Chris@102: //////////////////////////////////////////////////////////////////////////////
Chris@102: //
Chris@102: // (C) Copyright Ion Gaztanaga 2012-2012.
Chris@102: // Distributed under the Boost Software License, Version 1.0.
Chris@102: // (See accompanying file LICENSE_1_0.txt or copy at
Chris@102: // http://www.boost.org/LICENSE_1_0.txt)
Chris@102: //
Chris@102: // See http://www.boost.org/libs/move for documentation.
Chris@102: //
Chris@102: //////////////////////////////////////////////////////////////////////////////
Chris@102: 
Chris@102: //! \file
Chris@102: //! This header defines core utilities to ease the development
Chris@102: //! of move-aware functions. This header minimizes dependencies
Chris@102: //! from other libraries.
Chris@102: 
Chris@102: #ifndef BOOST_MOVE_MOVE_UTILITY_CORE_HPP
Chris@102: #define BOOST_MOVE_MOVE_UTILITY_CORE_HPP
Chris@102: 
Chris@102: #ifndef BOOST_CONFIG_HPP
Chris@102: #  include <boost/config.hpp>
Chris@102: #endif
Chris@102: #
Chris@102: #if defined(BOOST_HAS_PRAGMA_ONCE)
Chris@102: #  pragma once
Chris@102: #endif
Chris@102: 
Chris@102: #include <boost/move/detail/config_begin.hpp>
Chris@102: #include <boost/move/core.hpp>
Chris@102: #include <boost/move/detail/meta_utils.hpp>
Chris@102: #include <boost/static_assert.hpp>
Chris@102: 
Chris@102: #if defined(BOOST_NO_CXX11_RVALUE_REFERENCES) && !defined(BOOST_MOVE_DOXYGEN_INVOKED)
Chris@102: 
Chris@102:    namespace boost {
Chris@102: 
Chris@102:    template<class T>
Chris@102:    struct enable_move_utility_emulation
Chris@102:    {
Chris@102:       static const bool value = true;
Chris@102:    };
Chris@102:     
Chris@102:    //////////////////////////////////////////////////////////////////////////////
Chris@102:    //
Chris@102:    //                            move()
Chris@102:    //
Chris@102:    //////////////////////////////////////////////////////////////////////////////
Chris@102: 
Chris@102:    template <class T>
Chris@102:    inline typename ::boost::move_detail::enable_if_c
Chris@102:       < enable_move_utility_emulation<T>::value && !has_move_emulation_enabled<T>::value, T&>::type
Chris@102:          move(T& x) BOOST_NOEXCEPT
Chris@102:    {
Chris@102:       return x;
Chris@102:    }
Chris@102: 
Chris@102:    template <class T>
Chris@102:    inline typename ::boost::move_detail::enable_if_c
Chris@102:       < enable_move_utility_emulation<T>::value && has_move_emulation_enabled<T>::value, rv<T>&>::type
Chris@102:          move(T& x) BOOST_NOEXCEPT
Chris@102:    {
Chris@102:       return *static_cast<rv<T>* >(::boost::move_detail::addressof(x));
Chris@102:    }
Chris@102: 
Chris@102:    template <class T>
Chris@102:    inline typename ::boost::move_detail::enable_if_c
Chris@102:       < enable_move_utility_emulation<T>::value && has_move_emulation_enabled<T>::value, rv<T>&>::type
Chris@102:          move(rv<T>& x) BOOST_NOEXCEPT
Chris@102:    {
Chris@102:       return x;
Chris@102:    }
Chris@102: 
Chris@102:    //////////////////////////////////////////////////////////////////////////////
Chris@102:    //
Chris@102:    //                            forward()
Chris@102:    //
Chris@102:    //////////////////////////////////////////////////////////////////////////////
Chris@102: 
Chris@102:    template <class T>
Chris@102:    inline typename ::boost::move_detail::enable_if_c
Chris@102:       < enable_move_utility_emulation<T>::value && ::boost::move_detail::is_rv<T>::value, T &>::type
Chris@102:          forward(const typename ::boost::move_detail::identity<T>::type &x) BOOST_NOEXCEPT
Chris@102:    {
Chris@102:       return const_cast<T&>(x);
Chris@102:    }
Chris@102: 
Chris@102:    template <class T>
Chris@102:    inline typename ::boost::move_detail::enable_if_c
Chris@102:       < enable_move_utility_emulation<T>::value && !::boost::move_detail::is_rv<T>::value, const T &>::type
Chris@102:       forward(const typename ::boost::move_detail::identity<T>::type &x) BOOST_NOEXCEPT
Chris@102:    {
Chris@102:       return x;
Chris@102:    }
Chris@102: 
Chris@102:    //////////////////////////////////////////////////////////////////////////////
Chris@102:    //
Chris@102:    //                        move_if_not_lvalue_reference()
Chris@102:    //
Chris@102:    //////////////////////////////////////////////////////////////////////////////
Chris@102: 
Chris@102:    template <class T>
Chris@102:    inline typename ::boost::move_detail::enable_if_c
Chris@102:       < enable_move_utility_emulation<T>::value &&
Chris@102:         ::boost::move_detail::is_rv<T>::value
Chris@102:       , T &>::type
Chris@102:          move_if_not_lvalue_reference(const typename ::boost::move_detail::identity<T>::type &x) BOOST_NOEXCEPT
Chris@102:    {
Chris@102:       return const_cast<T&>(x);
Chris@102:    }
Chris@102: 
Chris@102:    template <class T>
Chris@102:    inline typename ::boost::move_detail::enable_if_c
Chris@102:       < enable_move_utility_emulation<T>::value &&
Chris@102:         !::boost::move_detail::is_rv<T>::value  &&
Chris@102:         (::boost::move_detail::is_lvalue_reference<T>::value ||
Chris@102:          !has_move_emulation_enabled<T>::value)
Chris@102:       , typename ::boost::move_detail::add_lvalue_reference<T>::type
Chris@102:       >::type
Chris@102:          move_if_not_lvalue_reference(typename ::boost::move_detail::remove_reference<T>::type &x) BOOST_NOEXCEPT
Chris@102:    {
Chris@102:       return x;
Chris@102:    }
Chris@102: 
Chris@102:    template <class T>
Chris@102:    inline typename ::boost::move_detail::enable_if_c
Chris@102:       < enable_move_utility_emulation<T>::value &&
Chris@102:         !::boost::move_detail::is_rv<T>::value  &&
Chris@102:         (!::boost::move_detail::is_lvalue_reference<T>::value &&
Chris@102:          has_move_emulation_enabled<T>::value)
Chris@102:       , rv<T>&
Chris@102:       >::type
Chris@102:          move_if_not_lvalue_reference(typename ::boost::move_detail::remove_reference<T>::type &x) BOOST_NOEXCEPT
Chris@102:    {
Chris@102:       return move(x);
Chris@102:    }
Chris@102: 
Chris@102:    }  //namespace boost
Chris@102: 
Chris@102: #else    //#if defined(BOOST_NO_CXX11_RVALUE_REFERENCES) && !defined(BOOST_MOVE_DOXYGEN_INVOKED)
Chris@102: 
Chris@102:    #if defined(BOOST_MOVE_USE_STANDARD_LIBRARY_MOVE)
Chris@102:       #include <utility>
Chris@102: 
Chris@102:       namespace boost{
Chris@102: 
Chris@102:       using ::std::move;
Chris@102:       using ::std::forward;
Chris@102: 
Chris@102:       }  //namespace boost
Chris@102: 
Chris@102:    #else //!BOOST_MOVE_USE_STANDARD_LIBRARY_MOVE
Chris@102: 
Chris@102:       namespace boost {
Chris@102: 
Chris@102:       //! This trait's internal boolean `value` is false in compilers with rvalue references
Chris@102:       //! and true in compilers without rvalue references.
Chris@102:       //!
Chris@102:       //! A user can specialize this trait for a type T to false to SFINAE out `move` and `forward`
Chris@102:       //! so that the user can define a different move emulation for that type in namespace boost
Chris@102:       //! (e.g. another Boost library for its types) and avoid any overload ambiguity.
Chris@102:       template<class T>
Chris@102:       struct enable_move_utility_emulation
Chris@102:       {
Chris@102:          static const bool value = false;
Chris@102:       };
Chris@102: 
Chris@102:       //////////////////////////////////////////////////////////////////////////////
Chris@102:       //
Chris@102:       //                                  move
Chris@102:       //
Chris@102:       //////////////////////////////////////////////////////////////////////////////
Chris@102: 
Chris@102:       #if defined(BOOST_MOVE_DOXYGEN_INVOKED)
Chris@102:          //! This function provides a way to convert a reference into a rvalue reference
Chris@102:          //! in compilers with rvalue references. For other compilers if `T` is Boost.Move
Chris@102:          //! enabled type then it converts `T&` into <tt>::boost::rv<T> &</tt> so that
Chris@102:          //! move emulation is activated, else it returns `T &`.
Chris@102:          template <class T>
Chris@102:          rvalue_reference move(input_reference) noexcept;
Chris@102: 
Chris@102:       #elif defined(BOOST_MOVE_OLD_RVALUE_REF_BINDING_RULES)
Chris@102: 
Chris@102:          //Old move approach, lvalues could bind to rvalue references
Chris@102:          template <class T>
Chris@102:          inline typename ::boost::move_detail::remove_reference<T>::type && move(T&& t) BOOST_NOEXCEPT
Chris@102:          {  return t;   }
Chris@102: 
Chris@102:       #else //BOOST_MOVE_OLD_RVALUE_REF_BINDING_RULES
Chris@102: 
Chris@102:          template <class T>
Chris@102:          inline typename ::boost::move_detail::remove_reference<T>::type && move(T&& t) BOOST_NOEXCEPT
Chris@102:          { return static_cast<typename ::boost::move_detail::remove_reference<T>::type &&>(t); }
Chris@102: 
Chris@102:       #endif   //BOOST_MOVE_OLD_RVALUE_REF_BINDING_RULES
Chris@102: 
Chris@102:       //////////////////////////////////////////////////////////////////////////////
Chris@102:       //
Chris@102:       //                                  forward
Chris@102:       //
Chris@102:       //////////////////////////////////////////////////////////////////////////////
Chris@102: 
Chris@102: 
Chris@102:       #if defined(BOOST_MOVE_DOXYGEN_INVOKED)
Chris@102:          //! This function provides limited form of forwarding that is usually enough for
Chris@102:          //! in-place construction and avoids the exponential overloading for
Chris@102:          //! achieve the limited forwarding in C++03.
Chris@102:          //!
Chris@102:          //! For compilers with rvalue references this function provides perfect forwarding.
Chris@102:          //!
Chris@102:          //! Otherwise:
Chris@102:          //! * If input_reference binds to const ::boost::rv<T> & then it output_reference is
Chris@102:          //!   ::boost::rv<T> &
Chris@102:          //!
Chris@102:          //! * Else, output_reference is equal to input_reference.
Chris@102:          template <class T> output_reference forward(input_reference) noexcept;
Chris@102:       #elif defined(BOOST_MOVE_OLD_RVALUE_REF_BINDING_RULES)
Chris@102: 
Chris@102:          //Old move approach, lvalues could bind to rvalue references
Chris@102: 
Chris@102:          template <class T>
Chris@102:          inline T&& forward(typename ::boost::move_detail::identity<T>::type&& t) BOOST_NOEXCEPT
Chris@102:          {  return t;   }
Chris@102: 
Chris@102:       #else //Old move
Chris@102: 
Chris@102:          template <class T>
Chris@102:          inline T&& forward(typename ::boost::move_detail::remove_reference<T>::type& t) BOOST_NOEXCEPT
Chris@102:          {  return static_cast<T&&>(t);   }
Chris@102: 
Chris@102:          template <class T>
Chris@102:          inline T&& forward(typename ::boost::move_detail::remove_reference<T>::type&& t) BOOST_NOEXCEPT
Chris@102:          {
Chris@102:             //"boost::forward<T> error: 'T' is a lvalue reference, can't forward as rvalue.";
Chris@102:             BOOST_STATIC_ASSERT(!boost::move_detail::is_lvalue_reference<T>::value);
Chris@102:             return static_cast<T&&>(t);
Chris@102:          }
Chris@102: 
Chris@102:       #endif   //BOOST_MOVE_DOXYGEN_INVOKED
Chris@102: 
Chris@102:       //////////////////////////////////////////////////////////////////////////////
Chris@102:       //
Chris@102:       //                         move_if_not_lvalue_reference
Chris@102:       //
Chris@102:       //////////////////////////////////////////////////////////////////////////////
Chris@102: 
Chris@102: 
Chris@102:       #if defined(BOOST_MOVE_DOXYGEN_INVOKED)
Chris@102:          template <class T> output_reference move_if_not_lvalue_reference(input_reference) noexcept;
Chris@102:       #elif defined(BOOST_MOVE_OLD_RVALUE_REF_BINDING_RULES)
Chris@102: 
Chris@102:          //Old move approach, lvalues could bind to rvalue references
Chris@102: 
Chris@102:          template <class T>
Chris@102:          inline T&& move_if_not_lvalue_reference(typename ::boost::move_detail::identity<T>::type&& t) BOOST_NOEXCEPT
Chris@102:          {  return t;   }
Chris@102: 
Chris@102:       #else //Old move
Chris@102: 
Chris@102:          template <class T>
Chris@102:          inline T&& move_if_not_lvalue_reference(typename ::boost::move_detail::remove_reference<T>::type& t) BOOST_NOEXCEPT
Chris@102:          {  return static_cast<T&&>(t);   }
Chris@102: 
Chris@102:          template <class T>
Chris@102:          inline T&& move_if_not_lvalue_reference(typename ::boost::move_detail::remove_reference<T>::type&& t) BOOST_NOEXCEPT
Chris@102:          {
Chris@102:             //"boost::forward<T> error: 'T' is a lvalue reference, can't forward as rvalue.";
Chris@102:             BOOST_STATIC_ASSERT(!boost::move_detail::is_lvalue_reference<T>::value);
Chris@102:             return static_cast<T&&>(t);
Chris@102:          }
Chris@102: 
Chris@102:       #endif   //BOOST_MOVE_DOXYGEN_INVOKED
Chris@102: 
Chris@102:       }  //namespace boost {
Chris@102: 
Chris@102:    #endif   //#if defined(BOOST_MOVE_USE_STANDARD_LIBRARY_MOVE)
Chris@102: 
Chris@102: #endif   //BOOST_NO_CXX11_RVALUE_REFERENCES
Chris@102: 
Chris@102: #if !defined(BOOST_MOVE_DOXYGEN_INVOKED)
Chris@102: 
Chris@102: namespace boost{
Chris@102: namespace move_detail{
Chris@102: 
Chris@102: template <typename T>
Chris@102: typename boost::move_detail::add_rvalue_reference<T>::type declval();
Chris@102: 
Chris@102: }  //namespace move_detail{
Chris@102: }  //namespace boost{
Chris@102: 
Chris@102: #endif   //#if !defined(BOOST_MOVE_DOXYGEN_INVOKED)
Chris@102: 
Chris@102: 
Chris@102: #include <boost/move/detail/config_end.hpp>
Chris@102: 
Chris@102: #endif //#ifndef BOOST_MOVE_MOVE_UTILITY_CORE_HPP