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1 | // |
2 | // Copyright (c) Chris Glover, 2016. | |
3 | // | |
4 | // | |
5 | // Distributed under the Boost Software License, Version 1.0. (See accompanying | |
6 | // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) | |
7 | // | |
8 | ||
9 | #ifndef BOOST_TYPE_INDEX_RUNTIME_CAST_STD_SHARED_PTR_CAST_HPP | |
10 | #define BOOST_TYPE_INDEX_RUNTIME_CAST_STD_SHARED_PTR_CAST_HPP | |
11 | ||
12 | /// \file std_shared_ptr_cast.hpp | |
13 | /// \brief Contains the overload of boost::typeindex::runtime_pointer_cast for | |
14 | /// std::shared_ptr types. | |
15 | ||
16 | #include <boost/type_index/runtime_cast/detail/runtime_cast_impl.hpp> | |
17 | #include <boost/type_traits/is_base_and_derived.hpp> | |
18 | #include <memory> | |
19 | ||
20 | #ifdef BOOST_HAS_PRAGMA_ONCE | |
21 | # pragma once | |
22 | #endif | |
23 | ||
24 | namespace boost { namespace typeindex { | |
25 | ||
26 | /// \brief Creates a new instance of std::shared_ptr whose stored pointer is obtained from u's | |
27 | /// stored pointer using a runtime_cast. | |
28 | /// | |
29 | /// The new shared_ptr will share ownership with u, except that it is empty if the runtime_cast | |
30 | /// performed by runtime_pointer_cast returns a null pointer. | |
31 | /// \tparam T The desired target type to return a pointer of. | |
32 | /// \tparam U A complete class type of the source instance pointed to from u. | |
33 | /// \return If there exists a valid conversion from U* to T*, returns a std::shared_ptr<T> | |
34 | /// that points to an address suitably offset from u. | |
35 | /// If no such conversion exists, returns std::shared_ptr<T>(); | |
36 | template<typename T, typename U> | |
37 | std::shared_ptr<T> runtime_pointer_cast(std::shared_ptr<U> const& u) { | |
38 | T* value = detail::runtime_cast_impl<T>(u.get(), boost::is_base_and_derived<T, U>()); | |
39 | if(value) | |
40 | return std::shared_ptr<T>(u, value); | |
41 | return std::shared_ptr<T>(); | |
42 | } | |
43 | ||
44 | }} // namespace boost::typeindex | |
45 | ||
46 | #endif // BOOST_TYPE_INDEX_RUNTIME_CAST_STD_SHARED_PTR_CAST_HPP |