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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> | |
28 | #include <boost/detail/workaround.hpp> | |
29 | #include <boost/detail/sp_typeinfo.hpp> | |
30 | ||
31 | namespace boost | |
32 | { | |
33 | ||
34 | namespace detail | |
35 | { | |
36 | ||
37 | class sp_counted_base | |
38 | { | |
39 | private: | |
40 | ||
41 | sp_counted_base( sp_counted_base const & ); | |
42 | sp_counted_base & operator= ( sp_counted_base const & ); | |
43 | ||
44 | long use_count_; // #shared | |
45 | long weak_count_; // #weak + (#shared != 0) | |
46 | ||
47 | public: | |
48 | ||
49 | sp_counted_base(): use_count_( 1 ), weak_count_( 1 ) | |
50 | { | |
51 | } | |
52 | ||
53 | virtual ~sp_counted_base() // nothrow | |
54 | { | |
55 | } | |
56 | ||
57 | // dispose() is called when use_count_ drops to zero, to release | |
58 | // the resources managed by *this. | |
59 | ||
60 | virtual void dispose() = 0; // nothrow | |
61 | ||
62 | // destroy() is called when weak_count_ drops to zero. | |
63 | ||
64 | virtual void destroy() // nothrow | |
65 | { | |
66 | delete this; | |
67 | } | |
68 | ||
69 | virtual void * get_deleter( sp_typeinfo const & ti ) = 0; | |
70 | virtual void * get_untyped_deleter() = 0; | |
71 | ||
72 | void add_ref_copy() | |
73 | { | |
74 | BOOST_SP_INTERLOCKED_INCREMENT( &use_count_ ); | |
75 | } | |
76 | ||
77 | bool add_ref_lock() // true on success | |
78 | { | |
79 | for( ;; ) | |
80 | { | |
81 | long tmp = static_cast< long const volatile& >( use_count_ ); | |
82 | if( tmp == 0 ) return false; | |
83 | ||
84 | #if defined( BOOST_MSVC ) && BOOST_WORKAROUND( BOOST_MSVC, == 1200 ) | |
85 | ||
86 | // work around a code generation bug | |
87 | ||
88 | long tmp2 = tmp + 1; | |
89 | if( BOOST_SP_INTERLOCKED_COMPARE_EXCHANGE( &use_count_, tmp2, tmp ) == tmp2 - 1 ) return true; | |
90 | ||
91 | #else | |
92 | ||
93 | if( BOOST_SP_INTERLOCKED_COMPARE_EXCHANGE( &use_count_, tmp + 1, tmp ) == tmp ) return true; | |
94 | ||
95 | #endif | |
96 | } | |
97 | } | |
98 | ||
99 | void release() // nothrow | |
100 | { | |
101 | if( BOOST_SP_INTERLOCKED_DECREMENT( &use_count_ ) == 0 ) | |
102 | { | |
103 | dispose(); | |
104 | weak_release(); | |
105 | } | |
106 | } | |
107 | ||
108 | void weak_add_ref() // nothrow | |
109 | { | |
110 | BOOST_SP_INTERLOCKED_INCREMENT( &weak_count_ ); | |
111 | } | |
112 | ||
113 | void weak_release() // nothrow | |
114 | { | |
115 | if( BOOST_SP_INTERLOCKED_DECREMENT( &weak_count_ ) == 0 ) | |
116 | { | |
117 | destroy(); | |
118 | } | |
119 | } | |
120 | ||
121 | long use_count() const // nothrow | |
122 | { | |
123 | return static_cast<long const volatile &>( use_count_ ); | |
124 | } | |
125 | }; | |
126 | ||
127 | } // namespace detail | |
128 | ||
129 | } // namespace boost | |
130 | ||
131 | #endif // #ifndef BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_W32_HPP_INCLUDED |