Chris@16: // Copyright David Abrahams 2002.
Chris@16: // Distributed under the Boost Software License, Version 1.0. (See
Chris@16: // accompanying file LICENSE_1_0.txt or copy at
Chris@16: // http://www.boost.org/LICENSE_1_0.txt)
Chris@16: #ifndef CAST_DWA200269_HPP
Chris@16: # define CAST_DWA200269_HPP
Chris@16: 
Chris@16: # include <boost/python/detail/prefix.hpp>
Chris@16: 
Chris@16: # include <boost/type_traits/same_traits.hpp>
Chris@16: # include <boost/type_traits/cv_traits.hpp>
Chris@16: # include <boost/type.hpp>
Chris@16: # include <boost/python/base_type_traits.hpp>
Chris@16: # include <boost/python/detail/convertible.hpp>
Chris@16: 
Chris@16: namespace boost { namespace python { 
Chris@16: 
Chris@16: namespace detail
Chris@16: {
Chris@16:   template <class Source, class Target> inline Target* upcast_impl(Source*, Target*);
Chris@16:   
Chris@16:   template <class Source, class Target>
Chris@16:   inline Target* upcast(Source* p, yes_convertible, no_convertible, Target*)
Chris@16:   {
Chris@16:       return p;
Chris@16:   }
Chris@16: 
Chris@16:   template <class Source, class Target>
Chris@16:   inline Target* upcast(Source* p, no_convertible, no_convertible, Target*)
Chris@16:   {
Chris@16:       typedef typename base_type_traits<Source>::type base;
Chris@16:       
Chris@16:       return detail::upcast_impl((base*)p, (Target*)0);
Chris@16:   }
Chris@16: 
Chris@16:   template <bool is_same = true>
Chris@16:   struct upcaster
Chris@16:   {
Chris@16:       template <class T>
Chris@16:       static inline T* execute(T* x, T*) { return x; }
Chris@16:   };
Chris@16:   
Chris@16:   template <>
Chris@16:   struct upcaster<false>
Chris@16:   {
Chris@16:       template <class Source, class Target>
Chris@16:       static inline Target* execute(Source* x, Target*)
Chris@16:       {
Chris@16:           return detail::upcast(
Chris@16:               x, detail::convertible<Target*>::check(x)
Chris@16:               , detail::convertible<Source*>::check((Target*)0)
Chris@16:               , (Target*)0);
Chris@16:       }
Chris@16:   };
Chris@16: 
Chris@16: 
Chris@16:   template <class Target, class Source>
Chris@16:   inline Target* downcast(Source* p, yes_convertible)
Chris@16:   {
Chris@16:       return static_cast<Target*>(p);
Chris@16:   }
Chris@16: 
Chris@16:   template <class Target, class Source>
Chris@16:   inline Target* downcast(Source* p, no_convertible, boost::type<Target>* = 0)
Chris@16:   {
Chris@16:       typedef typename base_type_traits<Source>::type base;
Chris@16:       return (Target*)detail::downcast<base>(p, convertible<Source*>::check((base*)0));
Chris@16:   }
Chris@16: 
Chris@16:   template <class T>
Chris@16:   inline void assert_castable(boost::type<T>* = 0)
Chris@16:   {
Chris@16:       typedef char must_be_a_complete_type[sizeof(T)];
Chris@16:   }
Chris@16: 
Chris@16:   template <class Source, class Target>
Chris@16:   inline Target* upcast_impl(Source* x, Target*)
Chris@16:   {
Chris@16:       typedef typename add_cv<Source>::type src_t;
Chris@16:       typedef typename add_cv<Target>::type target_t;
Chris@16:       bool const same = is_same<src_t,target_t>::value;
Chris@16:       
Chris@16:       return detail::upcaster<same>::execute(x, (Target*)0);
Chris@16:   }
Chris@16: }
Chris@16: 
Chris@16: template <class Target, class Source>
Chris@16: inline Target* upcast(Source* x, Target* = 0)
Chris@16: {
Chris@16:     detail::assert_castable<Source>();
Chris@16:     detail::assert_castable<Target>();
Chris@16:     return detail::upcast_impl(x, (Target*)0);
Chris@16:     
Chris@16: }
Chris@16: 
Chris@16: template <class Target, class Source>
Chris@16: inline Target* downcast(Source* x, Target* = 0)
Chris@16: {
Chris@16:     detail::assert_castable<Source>();
Chris@16:     detail::assert_castable<Target>();
Chris@16:     return detail::downcast<Target>(x, detail::convertible<Source*>::check((Target*)0));
Chris@16: }
Chris@16: 
Chris@16: }} // namespace boost::python
Chris@16: 
Chris@16: #endif // CAST_DWA200269_HPP