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1 | #ifndef BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_W32_HPP_INCLUDED |
2 | #define BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_W32_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 | // detail/sp_counted_base_w32.hpp | |
12 | // | |
13 | // Copyright (c) 2001, 2002, 2003 Peter Dimov and Multi Media Ltd. | |
14 | // Copyright 2004-2005 Peter Dimov | |
15 | // | |
16 | // Distributed under the Boost Software License, Version 1.0. (See | |
17 | // accompanying file LICENSE_1_0.txt or copy at | |
18 | // http://www.boost.org/LICENSE_1_0.txt) | |
19 | // | |
20 | // | |
21 | // Lock-free algorithm by Alexander Terekhov | |
22 | // | |
23 | // Thanks to Ben Hitchings for the #weak + (#shared != 0) | |
24 | // formulation | |
25 | // | |
26 | ||
27 | #include <boost/smart_ptr/detail/sp_interlocked.hpp> | |
92f5a8d4 | 28 | #include <boost/smart_ptr/detail/sp_typeinfo_.hpp> |
7c673cae | 29 | #include <boost/detail/workaround.hpp> |
92f5a8d4 | 30 | #include <boost/config.hpp> |
7c673cae FG |
31 | |
32 | namespace boost | |
33 | { | |
34 | ||
35 | namespace detail | |
36 | { | |
37 | ||
92f5a8d4 | 38 | class BOOST_SYMBOL_VISIBLE sp_counted_base |
7c673cae FG |
39 | { |
40 | private: | |
41 | ||
42 | sp_counted_base( sp_counted_base const & ); | |
43 | sp_counted_base & operator= ( sp_counted_base const & ); | |
44 | ||
45 | long use_count_; // #shared | |
46 | long weak_count_; // #weak + (#shared != 0) | |
47 | ||
48 | public: | |
49 | ||
50 | sp_counted_base(): use_count_( 1 ), weak_count_( 1 ) | |
51 | { | |
52 | } | |
53 | ||
54 | virtual ~sp_counted_base() // nothrow | |
55 | { | |
56 | } | |
57 | ||
58 | // dispose() is called when use_count_ drops to zero, to release | |
59 | // the resources managed by *this. | |
60 | ||
61 | virtual void dispose() = 0; // nothrow | |
62 | ||
63 | // destroy() is called when weak_count_ drops to zero. | |
64 | ||
65 | virtual void destroy() // nothrow | |
66 | { | |
67 | delete this; | |
68 | } | |
69 | ||
92f5a8d4 TL |
70 | virtual void * get_deleter( sp_typeinfo_ const & ti ) = 0; |
71 | virtual void * get_local_deleter( sp_typeinfo_ const & ti ) = 0; | |
7c673cae FG |
72 | virtual void * get_untyped_deleter() = 0; |
73 | ||
74 | void add_ref_copy() | |
75 | { | |
76 | BOOST_SP_INTERLOCKED_INCREMENT( &use_count_ ); | |
77 | } | |
78 | ||
79 | bool add_ref_lock() // true on success | |
80 | { | |
81 | for( ;; ) | |
82 | { | |
83 | long tmp = static_cast< long const volatile& >( use_count_ ); | |
84 | if( tmp == 0 ) return false; | |
85 | ||
86 | #if defined( BOOST_MSVC ) && BOOST_WORKAROUND( BOOST_MSVC, == 1200 ) | |
87 | ||
88 | // work around a code generation bug | |
89 | ||
90 | long tmp2 = tmp + 1; | |
91 | if( BOOST_SP_INTERLOCKED_COMPARE_EXCHANGE( &use_count_, tmp2, tmp ) == tmp2 - 1 ) return true; | |
92 | ||
93 | #else | |
94 | ||
95 | if( BOOST_SP_INTERLOCKED_COMPARE_EXCHANGE( &use_count_, tmp + 1, tmp ) == tmp ) return true; | |
96 | ||
97 | #endif | |
98 | } | |
99 | } | |
100 | ||
101 | void release() // nothrow | |
102 | { | |
103 | if( BOOST_SP_INTERLOCKED_DECREMENT( &use_count_ ) == 0 ) | |
104 | { | |
105 | dispose(); | |
106 | weak_release(); | |
107 | } | |
108 | } | |
109 | ||
110 | void weak_add_ref() // nothrow | |
111 | { | |
112 | BOOST_SP_INTERLOCKED_INCREMENT( &weak_count_ ); | |
113 | } | |
114 | ||
115 | void weak_release() // nothrow | |
116 | { | |
117 | if( BOOST_SP_INTERLOCKED_DECREMENT( &weak_count_ ) == 0 ) | |
118 | { | |
119 | destroy(); | |
120 | } | |
121 | } | |
122 | ||
123 | long use_count() const // nothrow | |
124 | { | |
125 | return static_cast<long const volatile &>( use_count_ ); | |
126 | } | |
127 | }; | |
128 | ||
129 | } // namespace detail | |
130 | ||
131 | } // namespace boost | |
132 | ||
133 | #endif // #ifndef BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_W32_HPP_INCLUDED |