Chris@102: #ifndef BOOST_SMART_PTR_DETAIL_SPINLOCK_STD_ATOMIC_HPP_INCLUDED
Chris@102: #define BOOST_SMART_PTR_DETAIL_SPINLOCK_STD_ATOMIC_HPP_INCLUDED
Chris@102: 
Chris@102: // MS compatible compilers support #pragma once
Chris@102: 
Chris@102: #if defined(_MSC_VER) && (_MSC_VER >= 1020)
Chris@102: # pragma once
Chris@102: #endif
Chris@102: 
Chris@102: //
Chris@102: //  Copyright (c) 2014 Peter Dimov
Chris@102: //
Chris@102: //  Distributed under the Boost Software License, Version 1.0.
Chris@102: //  See accompanying file LICENSE_1_0.txt or copy at
Chris@102: //  http://www.boost.org/LICENSE_1_0.txt)
Chris@102: //
Chris@102: 
Chris@102: #include <boost/smart_ptr/detail/yield_k.hpp>
Chris@102: #include <atomic>
Chris@102: 
Chris@102: namespace boost
Chris@102: {
Chris@102: 
Chris@102: namespace detail
Chris@102: {
Chris@102: 
Chris@102: class spinlock
Chris@102: {
Chris@102: public:
Chris@102: 
Chris@102:     std::atomic_flag v_;
Chris@102: 
Chris@102: public:
Chris@102: 
Chris@102:     bool try_lock()
Chris@102:     {
Chris@102:         return !v_.test_and_set( std::memory_order_acquire );
Chris@102:     }
Chris@102: 
Chris@102:     void lock()
Chris@102:     {
Chris@102:         for( unsigned k = 0; !try_lock(); ++k )
Chris@102:         {
Chris@102:             boost::detail::yield( k );
Chris@102:         }
Chris@102:     }
Chris@102: 
Chris@102:     void unlock()
Chris@102:     {
Chris@102:         v_ .clear( std::memory_order_release );
Chris@102:     }
Chris@102: 
Chris@102: public:
Chris@102: 
Chris@102:     class scoped_lock
Chris@102:     {
Chris@102:     private:
Chris@102: 
Chris@102:         spinlock & sp_;
Chris@102: 
Chris@102:         scoped_lock( scoped_lock const & );
Chris@102:         scoped_lock & operator=( scoped_lock const & );
Chris@102: 
Chris@102:     public:
Chris@102: 
Chris@102:         explicit scoped_lock( spinlock & sp ): sp_( sp )
Chris@102:         {
Chris@102:             sp.lock();
Chris@102:         }
Chris@102: 
Chris@102:         ~scoped_lock()
Chris@102:         {
Chris@102:             sp_.unlock();
Chris@102:         }
Chris@102:     };
Chris@102: };
Chris@102: 
Chris@102: } // namespace detail
Chris@102: } // namespace boost
Chris@102: 
Chris@102: #define BOOST_DETAIL_SPINLOCK_INIT { ATOMIC_FLAG_INIT }
Chris@102: 
Chris@102: #endif // #ifndef BOOST_SMART_PTR_DETAIL_SPINLOCK_STD_ATOMIC_HPP_INCLUDED