Chris@16: //////////////////////////////////////////////////////////////////////////////
Chris@16: //
Chris@16: // (C) Copyright Ion Gaztanaga 2005-2012. Distributed under the Boost
Chris@16: // Software License, Version 1.0. (See accompanying file
Chris@16: // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
Chris@16: //
Chris@16: // See http://www.boost.org/libs/interprocess for documentation.
Chris@16: //
Chris@16: //////////////////////////////////////////////////////////////////////////////
Chris@16: 
Chris@16: #ifndef BOOST_INTERPROCESS_DETAIL_SPIN_MUTEX_HPP
Chris@16: #define BOOST_INTERPROCESS_DETAIL_SPIN_MUTEX_HPP
Chris@16: 
Chris@101: #ifndef BOOST_CONFIG_HPP
Chris@101: #  include <boost/config.hpp>
Chris@101: #endif
Chris@101: #
Chris@101: #if defined(BOOST_HAS_PRAGMA_ONCE)
Chris@16: #  pragma once
Chris@16: #endif
Chris@16: 
Chris@16: #include <boost/interprocess/detail/config_begin.hpp>
Chris@16: #include <boost/interprocess/detail/workaround.hpp>
Chris@16: #include <boost/interprocess/detail/posix_time_types_wrk.hpp>
Chris@16: #include <boost/assert.hpp>
Chris@16: #include <boost/interprocess/detail/atomic.hpp>
Chris@16: #include <boost/cstdint.hpp>
Chris@16: #include <boost/interprocess/detail/os_thread_functions.hpp>
Chris@101: #include <boost/interprocess/sync/detail/common_algorithms.hpp>
Chris@16: 
Chris@16: namespace boost {
Chris@16: namespace interprocess {
Chris@16: namespace ipcdetail {
Chris@16: 
Chris@16: class spin_mutex
Chris@16: {
Chris@16:    spin_mutex(const spin_mutex &);
Chris@16:    spin_mutex &operator=(const spin_mutex &);
Chris@16:    public:
Chris@16: 
Chris@16:    spin_mutex();
Chris@16:    ~spin_mutex();
Chris@16: 
Chris@16:    void lock();
Chris@16:    bool try_lock();
Chris@16:    bool timed_lock(const boost::posix_time::ptime &abs_time);
Chris@16:    void unlock();
Chris@16:    void take_ownership(){};
Chris@16:    private:
Chris@16:    volatile boost::uint32_t m_s;
Chris@16: };
Chris@16: 
Chris@16: inline spin_mutex::spin_mutex()
Chris@16:    : m_s(0)
Chris@16: {
Chris@16:    //Note that this class is initialized to zero.
Chris@16:    //So zeroed memory can be interpreted as an
Chris@16:    //initialized mutex
Chris@16: }
Chris@16: 
Chris@16: inline spin_mutex::~spin_mutex()
Chris@16: {
Chris@16:    //Trivial destructor
Chris@16: }
Chris@16: 
Chris@16: inline void spin_mutex::lock(void)
Chris@101: {  return ipcdetail::try_based_lock(*this); }
Chris@16: 
Chris@16: inline bool spin_mutex::try_lock(void)
Chris@16: {
Chris@16:    boost::uint32_t prev_s = ipcdetail::atomic_cas32(const_cast<boost::uint32_t*>(&m_s), 1, 0);
Chris@16:    return m_s == 1 && prev_s == 0;
Chris@16: }
Chris@16: 
Chris@16: inline bool spin_mutex::timed_lock(const boost::posix_time::ptime &abs_time)
Chris@101: {  return ipcdetail::try_based_timed_lock(*this, abs_time); }
Chris@16: 
Chris@16: inline void spin_mutex::unlock(void)
Chris@16: {  ipcdetail::atomic_cas32(const_cast<boost::uint32_t*>(&m_s), 0, 1);   }
Chris@16: 
Chris@16: }  //namespace ipcdetail {
Chris@16: }  //namespace interprocess {
Chris@16: }  //namespace boost {
Chris@16: 
Chris@16: #include <boost/interprocess/detail/config_end.hpp>
Chris@16: 
Chris@16: #endif   //BOOST_INTERPROCESS_DETAIL_SPIN_MUTEX_HPP