Chris@16: // Boost.Geometry (aka GGL, Generic Geometry Library)
Chris@16: 
Chris@16: // Copyright (c) 2008-2012 Bruno Lalande, Paris, France.
Chris@16: // Copyright (c) 2008-2012 Barend Gehrels, Amsterdam, the Netherlands.
Chris@16: // Copyright (c) 2009-2012 Mateusz Loskot, London, UK.
Chris@16: 
Chris@16: // Parts of Boost.Geometry are redesigned from Geodan's Geographic Library
Chris@16: // (geolib/GGL), copyright (c) 1995-2010 Geodan, Amsterdam, the Netherlands.
Chris@16: 
Chris@16: // Use, modification and distribution is subject to the Boost Software License,
Chris@16: // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
Chris@16: // http://www.boost.org/LICENSE_1_0.txt)
Chris@16: 
Chris@16: #ifndef BOOST_GEOMETRY_STRATEGIES_CARTESIAN_DISTANCE_PYTHAGORAS_HPP
Chris@16: #define BOOST_GEOMETRY_STRATEGIES_CARTESIAN_DISTANCE_PYTHAGORAS_HPP
Chris@16: 
Chris@16: 
Chris@16: #include <boost/mpl/if.hpp>
Chris@16: #include <boost/type_traits.hpp>
Chris@16: 
Chris@16: #include <boost/geometry/core/access.hpp>
Chris@16: 
Chris@16: #include <boost/geometry/strategies/distance.hpp>
Chris@16: 
Chris@101: #include <boost/geometry/util/math.hpp>
Chris@16: #include <boost/geometry/util/calculation_type.hpp>
Chris@16: 
Chris@16: 
Chris@16: 
Chris@16: 
Chris@16: namespace boost { namespace geometry
Chris@16: {
Chris@16: 
Chris@16: namespace strategy { namespace distance
Chris@16: {
Chris@16: 
Chris@16: #ifndef DOXYGEN_NO_DETAIL
Chris@16: namespace detail
Chris@16: {
Chris@16: 
Chris@16: template <size_t I, typename T>
Chris@16: struct compute_pythagoras
Chris@16: {
Chris@16:     template <typename Point1, typename Point2>
Chris@16:     static inline T apply(Point1 const& p1, Point2 const& p2)
Chris@16:     {
Chris@16:         T const c1 = boost::numeric_cast<T>(get<I-1>(p1));
Chris@16:         T const c2 = boost::numeric_cast<T>(get<I-1>(p2));
Chris@16:         T const d = c1 - c2;
Chris@16:         return d * d + compute_pythagoras<I-1, T>::apply(p1, p2);
Chris@16:     }
Chris@16: };
Chris@16: 
Chris@16: template <typename T>
Chris@16: struct compute_pythagoras<0, T>
Chris@16: {
Chris@16:     template <typename Point1, typename Point2>
Chris@16:     static inline T apply(Point1 const&, Point2 const&)
Chris@16:     {
Chris@16:         return boost::numeric_cast<T>(0);
Chris@16:     }
Chris@16: };
Chris@16: 
Chris@16: }
Chris@16: #endif // DOXYGEN_NO_DETAIL
Chris@16: 
Chris@16: 
Chris@16: namespace comparable
Chris@16: {
Chris@16: 
Chris@16: /*!
Chris@16: \brief Strategy to calculate comparable distance between two points
Chris@16: \ingroup strategies
Chris@16: \tparam Point1 \tparam_first_point
Chris@16: \tparam Point2 \tparam_second_point
Chris@16: \tparam CalculationType \tparam_calculation
Chris@16: */
Chris@16: template <typename CalculationType = void>
Chris@16: class pythagoras
Chris@16: {
Chris@16: public :
Chris@16: 
Chris@16:     template <typename Point1, typename Point2>
Chris@16:     struct calculation_type
Chris@16:         : util::calculation_type::geometric::binary
Chris@16:           <
Chris@16:               Point1,
Chris@16:               Point2,
Chris@101:               CalculationType,
Chris@101:               double,
Chris@101:               double
Chris@16:           >
Chris@16:     {};
Chris@16: 
Chris@16:     template <typename Point1, typename Point2>
Chris@16:     static inline typename calculation_type<Point1, Point2>::type
Chris@16:     apply(Point1 const& p1, Point2 const& p2)
Chris@16:     {
Chris@16:         BOOST_CONCEPT_ASSERT( (concept::ConstPoint<Point1>) );
Chris@16:         BOOST_CONCEPT_ASSERT( (concept::ConstPoint<Point2>) );
Chris@16: 
Chris@16:         // Calculate distance using Pythagoras
Chris@16:         // (Leave comment above for Doxygen)
Chris@16: 
Chris@16:         assert_dimension_equal<Point1, Point2>();
Chris@16: 
Chris@16:         return detail::compute_pythagoras
Chris@16:             <
Chris@16:                 dimension<Point1>::value,
Chris@16:                 typename calculation_type<Point1, Point2>::type
Chris@16:             >::apply(p1, p2);
Chris@16:     }
Chris@16: };
Chris@16: 
Chris@16: } // namespace comparable
Chris@16: 
Chris@16: 
Chris@16: /*!
Chris@16: \brief Strategy to calculate the distance between two points
Chris@16: \ingroup strategies
Chris@16: \tparam CalculationType \tparam_calculation
Chris@16: 
Chris@16: \qbk{
Chris@16: [heading Notes]
Chris@16: [note Can be used for points with two\, three or more dimensions]
Chris@16: [heading See also]
Chris@16: [link geometry.reference.algorithms.distance.distance_3_with_strategy distance (with strategy)]
Chris@16: }
Chris@16: 
Chris@16: */
Chris@16: template
Chris@16: <
Chris@16:     typename CalculationType = void
Chris@16: >
Chris@16: class pythagoras
Chris@16: {
Chris@16: public :
Chris@16: 
Chris@16:     template <typename P1, typename P2>
Chris@16:     struct calculation_type
Chris@16:         : util::calculation_type::geometric::binary
Chris@16:           <
Chris@16:               P1,
Chris@16:               P2,
Chris@16:               CalculationType,
Chris@16:               double,
Chris@16:               double // promote integer to double
Chris@16:           >
Chris@16:     {};
Chris@16: 
Chris@16:     /*!
Chris@16:     \brief applies the distance calculation using pythagoras
Chris@16:     \return the calculated distance (including taking the square root)
Chris@16:     \param p1 first point
Chris@16:     \param p2 second point
Chris@16:     */
Chris@16:     template <typename P1, typename P2>
Chris@16:     static inline typename calculation_type<P1, P2>::type
Chris@16:     apply(P1 const& p1, P2 const& p2)
Chris@16:     {
Chris@16:         // The cast is necessary for MSVC which considers sqrt __int64 as an ambiguous call
Chris@101:         return math::sqrt
Chris@16:             (
Chris@16:                  boost::numeric_cast<typename calculation_type<P1, P2>::type>
Chris@16:                     (
Chris@16:                         comparable::pythagoras<CalculationType>::apply(p1, p2)
Chris@16:                     )
Chris@16:             );
Chris@16:     }
Chris@16: };
Chris@16: 
Chris@16: 
Chris@16: #ifndef DOXYGEN_NO_STRATEGY_SPECIALIZATIONS
Chris@16: namespace services
Chris@16: {
Chris@16: 
Chris@16: template <typename CalculationType>
Chris@16: struct tag<pythagoras<CalculationType> >
Chris@16: {
Chris@16:     typedef strategy_tag_distance_point_point type;
Chris@16: };
Chris@16: 
Chris@16: 
Chris@16: template <typename CalculationType, typename P1, typename P2>
Chris@16: struct return_type<distance::pythagoras<CalculationType>, P1, P2>
Chris@16:     : pythagoras<CalculationType>::template calculation_type<P1, P2>
Chris@16: {};
Chris@16: 
Chris@16: 
Chris@16: template <typename CalculationType>
Chris@16: struct comparable_type<pythagoras<CalculationType> >
Chris@16: {
Chris@16:     typedef comparable::pythagoras<CalculationType> type;
Chris@16: };
Chris@16: 
Chris@16: 
Chris@16: template <typename CalculationType>
Chris@16: struct get_comparable<pythagoras<CalculationType> >
Chris@16: {
Chris@16:     typedef comparable::pythagoras<CalculationType> comparable_type;
Chris@16: public :
Chris@16:     static inline comparable_type apply(pythagoras<CalculationType> const& )
Chris@16:     {
Chris@16:         return comparable_type();
Chris@16:     }
Chris@16: };
Chris@16: 
Chris@16: 
Chris@16: template <typename CalculationType, typename Point1, typename Point2>
Chris@16: struct result_from_distance<pythagoras<CalculationType>, Point1, Point2>
Chris@16: {
Chris@16: private :
Chris@16:     typedef typename return_type<pythagoras<CalculationType>, Point1, Point2>::type return_type;
Chris@16: public :
Chris@16:     template <typename T>
Chris@16:     static inline return_type apply(pythagoras<CalculationType> const& , T const& value)
Chris@16:     {
Chris@16:         return return_type(value);
Chris@16:     }
Chris@16: };
Chris@16: 
Chris@16: 
Chris@16: // Specializations for comparable::pythagoras
Chris@16: template <typename CalculationType>
Chris@16: struct tag<comparable::pythagoras<CalculationType> >
Chris@16: {
Chris@16:     typedef strategy_tag_distance_point_point type;
Chris@16: };
Chris@16: 
Chris@16: 
Chris@16: template <typename CalculationType, typename P1, typename P2>
Chris@16: struct return_type<comparable::pythagoras<CalculationType>, P1, P2>
Chris@16:     : comparable::pythagoras<CalculationType>::template calculation_type<P1, P2>
Chris@16: {};
Chris@16: 
Chris@16: 
Chris@16: 
Chris@16: 
Chris@16: template <typename CalculationType>
Chris@16: struct comparable_type<comparable::pythagoras<CalculationType> >
Chris@16: {
Chris@16:     typedef comparable::pythagoras<CalculationType> type;
Chris@16: };
Chris@16: 
Chris@16: 
Chris@16: template <typename CalculationType>
Chris@16: struct get_comparable<comparable::pythagoras<CalculationType> >
Chris@16: {
Chris@16:     typedef comparable::pythagoras<CalculationType> comparable_type;
Chris@16: public :
Chris@16:     static inline comparable_type apply(comparable::pythagoras<CalculationType> const& )
Chris@16:     {
Chris@16:         return comparable_type();
Chris@16:     }
Chris@16: };
Chris@16: 
Chris@16: 
Chris@16: template <typename CalculationType, typename Point1, typename Point2>
Chris@16: struct result_from_distance<comparable::pythagoras<CalculationType>, Point1, Point2>
Chris@16: {
Chris@16: private :
Chris@16:     typedef typename return_type<comparable::pythagoras<CalculationType>, Point1, Point2>::type return_type;
Chris@16: public :
Chris@16:     template <typename T>
Chris@16:     static inline return_type apply(comparable::pythagoras<CalculationType> const& , T const& value)
Chris@16:     {
Chris@16:         return_type const v = value;
Chris@16:         return v * v;
Chris@16:     }
Chris@16: };
Chris@16: 
Chris@16: 
Chris@16: template <typename Point1, typename Point2>
Chris@101: struct default_strategy
Chris@101:     <
Chris@101:         point_tag, point_tag, Point1, Point2, cartesian_tag, cartesian_tag
Chris@101:     >
Chris@16: {
Chris@16:     typedef pythagoras<> type;
Chris@16: };
Chris@16: 
Chris@16: 
Chris@16: } // namespace services
Chris@16: #endif // DOXYGEN_NO_STRATEGY_SPECIALIZATIONS
Chris@16: 
Chris@16: 
Chris@16: }} // namespace strategy::distance
Chris@16: 
Chris@16: 
Chris@16: }} // namespace boost::geometry
Chris@16: 
Chris@16: 
Chris@16: #endif // BOOST_GEOMETRY_STRATEGIES_CARTESIAN_DISTANCE_PYTHAGORAS_HPP