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