Chris@16: //-----------------------------------------------------------------------------
Chris@16: // boost variant/detail/initializer.hpp header file
Chris@16: // See http://www.boost.org for updates, documentation, and revision history.
Chris@16: //-----------------------------------------------------------------------------
Chris@16: //
Chris@16: // Copyright (c) 2002-2003
Chris@16: // Eric Friedman, Itay Maman
Chris@16: //
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: 
Chris@16: #ifndef BOOST_VARIANT_DETAIL_INITIALIZER_HPP
Chris@16: #define BOOST_VARIANT_DETAIL_INITIALIZER_HPP
Chris@16: 
Chris@16: #include <new> // for placement new
Chris@16: 
Chris@16: #include "boost/config.hpp"
Chris@16: 
Chris@16: #include "boost/call_traits.hpp"
Chris@16: #include "boost/detail/reference_content.hpp"
Chris@16: #include "boost/variant/recursive_wrapper_fwd.hpp"
Chris@16: #include "boost/variant/detail/move.hpp"
Chris@16: 
Chris@16: #if !defined(BOOST_NO_USING_DECLARATION_OVERLOADS_FROM_TYPENAME_BASE)
Chris@16: #   include "boost/mpl/aux_/value_wknd.hpp"
Chris@16: #   include "boost/mpl/int.hpp"
Chris@16: #   include "boost/mpl/iter_fold.hpp"
Chris@16: #   include "boost/mpl/next.hpp"
Chris@16: #   include "boost/mpl/deref.hpp"
Chris@16: #   include "boost/mpl/pair.hpp"
Chris@16: #   include "boost/mpl/protect.hpp"
Chris@16: #else
Chris@16: #   include "boost/variant/variant_fwd.hpp"
Chris@16: #   include "boost/preprocessor/cat.hpp"
Chris@16: #   include "boost/preprocessor/enum.hpp"
Chris@16: #   include "boost/preprocessor/repeat.hpp"
Chris@16: #endif
Chris@16: 
Chris@16: namespace boost {
Chris@16: namespace detail { namespace variant {
Chris@16: 
Chris@16: ///////////////////////////////////////////////////////////////////////////////
Chris@16: // (detail) support to simulate standard overload resolution rules
Chris@16: //
Chris@16: // The below initializers allows variant to follow standard overload
Chris@16: // resolution rules over the specified set of bounded types.
Chris@16: //
Chris@16: // On compilers where using declarations in class templates can correctly
Chris@16: // avoid name hiding, use an optimal solution based on the variant's typelist.
Chris@16: //
Chris@16: // Otherwise, use a preprocessor workaround based on knowledge of the fixed
Chris@16: // size of the variant's psuedo-variadic template parameter list.
Chris@16: //
Chris@16: 
Chris@16: #if !defined(BOOST_NO_USING_DECLARATION_OVERLOADS_FROM_TYPENAME_BASE)
Chris@16: 
Chris@16: // (detail) quoted metafunction make_initializer_node
Chris@16: //
Chris@16: // Exposes a pair whose first type is a node in the initializer hierarchy.
Chris@16: //
Chris@16: struct make_initializer_node
Chris@16: {
Chris@16:     template <typename BaseIndexPair, typename Iterator>
Chris@16:     struct apply
Chris@16:     {
Chris@16:     private: // helpers, for metafunction result (below)
Chris@16: 
Chris@16:         typedef typename BaseIndexPair::first
Chris@16:             base;
Chris@16:         typedef typename BaseIndexPair::second
Chris@16:             index;
Chris@16: 
Chris@16:         class initializer_node
Chris@16:             : public base
Chris@16:         {
Chris@16:         private: // helpers, for static functions (below)
Chris@16: 
Chris@16:             typedef typename mpl::deref<Iterator>::type
Chris@16:                 recursive_enabled_T;
Chris@16:             typedef typename unwrap_recursive<recursive_enabled_T>::type
Chris@16:                 public_T;
Chris@16: 
Chris@16: #ifndef BOOST_NO_CXX11_RVALUE_REFERENCES
Chris@16:             typedef boost::is_reference<public_T> 
Chris@16:                 is_reference_content_t;
Chris@16: 
Chris@16:             typedef typename boost::mpl::if_<is_reference_content_t, public_T, const public_T& >::type 
Chris@16:                 param_T;
Chris@16: 
Chris@16:             template <class T> struct disable_overload{};
Chris@16: 
Chris@16:             typedef typename boost::mpl::if_<is_reference_content_t, disable_overload<public_T>, public_T&& >::type 
Chris@16:                 param2_T;
Chris@16: #else
Chris@16:             typedef typename call_traits<public_T>::param_type
Chris@16:                 param_T;
Chris@16: #endif
Chris@16: 
Chris@16:         public: // static functions
Chris@16: 
Chris@16:             using base::initialize;
Chris@16: 
Chris@16:             static int initialize(void* dest, param_T operand)
Chris@16:             {
Chris@16:                 typedef typename boost::detail::make_reference_content<
Chris@16:                       recursive_enabled_T
Chris@16:                     >::type internal_T;
Chris@16: 
Chris@16:                 new(dest) internal_T(operand);
Chris@16:                 return BOOST_MPL_AUX_VALUE_WKND(index)::value; // which
Chris@16:             }
Chris@16: 
Chris@16: #ifndef BOOST_NO_CXX11_RVALUE_REFERENCES            
Chris@16:             static int initialize(void* dest, param2_T operand)
Chris@16:             {
Chris@16:                 // This assert must newer trigger, because all the reference contents are
Chris@16:                 // handled by the initilize(void* dest, param_T operand) function above
Chris@16:                 BOOST_ASSERT(!is_reference_content_t::value);
Chris@16: 
Chris@16:                 typedef typename boost::mpl::if_<is_reference_content_t, param2_T, recursive_enabled_T>::type value_T;
Chris@16:                 new(dest) value_T( boost::detail::variant::move(operand) );
Chris@16:                 return BOOST_MPL_AUX_VALUE_WKND(index)::value; // which
Chris@16:             }
Chris@16: #endif
Chris@16:         };
Chris@16: 
Chris@16:         friend class initializer_node;
Chris@16: 
Chris@16:     public: // metafunction result
Chris@16: 
Chris@16:         typedef mpl::pair<
Chris@16:               initializer_node
Chris@16:             , typename mpl::next< index >::type
Chris@16:             > type;
Chris@16: 
Chris@16:     };
Chris@16: };
Chris@16: 
Chris@16: // (detail) class initializer_root
Chris@16: //
Chris@16: // Every level of the initializer hierarchy must expose the name
Chris@16: // "initialize," so initializer_root provides a dummy function:
Chris@16: //
Chris@16: class initializer_root
Chris@16: {
Chris@16: public: // static functions
Chris@16: 
Chris@16:     static void initialize();
Chris@16: 
Chris@16: };
Chris@16: 
Chris@16: #else // defined(BOOST_NO_USING_DECLARATION_OVERLOADS_FROM_TYPENAME_BASE)
Chris@16: 
Chris@101:     // Obsolete. Remove.
Chris@16:     #define BOOST_VARIANT_AUX_PP_INITIALIZER_TEMPLATE_PARAMS \
Chris@16:           BOOST_VARIANT_ENUM_PARAMS(typename recursive_enabled_T) \
Chris@16:     /**/
Chris@16: 
Chris@101:     // Obsolete. Remove.
Chris@16:     #define BOOST_VARIANT_AUX_PP_INITIALIZER_DEFINE_PARAM_T(N) \
Chris@16:         typedef typename unwrap_recursive< \
Chris@16:               BOOST_PP_CAT(recursive_enabled_T,N) \
Chris@16:             >::type BOOST_PP_CAT(public_T,N); \
Chris@16:         typedef typename call_traits< \
Chris@16:               BOOST_PP_CAT(public_T,N) \
Chris@16:             >::param_type BOOST_PP_CAT(param_T,N); \
Chris@16:     /**/
Chris@16: 
Chris@101: template < BOOST_VARIANT_ENUM_PARAMS(typename recursive_enabled_T) >
Chris@16: struct preprocessor_list_initializer
Chris@16: {
Chris@16: public: // static functions
Chris@16: 
Chris@16:     #define BOOST_VARIANT_AUX_PP_INITIALIZE_FUNCTION(z,N,_) \
Chris@101:         typedef typename unwrap_recursive< \
Chris@101:               BOOST_PP_CAT(recursive_enabled_T,N) \
Chris@101:             >::type BOOST_PP_CAT(public_T,N); \
Chris@101:         typedef typename call_traits< \
Chris@101:               BOOST_PP_CAT(public_T,N) \
Chris@101:             >::param_type BOOST_PP_CAT(param_T,N); \
Chris@16:         static int initialize( \
Chris@16:               void* dest \
Chris@16:             , BOOST_PP_CAT(param_T,N) operand \
Chris@16:             ) \
Chris@16:         { \
Chris@16:             typedef typename boost::detail::make_reference_content< \
Chris@16:                   BOOST_PP_CAT(recursive_enabled_T,N) \
Chris@16:                 >::type internal_T; \
Chris@16:             \
Chris@16:             new(dest) internal_T(operand); \
Chris@16:             return (N); /*which*/ \
Chris@16:         } \
Chris@16:         /**/
Chris@16: 
Chris@16:     BOOST_PP_REPEAT(
Chris@16:           BOOST_VARIANT_LIMIT_TYPES
Chris@16:         , BOOST_VARIANT_AUX_PP_INITIALIZE_FUNCTION
Chris@16:         , _
Chris@16:         )
Chris@16: 
Chris@16:     #undef BOOST_VARIANT_AUX_PP_INITIALIZE_FUNCTION
Chris@16: 
Chris@16: };
Chris@16: 
Chris@16: #endif // BOOST_NO_USING_DECLARATION_OVERLOADS_FROM_TYPENAME_BASE workaround
Chris@16: 
Chris@16: }} // namespace detail::variant
Chris@16: } // namespace boost
Chris@16: 
Chris@16: ///////////////////////////////////////////////////////////////////////////////
Chris@16: // macro BOOST_VARIANT_AUX_INITIALIZER_T
Chris@16: //
Chris@16: // Given both the variant's typelist and a basename for forming the list of
Chris@16: // bounded types (i.e., T becomes T1, T2, etc.), exposes the initializer
Chris@16: // most appropriate to the current compiler.
Chris@16: //
Chris@16: 
Chris@16: #if !defined(BOOST_NO_USING_DECLARATION_OVERLOADS_FROM_TYPENAME_BASE)
Chris@16: 
Chris@16: #define BOOST_VARIANT_AUX_INITIALIZER_T( mpl_seq, typename_base ) \
Chris@16:     ::boost::mpl::iter_fold< \
Chris@16:           mpl_seq \
Chris@16:         , ::boost::mpl::pair< \
Chris@16:               ::boost::detail::variant::initializer_root \
Chris@16:             , ::boost::mpl::int_<0> \
Chris@16:             > \
Chris@16:         , ::boost::mpl::protect< \
Chris@16:               ::boost::detail::variant::make_initializer_node \
Chris@16:             > \
Chris@16:         >::type::first \
Chris@16:     /**/
Chris@16: 
Chris@16: #else // defined(BOOST_NO_USING_DECLARATION_OVERLOADS_FROM_TYPENAME_BASE)
Chris@16: 
Chris@101:     // Obsolete. Remove.
Chris@16:     #define BOOST_VARIANT_AUX_PP_INITIALIZER_TEMPLATE_ARGS(typename_base) \
Chris@16:           BOOST_VARIANT_ENUM_PARAMS(typename_base) \
Chris@16:         /**/
Chris@16: 
Chris@16: #define BOOST_VARIANT_AUX_INITIALIZER_T( mpl_seq, typename_base ) \
Chris@16:     ::boost::detail::variant::preprocessor_list_initializer< \
Chris@101:           BOOST_VARIANT_ENUM_PARAMS(typename_base) \
Chris@16:         > \
Chris@16:     /**/
Chris@16: 
Chris@16: #endif // BOOST_NO_USING_DECLARATION_OVERLOADS_FROM_TYPENAME_BASE workaround
Chris@16: 
Chris@16: #endif // BOOST_VARIANT_DETAIL_INITIALIZER_HPP