williamr@2: #ifndef  BOOST_SERIALIZATION_VOID_CAST_HPP
williamr@2: #define BOOST_SERIALIZATION_VOID_CAST_HPP
williamr@2: 
williamr@2: // MS compatible compilers support #pragma once
williamr@2: #if defined(_MSC_VER) && (_MSC_VER >= 1020)
williamr@2: # pragma once
williamr@2: #endif
williamr@2: 
williamr@2: /////////1/////////2/////////3/////////4/////////5/////////6/////////7/////////8
williamr@2: // void_cast.hpp:   interface for run-time casting of void pointers.
williamr@2: 
williamr@2: // (C) Copyright 2002 Robert Ramey - http://www.rrsd.com . 
williamr@2: // Use, modification and distribution is subject to the Boost Software
williamr@2: // License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
williamr@2: // http://www.boost.org/LICENSE_1_0.txt)
williamr@2: // gennadiy.rozental@tfn.com
williamr@2: 
williamr@2: //  See http://www.boost.org for updates, documentation, and revision history.
williamr@2: 
williamr@2: #include <boost/smart_cast.hpp>
williamr@2: #include <boost/mpl/eval_if.hpp>
williamr@2: #include <boost/mpl/identity.hpp>
williamr@2: 
williamr@2: #include <boost/serialization/config.hpp>
williamr@2: #include <boost/serialization/force_include.hpp>
williamr@2: #include <boost/serialization/type_info_implementation.hpp>
williamr@2: 
williamr@2: #include <boost/config/abi_prefix.hpp> // must be the last header
williamr@2: 
williamr@2: #ifdef BOOST_MSVC
williamr@2: #  pragma warning(push)
williamr@2: #  pragma warning(disable : 4251 4231 4660 4275)
williamr@2: #endif
williamr@2: 
williamr@2: namespace boost { 
williamr@2: namespace serialization { 
williamr@2: 
williamr@2: class BOOST_SERIALIZATION_DECL(BOOST_PP_EMPTY()) extended_type_info;
williamr@2: 
williamr@2: // Given a void *, assume that it really points to an instance of one type
williamr@2: // and alter it so that it would point to an instance of a related type.
williamr@2: // Return the altered pointer. If there exists no sequence of casts that
williamr@2: // can transform from_type to to_type, return a NULL.  
williamr@2: 
williamr@2: BOOST_SERIALIZATION_DECL(void const *)
williamr@2: void_upcast(
williamr@2:     extended_type_info const & derived_type,  
williamr@2:     extended_type_info const & base_type, 
williamr@2:     void const * const t,
williamr@2:     bool top = true
williamr@2: );
williamr@2: 
williamr@2: inline void *
williamr@2: void_upcast(
williamr@2:     extended_type_info const & derived_type_,
williamr@2:     extended_type_info const & base_type_,
williamr@2:     void * const t 
williamr@2: ){
williamr@2:     return const_cast<void*>(void_upcast(
williamr@2:         derived_type_, 
williamr@2:         base_type_, 
williamr@2:         const_cast<void const *>(t)
williamr@2:     ));
williamr@2: }
williamr@2: 
williamr@2: BOOST_SERIALIZATION_DECL(void const *)
williamr@2: void_downcast(
williamr@2:     extended_type_info const & derived_type,  
williamr@2:     extended_type_info const & base_type, 
williamr@2:     void const * const t,
williamr@2:     bool top = true
williamr@2: );
williamr@2: 
williamr@2: inline void *
williamr@2: void_downcast(
williamr@2:     extended_type_info const & derived_type_,
williamr@2:     extended_type_info const & base_type_,
williamr@2:     void * const t 
williamr@2: ){
williamr@2:     return const_cast<void*>(void_downcast(
williamr@2:         derived_type_, 
williamr@2:         base_type_, 
williamr@2:         const_cast<void const *>(t)
williamr@2:     ));
williamr@2: }
williamr@2: 
williamr@2: namespace void_cast_detail {
williamr@2: 
williamr@2: // note: can't be abstract because an instance is used as a search argument
williamr@2: class BOOST_SERIALIZATION_DECL(BOOST_PP_EMPTY()) void_caster
williamr@2: {
williamr@2:     friend struct void_caster_compare ;
williamr@2:     friend 
williamr@2:     BOOST_SERIALIZATION_DECL(void const *)  
williamr@2:     boost::serialization::void_upcast(
williamr@2:         const extended_type_info & derived_type,
williamr@2:         const extended_type_info & base_type,
williamr@2:         const void * t,
williamr@2:         bool top
williamr@2:     );
williamr@2:     friend 
williamr@2:     BOOST_SERIALIZATION_DECL(void const *)  
williamr@2:     boost::serialization::void_downcast(
williamr@2:         const extended_type_info & derived_type,
williamr@2:         const extended_type_info & base_type,
williamr@2:         const void * t,
williamr@2:         bool top
williamr@2:     );
williamr@2:     // each derived class must re-implement these;
williamr@2:     virtual void const * upcast(void const * t) const = 0;
williamr@2:     virtual void const * downcast(void const * t) const = 0;
williamr@2:     // Data members
williamr@2:     extended_type_info const & m_derived_type;
williamr@2:     extended_type_info const & m_base_type;
williamr@2: protected:
williamr@2:     static void static_register(const void_caster *);
williamr@2: public:
williamr@2:     // Constructor
williamr@2:     void_caster(
williamr@2:         extended_type_info const & derived_type_,
williamr@2:         extended_type_info const & base_type_ 
williamr@2:     );
williamr@2:     // predicate used to determine if this void caster includes
williamr@2:     // a particular eti *
williamr@2:     bool includes(const extended_type_info * eti) const;
williamr@2:     virtual ~void_caster();
williamr@2: private:
williamr@2:     // cw 8.3 requires this!!
williamr@2:     void_caster& operator=(void_caster const&);
williamr@2: };
williamr@2: 
williamr@2: template <class Derived, class Base>
williamr@2: class void_caster_primitive : 
williamr@2:     public void_caster
williamr@2: {
williamr@2:     virtual void const* downcast( void const * t ) const {
williamr@2:         Derived * d = boost::smart_cast<const Derived *, const Base *>(
williamr@2:             static_cast<const Base *>(t)
williamr@2:         );
williamr@2:         return d;
williamr@2:     }
williamr@2:     virtual void const* upcast(void const * t) const {
williamr@2:         Base * b = boost::smart_cast<const Base *, const Derived *>(
williamr@2:             static_cast<const Derived *>(t)
williamr@2:         );
williamr@2:         return b;
williamr@2:     }
williamr@2: 
williamr@2: public:
williamr@2:     static const void_caster_primitive instance;
williamr@2:     void_caster_primitive() BOOST_USED;
williamr@2: };
williamr@2: 
williamr@2: template <class Derived, class Base>
williamr@2: void_caster_primitive<Derived, Base>::void_caster_primitive() :
williamr@2:     void_caster( 
williamr@2:         * type_info_implementation<Derived>::type::get_instance(), 
williamr@2:         * type_info_implementation<Base>::type::get_instance() 
williamr@2:     )
williamr@2: {
williamr@2:     this->static_register(& instance);
williamr@2: }
williamr@2: 
williamr@2: // the purpose of this class is to create to->from and from->to instances
williamr@2: // of void_caster_primitive for each related pair of types.  This has to be
williamr@2: // done a pre-execution time - hence the usage of static variable.
williamr@2: template<class Derived, class Base>
williamr@2: const void_caster_primitive<Derived, Base>
williamr@2:     void_caster_primitive<Derived, Base>::instance;
williamr@2: 
williamr@2: } // void_cast_detail 
williamr@2: 
williamr@2: // Register a base/derived pair.  This indicates that it is possible
williamr@2: // to upcast a void pointer from Derived to Base and downcast a
williamr@2: // void pointer from Base to Derived.  Note bogus arguments to workaround
williamr@2: // bug in msvc 6.0
williamr@2: template<class Derived, class Base>
williamr@2: BOOST_DLLEXPORT 
williamr@2: inline const void_cast_detail::void_caster & void_cast_register(
williamr@2:     const Derived * dnull, 
williamr@2:     const Base * bnull
williamr@2: ) BOOST_USED;
williamr@2: template<class Derived, class Base>
williamr@2: BOOST_DLLEXPORT 
williamr@2: inline const void_cast_detail::void_caster & void_cast_register(
williamr@2:     const Derived * /* dnull = NULL */, 
williamr@2:     const Base * /* bnull = NULL */
williamr@2: ){
williamr@2:     return void_cast_detail::void_caster_primitive<
williamr@2:         const Derived, 
williamr@2:         const Base
williamr@2:     >::instance;
williamr@2: }
williamr@2: 
williamr@2: } // namespace serialization
williamr@2: } // namespace boost
williamr@2: 
williamr@2: #include <boost/config/abi_suffix.hpp> // pops abi_suffix.hpp pragmas
williamr@2: 
williamr@2: #endif // BOOST_SERIALIZATION_VOID_CAST_HPP