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1 | #ifndef BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_STD_ATOMIC_HPP_INCLUDED |
2 | #define BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_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 | // detail/sp_counted_base_std_atomic.hpp - C++11 std::atomic | |
11 | // | |
12 | // Copyright (c) 2007, 2013 Peter Dimov | |
13 | // | |
14 | // Distributed under the Boost Software License, Version 1.0. | |
15 | // See accompanying file LICENSE_1_0.txt or copy at | |
16 | // http://www.boost.org/LICENSE_1_0.txt | |
17 | ||
92f5a8d4 TL |
18 | #include <boost/smart_ptr/detail/sp_typeinfo_.hpp> |
19 | #include <boost/smart_ptr/detail/sp_noexcept.hpp> | |
20 | #include <boost/config.hpp> | |
7c673cae FG |
21 | #include <atomic> |
22 | #include <cstdint> | |
23 | ||
20effc67 TL |
24 | #if defined(BOOST_SP_REPORT_IMPLEMENTATION) |
25 | ||
26 | #include <boost/config/pragma_message.hpp> | |
27 | BOOST_PRAGMA_MESSAGE("Using std::atomic sp_counted_base") | |
28 | ||
29 | #endif | |
30 | ||
7c673cae FG |
31 | namespace boost |
32 | { | |
33 | ||
34 | namespace detail | |
35 | { | |
36 | ||
92f5a8d4 | 37 | inline void atomic_increment( std::atomic_int_least32_t * pw ) BOOST_SP_NOEXCEPT |
7c673cae FG |
38 | { |
39 | pw->fetch_add( 1, std::memory_order_relaxed ); | |
40 | } | |
41 | ||
92f5a8d4 | 42 | inline std::int_least32_t atomic_decrement( std::atomic_int_least32_t * pw ) BOOST_SP_NOEXCEPT |
7c673cae FG |
43 | { |
44 | return pw->fetch_sub( 1, std::memory_order_acq_rel ); | |
45 | } | |
46 | ||
92f5a8d4 | 47 | inline std::int_least32_t atomic_conditional_increment( std::atomic_int_least32_t * pw ) BOOST_SP_NOEXCEPT |
7c673cae FG |
48 | { |
49 | // long r = *pw; | |
50 | // if( r != 0 ) ++*pw; | |
51 | // return r; | |
52 | ||
53 | std::int_least32_t r = pw->load( std::memory_order_relaxed ); | |
54 | ||
55 | for( ;; ) | |
56 | { | |
57 | if( r == 0 ) | |
58 | { | |
59 | return r; | |
60 | } | |
61 | ||
62 | if( pw->compare_exchange_weak( r, r + 1, std::memory_order_relaxed, std::memory_order_relaxed ) ) | |
63 | { | |
64 | return r; | |
65 | } | |
66 | } | |
67 | } | |
68 | ||
92f5a8d4 | 69 | class BOOST_SYMBOL_VISIBLE sp_counted_base |
7c673cae FG |
70 | { |
71 | private: | |
72 | ||
73 | sp_counted_base( sp_counted_base const & ); | |
74 | sp_counted_base & operator= ( sp_counted_base const & ); | |
75 | ||
11fdf7f2 TL |
76 | std::atomic_int_least32_t use_count_; // #shared |
77 | std::atomic_int_least32_t weak_count_; // #weak + (#shared != 0) | |
7c673cae FG |
78 | |
79 | public: | |
80 | ||
92f5a8d4 | 81 | sp_counted_base() BOOST_SP_NOEXCEPT: use_count_( 1 ), weak_count_( 1 ) |
7c673cae FG |
82 | { |
83 | } | |
84 | ||
92f5a8d4 | 85 | virtual ~sp_counted_base() /*BOOST_SP_NOEXCEPT*/ |
7c673cae FG |
86 | { |
87 | } | |
88 | ||
89 | // dispose() is called when use_count_ drops to zero, to release | |
90 | // the resources managed by *this. | |
91 | ||
92f5a8d4 | 92 | virtual void dispose() BOOST_SP_NOEXCEPT = 0; |
7c673cae FG |
93 | |
94 | // destroy() is called when weak_count_ drops to zero. | |
95 | ||
92f5a8d4 | 96 | virtual void destroy() BOOST_SP_NOEXCEPT |
7c673cae FG |
97 | { |
98 | delete this; | |
99 | } | |
100 | ||
92f5a8d4 TL |
101 | virtual void * get_deleter( sp_typeinfo_ const & ti ) BOOST_SP_NOEXCEPT = 0; |
102 | virtual void * get_local_deleter( sp_typeinfo_ const & ti ) BOOST_SP_NOEXCEPT = 0; | |
103 | virtual void * get_untyped_deleter() BOOST_SP_NOEXCEPT = 0; | |
7c673cae | 104 | |
92f5a8d4 | 105 | void add_ref_copy() BOOST_SP_NOEXCEPT |
7c673cae FG |
106 | { |
107 | atomic_increment( &use_count_ ); | |
108 | } | |
109 | ||
92f5a8d4 | 110 | bool add_ref_lock() BOOST_SP_NOEXCEPT // true on success |
7c673cae FG |
111 | { |
112 | return atomic_conditional_increment( &use_count_ ) != 0; | |
113 | } | |
114 | ||
92f5a8d4 | 115 | void release() BOOST_SP_NOEXCEPT |
7c673cae FG |
116 | { |
117 | if( atomic_decrement( &use_count_ ) == 1 ) | |
118 | { | |
119 | dispose(); | |
120 | weak_release(); | |
121 | } | |
122 | } | |
123 | ||
92f5a8d4 | 124 | void weak_add_ref() BOOST_SP_NOEXCEPT |
7c673cae FG |
125 | { |
126 | atomic_increment( &weak_count_ ); | |
127 | } | |
128 | ||
92f5a8d4 | 129 | void weak_release() BOOST_SP_NOEXCEPT |
7c673cae FG |
130 | { |
131 | if( atomic_decrement( &weak_count_ ) == 1 ) | |
132 | { | |
133 | destroy(); | |
134 | } | |
135 | } | |
136 | ||
92f5a8d4 | 137 | long use_count() const BOOST_SP_NOEXCEPT |
7c673cae FG |
138 | { |
139 | return use_count_.load( std::memory_order_acquire ); | |
140 | } | |
141 | }; | |
142 | ||
143 | } // namespace detail | |
144 | ||
145 | } // namespace boost | |
146 | ||
147 | #endif // #ifndef BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_STD_ATOMIC_HPP_INCLUDED |