Chris@16: // Boost.Geometry (aka GGL, Generic Geometry Library)
Chris@16: 
Chris@16: // Copyright (c) 2007-2012 Barend Gehrels, Amsterdam, the Netherlands.
Chris@16: // Copyright (c) 2008-2012 Bruno Lalande, Paris, France.
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_ALGORITHMS_LENGTH_HPP
Chris@16: #define BOOST_GEOMETRY_ALGORITHMS_LENGTH_HPP
Chris@16: 
Chris@16: #include <iterator>
Chris@16: 
Chris@16: #include <boost/concept_check.hpp>
Chris@16: #include <boost/range.hpp>
Chris@16: 
Chris@16: #include <boost/mpl/fold.hpp>
Chris@16: #include <boost/mpl/greater.hpp>
Chris@16: #include <boost/mpl/if.hpp>
Chris@16: #include <boost/mpl/insert.hpp>
Chris@16: #include <boost/mpl/int.hpp>
Chris@16: #include <boost/mpl/set.hpp>
Chris@16: #include <boost/mpl/size.hpp>
Chris@16: #include <boost/mpl/transform.hpp>
Chris@16: #include <boost/type_traits.hpp>
Chris@16: 
Chris@16: #include <boost/geometry/core/cs.hpp>
Chris@16: #include <boost/geometry/core/closure.hpp>
Chris@16: 
Chris@16: #include <boost/geometry/geometries/concepts/check.hpp>
Chris@16: 
Chris@16: #include <boost/geometry/algorithms/assign.hpp>
Chris@16: #include <boost/geometry/algorithms/detail/calculate_null.hpp>
Chris@16: // #include <boost/geometry/algorithms/detail/throw_on_empty_input.hpp>
Chris@16: #include <boost/geometry/views/closeable_view.hpp>
Chris@16: #include <boost/geometry/strategies/distance.hpp>
Chris@16: #include <boost/geometry/strategies/default_length_result.hpp>
Chris@16: 
Chris@16: #include <boost/variant/apply_visitor.hpp>
Chris@16: #include <boost/variant/static_visitor.hpp>
Chris@16: #include <boost/variant/variant_fwd.hpp>
Chris@16: 
Chris@16: 
Chris@16: namespace boost { namespace geometry
Chris@16: {
Chris@16: 
Chris@16: 
Chris@16: #ifndef DOXYGEN_NO_DETAIL
Chris@16: namespace detail { namespace length
Chris@16: {
Chris@16: 
Chris@16: 
Chris@16: template<typename Segment>
Chris@16: struct segment_length
Chris@16: {
Chris@16:     template <typename Strategy>
Chris@16:     static inline typename default_length_result<Segment>::type apply(
Chris@16:             Segment const& segment, Strategy const& strategy)
Chris@16:     {
Chris@16:         typedef typename point_type<Segment>::type point_type;
Chris@16:         point_type p1, p2;
Chris@16:         geometry::detail::assign_point_from_index<0>(segment, p1);
Chris@16:         geometry::detail::assign_point_from_index<1>(segment, p2);
Chris@16:         return strategy.apply(p1, p2);
Chris@16:     }
Chris@16: };
Chris@16: 
Chris@16: /*!
Chris@16: \brief Internal, calculates length of a linestring using iterator pairs and
Chris@16:     specified strategy
Chris@16: \note for_each could be used here, now that point_type is changed by boost
Chris@16:     range iterator
Chris@16: */
Chris@16: template<typename Range, closure_selector Closure>
Chris@16: struct range_length
Chris@16: {
Chris@16:     typedef typename default_length_result<Range>::type return_type;
Chris@16: 
Chris@16:     template <typename Strategy>
Chris@16:     static inline return_type apply(
Chris@16:             Range const& range, Strategy const& strategy)
Chris@16:     {
Chris@16:         boost::ignore_unused_variable_warning(strategy);
Chris@16:         typedef typename closeable_view<Range const, Closure>::type view_type;
Chris@16:         typedef typename boost::range_iterator
Chris@16:             <
Chris@16:                 view_type const
Chris@16:             >::type iterator_type;
Chris@16: 
Chris@16:         return_type sum = return_type();
Chris@16:         view_type view(range);
Chris@16:         iterator_type it = boost::begin(view), end = boost::end(view);
Chris@16:         if(it != end)
Chris@16:         {
Chris@16:             for(iterator_type previous = it++;
Chris@16:                     it != end;
Chris@16:                     ++previous, ++it)
Chris@16:             {
Chris@16:                 // Add point-point distance using the return type belonging
Chris@16:                 // to strategy
Chris@16:                 sum += strategy.apply(*previous, *it);
Chris@16:             }
Chris@16:         }
Chris@16: 
Chris@16:         return sum;
Chris@16:     }
Chris@16: };
Chris@16: 
Chris@16: 
Chris@16: }} // namespace detail::length
Chris@16: #endif // DOXYGEN_NO_DETAIL
Chris@16: 
Chris@16: 
Chris@16: #ifndef DOXYGEN_NO_DISPATCH
Chris@16: namespace dispatch
Chris@16: {
Chris@16: 
Chris@16: 
Chris@16: template <typename Geometry, typename Tag = typename tag<Geometry>::type>
Chris@16: struct length : detail::calculate_null
Chris@16: {
Chris@16:     typedef typename default_length_result<Geometry>::type return_type;
Chris@16: 
Chris@16:     template <typename Strategy>
Chris@16:     static inline return_type apply(Geometry const& geometry, Strategy const& strategy)
Chris@16:     {
Chris@16:         return calculate_null::apply<return_type>(geometry, strategy);
Chris@16:     }
Chris@16: };
Chris@16: 
Chris@16: 
Chris@16: template <typename Geometry>
Chris@16: struct length<Geometry, linestring_tag>
Chris@16:     : detail::length::range_length<Geometry, closed>
Chris@16: {};
Chris@16: 
Chris@16: 
Chris@16: // RING: length is currently 0; it might be argued that it is the "perimeter"
Chris@16: 
Chris@16: 
Chris@16: template <typename Geometry>
Chris@16: struct length<Geometry, segment_tag>
Chris@16:     : detail::length::segment_length<Geometry>
Chris@16: {};
Chris@16: 
Chris@16: 
Chris@16: template <typename Geometry>
Chris@16: struct devarianted_length
Chris@16: {
Chris@16:     typedef typename default_length_result<Geometry>::type result_type;
Chris@16: 
Chris@16:     template <typename Strategy>
Chris@16:     static inline result_type apply(Geometry const& geometry,
Chris@16:                                     Strategy const& strategy)
Chris@16:     {
Chris@16:         return length<Geometry>::apply(geometry, strategy);
Chris@16:     }
Chris@16: };
Chris@16: 
Chris@16: template <BOOST_VARIANT_ENUM_PARAMS(typename T)>
Chris@16: struct devarianted_length<variant<BOOST_VARIANT_ENUM_PARAMS(T)> >
Chris@16: {
Chris@16:     typedef typename mpl::fold<
Chris@16:                 typename mpl::transform<
Chris@16:                     typename variant<BOOST_VARIANT_ENUM_PARAMS(T)>::types,
Chris@16:                     default_length_result<mpl::_>
Chris@16:                 >::type,
Chris@16:                 mpl::set0<>,
Chris@16:                 mpl::insert<mpl::_1, mpl::_2>
Chris@16:             >::type possible_result_types;
Chris@16: 
Chris@16:     typedef typename mpl::if_<
Chris@16:                 mpl::greater<
Chris@16:                     mpl::size<possible_result_types>,
Chris@16:                     mpl::int_<1>
Chris@16:                 >,
Chris@16:                 typename make_variant_over<possible_result_types>::type,
Chris@16:                 typename mpl::front<possible_result_types>::type
Chris@16:             >::type result_type;
Chris@16: 
Chris@16:     template <typename Strategy>
Chris@16:     struct visitor
Chris@16:         : static_visitor<result_type>
Chris@16:     {
Chris@16:         Strategy const& m_strategy;
Chris@16: 
Chris@16:         visitor(Strategy const& strategy)
Chris@16:             : m_strategy(strategy)
Chris@16:         {}
Chris@16: 
Chris@16:         template <typename Geometry>
Chris@16:         inline typename devarianted_length<Geometry>::result_type
Chris@16:         operator()(Geometry const& geometry) const
Chris@16:         {
Chris@16:             return devarianted_length<Geometry>::apply(geometry, m_strategy);
Chris@16:         }
Chris@16:     };
Chris@16: 
Chris@16:     template <typename Strategy>
Chris@16:     static inline result_type apply(
Chris@16:         variant<BOOST_VARIANT_ENUM_PARAMS(T)> const& geometry,
Chris@16:         Strategy const& strategy
Chris@16:     )
Chris@16:     {
Chris@16:         return apply_visitor(visitor<Strategy>(strategy), geometry);
Chris@16:     }
Chris@16: };
Chris@16: 
Chris@16: 
Chris@16: } // namespace dispatch
Chris@16: #endif // DOXYGEN_NO_DISPATCH
Chris@16: 
Chris@16: 
Chris@16: /*!
Chris@16: \brief \brief_calc{length}
Chris@16: \ingroup length
Chris@16: \details \details_calc{length, length (the sum of distances between consecutive points)}. \details_default_strategy
Chris@16: \tparam Geometry \tparam_geometry
Chris@16: \param geometry \param_geometry
Chris@16: \return \return_calc{length}
Chris@16: 
Chris@16: \qbk{[include reference/algorithms/length.qbk]}
Chris@16: \qbk{[length] [length_output]}
Chris@16:  */
Chris@16: template<typename Geometry>
Chris@16: inline typename dispatch::devarianted_length<Geometry>::result_type
Chris@16: length(Geometry const& geometry)
Chris@16: {
Chris@16:     concept::check<Geometry const>();
Chris@16: 
Chris@16:     // detail::throw_on_empty_input(geometry);
Chris@16: 
Chris@16:     typedef typename strategy::distance::services::default_strategy
Chris@16:         <
Chris@16:             point_tag, typename point_type<Geometry>::type
Chris@16:         >::type strategy_type;
Chris@16: 
Chris@16:     return dispatch::devarianted_length<Geometry>::apply(geometry, strategy_type());
Chris@16: }
Chris@16: 
Chris@16: 
Chris@16: /*!
Chris@16: \brief \brief_calc{length} \brief_strategy
Chris@16: \ingroup length
Chris@16: \details \details_calc{length, length (the sum of distances between consecutive points)} \brief_strategy. \details_strategy_reasons
Chris@16: \tparam Geometry \tparam_geometry
Chris@16: \tparam Strategy \tparam_strategy{distance}
Chris@16: \param geometry \param_geometry
Chris@16: \param strategy \param_strategy{distance}
Chris@16: \return \return_calc{length}
Chris@16: 
Chris@16: \qbk{distinguish,with strategy}
Chris@16: \qbk{[include reference/algorithms/length.qbk]}
Chris@16: \qbk{[length_with_strategy] [length_with_strategy_output]}
Chris@16:  */
Chris@16: template<typename Geometry, typename Strategy>
Chris@16: inline typename dispatch::devarianted_length<Geometry>::result_type
Chris@16: length(Geometry const& geometry, Strategy const& strategy)
Chris@16: {
Chris@16:     concept::check<Geometry const>();
Chris@16: 
Chris@16:     // detail::throw_on_empty_input(geometry);
Chris@16:     
Chris@16:     return dispatch::devarianted_length<Geometry>::apply(geometry, strategy);
Chris@16: }
Chris@16: 
Chris@16: 
Chris@16: }} // namespace boost::geometry
Chris@16: 
Chris@16: #endif // BOOST_GEOMETRY_ALGORITHMS_LENGTH_HPP