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// Boost.Geometry (aka GGL, Generic Geometry Library)
// Copyright (c) 2007-2012 Barend Gehrels, Amsterdam, the Netherlands.
// Copyright (c) 2008-2012 Bruno Lalande, Paris, France.
// Copyright (c) 2009-2012 Mateusz Loskot, London, UK.
// Parts of Boost.Geometry are redesigned from Geodan's Geographic Library
// (geolib/GGL), copyright (c) 1995-2010 Geodan, Amsterdam, the Netherlands.
// Use, modification and distribution is subject to the Boost Software License,
// Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
#ifndef BOOST_GEOMETRY_ALGORITHMS_LENGTH_HPP
#define BOOST_GEOMETRY_ALGORITHMS_LENGTH_HPP
#include <iterator>
#include <boost/range.hpp>
#include <boost/mpl/if.hpp>
#include <boost/type_traits.hpp>
#include <boost/geometry/core/cs.hpp>
#include <boost/geometry/core/closure.hpp>
#include <boost/geometry/geometries/concepts/check.hpp>
#include <boost/geometry/algorithms/assign.hpp>
#include <boost/geometry/algorithms/detail/calculate_null.hpp>
// #include <boost/geometry/algorithms/detail/throw_on_empty_input.hpp>
#include <boost/geometry/views/closeable_view.hpp>
#include <boost/geometry/strategies/distance.hpp>
#include <boost/geometry/strategies/default_length_result.hpp>
namespace boost { namespace geometry
{
#ifndef DOXYGEN_NO_DETAIL
namespace detail { namespace length
{
template<typename Segment, typename Strategy>
struct segment_length
{
static inline typename default_length_result<Segment>::type apply(
Segment const& segment, Strategy const& strategy)
{
typedef typename point_type<Segment>::type point_type;
point_type p1, p2;
geometry::detail::assign_point_from_index<0>(segment, p1);
geometry::detail::assign_point_from_index<1>(segment, p2);
return strategy.apply(p1, p2);
}
};
/*!
\brief Internal, calculates length of a linestring using iterator pairs and
specified strategy
\note for_each could be used here, now that point_type is changed by boost
range iterator
*/
template<typename Range, typename Strategy, closure_selector Closure>
struct range_length
{
typedef typename default_length_result<Range>::type return_type;
static inline return_type apply(
Range const& range, Strategy const& strategy)
{
typedef typename closeable_view<Range const, Closure>::type view_type;
typedef typename boost::range_iterator
<
view_type const
>::type iterator_type;
return_type sum = return_type();
view_type view(range);
iterator_type it = boost::begin(view), end = boost::end(view);
if(it != end)
{
for(iterator_type previous = it++;
it != end;
++previous, ++it)
{
// Add point-point distance using the return type belonging
// to strategy
sum += strategy.apply(*previous, *it);
}
}
return sum;
}
};
}} // namespace detail::length
#endif // DOXYGEN_NO_DETAIL
#ifndef DOXYGEN_NO_DISPATCH
namespace dispatch
{
template <typename Tag, typename Geometry, typename Strategy>
struct length : detail::calculate_null
<
typename default_length_result<Geometry>::type,
Geometry,
Strategy
>
{};
template <typename Geometry, typename Strategy>
struct length<linestring_tag, Geometry, Strategy>
: detail::length::range_length<Geometry, Strategy, closed>
{};
// RING: length is currently 0; it might be argued that it is the "perimeter"
template <typename Geometry, typename Strategy>
struct length<segment_tag, Geometry, Strategy>
: detail::length::segment_length<Geometry, Strategy>
{};
} // namespace dispatch
#endif // DOXYGEN_NO_DISPATCH
/*!
\brief \brief_calc{length}
\ingroup length
\details \details_calc{length, length (the sum of distances between consecutive points)}. \details_default_strategy
\tparam Geometry \tparam_geometry
\param geometry \param_geometry
\return \return_calc{length}
\qbk{[include reference/algorithms/length.qbk]}
\qbk{[length] [length_output]}
*/
template<typename Geometry>
inline typename default_length_result<Geometry>::type length(
Geometry const& geometry)
{
concept::check<Geometry const>();
// detail::throw_on_empty_input(geometry);
typedef typename strategy::distance::services::default_strategy
<
point_tag, typename point_type<Geometry>::type
>::type strategy_type;
return dispatch::length
<
typename tag<Geometry>::type,
Geometry,
strategy_type
>::apply(geometry, strategy_type());
}
/*!
\brief \brief_calc{length} \brief_strategy
\ingroup length
\details \details_calc{length, length (the sum of distances between consecutive points)} \brief_strategy. \details_strategy_reasons
\tparam Geometry \tparam_geometry
\tparam Strategy \tparam_strategy{distance}
\param geometry \param_geometry
\param strategy \param_strategy{distance}
\return \return_calc{length}
\qbk{distinguish,with strategy}
\qbk{[include reference/algorithms/length.qbk]}
\qbk{[length_with_strategy] [length_with_strategy_output]}
*/
template<typename Geometry, typename Strategy>
inline typename default_length_result<Geometry>::type length(
Geometry const& geometry, Strategy const& strategy)
{
concept::check<Geometry const>();
// detail::throw_on_empty_input(geometry);
return dispatch::length
<
typename tag<Geometry>::type,
Geometry,
Strategy
>::apply(geometry, strategy);
}
}} // namespace boost::geometry
#endif // BOOST_GEOMETRY_ALGORITHMS_LENGTH_HPP
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