| // Boost.Geometry (aka GGL, Generic Geometry Library) |
| |
| // Copyright (c) 2007-2011 Barend Gehrels, Amsterdam, the Netherlands. |
| // Copyright (c) 2008-2011 Bruno Lalande, Paris, France. |
| // Copyright (c) 2009-2011 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_UTIL_SELECT_CALCULATION_TYPE_HPP |
| #define BOOST_GEOMETRY_UTIL_SELECT_CALCULATION_TYPE_HPP |
| |
| |
| #include <boost/mpl/if.hpp> |
| #include <boost/type_traits.hpp> |
| |
| #include <boost/geometry/util/select_coordinate_type.hpp> |
| |
| |
| namespace boost { namespace geometry |
| { |
| |
| |
| /*! |
| \brief Meta-function selecting the "calculation" type |
| \details Based on two input geometry types, and an input calculation type, |
| (which defaults to void in the calling function), this meta-function |
| selects the most appropriate: |
| - if calculation type is specified, that one is used, |
| - if it is void, the most precise of the two points is used |
| \ingroup utility |
| */ |
| template <typename Geometry1, typename Geometry2, typename CalculationType> |
| struct select_calculation_type |
| { |
| typedef typename |
| boost::mpl::if_ |
| < |
| boost::is_void<CalculationType>, |
| typename select_coordinate_type |
| < |
| Geometry1, |
| Geometry2 |
| >::type, |
| CalculationType |
| >::type type; |
| }; |
| |
| |
| }} // namespace boost::geometry |
| |
| |
| #endif // BOOST_GEOMETRY_UTIL_SELECT_CALCULATION_TYPE_HPP |