invocation/detail/that_ptr.hpp

0001 /*=============================================================================
0002     Copyright (c) 2006-2007 Tobias Schwinger
0003
0004     Use modification and distribution are subject to the Boost Software
0005     License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
0006     http://www.boost.org/LICENSE_1_0.txt).
0007 ==============================================================================*/
0008
0009 #if !defined(BOOST_FUSION_FUNCTIONAL_INVOCATION_DETAIL_THAT_PTR_HPP_INCLUDED)
0010 #define BOOST_FUSION_FUNCTIONAL_INVOCATION_DETAIL_THAT_PTR_HPP_INCLUDED
0011
0012 #include <boost/fusion/support/config.hpp>
0013 #include <boost/get_pointer.hpp>
0014 #include <boost/utility/addressof.hpp>
0015 #include <boost/type_traits/remove_reference.hpp>
0016
0017 namespace boost { namespace fusion { namespace detail
0018 {
0019     template <typename Wanted>
0020     struct that_ptr
0021     {
0022       private:
0023
0024         typedef typename remove_reference<Wanted>::type pointee;
0025
0026         template <typename T>
0027         BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
0028         static inline pointee * do_get_pointer(T &, pointee * x)
0029         {
0030             return x;
0031         }
0032         template <typename T>
0033         BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
0034         static inline pointee * do_get_pointer(T & x, void const *)
0035         {
0036             return get_pointer(x);
0037         }
0038
0039       public:
0040
0041         BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
0042         static inline pointee * get(pointee * x)
0043         {
0044             return x;
0045         }
0046
0047         BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
0048         static inline pointee * get(pointee & x)
0049         {
0050             return boost::addressof(x);
0051         }
0052
0053         template <typename T>
0054         BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
0055         static inline pointee * get(T & x)
0056         {
0057             return do_get_pointer(x, boost::addressof(x));
0058         }
0059     };
0060
0061     template <typename PtrOrSmartPtr> struct non_const_pointee;
0062
0063 #if defined(BOOST_MSVC) || (defined(BOOST_BORLANDC) && !defined(BOOST_DISABLE_WIN32))
0064 #   define BOOST_FUSION_TRAIT_DECL __cdecl
0065 #else
0066 #   define BOOST_FUSION_TRAIT_DECL /**/
0067 #endif
0068
0069 namespace adl_barrier
0070     {
0071         using boost::get_pointer;
0072         void const * BOOST_FUSION_TRAIT_DECL get_pointer(...); // fallback
0073
0074         template< typename T> char const_tester(T *);
0075         template< typename T> long const_tester(T const *);
0076
0077         template <typename Ptr>
0078         struct non_const_pointee_impl
0079         {
0080             static Ptr & what;
0081
0082             static bool const value =
0083                 sizeof(const_tester(get_pointer(what))) == 1;
0084         };
0085     }
0086
0087     template <typename PtrOrSmartPtr> struct non_const_pointee
0088         : adl_barrier::non_const_pointee_impl<
0089               typename remove_cv<
0090                   typename remove_reference<PtrOrSmartPtr>::type >::type >
0091     {
0092         typedef non_const_pointee type;
0093         typedef bool value_type;
0094     };
0095
0096 }}}
0097
0098 #endif
0099