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//////////////////////////////////////////////////////////////////////////////
//
// (C) Copyright Ion Gaztanaga 2005-2012. Distributed under the Boost
// Software License, Version 1.0. (See accompanying file
// LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//
// See http://www.boost.org/libs/interprocess for documentation.
//
//////////////////////////////////////////////////////////////////////////////
#ifndef BOOST_INTERPROCESS_DETAIL_SPIN_MUTEX_HPP
#define BOOST_INTERPROCESS_DETAIL_SPIN_MUTEX_HPP
#if defined(_MSC_VER)
# pragma once
#endif
#include <boost/interprocess/detail/config_begin.hpp>
#include <boost/interprocess/detail/workaround.hpp>
#include <boost/interprocess/detail/posix_time_types_wrk.hpp>
#include <boost/assert.hpp>
#include <boost/interprocess/detail/atomic.hpp>
#include <boost/cstdint.hpp>
#include <boost/interprocess/detail/os_thread_functions.hpp>
#include <boost/interprocess/sync/detail/common_algorithms.hpp>
namespace boost {
namespace interprocess {
namespace ipcdetail {
class spin_mutex
{
spin_mutex(const spin_mutex &);
spin_mutex &operator=(const spin_mutex &);
public:
spin_mutex();
~spin_mutex();
void lock();
bool try_lock();
bool timed_lock(const boost::posix_time::ptime &abs_time);
void unlock();
void take_ownership(){};
private:
volatile boost::uint32_t m_s;
};
inline spin_mutex::spin_mutex()
: m_s(0)
{
//Note that this class is initialized to zero.
//So zeroed memory can be interpreted as an
//initialized mutex
}
inline spin_mutex::~spin_mutex()
{
//Trivial destructor
}
inline void spin_mutex::lock(void)
{ return ipcdetail::try_based_lock(*this); }
inline bool spin_mutex::try_lock(void)
{
boost::uint32_t prev_s = ipcdetail::atomic_cas32(const_cast<boost::uint32_t*>(&m_s), 1, 0);
return m_s == 1 && prev_s == 0;
}
inline bool spin_mutex::timed_lock(const boost::posix_time::ptime &abs_time)
{ return ipcdetail::try_based_timed_lock(*this, abs_time); }
inline void spin_mutex::unlock(void)
{ ipcdetail::atomic_cas32(const_cast<boost::uint32_t*>(&m_s), 0, 1); }
} //namespace ipcdetail {
} //namespace interprocess {
} //namespace boost {
#include <boost/interprocess/detail/config_end.hpp>
#endif //BOOST_INTERPROCESS_DETAIL_SPIN_MUTEX_HPP
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