我尝试按照https://www.boost.org/doc/libs/1_75_0/libs/geometry/doc/html/geometry/examples/example__adapting_a_legacy_geometry_object_model.html给出的示例来处理以下不可变无指针变量。
#include <boost/geometry.hpp>
#include <boost/geometry/geometries/register/linestring.hpp>
#include <boost/geometry/geometries/register/point.hpp>
#include <boost/range.hpp>
#include <vector>
class Point
{
public:
Point( double x, double y ) : m_x( x ), m_y( y ) {}
double getX() const { return m_x; }
double getY() const { return m_y; }
private:
double m_x, m_y;
};
using TyPoints = std::vector< Point >;
class LineString
{
public:
LineString( TyPoints points ) : m_points( std::move( points ) ) {}
const TyPoints& getPoints() const { return m_points; }
private:
TyPoints m_points;
};
// Provide read only Boost.Range for LineString
namespace boost
{
template<>
struct range_const_iterator< LineString >
{
typedef std::vector< Point >::const_iterator type;
};
}
inline std::vector< Point >::const_iterator range_begin( const LineString& ls )
{
return ls.getPoints().cbegin();
}
inline std::vector< Point >::const_iterator
range_end( const LineString& ls )
{
return ls.getPoints().cend();
}
BOOST_GEOMETRY_REGISTER_POINT_2D_CONST( Point, double, cs::cartesian, getX(), getY() );
BOOST_GEOMETRY_REGISTER_LINESTRING( LineString );
int main( int argc, char* argv[] )
{
const LineString lineString( { { 0.0, 0.0 }, { 1.0, 0.0 }, { 1.0, 1.0 } } );
boost::geometry::length( lineString );
return 0;
}
然而，升压几何注册失败，我不知道如何解决这个问题。
In file included from /usr/include/boost/geometry/core/closure.hpp:24,
from /usr/include/boost/geometry/geometry.hpp:25,
from /usr/include/boost/geometry.hpp:17,
from main.cpp:1:
/usr/include/boost/range/value_type.hpp: In instantiation of ‘struct boost::range_value<LineString>’:
/usr/include/boost/geometry/core/point_type.hpp:82:59: required from ‘struct boost::geometry::core_dispatch::point_type<boost::geometry::linestring_tag, LineString>’
/usr/include/boost/geometry/core/coordinate_type.hpp:58:62: required from ‘struct boost::geometry::core_dispatch::coordinate_type<boost::geometry::linestring_tag, LineString>’
/usr/include/boost/geometry/core/coordinate_type.hpp:92:25: required from ‘struct boost::geometry::coordinate_type<LineString>’
/usr/include/boost/geometry/strategies/default_length_result.hpp:45:17: required from ‘struct boost::geometry::resolve_strategy::default_length_result<LineString>’
/usr/include/boost/geometry/strategies/default_length_result.hpp:55:8: required from ‘struct boost::geometry::resolve_variant::default_length_result<LineString>’
/usr/include/boost/geometry/strategies/default_length_result.hpp:82:8: required from ‘struct boost::geometry::default_length_result<LineString>’
/usr/include/boost/geometry/algorithms/length.hpp:280:1: required by substitution of ‘template<class Geometry> typename boost::geometry::default_length_result<Geometry>::type boost::geometry::length(const Geometry&) [with Geometry = LineString]’
main.cpp:62:40: required from here
/usr/include/boost/range/value_type.hpp:26:12: error: no type named ‘type’ in ‘struct boost::range_iterator<LineString, void>’
26 | struct range_value : iterator_value< typename range_iterator<T>::type >
| ^~~~~~~~~~~
In file included from /usr/include/boost/geometry/core/coordinate_dimension.hpp:23,
from /usr/include/boost/geometry/geometry.hpp:26,
from /usr/include/boost/geometry.hpp:17,
from main.cpp:1:
/usr/include/boost/geometry/core/point_type.hpp: In instantiation of ‘struct boost::geometry::core_dispatch::point_type<boost::geometry::linestring_tag, LineString>’:
/usr/include/boost/geometry/core/coordinate_type.hpp:58:62: required from ‘struct boost::geometry::core_dispatch::coordinate_type<boost::geometry::linestring_tag, LineString>’
/usr/include/boost/geometry/core/coordinate_type.hpp:92:25: required from ‘struct boost::geometry::coordinate_type<LineString>’
/usr/include/boost/geometry/strategies/default_length_result.hpp:45:17: required from ‘struct boost::geometry::resolve_strategy::default_length_result<LineString>’
/usr/include/boost/geometry/strategies/default_length_result.hpp:55:8: required from ‘struct boost::geometry::resolve_variant::default_length_result<LineString>’
/usr/include/boost/geometry/strategies/default_length_result.hpp:82:8: required from ‘struct boost::geometry::default_length_result<LineString>’
/usr/include/boost/geometry/algorithms/length.hpp:280:1: required by substitution of ‘template<class Geometry> typename boost::geometry::default_length_result<Geometry>::type boost::geometry::length(const Geometry&) [with Geometry = LineString]’
main.cpp:62:40: required from here
/usr/include/boost/geometry/core/point_type.hpp:82:59: error: no type named ‘type’ in ‘struct boost::range_value<LineString>’
82 | typedef typename boost::range_value<Linestring>::type type;
| ^~~~
main.cpp: In function ‘int main(int, char**)’:
main.cpp:62:40: error: no matching function for call to ‘length(const LineString&)’
62 | boost::geometry::length( lineString );
| ^
In file included from /usr/include/boost/geometry/algorithms/detail/equals/implementation.hpp:38,
from /usr/include/boost/geometry/algorithms/equals.hpp:26,
from /usr/include/boost/geometry/algorithms/detail/buffer/get_piece_turns.hpp:21,
from /usr/include/boost/geometry/algorithms/detail/buffer/buffered_piece_collection.hpp:40,
from /usr/include/boost/geometry/algorithms/detail/buffer/buffer_inserter.hpp:34,
from /usr/include/boost/geometry/algorithms/buffer.hpp:41,
from /usr/include/boost/geometry/geometry.hpp:54,
from /usr/include/boost/geometry.hpp:17,
from main.cpp:1:
/usr/include/boost/geometry/algorithms/length.hpp:280:1: note: candidate: ‘template<class Geometry> typename boost::geometry::default_length_result<Geometry>::type boost::geometry::length(const Geometry&)’
280 | length(Geometry const& geometry)
| ^~~~~~
/usr/include/boost/geometry/algorithms/length.hpp:280:1: note: substitution of deduced template arguments resulted in errors seen above
In file included from /usr/include/boost/geometry/algorithms/detail/equals/implementation.hpp:38,
from /usr/include/boost/geometry/algorithms/equals.hpp:26,
from /usr/include/boost/geometry/algorithms/detail/buffer/get_piece_turns.hpp:21,
from /usr/include/boost/geometry/algorithms/detail/buffer/buffered_piece_collection.hpp:40,
from /usr/include/boost/geometry/algorithms/detail/buffer/buffer_inserter.hpp:34,
from /usr/include/boost/geometry/algorithms/buffer.hpp:41,
from /usr/include/boost/geometry/geometry.hpp:54,
from /usr/include/boost/geometry.hpp:17,
from main.cpp:1:
/usr/include/boost/geometry/algorithms/length.hpp:306:1: note: candidate: ‘template<class Geometry, class Strategy> typename boost::geometry::default_length_result<Geometry>::type boost::geometry::length(const Geometry&, const Strategy&)’
306 | length(Geometry const& geometry, Strategy const& strategy)
| ^~~~~~
/usr/include/boost/geometry/algorithms/length.hpp:306:1: note: template argument deduction/substitution failed:
main.cpp:62:40: note: candidate expects 2 arguments, 1 provided
62 | boost::geometry::length( lineString );
| ^
编译器抱怨这个缺失:
/usr/include/boost/geometry/core/point_type.hpp:82:59:错误:在struct boost::range_value中没有名为type的类型82 | typedef typename boost::range_value::type type;
添加它将修复编译错误:
// Provide read only Boost.Range for LineString
namespace boost
{
template<>
struct range_const_iterator< LineString >
{
typedef std::vector< Point >::const_iterator type;
};
//adding the missing part
template<>
struct range_value< LineString >
{
typedef Point type;
};
}