/* Copyright 2016 Joaquin M Lopez Munoz. * 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) * * See http://www.boost.org/libs/poly_collection for library home page. */ #ifndef BOOST_POLY_COLLECTION_DETAIL_ANY_ITERATOR_HPP #define BOOST_POLY_COLLECTION_DETAIL_ANY_ITERATOR_HPP #if defined(_MSC_VER) #pragma once #endif #include <boost/iterator/iterator_adaptor.hpp> #include <boost/type_erasure/any_cast.hpp> #include <type_traits> #include <utility> namespace boost{ namespace poly_collection{ namespace detail{ /* type_erasure::any<Concept>* adaptor convertible to pointer to wrapped * entity. */ template<typename Any> class any_iterator:public boost::iterator_adaptor<any_iterator<Any>,Any*> { public: any_iterator()=default; explicit any_iterator(Any* p)noexcept:any_iterator::iterator_adaptor_{p}{} any_iterator(const any_iterator&)=default; any_iterator& operator=(const any_iterator&)=default; template< typename NonConstAny, typename std::enable_if< std::is_same<Any,const NonConstAny>::value>::type* =nullptr > any_iterator(const any_iterator<NonConstAny>& x)noexcept: any_iterator::iterator_adaptor_{x.base()}{} template< typename NonConstAny, typename std::enable_if< std::is_same<Any,const NonConstAny>::value>::type* =nullptr > any_iterator& operator=(const any_iterator<NonConstAny>& x)noexcept { this->base_reference()=x.base(); return *this; } /* interoperability with Any* */ any_iterator& operator=(Any* p)noexcept {this->base_reference()=p;return *this;} operator Any*()const noexcept{return this->base();} /* interoperability with Concrete* */ template< typename Concrete, typename std::enable_if< /* can't compile-time check concept compliance */ !std::is_const<Any>::value||std::is_const<Concrete>::value >::type* =nullptr > explicit operator Concrete*()const noexcept { return const_cast<Concrete*>( static_cast<typename std::remove_const<Concrete>::type*>( type_erasure::any_cast<void*>(this->base()))); } private: template<typename> friend class any_iterator; }; } /* namespace poly_collection::detail */ } /* namespace poly_collection */ } /* namespace boost */ #endif