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