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Diffstat (limited to 'boost/geometry/algorithms/detail/closest_feature/point_to_range.hpp')
| -rw-r--r-- | boost/geometry/algorithms/detail/closest_feature/point_to_range.hpp | 250 |
1 files changed, 250 insertions, 0 deletions
diff --git a/boost/geometry/algorithms/detail/closest_feature/point_to_range.hpp b/boost/geometry/algorithms/detail/closest_feature/point_to_range.hpp new file mode 100644 index 0000000000..91be6b0ad0 --- /dev/null +++ b/boost/geometry/algorithms/detail/closest_feature/point_to_range.hpp @@ -0,0 +1,250 @@ +// 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_POINT_TO_RANGE_HPP +#define BOOST_GEOMETRY_ALGORITHMS_DETAIL_CLOSEST_FEATURE_POINT_TO_RANGE_HPP + +#include <utility> + +#include <boost/assert.hpp> +#include <boost/range.hpp> + +#include <boost/geometry/core/closure.hpp> +#include <boost/geometry/strategies/distance.hpp> +#include <boost/geometry/util/math.hpp> + + +namespace boost { namespace geometry +{ + +#ifndef DOXYGEN_NO_DETAIL +namespace detail { namespace closest_feature +{ + + +// returns the segment (pair of iterators) that realizes the closest +// distance of the point to the range +template +< + typename Point, + typename Range, + closure_selector Closure, + typename Strategy +> +class point_to_point_range +{ +protected: + typedef typename boost::range_iterator<Range const>::type iterator_type; + + template <typename Distance> + static inline void apply(Point const& point, + iterator_type first, + iterator_type last, + Strategy const& strategy, + iterator_type& it_min1, + iterator_type& it_min2, + Distance& dist_min) + { + BOOST_ASSERT( first != last ); + + Distance const zero = Distance(0); + + iterator_type it = first; + iterator_type prev = it++; + if (it == last) + { + it_min1 = it_min2 = first; + dist_min = strategy.apply(point, *first, *first); + return; + } + + // start with first segment distance + dist_min = strategy.apply(point, *prev, *it); + iterator_type prev_min_dist = prev; + + // check if other segments are closer + for (++prev, ++it; it != last; ++prev, ++it) + { + Distance dist = strategy.apply(point, *prev, *it); + if (geometry::math::equals(dist, zero)) + { + dist_min = zero; + it_min1 = prev; + it_min2 = it; + return; + } + else if (dist < dist_min) + { + dist_min = dist; + prev_min_dist = prev; + } + } + + it_min1 = it_min2 = prev_min_dist; + ++it_min2; + } + +public: + typedef typename std::pair<iterator_type, iterator_type> return_type; + + template <typename Distance> + static inline return_type apply(Point const& point, + iterator_type first, + iterator_type last, + Strategy const& strategy, + Distance& dist_min) + { + iterator_type it_min1, it_min2; + apply(point, first, last, strategy, it_min1, it_min2, dist_min); + + return std::make_pair(it_min1, it_min2); + } + + static inline return_type apply(Point const& point, + iterator_type first, + iterator_type last, + Strategy const& strategy) + { + typename strategy::distance::services::return_type + < + Strategy, + Point, + typename boost::range_value<Range>::type + >::type dist_min; + + return apply(point, first, last, strategy, dist_min); + } + + template <typename Distance> + static inline return_type apply(Point const& point, + Range const& range, + Strategy const& strategy, + Distance& dist_min) + { + return apply(point, + boost::begin(range), + boost::end(range), + strategy, + dist_min); + } + + static inline return_type apply(Point const& point, + Range const& range, + Strategy const& strategy) + { + return apply(point, boost::begin(range), boost::end(range), strategy); + } +}; + + + +// specialization for open ranges +template <typename Point, typename Range, typename Strategy> +class point_to_point_range<Point, Range, open, Strategy> + : point_to_point_range<Point, Range, closed, Strategy> +{ +private: + typedef point_to_point_range<Point, Range, closed, Strategy> base_type; + typedef typename base_type::iterator_type iterator_type; + + template <typename Distance> + static inline void apply(Point const& point, + iterator_type first, + iterator_type last, + Strategy const& strategy, + iterator_type& it_min1, + iterator_type& it_min2, + Distance& dist_min) + { + BOOST_ASSERT( first != last ); + + base_type::apply(point, first, last, strategy, + it_min1, it_min2, dist_min); + + iterator_type it_back = --last; + Distance const zero = Distance(0); + Distance dist = strategy.apply(point, *it_back, *first); + + if (geometry::math::equals(dist, zero)) + { + dist_min = zero; + it_min1 = it_back; + it_min2 = first; + } + else if (dist < dist_min) + { + dist_min = dist; + it_min1 = it_back; + it_min2 = first; + } + } + +public: + typedef typename std::pair<iterator_type, iterator_type> return_type; + + template <typename Distance> + static inline return_type apply(Point const& point, + iterator_type first, + iterator_type last, + Strategy const& strategy, + Distance& dist_min) + { + iterator_type it_min1, it_min2; + + apply(point, first, last, strategy, it_min1, it_min2, dist_min); + + return std::make_pair(it_min1, it_min2); + } + + static inline return_type apply(Point const& point, + iterator_type first, + iterator_type last, + Strategy const& strategy) + { + typedef typename strategy::distance::services::return_type + < + Strategy, + Point, + typename boost::range_value<Range>::type + >::type distance_return_type; + + distance_return_type dist_min; + + return apply(point, first, last, strategy, dist_min); + } + + template <typename Distance> + static inline return_type apply(Point const& point, + Range const& range, + Strategy const& strategy, + Distance& dist_min) + { + return apply(point, + boost::begin(range), + boost::end(range), + strategy, + dist_min); + } + + static inline return_type apply(Point const& point, + Range const& range, + Strategy const& strategy) + { + return apply(point, boost::begin(range), boost::end(range), strategy); + } +}; + + +}} // namespace detail::closest_feature +#endif // DOXYGEN_NO_DETAIL + +}} // namespace boost::geometry + + +#endif // BOOST_GEOMETRY_ALGORITHMS_DETAIL_CLOSEST_FEATURE_POINT_TO_RANGE_HPP |