Chris@16: //  boost utility/base_from_member.hpp header file  --------------------------//
Chris@16: 
Chris@16: //  Copyright 2001, 2003, 2004, 2012 Daryle Walker.  Use, modification, and
Chris@16: //  distribution are subject to the Boost Software License, Version 1.0.  (See
Chris@16: //  accompanying file LICENSE_1_0.txt or a copy at
Chris@16: //  <http://www.boost.org/LICENSE_1_0.txt>.)
Chris@16: 
Chris@16: //  See <http://www.boost.org/libs/utility/> for the library's home page.
Chris@16: 
Chris@16: #ifndef BOOST_UTILITY_BASE_FROM_MEMBER_HPP
Chris@16: #define BOOST_UTILITY_BASE_FROM_MEMBER_HPP
Chris@16: 
Chris@16: #include <boost/config.hpp>
Chris@16: #include <boost/preprocessor/arithmetic/inc.hpp>
Chris@16: #include <boost/preprocessor/repetition/enum_binary_params.hpp>
Chris@16: #include <boost/preprocessor/repetition/enum_params.hpp>
Chris@16: #include <boost/preprocessor/repetition/repeat_from_to.hpp>
Chris@16: #include <boost/type_traits/is_same.hpp>
Chris@16: #include <boost/type_traits/remove_cv.hpp>
Chris@16: #include <boost/type_traits/remove_reference.hpp>
Chris@16: #include <boost/utility/enable_if.hpp>
Chris@16: 
Chris@16: 
Chris@16: //  Base-from-member arity configuration macro  ------------------------------//
Chris@16: 
Chris@16: // The following macro determines how many arguments will be in the largest
Chris@16: // constructor template of base_from_member.  Constructor templates will be
Chris@16: // generated from one argument to this maximum.  Code from other files can read
Chris@16: // this number if they need to always match the exact maximum base_from_member
Chris@16: // uses.  The maximum constructor length can be changed by overriding the
Chris@16: // #defined constant.  Make sure to apply the override, if any, for all source
Chris@16: // files during project compiling for consistency.
Chris@16: 
Chris@16: // Contributed by Jonathan Turkanis
Chris@16: 
Chris@16: #ifndef BOOST_BASE_FROM_MEMBER_MAX_ARITY
Chris@16: #define BOOST_BASE_FROM_MEMBER_MAX_ARITY  10
Chris@16: #endif
Chris@16: 
Chris@16: 
Chris@16: //  An iteration of a constructor template for base_from_member  -------------//
Chris@16: 
Chris@16: // A macro that should expand to:
Chris@16: //     template < typename T1, ..., typename Tn >
Chris@16: //     base_from_member( T1 x1, ..., Tn xn )
Chris@16: //         : member( x1, ..., xn )
Chris@16: //         {}
Chris@16: // This macro should only persist within this file.
Chris@16: 
Chris@16: #define BOOST_PRIVATE_CTR_DEF( z, n, data )                            \
Chris@16:     template < BOOST_PP_ENUM_PARAMS(n, typename T) >                   \
Chris@16:     explicit base_from_member( BOOST_PP_ENUM_BINARY_PARAMS(n, T, x) )  \
Chris@16:         : member( BOOST_PP_ENUM_PARAMS(n, x) )                         \
Chris@16:         {}                                                             \
Chris@16:     /**/
Chris@16: 
Chris@16: 
Chris@16: namespace boost
Chris@16: {
Chris@16: 
Chris@16: namespace detail
Chris@16: {
Chris@16: 
Chris@16: //  Type-unmarking class template  -------------------------------------------//
Chris@16: 
Chris@16: // Type-trait to get the raw type, i.e. the type without top-level reference nor
Chris@16: // cv-qualification, from a type expression.  Mainly for function arguments, any
Chris@16: // reference part is stripped first.
Chris@16: 
Chris@16: // Contributed by Daryle Walker
Chris@16: 
Chris@16: template < typename T >
Chris@16: struct remove_cv_ref
Chris@16: {
Chris@16:     typedef typename ::boost::remove_cv<typename
Chris@16:      ::boost::remove_reference<T>::type>::type  type;
Chris@16: 
Chris@16: };  // boost::detail::remove_cv_ref
Chris@16: 
Chris@16: //  Unmarked-type comparison class template  ---------------------------------//
Chris@16: 
Chris@16: // Type-trait to check if two type expressions have the same raw type.
Chris@16: 
Chris@16: // Contributed by Daryle Walker, based on a work-around by Luc Danton
Chris@16: 
Chris@16: template < typename T, typename U >
Chris@16: struct is_related
Chris@16:     : public ::boost::is_same<
Chris@16:      typename ::boost::detail::remove_cv_ref<T>::type,
Chris@16:      typename ::boost::detail::remove_cv_ref<U>::type >
Chris@16: {};
Chris@16: 
Chris@16: //  Enable-if-on-unidentical-unmarked-type class template  -------------------//
Chris@16: 
Chris@16: // Enable-if on the first two type expressions NOT having the same raw type.
Chris@16: 
Chris@16: // Contributed by Daryle Walker, based on a work-around by Luc Danton
Chris@16: 
Chris@16: #ifndef BOOST_NO_CXX11_VARIADIC_TEMPLATES
Chris@16: template<typename ...T>
Chris@16: struct enable_if_unrelated
Chris@16:     : public ::boost::enable_if_c<true>
Chris@16: {};
Chris@16: 
Chris@16: template<typename T, typename U, typename ...U2>
Chris@16: struct enable_if_unrelated<T, U, U2...>
Chris@16:     : public ::boost::disable_if< ::boost::detail::is_related<T, U> >
Chris@16: {};
Chris@16: #endif
Chris@16: 
Chris@16: }  // namespace boost::detail
Chris@16: 
Chris@16: 
Chris@16: //  Base-from-member class template  -----------------------------------------//
Chris@16: 
Chris@16: // Helper to initialize a base object so a derived class can use this
Chris@16: // object in the initialization of another base class.  Used by
Chris@16: // Dietmar Kuehl from ideas by Ron Klatcho to solve the problem of a
Chris@16: // base class needing to be initialized by a member.
Chris@16: 
Chris@16: // Contributed by Daryle Walker
Chris@16: 
Chris@16: template < typename MemberType, int UniqueID = 0 >
Chris@16: class base_from_member
Chris@16: {
Chris@16: protected:
Chris@16:     MemberType  member;
Chris@16: 
Chris@16: #if !defined(BOOST_NO_CXX11_RVALUE_REFERENCES) && \
Chris@16:     !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES) && \
Chris@16:     !defined(BOOST_NO_CXX11_FUNCTION_TEMPLATE_DEFAULT_ARGS) && \
Chris@16:     !(defined(__GNUC__) && (__GNUC__ == 4) && (__GNUC_MINOR__ < 4))
Chris@16:     template <typename ...T, typename EnableIf = typename
Chris@16:      ::boost::detail::enable_if_unrelated<base_from_member, T...>::type>
Chris@16:     explicit BOOST_CONSTEXPR base_from_member( T&& ...x )
Chris@16:         BOOST_NOEXCEPT_IF( BOOST_NOEXCEPT_EXPR(::new ((void*) 0) MemberType(
Chris@16:          static_cast<T&&>(x)... )) )  // no std::is_nothrow_constructible...
Chris@16:         : member( static_cast<T&&>(x)... )     // ...nor std::forward needed
Chris@16:         {}
Chris@16: #else
Chris@16:     base_from_member()
Chris@16:         : member()
Chris@16:         {}
Chris@16: 
Chris@16:     BOOST_PP_REPEAT_FROM_TO( 1, BOOST_PP_INC(BOOST_BASE_FROM_MEMBER_MAX_ARITY),
Chris@16:      BOOST_PRIVATE_CTR_DEF, _ )
Chris@16: #endif
Chris@16: 
Chris@16: };  // boost::base_from_member
Chris@16: 
Chris@101: template < typename MemberType, int UniqueID >
Chris@101: class base_from_member<MemberType&, UniqueID>
Chris@101: {
Chris@101: protected:
Chris@101:     MemberType& member;
Chris@101: 
Chris@101:     explicit BOOST_CONSTEXPR base_from_member( MemberType& x )
Chris@101:         BOOST_NOEXCEPT
Chris@101:         : member( x )
Chris@101:         {}
Chris@101: 
Chris@101: };  // boost::base_from_member
Chris@101: 
Chris@16: }  // namespace boost
Chris@16: 
Chris@16: 
Chris@16: // Undo any private macros
Chris@16: #undef BOOST_PRIVATE_CTR_DEF
Chris@16: 
Chris@16: 
Chris@16: #endif  // BOOST_UTILITY_BASE_FROM_MEMBER_HPP