[3428] | 1 | #ifndef BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_CW_X86_HPP_INCLUDED |
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| 2 | #define BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_CW_X86_HPP_INCLUDED |
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| 3 | |
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| 4 | // MS compatible compilers support #pragma once |
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| 5 | |
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| 6 | #if defined(_MSC_VER) && (_MSC_VER >= 1020) |
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| 7 | # pragma once |
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| 8 | #endif |
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| 9 | |
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| 10 | // |
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| 11 | // detail/sp_counted_base_cw_x86.hpp - CodeWarrion on 486+ |
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| 12 | // |
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| 13 | // Copyright (c) 2001, 2002, 2003 Peter Dimov and Multi Media Ltd. |
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| 14 | // Copyright 2004-2005 Peter Dimov |
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| 15 | // Copyright 2005 Rene Rivera |
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| 16 | // |
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| 17 | // Distributed under the Boost Software License, Version 1.0. (See |
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| 18 | // accompanying file LICENSE_1_0.txt or copy at |
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| 19 | // http://www.boost.org/LICENSE_1_0.txt) |
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| 20 | // |
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| 21 | // |
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| 22 | // Lock-free algorithm by Alexander Terekhov |
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| 23 | // |
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| 24 | // Thanks to Ben Hitchings for the #weak + (#shared != 0) |
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| 25 | // formulation |
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| 26 | // |
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| 27 | |
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| 28 | #include <boost/detail/sp_typeinfo.hpp> |
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| 29 | |
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| 30 | namespace boost |
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| 31 | { |
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| 32 | |
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| 33 | namespace detail |
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| 34 | { |
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| 35 | |
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| 36 | inline int atomic_exchange_and_add( int * pw, int dv ) |
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| 37 | { |
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| 38 | // int r = *pw; |
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| 39 | // *pw += dv; |
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| 40 | // return r; |
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| 41 | |
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| 42 | asm |
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| 43 | { |
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| 44 | mov esi, [pw] |
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| 45 | mov eax, dv |
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| 46 | lock xadd dword ptr [esi], eax |
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| 47 | } |
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| 48 | } |
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| 49 | |
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| 50 | inline void atomic_increment( int * pw ) |
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| 51 | { |
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| 52 | //atomic_exchange_and_add( pw, 1 ); |
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| 53 | |
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| 54 | asm |
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| 55 | { |
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| 56 | mov esi, [pw] |
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| 57 | lock inc dword ptr [esi] |
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| 58 | } |
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| 59 | } |
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| 60 | |
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| 61 | inline int atomic_conditional_increment( int * pw ) |
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| 62 | { |
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| 63 | // int rv = *pw; |
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| 64 | // if( rv != 0 ) ++*pw; |
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| 65 | // return rv; |
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| 66 | |
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| 67 | asm |
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| 68 | { |
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| 69 | mov esi, [pw] |
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| 70 | mov eax, dword ptr [esi] |
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| 71 | L0: |
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| 72 | test eax, eax |
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| 73 | je L1 |
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| 74 | mov ebx, eax |
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| 75 | inc ebx |
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| 76 | lock cmpxchg dword ptr [esi], ebx |
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| 77 | jne L0 |
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| 78 | L1: |
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| 79 | } |
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| 80 | } |
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| 81 | |
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| 82 | class sp_counted_base |
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| 83 | { |
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| 84 | private: |
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| 85 | |
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| 86 | sp_counted_base( sp_counted_base const & ); |
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| 87 | sp_counted_base & operator= ( sp_counted_base const & ); |
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| 88 | |
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| 89 | int use_count_; // #shared |
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| 90 | int weak_count_; // #weak + (#shared != 0) |
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| 91 | |
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| 92 | public: |
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| 93 | |
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| 94 | sp_counted_base(): use_count_( 1 ), weak_count_( 1 ) |
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| 95 | { |
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| 96 | } |
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| 97 | |
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| 98 | virtual ~sp_counted_base() // nothrow |
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| 99 | { |
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| 100 | } |
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| 101 | |
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| 102 | // dispose() is called when use_count_ drops to zero, to release |
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| 103 | // the resources managed by *this. |
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| 104 | |
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| 105 | virtual void dispose() = 0; // nothrow |
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| 106 | |
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| 107 | // destroy() is called when weak_count_ drops to zero. |
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| 108 | |
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| 109 | virtual void destroy() // nothrow |
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| 110 | { |
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| 111 | delete this; |
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| 112 | } |
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| 113 | |
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| 114 | virtual void * get_deleter( sp_typeinfo const & ti ) = 0; |
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| 115 | |
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| 116 | void add_ref_copy() |
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| 117 | { |
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| 118 | atomic_increment( &use_count_ ); |
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| 119 | } |
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| 120 | |
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| 121 | bool add_ref_lock() // true on success |
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| 122 | { |
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| 123 | return atomic_conditional_increment( &use_count_ ) != 0; |
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| 124 | } |
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| 125 | |
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| 126 | void release() // nothrow |
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| 127 | { |
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| 128 | if( atomic_exchange_and_add( &use_count_, -1 ) == 1 ) |
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| 129 | { |
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| 130 | dispose(); |
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| 131 | weak_release(); |
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| 132 | } |
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| 133 | } |
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| 134 | |
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| 135 | void weak_add_ref() // nothrow |
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| 136 | { |
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| 137 | atomic_increment( &weak_count_ ); |
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| 138 | } |
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| 139 | |
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| 140 | void weak_release() // nothrow |
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| 141 | { |
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| 142 | if( atomic_exchange_and_add( &weak_count_, -1 ) == 1 ) |
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| 143 | { |
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| 144 | destroy(); |
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| 145 | } |
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| 146 | } |
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| 147 | |
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| 148 | long use_count() const // nothrow |
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| 149 | { |
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| 150 | return static_cast<int const volatile &>( use_count_ ); |
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| 151 | } |
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| 152 | }; |
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| 153 | |
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| 154 | } // namespace detail |
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| 155 | |
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| 156 | } // namespace boost |
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| 157 | |
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| 158 | #endif // #ifndef BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_CW_X86_HPP_INCLUDED |
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