| | 1 | #ifndef BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_AIX_HPP_INCLUDED |
| | 2 | #define BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_AIX_HPP_INCLUDED |
| | 3 | |
| | 4 | // |
| | 5 | // detail/sp_counted_base_aix.hpp |
| | 6 | // based on: detail/sp_counted_base_w32.hpp |
| | 7 | // |
| | 8 | // Copyright (c) 2001, 2002, 2003 Peter Dimov and Multi Media Ltd. |
| | 9 | // Copyright 2004-2005 Peter Dimov |
| | 10 | // Copyright 2006 Michael van der Westhuizen |
| | 11 | // |
| | 12 | // Distributed under the Boost Software License, Version 1.0. (See |
| | 13 | // accompanying file LICENSE_1_0.txt or copy at |
| | 14 | // http://www.boost.org/LICENSE_1_0.txt) |
| | 15 | // |
| | 16 | // |
| | 17 | // Lock-free algorithm by Alexander Terekhov |
| | 18 | // |
| | 19 | // Thanks to Ben Hitchings for the #weak + (#shared != 0) |
| | 20 | // formulation |
| | 21 | // |
| | 22 | |
| | 23 | #include <boost/detail/sp_typeinfo.hpp> |
| | 24 | #include <sys/atomic_op.h> |
| | 25 | |
| | 26 | namespace boost |
| | 27 | { |
| | 28 | |
| | 29 | namespace detail |
| | 30 | { |
| | 31 | |
| | 32 | class sp_counted_base |
| | 33 | { |
| | 34 | private: |
| | 35 | |
| | 36 | sp_counted_base( sp_counted_base const & ); |
| | 37 | sp_counted_base & operator= ( sp_counted_base const & ); |
| | 38 | |
| | 39 | int32_t use_count_; // #shared |
| | 40 | int32_t weak_count_; // #weak + (#shared != 0) |
| | 41 | |
| | 42 | public: |
| | 43 | |
| | 44 | sp_counted_base(): use_count_( 1 ), weak_count_( 1 ) |
| | 45 | { |
| | 46 | } |
| | 47 | |
| | 48 | virtual ~sp_counted_base() // nothrow |
| | 49 | { |
| | 50 | } |
| | 51 | |
| | 52 | // dispose() is called when use_count_ drops to zero, to release |
| | 53 | // the resources managed by *this. |
| | 54 | |
| | 55 | virtual void dispose() = 0; // nothrow |
| | 56 | |
| | 57 | // destroy() is called when weak_count_ drops to zero. |
| | 58 | |
| | 59 | virtual void destroy() // nothrow |
| | 60 | { |
| | 61 | delete this; |
| | 62 | } |
| | 63 | |
| | 64 | virtual void * get_deleter( sp_typeinfo const & ti ) = 0; |
| | 65 | |
| | 66 | void add_ref_copy() |
| | 67 | { |
| | 68 | fetch_and_add( &use_count_, 1 ); |
| | 69 | } |
| | 70 | |
| | 71 | bool add_ref_lock() // true on success |
| | 72 | { |
| | 73 | int32_t tmp = fetch_and_add( &use_count_, 0 ); |
| | 74 | for( ;; ) |
| | 75 | { |
| | 76 | if( tmp == 0 ) return false; |
| | 77 | if( compare_and_swap( &use_count_, &tmp, tmp + 1 ) ) return true; |
| | 78 | } |
| | 79 | } |
| | 80 | |
| | 81 | void release() // nothrow |
| | 82 | { |
| | 83 | if( fetch_and_add( &use_count_, -1 ) == 1 ) |
| | 84 | { |
| | 85 | dispose(); |
| | 86 | weak_release(); |
| | 87 | } |
| | 88 | } |
| | 89 | |
| | 90 | void weak_add_ref() // nothrow |
| | 91 | { |
| | 92 | fetch_and_add( &weak_count_, 1 ); |
| | 93 | } |
| | 94 | |
| | 95 | void weak_release() // nothrow |
| | 96 | { |
| | 97 | if( fetch_and_add( &weak_count_, -1 ) == 1 ) |
| | 98 | { |
| | 99 | destroy(); |
| | 100 | } |
| | 101 | } |
| | 102 | |
| | 103 | long use_count() const // nothrow |
| | 104 | { |
| | 105 | return fetch_and_add( const_cast<int32_t*>(&use_count_), 0 ); |
| | 106 | } |
| | 107 | }; |
| | 108 | |
| | 109 | } // namespace detail |
| | 110 | |
| | 111 | } // namespace boost |
| | 112 | |
| | 113 | #endif // #ifndef BOOST_SMART_PTR_DETAIL_SP_COUNTED_BASE_AIX_HPP_INCLUDED |