smart_ptr/detail/atomic_count_std_atomic.hpp

0001 #ifndef BOOST_SMART_PTR_DETAIL_ATOMIC_COUNT_STD_ATOMIC_HPP_INCLUDED
0002 #define BOOST_SMART_PTR_DETAIL_ATOMIC_COUNT_STD_ATOMIC_HPP_INCLUDED
0003
0004 //
0005 //  boost/detail/atomic_count_std_atomic.hpp
0006 //
0007 //  atomic_count for std::atomic
0008 //
0009 //  Copyright 2013 Peter Dimov
0010 //
0011 //  Distributed under the Boost Software License, Version 1.0.
0012 //  See accompanying file LICENSE_1_0.txt or copy at
0013 //  http://www.boost.org/LICENSE_1_0.txt
0014 //
0015
0016 #include <atomic>
0017 #include <cstdint>
0018
0019 #if defined(BOOST_SP_REPORT_IMPLEMENTATION)
0020
0021 #include <boost/config/pragma_message.hpp>
0022 BOOST_PRAGMA_MESSAGE("Using std::atomic atomic_count")
0023
0024 #endif
0025
0026 namespace boost
0027 {
0028
0029 namespace detail
0030 {
0031
0032 class atomic_count
0033 {
0034 public:
0035
0036     explicit atomic_count( long v ): value_( static_cast< std::int_least32_t >( v ) )
0037     {
0038     }
0039
0040     long operator++()
0041     {
0042         return value_.fetch_add( 1, std::memory_order_acq_rel ) + 1;
0043     }
0044
0045     long operator--()
0046     {
0047         return value_.fetch_sub( 1, std::memory_order_acq_rel ) - 1;
0048     }
0049
0050     operator long() const
0051     {
0052         return value_.load( std::memory_order_acquire );
0053     }
0054
0055 private:
0056
0057     atomic_count(atomic_count const &);
0058     atomic_count & operator=(atomic_count const &);
0059
0060     std::atomic_int_least32_t value_;
0061 };
0062
0063 } // namespace detail
0064
0065 } // namespace boost
0066
0067 #endif // #ifndef BOOST_SMART_PTR_DETAIL_ATOMIC_COUNT_STD_ATOMIC_HPP_INCLUDED