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1 | ////////////////////////////////////////////////////////////////////////////// |
2 | // | |
3 | // (C) Copyright Ion Gaztanaga 2009-2012. | |
4 | // Distributed under the Boost Software License, Version 1.0. | |
5 | // (See accompanying file LICENSE_1_0.txt or copy at | |
6 | // http://www.boost.org/LICENSE_1_0.txt) | |
7 | // | |
8 | // See http://www.boost.org/libs/move for documentation. | |
9 | // | |
10 | ////////////////////////////////////////////////////////////////////////////// | |
11 | ||
12 | //! \file | |
13 | ||
14 | #ifndef BOOST_MOVE_TRAITS_HPP | |
15 | #define BOOST_MOVE_TRAITS_HPP | |
16 | ||
17 | #ifndef BOOST_CONFIG_HPP | |
18 | # include <boost/config.hpp> | |
19 | #endif | |
20 | # | |
21 | #if defined(BOOST_HAS_PRAGMA_ONCE) | |
22 | # pragma once | |
23 | #endif | |
24 | ||
25 | #include <boost/move/detail/config_begin.hpp> | |
26 | ||
27 | #ifndef BOOST_NO_CXX11_RVALUE_REFERENCES | |
28 | #include <boost/move/core.hpp> | |
29 | #endif | |
30 | #include <boost/move/detail/meta_utils.hpp> | |
31 | #include <boost/move/detail/type_traits.hpp> | |
32 | ||
33 | namespace boost { | |
34 | ||
35 | //! If this trait yields to true | |
36 | //! (<i>has_trivial_destructor_after_move <T>::value == true</i>) | |
37 | //! means that if T is used as argument of a move construction/assignment, | |
38 | //! there is no need to call T's destructor. | |
39 | //! This optimization tipically is used to improve containers' performance. | |
40 | //! | |
41 | //! By default this trait is true if the type has trivial destructor, | |
42 | //! every class should specialize this trait if it wants to improve performance | |
43 | //! when inserted in containers. | |
44 | template <class T> | |
45 | struct has_trivial_destructor_after_move | |
46 | : ::boost::move_detail::is_trivially_destructible<T> | |
47 | {}; | |
48 | ||
49 | //! By default this traits returns | |
50 | //! <pre>boost::is_nothrow_move_constructible<T>::value && boost::is_nothrow_move_assignable<T>::value </pre>. | |
51 | //! Classes with non-throwing move constructor | |
52 | //! and assignment can specialize this trait to obtain some performance improvements. | |
53 | template <class T> | |
54 | struct has_nothrow_move | |
55 | { | |
56 | static const bool value = boost::move_detail::is_nothrow_move_constructible<T>::value && | |
57 | boost::move_detail::is_nothrow_move_assignable<T>::value; | |
58 | }; | |
59 | ||
60 | namespace move_detail { | |
61 | ||
62 | template <class T> | |
63 | struct is_nothrow_move_constructible_or_uncopyable | |
64 | { | |
65 | //The standard requires is_nothrow_move_constructible for move_if_noexcept | |
66 | //but a user (usually in C++03) might specialize has_nothrow_move which includes it | |
67 | static const bool value = is_nothrow_move_constructible<T>::value || | |
68 | has_nothrow_move<T>::value || | |
69 | !is_copy_constructible<T>::value; | |
70 | }; | |
71 | ||
72 | } //move_detail { | |
73 | } //namespace boost { | |
74 | ||
75 | #include <boost/move/detail/config_end.hpp> | |
76 | ||
77 | #endif //#ifndef BOOST_MOVE_TRAITS_HPP |