| 1 | #ifndef BOOST_DETAIL_SP_COUNTED_BASE_ATOMIC_HPP_INCLUDED
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| 2 | #define BOOST_DETAIL_SP_COUNTED_BASE_ATOMIC_HPP_INCLUDED
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| 3 |
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| 4 | //#warning "Using experimental atomic shared pointer"
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| 5 |
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| 6 | // MS compatible compilers support #pragma once
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| 7 |
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| 8 | #if defined(_MSC_VER) && (_MSC_VER >= 1020)
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| 9 | # pragma once
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| 10 | #endif
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| 11 |
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| 12 | //
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| 13 | // detail/sp_counted_base_atomic.hpp
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| 14 | //
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| 15 | // Copyright (c) 2001, 2002, 2003 Peter Dimov and Multi Media Ltd.
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| 16 | // Copyright 2004-2005 Peter Dimov
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| 17 | // Copyright 2009 Philip Endecott
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| 18 | //
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| 19 | // Distributed under the Boost Software License, Version 1.0. (See
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| 20 | // accompanying file LICENSE_1_0.txt or copy at
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| 21 | // http://www.boost.org/LICENSE_1_0.txt)
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| 22 | //
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| 23 |
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| 24 | #include <boost/detail/sp_typeinfo.hpp>
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| 25 | #include <boost/atomic.hpp>
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| 26 |
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| 27 |
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| 28 | namespace boost
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| 29 | {
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| 30 |
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| 31 | namespace detail
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| 32 | {
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| 33 |
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| 34 | class sp_counted_base
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| 35 | {
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| 36 | private:
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| 37 |
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| 38 | sp_counted_base( sp_counted_base const & );
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| 39 | sp_counted_base & operator= ( sp_counted_base const & );
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| 40 |
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| 41 | boost::atomic<long> use_count_; // #shared
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| 42 | boost::atomic<long> weak_count_; // #weak + (#shared != 0)
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| 43 |
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| 44 | public:
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| 45 |
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| 46 | sp_counted_base(): use_count_( 1 ), weak_count_( 1 )
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| 47 | {
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| 48 | }
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| 49 |
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| 50 | virtual ~sp_counted_base() // nothrow
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| 51 | {
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| 52 | }
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| 53 |
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| 54 | // dispose() is called when use_count_ drops to zero, to release
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| 55 | // the resources managed by *this.
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| 56 |
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| 57 | virtual void dispose() = 0; // nothrow
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| 58 |
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| 59 | // destroy() is called when weak_count_ drops to zero.
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| 60 |
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| 61 | virtual void destroy() // nothrow
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| 62 | {
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| 63 | delete this;
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| 64 | }
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| 65 |
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| 66 | virtual void * get_deleter( sp_typeinfo const & ti ) = 0;
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| 67 |
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| 68 | void add_ref_copy()
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| 69 | {
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| 70 | ++use_count_;
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| 71 | }
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| 72 |
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| 73 | bool add_ref_lock() // true on success
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| 74 | {
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| 75 | while (1) {
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| 76 | long c = use_count_;
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| 77 | if (c == 0) return false;
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| 78 | if (use_count_.compare_exchange_weak(c,c+1)) return true;
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| 79 | }
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| 80 | }
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| 81 |
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| 82 | void release() // nothrow
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| 83 | {
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| 84 | if( --use_count_ == 0 )
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| 85 | {
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| 86 | dispose();
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| 87 | weak_release();
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| 88 | }
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| 89 | }
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| 90 |
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| 91 | void weak_add_ref() // nothrow
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| 92 | {
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| 93 | ++weak_count_;
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| 94 | }
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| 95 |
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| 96 | void weak_release() // nothrow
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| 97 | {
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| 98 | if( --weak_count_ == 0 )
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| 99 | {
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| 100 | destroy();
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| 101 | }
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| 102 | }
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| 103 |
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| 104 | long use_count() const // nothrow
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| 105 | {
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| 106 | return use_count_;
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| 107 | }
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| 108 | };
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| 109 |
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| 110 | } // namespace detail
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| 111 |
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| 112 | } // namespace boost
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| 113 |
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| 114 | #endif // #ifndef BOOST_DETAIL_SP_COUNTED_BASE_ATOMIC_HPP_INCLUDED
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