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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/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_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
RangeIterator it = first;
for (++it; 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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