/* Copyright 2016-2020 Joaquin M Lopez Munoz.
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* Distributed under the Boost Software License, Version 1.0.
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* (See 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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* See http://www.boost.org/libs/poly_collection for library home page.
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*/
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#ifndef BOOST_POLY_COLLECTION_DETAIL_ANY_MODEL_HPP
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#define BOOST_POLY_COLLECTION_DETAIL_ANY_MODEL_HPP
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#if defined(_MSC_VER)
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#pragma once
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#endif
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#include <boost/core/addressof.hpp>
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#include <boost/mpl/map/map10.hpp>
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#include <boost/mpl/pair.hpp>
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#include <boost/mpl/vector/vector10.hpp>
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#include <boost/poly_collection/detail/any_iterator.hpp>
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#include <boost/poly_collection/detail/is_acceptable.hpp>
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#include <boost/poly_collection/detail/segment_backend.hpp>
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#include <boost/poly_collection/detail/split_segment.hpp>
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#include <boost/type_erasure/any.hpp>
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#include <boost/type_erasure/any_cast.hpp>
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#include <boost/type_erasure/binding.hpp>
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#include <boost/type_erasure/builtin.hpp>
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#include <boost/type_erasure/concept_of.hpp>
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#include <boost/type_erasure/is_subconcept.hpp>
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#include <boost/type_erasure/relaxed.hpp>
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#include <boost/type_erasure/static_binding.hpp>
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#include <boost/type_erasure/typeid_of.hpp>
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#include <memory>
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#include <type_traits>
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#include <typeinfo>
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#include <utility>
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namespace boost{
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namespace poly_collection{
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namespace detail{
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/* model for any_collection */
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template<typename Concept>
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struct any_model;
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/* Refine is_acceptable to cover type_erasure::any classes whose assignment
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* operator won't compile.
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*/
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template<typename Concept,typename Concept2,typename T>
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struct is_acceptable<
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type_erasure::any<Concept2,T>,any_model<Concept>,
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typename std::enable_if<
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!type_erasure::is_relaxed<Concept2>::value&&
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!type_erasure::is_subconcept<type_erasure::assignable<>,Concept2>::value&&
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!type_erasure::is_subconcept<
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type_erasure::assignable<type_erasure::_self,type_erasure::_self&&>,
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Concept2>::value
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>::type
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>:std::false_type{};
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/* is_terminal defined out-class to allow for partial specialization */
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template<typename Concept,typename T>
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using any_model_enable_if_has_typeid_=typename std::enable_if<
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type_erasure::is_subconcept<
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type_erasure::typeid_<typename std::decay<T>::type>,
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Concept
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>::value
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>::type*;
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template<typename T,typename=void*>
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struct any_model_is_terminal:std::true_type{};
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template<typename Concept,typename T>
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struct any_model_is_terminal<
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type_erasure::any<Concept,T>,any_model_enable_if_has_typeid_<Concept,T>
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>:std::false_type{};
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/* used for make_value_type */
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template<typename T,typename Q>
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struct any_model_make_reference
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{
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static T& apply(Q& x){return x;}
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};
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template<typename Concept>
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struct any_model
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{
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using value_type=type_erasure::any<
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typename std::conditional<
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type_erasure::is_subconcept<type_erasure::typeid_<>,Concept>::value,
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Concept,
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mpl::vector2<Concept,type_erasure::typeid_<>>
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>::type,
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type_erasure::_self&
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>;
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template<typename Concrete>
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using is_implementation=std::true_type; /* can't compile-time check concept
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* compliance */
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template<typename T>
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using is_terminal=any_model_is_terminal<T>;
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template<typename T>
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static const std::type_info& subtypeid(const T&){return typeid(T);}
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template<
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typename Concept2,typename T,
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any_model_enable_if_has_typeid_<Concept2,T> =nullptr
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>
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static const std::type_info& subtypeid(
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const type_erasure::any<Concept2,T>& a)
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{
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return type_erasure::typeid_of(a);
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}
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template<typename T>
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static void* subaddress(T& x){return boost::addressof(x);}
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template<typename T>
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static const void* subaddress(const T& x){return boost::addressof(x);}
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template<
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typename Concept2,typename T,
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any_model_enable_if_has_typeid_<Concept2,T> =nullptr
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>
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static void* subaddress(type_erasure::any<Concept2,T>& a)
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{
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return type_erasure::any_cast<void*>(&a);
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}
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template<
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typename Concept2,typename T,
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any_model_enable_if_has_typeid_<Concept2,T> =nullptr
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>
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static const void* subaddress(const type_erasure::any<Concept2,T>& a)
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{
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return type_erasure::any_cast<const void*>(&a);
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}
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using base_iterator=any_iterator<value_type>;
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using const_base_iterator=any_iterator<const value_type>;
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using base_sentinel=value_type*;
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using const_base_sentinel=const value_type*;
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template<typename Concrete>
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using iterator=Concrete*;
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template<typename Concrete>
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using const_iterator=const Concrete*;
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template<typename Allocator>
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using segment_backend=detail::segment_backend<any_model,Allocator>;
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template<typename Concrete,typename Allocator>
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using segment_backend_implementation=
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split_segment<any_model,Concrete,Allocator>;
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static base_iterator nonconst_iterator(const_base_iterator it)
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{
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return base_iterator{
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const_cast<value_type*>(static_cast<const value_type*>(it))};
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}
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template<typename T>
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static iterator<T> nonconst_iterator(const_iterator<T> it)
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{
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return const_cast<iterator<T>>(it);
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}
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private:
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template<typename,typename,typename>
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friend class split_segment;
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template<typename Concrete>
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static value_type make_value_type(Concrete& x){return value_type{x};}
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template<typename Concept2,typename T>
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static value_type make_value_type(type_erasure::any<Concept2,T>& x)
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{
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/* I don't pretend to understand what's going on here, see
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* https://lists.boost.org/boost-users/2017/05/87556.php
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*/
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using ref_type=type_erasure::any<Concept2,T>;
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using make_ref=any_model_make_reference<type_erasure::_self,ref_type>;
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using concept_=typename type_erasure::concept_of<value_type>::type;
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auto b=type_erasure::make_binding<
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mpl::map1<mpl::pair<type_erasure::_self,ref_type>>>();
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return {
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type_erasure::call(type_erasure::binding<make_ref>{b},make_ref{},x),
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type_erasure::binding<concept_>{b}
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};
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}
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};
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} /* namespace poly_collection::detail */
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} /* namespace poly_collection */
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} /* namespace boost */
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#endif
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