| // Copyright David Abrahams 2002. |
| // Distributed under 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 CAST_DWA200269_HPP |
| # define CAST_DWA200269_HPP |
| |
| # include <boost/python/detail/prefix.hpp> |
| |
| # include <boost/type_traits/same_traits.hpp> |
| # include <boost/type_traits/cv_traits.hpp> |
| # include <boost/type.hpp> |
| # include <boost/python/base_type_traits.hpp> |
| # include <boost/python/detail/convertible.hpp> |
| |
| namespace boost { namespace python { |
| |
| namespace detail |
| { |
| template <class Source, class Target> inline Target* upcast_impl(Source*, Target*); |
| |
| template <class Source, class Target> |
| inline Target* upcast(Source* p, yes_convertible, no_convertible, Target*) |
| { |
| return p; |
| } |
| |
| template <class Source, class Target> |
| inline Target* upcast(Source* p, no_convertible, no_convertible, Target*) |
| { |
| typedef typename base_type_traits<Source>::type base; |
| |
| return detail::upcast_impl((base*)p, (Target*)0); |
| } |
| |
| template <bool is_same = true> |
| struct upcaster |
| { |
| template <class T> |
| static inline T* execute(T* x, T*) { return x; } |
| }; |
| |
| template <> |
| struct upcaster<false> |
| { |
| template <class Source, class Target> |
| static inline Target* execute(Source* x, Target*) |
| { |
| return detail::upcast( |
| x, detail::convertible<Target*>::check(x) |
| , detail::convertible<Source*>::check((Target*)0) |
| , (Target*)0); |
| } |
| }; |
| |
| |
| template <class Target, class Source> |
| inline Target* downcast(Source* p, yes_convertible) |
| { |
| return static_cast<Target*>(p); |
| } |
| |
| template <class Target, class Source> |
| inline Target* downcast(Source* p, no_convertible, boost::type<Target>* = 0) |
| { |
| typedef typename base_type_traits<Source>::type base; |
| return (Target*)detail::downcast<base>(p, convertible<Source*>::check((base*)0)); |
| } |
| |
| template <class T> |
| inline void assert_castable(boost::type<T>* = 0) |
| { |
| typedef char must_be_a_complete_type[sizeof(T)]; |
| } |
| |
| template <class Source, class Target> |
| inline Target* upcast_impl(Source* x, Target*) |
| { |
| typedef typename add_cv<Source>::type src_t; |
| typedef typename add_cv<Target>::type target_t; |
| bool const same = is_same<src_t,target_t>::value; |
| |
| return detail::upcaster<same>::execute(x, (Target*)0); |
| } |
| } |
| |
| template <class Target, class Source> |
| inline Target* upcast(Source* x, Target* = 0) |
| { |
| detail::assert_castable<Source>(); |
| detail::assert_castable<Target>(); |
| return detail::upcast_impl(x, (Target*)0); |
| |
| } |
| |
| template <class Target, class Source> |
| inline Target* downcast(Source* x, Target* = 0) |
| { |
| detail::assert_castable<Source>(); |
| detail::assert_castable<Target>(); |
| return detail::downcast<Target>(x, detail::convertible<Source*>::check((Target*)0)); |
| } |
| |
| }} // namespace boost::python |
| |
| #endif // CAST_DWA200269_HPP |