// Boost.TypeErasure library
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//
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// Copyright 2012 Steven Watanabe
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//
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// Distributed under the Boost Software License Version 1.0. (See
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// accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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//
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// $Id$
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#ifndef BOOST_TYPE_ERASURE_DETAIL_CONST_HPP_INCLUDED
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#define BOOST_TYPE_ERASURE_DETAIL_CONST_HPP_INCLUDED
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#include <boost/mpl/if.hpp>
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#include <boost/mpl/bool.hpp>
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#include <boost/mpl/or.hpp>
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#include <boost/mpl/and.hpp>
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#include <boost/mpl/not.hpp>
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#include <boost/type_traits/is_same.hpp>
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#include <boost/type_traits/is_const.hpp>
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#include <boost/type_traits/is_reference.hpp>
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#include <boost/type_traits/remove_reference.hpp>
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#include <boost/type_traits/remove_cv.hpp>
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#include <boost/type_erasure/placeholder_of.hpp>
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#include <boost/type_erasure/derived.hpp>
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namespace boost {
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namespace type_erasure {
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namespace detail {
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template<class T>
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struct is_non_const_ref : boost::mpl::false_ {};
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template<class T>
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struct is_non_const_ref<T&> : boost::mpl::true_ {};
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template<class T>
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struct is_non_const_ref<const T&> : boost::mpl::false_ {};
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template<class Placeholder, class Base>
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struct should_be_const :
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::boost::mpl::or_<
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::boost::is_const<Placeholder>,
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::boost::type_erasure::detail::is_non_const_ref<
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typename ::boost::type_erasure::placeholder_of<Base>::type
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>
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>
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{};
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template<class Placeholder, class Base>
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struct should_be_non_const :
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::boost::mpl::and_<
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::boost::mpl::not_< ::boost::is_const<Placeholder> >,
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::boost::mpl::not_<
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::boost::is_reference<
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typename ::boost::type_erasure::placeholder_of<Base>::type
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>
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>
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>
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{};
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template<class Base>
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struct non_const_this_param
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{
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typedef typename ::boost::type_erasure::placeholder_of<Base>::type placeholder;
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typedef typename ::boost::type_erasure::derived<Base>::type plain_type;
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typedef typename ::boost::mpl::if_<
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::boost::is_same<
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placeholder,
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typename ::boost::remove_cv<
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typename ::boost::remove_reference<placeholder>::type
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>::type&
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>,
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const plain_type,
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plain_type
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>::type type;
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};
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template<class T>
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struct uncallable {};
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template<class Placeholder, class Base>
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struct maybe_const_this_param
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{
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typedef typename ::boost::type_erasure::derived<Base>::type plain_type;
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typedef typename ::boost::remove_reference<Placeholder>::type plain_placeholder;
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typedef typename ::boost::mpl::if_< ::boost::is_reference<Placeholder>,
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typename ::boost::mpl::if_<
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::boost::type_erasure::detail::should_be_non_const<plain_placeholder, Base>,
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plain_type&,
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typename ::boost::mpl::if_<
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::boost::type_erasure::detail::should_be_const<plain_placeholder, Base>,
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const plain_type&,
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uncallable<plain_type>
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>::type
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>::type,
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plain_type
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>::type type;
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};
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#ifndef BOOST_NO_CXX11_RVALUE_REFERENCES
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template<class Placeholder, class Base>
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struct maybe_const_this_param<Placeholder&&, Base>
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{
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typedef typename ::boost::type_erasure::derived<Base>::type plain_type;
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typedef typename ::boost::remove_reference<Placeholder>::type plain_placeholder;
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typedef typename ::boost::type_erasure::placeholder_of<plain_type>::type self_placeholder;
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typedef typename ::boost::mpl::if_< ::boost::is_lvalue_reference<self_placeholder>,
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::boost::type_erasure::detail::uncallable<plain_type>,
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typename ::boost::mpl::if_< ::boost::is_rvalue_reference<self_placeholder>,
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const plain_type&,
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plain_type&&
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>::type
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>::type type;
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};
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#endif
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}
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}
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}
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#endif
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