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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 | ||
24 | namespace boost | |
25 | { | |
26 | ||
27 | namespace detail | |
28 | { | |
29 | ||
92f5a8d4 | 30 | inline void atomic_increment( std::atomic_int_least32_t * pw ) BOOST_SP_NOEXCEPT |
7c673cae FG |
31 | { |
32 | pw->fetch_add( 1, std::memory_order_relaxed ); | |
33 | } | |
34 | ||
92f5a8d4 | 35 | inline std::int_least32_t atomic_decrement( std::atomic_int_least32_t * pw ) BOOST_SP_NOEXCEPT |
7c673cae FG |
36 | { |
37 | return pw->fetch_sub( 1, std::memory_order_acq_rel ); | |
38 | } | |
39 | ||
92f5a8d4 | 40 | inline std::int_least32_t atomic_conditional_increment( std::atomic_int_least32_t * pw ) BOOST_SP_NOEXCEPT |
7c673cae FG |
41 | { |
42 | // long r = *pw; | |
43 | // if( r != 0 ) ++*pw; | |
44 | // return r; | |
45 | ||
46 | std::int_least32_t r = pw->load( std::memory_order_relaxed ); | |
47 | ||
48 | for( ;; ) | |
49 | { | |
50 | if( r == 0 ) | |
51 | { | |
52 | return r; | |
53 | } | |
54 | ||
55 | if( pw->compare_exchange_weak( r, r + 1, std::memory_order_relaxed, std::memory_order_relaxed ) ) | |
56 | { | |
57 | return r; | |
58 | } | |
59 | } | |
60 | } | |
61 | ||
92f5a8d4 | 62 | class BOOST_SYMBOL_VISIBLE sp_counted_base |
7c673cae FG |
63 | { |
64 | private: | |
65 | ||
66 | sp_counted_base( sp_counted_base const & ); | |
67 | sp_counted_base & operator= ( sp_counted_base const & ); | |
68 | ||
11fdf7f2 TL |
69 | std::atomic_int_least32_t use_count_; // #shared |
70 | std::atomic_int_least32_t weak_count_; // #weak + (#shared != 0) | |
7c673cae FG |
71 | |
72 | public: | |
73 | ||
92f5a8d4 | 74 | sp_counted_base() BOOST_SP_NOEXCEPT: use_count_( 1 ), weak_count_( 1 ) |
7c673cae FG |
75 | { |
76 | } | |
77 | ||
92f5a8d4 | 78 | virtual ~sp_counted_base() /*BOOST_SP_NOEXCEPT*/ |
7c673cae FG |
79 | { |
80 | } | |
81 | ||
82 | // dispose() is called when use_count_ drops to zero, to release | |
83 | // the resources managed by *this. | |
84 | ||
92f5a8d4 | 85 | virtual void dispose() BOOST_SP_NOEXCEPT = 0; |
7c673cae FG |
86 | |
87 | // destroy() is called when weak_count_ drops to zero. | |
88 | ||
92f5a8d4 | 89 | virtual void destroy() BOOST_SP_NOEXCEPT |
7c673cae FG |
90 | { |
91 | delete this; | |
92 | } | |
93 | ||
92f5a8d4 TL |
94 | virtual void * get_deleter( sp_typeinfo_ const & ti ) BOOST_SP_NOEXCEPT = 0; |
95 | virtual void * get_local_deleter( sp_typeinfo_ const & ti ) BOOST_SP_NOEXCEPT = 0; | |
96 | virtual void * get_untyped_deleter() BOOST_SP_NOEXCEPT = 0; | |
7c673cae | 97 | |
92f5a8d4 | 98 | void add_ref_copy() BOOST_SP_NOEXCEPT |
7c673cae FG |
99 | { |
100 | atomic_increment( &use_count_ ); | |
101 | } | |
102 | ||
92f5a8d4 | 103 | bool add_ref_lock() BOOST_SP_NOEXCEPT // true on success |
7c673cae FG |
104 | { |
105 | return atomic_conditional_increment( &use_count_ ) != 0; | |
106 | } | |
107 | ||
92f5a8d4 | 108 | void release() BOOST_SP_NOEXCEPT |
7c673cae FG |
109 | { |
110 | if( atomic_decrement( &use_count_ ) == 1 ) | |
111 | { | |
112 | dispose(); | |
113 | weak_release(); | |
114 | } | |
115 | } | |
116 | ||
92f5a8d4 | 117 | void weak_add_ref() BOOST_SP_NOEXCEPT |
7c673cae FG |
118 | { |
119 | atomic_increment( &weak_count_ ); | |
120 | } | |
121 | ||
92f5a8d4 | 122 | void weak_release() BOOST_SP_NOEXCEPT |
7c673cae FG |
123 | { |
124 | if( atomic_decrement( &weak_count_ ) == 1 ) | |
125 | { | |
126 | destroy(); | |
127 | } | |
128 | } | |
129 | ||
92f5a8d4 | 130 | long use_count() const BOOST_SP_NOEXCEPT |
7c673cae FG |
131 | { |
132 | return use_count_.load( std::memory_order_acquire ); | |
133 | } | |
134 | }; | |
135 | ||
136 | } // namespace detail | |
137 | ||
138 | } // namespace boost | |
139 | ||
140 | #endif // #ifndef BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_STD_ATOMIC_HPP_INCLUDED |