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1 | #ifndef BOOST_SMART_PTR_DETAIL_SPINLOCK_STD_ATOMIC_HPP_INCLUDED |
2 | #define BOOST_SMART_PTR_DETAIL_SPINLOCK_STD_ATOMIC_HPP_INCLUDED | |
3 | ||
4 | // MS compatible compilers support #pragma once | |
5 | ||
6 | #if defined(_MSC_VER) && (_MSC_VER >= 1020) | |
7 | # pragma once | |
8 | #endif | |
9 | ||
10 | // | |
11 | // Copyright (c) 2014 Peter Dimov | |
12 | // | |
13 | // Distributed under the Boost Software License, Version 1.0. | |
14 | // See accompanying file LICENSE_1_0.txt or copy at | |
15 | // http://www.boost.org/LICENSE_1_0.txt) | |
16 | // | |
17 | ||
18 | #include <boost/smart_ptr/detail/yield_k.hpp> | |
92f5a8d4 | 19 | #include <boost/config.hpp> |
7c673cae FG |
20 | #include <atomic> |
21 | ||
22 | namespace boost | |
23 | { | |
24 | ||
25 | namespace detail | |
26 | { | |
27 | ||
28 | class spinlock | |
29 | { | |
30 | public: | |
31 | ||
32 | std::atomic_flag v_; | |
33 | ||
34 | public: | |
35 | ||
92f5a8d4 | 36 | bool try_lock() BOOST_NOEXCEPT |
7c673cae FG |
37 | { |
38 | return !v_.test_and_set( std::memory_order_acquire ); | |
39 | } | |
40 | ||
92f5a8d4 | 41 | void lock() BOOST_NOEXCEPT |
7c673cae FG |
42 | { |
43 | for( unsigned k = 0; !try_lock(); ++k ) | |
44 | { | |
45 | boost::detail::yield( k ); | |
46 | } | |
47 | } | |
48 | ||
92f5a8d4 | 49 | void unlock() BOOST_NOEXCEPT |
7c673cae FG |
50 | { |
51 | v_ .clear( std::memory_order_release ); | |
52 | } | |
53 | ||
54 | public: | |
55 | ||
56 | class scoped_lock | |
57 | { | |
58 | private: | |
59 | ||
60 | spinlock & sp_; | |
61 | ||
62 | scoped_lock( scoped_lock const & ); | |
63 | scoped_lock & operator=( scoped_lock const & ); | |
64 | ||
65 | public: | |
66 | ||
92f5a8d4 | 67 | explicit scoped_lock( spinlock & sp ) BOOST_NOEXCEPT: sp_( sp ) |
7c673cae FG |
68 | { |
69 | sp.lock(); | |
70 | } | |
71 | ||
92f5a8d4 | 72 | ~scoped_lock() /*BOOST_NOEXCEPT*/ |
7c673cae FG |
73 | { |
74 | sp_.unlock(); | |
75 | } | |
76 | }; | |
77 | }; | |
78 | ||
79 | } // namespace detail | |
80 | } // namespace boost | |
81 | ||
82 | #define BOOST_DETAIL_SPINLOCK_INIT { ATOMIC_FLAG_INIT } | |
83 | ||
84 | #endif // #ifndef BOOST_SMART_PTR_DETAIL_SPINLOCK_STD_ATOMIC_HPP_INCLUDED |