// 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