Chris@102: #ifndef BOOST_CORE_REF_HPP
Chris@102: #define BOOST_CORE_REF_HPP
Chris@102: 
Chris@102: // MS compatible compilers support #pragma once
Chris@102: 
Chris@102: #if defined(_MSC_VER) && (_MSC_VER >= 1020)
Chris@102: # pragma once
Chris@102: #endif
Chris@102: 
Chris@102: #include <boost/config.hpp>
Chris@102: #include <boost/utility/addressof.hpp>
Chris@102: #include <boost/detail/workaround.hpp>
Chris@102: 
Chris@102: //
Chris@102: //  ref.hpp - ref/cref, useful helper functions
Chris@102: //
Chris@102: //  Copyright (C) 1999, 2000 Jaakko Jarvi (jaakko.jarvi@cs.utu.fi)
Chris@102: //  Copyright (C) 2001, 2002 Peter Dimov
Chris@102: //  Copyright (C) 2002 David Abrahams
Chris@102: //
Chris@102: //  Copyright (C) 2014 Glen Joseph Fernandes
Chris@102: //  glenfe at live dot com
Chris@102: //  Copyright (C) 2014 Agustin Berge
Chris@102: //
Chris@102: // Distributed under the Boost Software License, Version 1.0. (See
Chris@102: // 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/core/doc/html/core/ref.html for documentation.
Chris@102: //
Chris@102: 
Chris@102: /**
Chris@102:  @file
Chris@102: */
Chris@102: 
Chris@102: /**
Chris@102:  Boost namespace.
Chris@102: */
Chris@102: namespace boost
Chris@102: {
Chris@102: 
Chris@102: #if defined( BOOST_MSVC ) && BOOST_WORKAROUND( BOOST_MSVC, == 1600 )
Chris@102: 
Chris@102:     struct ref_workaround_tag {};
Chris@102: 
Chris@102: #endif
Chris@102: 
Chris@102: // reference_wrapper
Chris@102: 
Chris@102: /**
Chris@102:  @brief Contains a reference to an object of type `T`.
Chris@102: 
Chris@102:  `reference_wrapper` is primarily used to "feed" references to
Chris@102:  function templates (algorithms) that take their parameter by
Chris@102:  value. It provides an implicit conversion to `T&`, which
Chris@102:  usually allows the function templates to work on references
Chris@102:  unmodified.
Chris@102: */
Chris@102: template<class T> class reference_wrapper
Chris@102: {
Chris@102: public:
Chris@102:     /**
Chris@102:      Type `T`.
Chris@102:     */
Chris@102:     typedef T type;
Chris@102: 
Chris@102:     /**
Chris@102:      Constructs a `reference_wrapper` object that stores a
Chris@102:      reference to `t`.
Chris@102: 
Chris@102:      @remark Does not throw.
Chris@102:     */
Chris@102:     BOOST_FORCEINLINE explicit reference_wrapper(T& t): t_(boost::addressof(t)) {}
Chris@102: 
Chris@102: #if defined( BOOST_MSVC ) && BOOST_WORKAROUND( BOOST_MSVC, == 1600 )
Chris@102: 
Chris@102:     BOOST_FORCEINLINE explicit reference_wrapper( T & t, ref_workaround_tag ): t_( boost::addressof( t ) ) {}
Chris@102: 
Chris@102: #endif
Chris@102: 
Chris@102: #if !defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
Chris@102:     /**
Chris@102:      @remark Construction from a temporary object is disabled.
Chris@102:     */
Chris@102:     BOOST_DELETED_FUNCTION(reference_wrapper(T&& t))
Chris@102: public:
Chris@102: #endif
Chris@102: 
Chris@102:     /**
Chris@102:      @return The stored reference.
Chris@102:      @remark Does not throw.
Chris@102:     */
Chris@102:     BOOST_FORCEINLINE operator T& () const { return *t_; }
Chris@102: 
Chris@102:     /**
Chris@102:      @return The stored reference.
Chris@102:      @remark Does not throw.
Chris@102:     */
Chris@102:     BOOST_FORCEINLINE T& get() const { return *t_; }
Chris@102: 
Chris@102:     /**
Chris@102:      @return A pointer to the object referenced by the stored
Chris@102:        reference.
Chris@102:      @remark Does not throw.
Chris@102:     */
Chris@102:     BOOST_FORCEINLINE T* get_pointer() const { return t_; }
Chris@102: 
Chris@102: private:
Chris@102: 
Chris@102:     T* t_;
Chris@102: };
Chris@102: 
Chris@102: // ref
Chris@102: 
Chris@102: /**
Chris@102:  @cond
Chris@102: */
Chris@102: #if defined( __BORLANDC__ ) && BOOST_WORKAROUND( __BORLANDC__, BOOST_TESTED_AT(0x581) )
Chris@102: #  define BOOST_REF_CONST
Chris@102: #else
Chris@102: #  define BOOST_REF_CONST const
Chris@102: #endif
Chris@102: /**
Chris@102:  @endcond
Chris@102: */
Chris@102: 
Chris@102: /**
Chris@102:  @return `reference_wrapper<T>(t)`
Chris@102:  @remark Does not throw.
Chris@102: */
Chris@102: template<class T> BOOST_FORCEINLINE reference_wrapper<T> BOOST_REF_CONST ref( T & t )
Chris@102: {
Chris@102: #if defined( BOOST_MSVC ) && BOOST_WORKAROUND( BOOST_MSVC, == 1600 )
Chris@102: 
Chris@102:     return reference_wrapper<T>( t, ref_workaround_tag() );
Chris@102: 
Chris@102: #else
Chris@102: 
Chris@102:     return reference_wrapper<T>( t );
Chris@102: 
Chris@102: #endif
Chris@102: }
Chris@102: 
Chris@102: // cref
Chris@102: 
Chris@102: /**
Chris@102:  @return `reference_wrapper<T const>(t)`
Chris@102:  @remark Does not throw.
Chris@102: */
Chris@102: template<class T> BOOST_FORCEINLINE reference_wrapper<T const> BOOST_REF_CONST cref( T const & t )
Chris@102: {
Chris@102:     return reference_wrapper<T const>(t);
Chris@102: }
Chris@102: 
Chris@102: #undef BOOST_REF_CONST
Chris@102: 
Chris@102: #if !defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
Chris@102: 
Chris@102: /**
Chris@102:  @cond
Chris@102: */
Chris@102: #if defined(BOOST_NO_CXX11_DELETED_FUNCTIONS)
Chris@102: #  define BOOST_REF_DELETE
Chris@102: #else
Chris@102: #  define BOOST_REF_DELETE = delete
Chris@102: #endif
Chris@102: /**
Chris@102:  @endcond
Chris@102: */
Chris@102: 
Chris@102: /**
Chris@102:  @remark Construction from a temporary object is disabled.
Chris@102: */
Chris@102: template<class T> void ref(T const&&) BOOST_REF_DELETE;
Chris@102: 
Chris@102: /**
Chris@102:  @remark Construction from a temporary object is disabled.
Chris@102: */
Chris@102: template<class T> void cref(T const&&) BOOST_REF_DELETE;
Chris@102: 
Chris@102: #undef BOOST_REF_DELETE
Chris@102: 
Chris@102: #endif
Chris@102: 
Chris@102: // is_reference_wrapper
Chris@102: 
Chris@102: /**
Chris@102:  @brief Determine if a type `T` is an instantiation of
Chris@102:  `reference_wrapper`.
Chris@102: 
Chris@102:  The value static constant will be true if the type `T` is a
Chris@102:  specialization of `reference_wrapper`.
Chris@102: */
Chris@102: template<typename T> struct is_reference_wrapper
Chris@102: {
Chris@102:     BOOST_STATIC_CONSTANT( bool, value = false );
Chris@102: };
Chris@102: 
Chris@102: /**
Chris@102:  @cond
Chris@102: */
Chris@102: template<typename T> struct is_reference_wrapper< reference_wrapper<T> >
Chris@102: {
Chris@102:     BOOST_STATIC_CONSTANT( bool, value = true );
Chris@102: };
Chris@102: 
Chris@102: #if !defined(BOOST_NO_CV_SPECIALIZATIONS)
Chris@102: 
Chris@102: template<typename T> struct is_reference_wrapper< reference_wrapper<T> const >
Chris@102: {
Chris@102:     BOOST_STATIC_CONSTANT( bool, value = true );
Chris@102: };
Chris@102: 
Chris@102: template<typename T> struct is_reference_wrapper< reference_wrapper<T> volatile >
Chris@102: {
Chris@102:     BOOST_STATIC_CONSTANT( bool, value = true );
Chris@102: };
Chris@102: 
Chris@102: template<typename T> struct is_reference_wrapper< reference_wrapper<T> const volatile >
Chris@102: {
Chris@102:     BOOST_STATIC_CONSTANT( bool, value = true );
Chris@102: };
Chris@102: 
Chris@102: #endif // !defined(BOOST_NO_CV_SPECIALIZATIONS)
Chris@102: 
Chris@102: /**
Chris@102:  @endcond
Chris@102: */
Chris@102: 
Chris@102: 
Chris@102: // unwrap_reference
Chris@102: 
Chris@102: /**
Chris@102:  @brief Find the type in a `reference_wrapper`.
Chris@102: 
Chris@102:  The `typedef` type is `T::type` if `T` is a
Chris@102:  `reference_wrapper`, `T` otherwise.
Chris@102: */
Chris@102: template<typename T> struct unwrap_reference
Chris@102: {
Chris@102:     typedef T type;
Chris@102: };
Chris@102: 
Chris@102: /**
Chris@102:  @cond
Chris@102: */
Chris@102: template<typename T> struct unwrap_reference< reference_wrapper<T> >
Chris@102: {
Chris@102:     typedef T type;
Chris@102: };
Chris@102: 
Chris@102: #if !defined(BOOST_NO_CV_SPECIALIZATIONS)
Chris@102: 
Chris@102: template<typename T> struct unwrap_reference< reference_wrapper<T> const >
Chris@102: {
Chris@102:     typedef T type;
Chris@102: };
Chris@102: 
Chris@102: template<typename T> struct unwrap_reference< reference_wrapper<T> volatile >
Chris@102: {
Chris@102:     typedef T type;
Chris@102: };
Chris@102: 
Chris@102: template<typename T> struct unwrap_reference< reference_wrapper<T> const volatile >
Chris@102: {
Chris@102:     typedef T type;
Chris@102: };
Chris@102: 
Chris@102: #endif // !defined(BOOST_NO_CV_SPECIALIZATIONS)
Chris@102: 
Chris@102: /**
Chris@102:  @endcond
Chris@102: */
Chris@102: 
Chris@102: // unwrap_ref
Chris@102: 
Chris@102: /**
Chris@102:  @return `unwrap_reference<T>::type&(t)`
Chris@102:  @remark Does not throw.
Chris@102: */
Chris@102: template<class T> BOOST_FORCEINLINE typename unwrap_reference<T>::type& unwrap_ref( T & t )
Chris@102: {
Chris@102:     return t;
Chris@102: }
Chris@102: 
Chris@102: // get_pointer
Chris@102: 
Chris@102: /**
Chris@102:  @cond
Chris@102: */
Chris@102: template<class T> BOOST_FORCEINLINE T* get_pointer( reference_wrapper<T> const & r )
Chris@102: {
Chris@102:     return r.get_pointer();
Chris@102: }
Chris@102: /**
Chris@102:  @endcond
Chris@102: */
Chris@102: 
Chris@102: } // namespace boost
Chris@102: 
Chris@102: #endif // #ifndef BOOST_CORE_REF_HPP