//
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// Copyright (c) Chris Glover, 2016.
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//
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//
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// Distributed under the Boost Software License, Version 1.0. (See accompanying
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// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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//
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#ifndef BOOST_TYPE_INDEX_RUNTIME_CAST_REGISTER_RUNTIME_CLASS_HPP
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#define BOOST_TYPE_INDEX_RUNTIME_CAST_REGISTER_RUNTIME_CLASS_HPP
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/// \file register_runtime_class.hpp
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/// \brief Contains the macros BOOST_TYPE_INDEX_IMPLEMENT_RUNTIME_CAST and
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/// BOOST_TYPE_INDEX_REGISTER_RUNTIME_CLASS
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#include <boost/type_index.hpp>
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#include <boost/preprocessor/seq/for_each.hpp>
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#ifdef BOOST_HAS_PRAGMA_ONCE
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# pragma once
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#endif
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namespace boost { namespace typeindex {
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namespace detail {
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template<typename T>
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inline type_index runtime_class_construct_type_id(T const*) {
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return type_id<T>();
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}
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} // namespace detail
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}} // namespace boost::typeindex
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/// @cond
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#define BOOST_TYPE_INDEX_CHECK_BASE_(r, data, Base) \
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if(void const* ret_val = this->Base::boost_type_index_find_instance_(idx)) return ret_val;
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/// @endcond
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/// \def BOOST_TYPE_INDEX_REGISTER_RUNTIME_CLASS
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/// \brief Macro used to make a class compatible with boost::typeindex::runtime_cast
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///
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/// BOOST_TYPE_INDEX_REGISTER_RUNTIME_CLASS generates a virtual function
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/// in the current class that, when combined with the supplied base class information, allows
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/// boost::typeindex::runtime_cast to accurately convert between dynamic types of instances of
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/// the current class.
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///
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/// BOOST_TYPE_INDEX_REGISTER_RUNTIME_CLASS also adds support for boost::typeindex::type_id_runtime
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/// by including BOOST_TYPE_INDEX_REGISTER_CLASS. It is typical that these features are used together,
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/// but in the event that BOOST_TYPE_INDEX_REGISTER_CLASS is undesirable in the current class,
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/// BOOST_TYPE_INDEX_IMPLEMENT_RUNTIME_CAST is provided.
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///
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/// \b Example:
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/// \code
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/// struct base1 {
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/// BOOST_TYPE_INDEX_REGISTER_RUNTIME_CLASS(BOOST_TYPE_INDEX_NO_BASE_CLASS)
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/// virtual ~base1();
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/// };
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///
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/// struct base2 {
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/// BOOST_TYPE_INDEX_REGISTER_RUNTIME_CLASS(BOOST_TYPE_INDEX_NO_BASE_CLASS)
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/// virtual ~base2();
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/// };
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///
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/// struct derived1 : base1 {
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/// BOOST_TYPE_INDEX_REGISTER_RUNTIME_CLASS((base1))
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/// };
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///
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/// struct derived2 : base1, base2 {
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/// BOOST_TYPE_INDEX_REGISTER_RUNTIME_CLASS((base1)(base2))
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/// };
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///
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/// ...
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///
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/// base1* pb1 = get_object();
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/// if(derived2* pb2 = boost::typeindex::runtime_cast<derived2*>(pb1)) {
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/// assert(boost::typeindex::type_id_runtime(*pb1)) == boost::typeindex::type_id<derived2>());
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/// }
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/// \endcode
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///
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/// \param base_class_seq A Boost.Preprocessor sequence of the current class' direct bases, or
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/// BOOST_TYPE_INDEX_NO_BASE_CLASS if this class has no direct base classes.
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#define BOOST_TYPE_INDEX_REGISTER_RUNTIME_CLASS(base_class_seq) \
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BOOST_TYPE_INDEX_REGISTER_CLASS \
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BOOST_TYPE_INDEX_IMPLEMENT_RUNTIME_CAST(base_class_seq)
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/// \def BOOST_TYPE_INDEX_IMPLEMENT_RUNTIME_CAST
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/// \brief Macro used to make a class compatible with boost::typeindex::runtime_cast without including
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/// support for boost::typeindex::type_id_runtime.
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///
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/// BOOST_TYPE_INDEX_IMPLEMENT_RUNTIME_CAST is provided as an alternative to BOOST_TYPE_INDEX_REGISTER_RUNTIME_CLASS
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/// in the event that support for boost::typeindex::type_id_runtime is undesirable.
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///
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/// \b Example:
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/// \code
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/// struct base1 {
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/// BOOST_TYPE_INDEX_IMPLEMENT_RUNTIME_CAST(BOOST_TYPE_INDEX_NO_BASE_CLASS)
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/// virtual ~base1();
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/// };
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///
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/// struct base2 {
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/// BOOST_TYPE_INDEX_IMPLEMENT_RUNTIME_CAST(BOOST_TYPE_INDEX_NO_BASE_CLASS)
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/// virtual ~base2();
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/// };
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///
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/// struct derived1 : base1 {
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/// BOOST_TYPE_INDEX_IMPLEMENT_RUNTIME_CAST((base1))
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/// };
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///
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/// struct derived2 : base1, base2 {
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/// BOOST_TYPE_INDEX_IMPLEMENT_RUNTIME_CAST((base1)(base2))
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/// };
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///
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/// ...
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///
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/// base1* pb1 = get_object();
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/// if(derived2* pb2 = boost::typeindex::runtime_cast<derived2*>(pb1))
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/// { /* can't call boost::typeindex::type_id_runtime(*pb1) here */ }
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/// \endcode
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///
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/// \param base_class_seq A Boost.Preprocessor sequence of the current class' direct bases, or
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/// BOOST_TYPE_INDEX_NO_BASE_CLASS if this class has no direct base classes.
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#define BOOST_TYPE_INDEX_IMPLEMENT_RUNTIME_CAST(base_class_seq) \
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virtual void const* boost_type_index_find_instance_(boost::typeindex::type_index const& idx) const BOOST_NOEXCEPT { \
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if(idx == boost::typeindex::detail::runtime_class_construct_type_id(this)) \
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return this; \
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BOOST_PP_SEQ_FOR_EACH(BOOST_TYPE_INDEX_CHECK_BASE_, _, base_class_seq) \
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return NULL; \
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}
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/// \def BOOST_TYPE_INDEX_NO_BASE_CLASS
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/// \brief Instructs BOOST_TYPE_INDEX_REGISTER_RUNTIME_CLASS and BOOST_TYPE_INDEX_IMPLEMENT_RUNTIME_CAST
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/// that this class has no base classes.
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#define BOOST_TYPE_INDEX_NO_BASE_CLASS BOOST_PP_SEQ_NIL
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#endif // BOOST_TYPE_INDEX_RUNTIME_CAST_REGISTER_RUNTIME_CLASS_HPP
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