| // Copyright Daniel Wallin, David Abrahams 2005. |
| // Copyright Cromwell D. Enage 2017. |
| // 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_PARAMETER_AUX_UNWRAP_CV_REFERENCE_HPP |
| #define BOOST_PARAMETER_AUX_UNWRAP_CV_REFERENCE_HPP |
| |
| namespace boost { |
| |
| template <typename T> |
| class reference_wrapper; |
| } // namespace boost |
| |
| #include <boost/parameter/aux_/yesno.hpp> |
| |
| namespace boost { namespace parameter { namespace aux { |
| |
| // |
| // reference_wrapper support -- if perfect forwarding is unsupported, |
| // then when passing arguments positionally by non-const reference, |
| // we ask users of named parameter interfaces to use ref(x) to wrap them. |
| // |
| |
| template <typename U> |
| ::boost::parameter::aux::yes_tag |
| is_cv_reference_wrapper_check( |
| ::boost::reference_wrapper<U> const volatile* |
| ); |
| |
| ::boost::parameter::aux::no_tag is_cv_reference_wrapper_check(...); |
| }}} // namespace boost::parameter::aux |
| |
| #include <boost/parameter/config.hpp> |
| |
| #if !defined(BOOST_NO_CXX11_HDR_FUNCTIONAL) |
| #include <functional> |
| |
| namespace boost { namespace parameter { namespace aux { |
| |
| // Support for std::ref(x) -- Cromwell D. Enage |
| template <typename U> |
| ::boost::parameter::aux::yes_tag |
| is_cv_reference_wrapper_check( |
| ::std::reference_wrapper<U> const volatile* |
| ); |
| }}} // namespace boost::parameter::aux |
| #endif |
| |
| #include <boost/parameter/aux_/preprocessor/nullptr.hpp> |
| |
| #if defined(BOOST_PARAMETER_CAN_USE_MP11) && !( \ |
| BOOST_WORKAROUND(BOOST_MSVC, >= 1900) && \ |
| BOOST_WORKAROUND(BOOST_MSVC, < 1910) \ |
| ) |
| #include <boost/mp11/integral.hpp> |
| #include <boost/mp11/utility.hpp> |
| #include <type_traits> |
| #else // !defined(BOOST_PARAMETER_CAN_USE_MP11) || MSVC-14.0 |
| #include <boost/mpl/bool.hpp> |
| #include <boost/type_traits/remove_reference.hpp> |
| #if !BOOST_WORKAROUND(BOOST_BORLANDC, BOOST_TESTED_AT(0x564)) && \ |
| !BOOST_WORKAROUND(BOOST_GCC, < 40000) |
| #include <boost/mpl/eval_if.hpp> |
| #endif |
| #endif // BOOST_PARAMETER_CAN_USE_MP11 && not MSVC-14.0 |
| |
| namespace boost { namespace parameter { namespace aux { |
| |
| #if defined(BOOST_PARAMETER_CAN_USE_MP11) && !( \ |
| BOOST_WORKAROUND(BOOST_MSVC, >= 1900) && \ |
| BOOST_WORKAROUND(BOOST_MSVC, < 1910) \ |
| ) |
| // This metafunction returns mp11::mp_true if T is of type |
| // reference_wrapper<U> cv. |
| template <typename T> |
| using is_cv_reference_wrapper = ::boost::mp11::mp_bool< |
| sizeof( |
| ::boost::parameter::aux::is_cv_reference_wrapper_check( |
| static_cast< |
| typename ::std::remove_reference<T>::type* |
| >(BOOST_PARAMETER_AUX_PP_NULLPTR) |
| ) |
| ) == sizeof(::boost::parameter::aux::yes_tag) |
| >; |
| |
| // Needed for unwrap_cv_reference below. T might be const, so |
| // mp_eval_if<> might fail because of deriving from T const on EDG. |
| template <typename T> |
| using unwrap_cv_reference_impl = typename ::std::remove_reference<T>::type; |
| |
| // Produces the unwrapped type to hold a reference to in |
| // tagged_argument<>. Can't use boost::unwrap_reference<> here |
| // because it doesn't handle the case where T = reference_wrapper<U> cv. |
| template <typename T> |
| using unwrap_cv_reference = ::boost::mp11::mp_eval_if< |
| ::boost::parameter::aux::is_cv_reference_wrapper<T> |
| , ::boost::parameter::aux::unwrap_cv_reference_impl<T> |
| , ::std::remove_reference |
| , T |
| >; |
| #else // !defined(BOOST_PARAMETER_CAN_USE_MP11) || MSVC-14.0 |
| // This metafunction returns mpl::true_ if T is of type |
| // reference_wrapper<U> cv. |
| template <typename T> |
| struct is_cv_reference_wrapper |
| { |
| BOOST_STATIC_CONSTANT( |
| bool, value = ( |
| sizeof( |
| ::boost::parameter::aux::is_cv_reference_wrapper_check( |
| static_cast< |
| typename ::boost::remove_reference<T>::type* |
| >(BOOST_PARAMETER_AUX_PP_NULLPTR) |
| ) |
| ) == sizeof(::boost::parameter::aux::yes_tag) |
| ) |
| ); |
| |
| typedef boost::mpl::bool_< |
| #if BOOST_WORKAROUND(BOOST_BORLANDC, BOOST_TESTED_AT(0x564)) |
| is_cv_reference_wrapper:: |
| #endif |
| value> type; |
| }; |
| |
| #if BOOST_WORKAROUND(BOOST_BORLANDC, BOOST_TESTED_AT(0x564)) || \ |
| BOOST_WORKAROUND(BOOST_GCC, < 40000) |
| template < |
| typename T |
| , typename = typename ::boost::parameter::aux |
| ::is_cv_reference_wrapper<T>::type |
| > |
| struct unwrap_cv_reference : ::boost::remove_reference<T> |
| { |
| }; |
| |
| template <typename T> |
| struct unwrap_cv_reference<T const,::boost::mpl::false_> |
| { |
| typedef T const type; |
| }; |
| |
| template <typename T> |
| struct unwrap_cv_reference<T,::boost::mpl::true_> : T |
| { |
| }; |
| #else // no Borland or GCC 3- workarounds needed |
| // Needed for unwrap_cv_reference below. T might be const, so |
| // eval_if<> might fail because of deriving from T const on EDG. |
| template <typename T> |
| struct unwrap_cv_reference_impl : ::boost::remove_reference<T>::type |
| { |
| }; |
| |
| // Produces the unwrapped type to hold a reference to in |
| // tagged_argument<>. Can't use boost::unwrap_reference<> here |
| // because it doesn't handle the case where T = reference_wrapper<U> cv. |
| template <typename T> |
| struct unwrap_cv_reference |
| : ::boost::mpl::eval_if< |
| ::boost::parameter::aux::is_cv_reference_wrapper<T> |
| , ::boost::parameter::aux::unwrap_cv_reference_impl<T> |
| , ::boost::remove_reference<T> |
| > |
| { |
| }; |
| #endif // Borland or GCC 3- workarounds needed |
| #endif // BOOST_PARAMETER_CAN_USE_MP11 && not MSVC-14.0 |
| }}} // namespace boost::parameter::aux |
| |
| #endif // include guard |
| |