boost/type_erasure/detail/const.hpp
// Boost.TypeErasure library
//
// Copyright 2012 Steven Watanabe
//
// 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)
//
// $Id: const.hpp 83332 2013-03-06 18:46:56Z steven_watanabe $
#ifndef BOOST_TYPE_ERASURE_DETAIL_CONST_HPP_INCLUDED
#define BOOST_TYPE_ERASURE_DETAIL_CONST_HPP_INCLUDED
#include <boost/mpl/if.hpp>
#include <boost/mpl/bool.hpp>
#include <boost/mpl/or.hpp>
#include <boost/mpl/and.hpp>
#include <boost/mpl/not.hpp>
#include <boost/type_traits/is_same.hpp>
#include <boost/type_traits/is_const.hpp>
#include <boost/type_traits/is_reference.hpp>
#include <boost/type_traits/remove_reference.hpp>
#include <boost/type_traits/remove_cv.hpp>
#include <boost/type_erasure/placeholder_of.hpp>
#include <boost/type_erasure/derived.hpp>
namespace boost {
namespace type_erasure {
namespace detail {
template<class T>
struct is_non_const_ref : boost::mpl::false_ {};
template<class T>
struct is_non_const_ref<T&> : boost::mpl::true_ {};
template<class T>
struct is_non_const_ref<const T&> : boost::mpl::false_ {};
template<class Placeholder, class Base>
struct should_be_const :
::boost::mpl::or_<
::boost::is_const<Placeholder>,
::boost::type_erasure::detail::is_non_const_ref<
typename ::boost::type_erasure::placeholder_of<Base>::type
>
>
{};
template<class Placeholder, class Base>
struct should_be_non_const :
::boost::mpl::and_<
::boost::mpl::not_< ::boost::is_const<Placeholder> >,
::boost::mpl::not_<
::boost::is_reference<
typename ::boost::type_erasure::placeholder_of<Base>::type
>
>
>
{};
template<class Base>
struct non_const_this_param
{
typedef typename ::boost::type_erasure::placeholder_of<Base>::type placeholder;
typedef typename ::boost::type_erasure::derived<Base>::type plain_type;
typedef typename ::boost::mpl::if_<
::boost::is_same<
placeholder,
typename ::boost::remove_cv<
typename ::boost::remove_reference<placeholder>::type
>::type&
>,
const plain_type,
plain_type
>::type type;
};
template<class T>
struct uncallable {};
template<class Placeholder, class Base>
struct maybe_const_this_param
{
typedef typename ::boost::type_erasure::derived<Base>::type plain_type;
typedef typename ::boost::remove_reference<Placeholder>::type plain_placeholder;
typedef typename ::boost::mpl::if_< ::boost::is_reference<Placeholder>,
typename ::boost::mpl::if_<
::boost::type_erasure::detail::should_be_non_const<plain_placeholder, Base>,
plain_type&,
typename ::boost::mpl::if_<
::boost::type_erasure::detail::should_be_const<plain_placeholder, Base>,
const plain_type&,
uncallable<plain_type>
>::type
>::type,
plain_type
>::type type;
};
#ifndef BOOST_NO_CXX11_RVALUE_REFERENCES
template<class Placeholder, class Base>
struct maybe_const_this_param<Placeholder&&, Base>
{
typedef typename ::boost::type_erasure::derived<Base>::type plain_type;
typedef typename ::boost::remove_reference<Placeholder>::type plain_placeholder;
typedef typename ::boost::type_erasure::placeholder_of<plain_type>::type self_placeholder;
typedef typename ::boost::mpl::if_< ::boost::is_lvalue_reference<self_placeholder>,
::boost::type_erasure::detail::uncallable<plain_type>,
typename ::boost::mpl::if_< ::boost::is_rvalue_reference<self_placeholder>,
const plain_type&,
plain_type&&
>::type
>::type type;
};
#endif
}
}
}
#endif