE_HPP
- #define BOOST_GEOMETRY_ALGORITHMS_DETAIL_CLOSEST_FEATURE_GEOMETRY_TO_RANGE_HPP
- #include <iterator>
- #include <boost/geometry/core/assert.hpp>
- #include <boost/geometry/core/point_type.hpp>
- #include <boost/geometry/strategies/distance.hpp>
- #include <boost/geometry/util/math.hpp>
- #include <boost/geometry/algorithms/dispatch/distance.hpp>
- namespace boost { namespace geometry
- {
- #ifndef DOXYGEN_NO_DETAIL
- namespace detail { namespace closest_feature
- {
- // returns the range iterator the realizes the closest
- // distance between the geometry and the element of the range
- class geometry_to_range
- {
- private:
- template
- <
- typename Geometry,
- typename RangeIterator,
- typename Strategy,
- typename Distance
- >
- static inline void apply(Geometry const& geometry,
- RangeIterator first,
- RangeIterator last,
- Strategy const& strategy,
- RangeIterator& it_min,
- Distance& dist_min)
- {
- BOOST_GEOMETRY_ASSERT( first != last );
- Distance const zero = Distance(0);
- // start with first distance
- it_min = first;
- dist_min = dispatch::distance
- <
- Geometry,
- typename std::iterator_traits<RangeIterator>::value_type,
- Strategy
- >::apply(geometry, *it_min, strategy);
- // check if other elements in the range are closer
- for (RangeIterator it = ++first; it != last; ++it)
- {
- Distance dist = dispatch::distance
- <
- Geometry,
- typename std::iterator_traits<RangeIterator>::value_type,
- Strategy
- >::apply(geometry, *it, strategy);
- if (geometry::math::equals(dist, zero))
- {
- dist_min = dist;
- it_min = it;
- return;
- }
- else if (dist < dist_min)
- {
- dist_min = dist;
- it_min = it;
- }
- }
- }
- public:
- template
- <
- typename Geometry,
- typename RangeIterator,
- typename Strategy,
- typename Distance
- >
- static inline RangeIterator apply(Geometry const& geometry,
- RangeIterator first,
- RangeIterator last,
- Strategy const& strategy,
- Distance& dist_min)
- {
- RangeIterator it_min;
- apply(geometry, first, last, strategy, it_min, dist_min);
- return it_min;
- }
- template
- <
- typename Geometry,
- typename RangeIterator,
- typename Strategy
- >
- static inline RangeIterator apply(Geometry const& geometry,
- RangeIterator first,
- RangeIterator last,
- Strategy const& strategy)
- {
- typename strategy::distance::services::return_type
- <
- Strategy,
- typename point_type<Geometry>::type,
- typename point_type
- <
- typename std::iterator_traits
- <
- RangeIterator
- >::value_type
- >::type
- >::type dist_min;
- return apply(geometry, first, last, strategy, dist_min);
- }
- };
- }} // namespace detail::closest_feature
- #endif // DOXYGEN_NO_DETAIL
- }} // namespace boost::geometry
- #endif // BOOST_GEOMETRY_ALGORITHMS_DETAIL_CLOSEST_FEATURE_GEOMETRY_TO_RANGE_HPP
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