geometry/strategies/default_length_result.hpp

0001 // Boost.Geometry (aka GGL, Generic Geometry Library)
0002
0003 // Copyright (c) 2007-2014 Barend Gehrels, Amsterdam, the Netherlands.
0004 // Copyright (c) 2008-2014 Bruno Lalande, Paris, France.
0005 // Copyright (c) 2009-2014 Mateusz Loskot, London, UK.
0006
0007 // This file was modified by Oracle on 2014-2021.
0008 // Modifications copyright (c) 2014-2021, Oracle and/or its affiliates.
0009 // Contributed and/or modified by Menelaos Karavelas, on behalf of Oracle
0010 // Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle
0011
0012 // Parts of Boost.Geometry are redesigned from Geodan's Geographic Library
0013 // (geolib/GGL), copyright (c) 1995-2010 Geodan, Amsterdam, the Netherlands.
0014
0015 // Use, modification and distribution is subject to the Boost Software License,
0016 // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
0017 // http://www.boost.org/LICENSE_1_0.txt)
0018
0019 #ifndef BOOST_GEOMETRY_STRATEGIES_DEFAULT_LENGTH_RESULT_HPP
0020 #define BOOST_GEOMETRY_STRATEGIES_DEFAULT_LENGTH_RESULT_HPP
0021
0022
0023 #include <boost/geometry/algorithms/detail/select_geometry_type.hpp>
0024 #include <boost/geometry/core/coordinate_type.hpp>
0025 #include <boost/geometry/util/select_most_precise.hpp>
0026 #include <boost/geometry/util/type_traits.hpp>
0027
0028
0029 namespace boost { namespace geometry
0030 {
0031
0032
0033 namespace resolve_strategy
0034 {
0035
0036 // NOTE: The implementation was simplified greately preserving the old
0037 //   behavior. In general case the result types of Strategies should be
0038 //   taken into account.
0039 // It would probably be enough to use distance_result and
0040 //   default_distance_result here.
0041
0042 } // namespace resolve_strategy
0043
0044
0045 namespace resolve_dynamic
0046 {
0047
0048 template <typename Sequence>
0049 struct default_length_result_impl;
0050
0051 template <typename ...Geometries>
0052 struct default_length_result_impl<util::type_sequence<Geometries...>>
0053 {
0054     using type = typename select_most_precise
0055         <
0056             typename coordinate_type<Geometries>::type...,
0057             long double
0058         >::type;
0059 };
0060
0061 template <typename Geometry>
0062 struct default_length_result
0063     : default_length_result_impl<typename detail::geometry_types<Geometry>::type>
0064 {};
0065
0066
0067 } // namespace resolve_dynamic
0068
0069
0070 /*!
0071     \brief Meta-function defining return type of length function
0072     \ingroup length
0073     \note Length of a line of integer coordinates can be double.
0074         So we take at least a double. If Big Number types are used,
0075         we take that type.
0076
0077  */
0078 template <typename Geometry>
0079 struct default_length_result
0080     : resolve_dynamic::default_length_result<Geometry>
0081 {};
0082
0083
0084 }} // namespace boost::geometry
0085
0086 #endif // BOOST_GEOMETRY_STRATEGIES_DEFAULT_LENGTH_RESULT_HPP