112 lines
2.8 KiB
C++
112 lines
2.8 KiB
C++
//////////////////////////////////////////////////////////////////////////////
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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_SEMAPHORE_HPP
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#define BOOST_INTERPROCESS_DETAIL_SPIN_SEMAPHORE_HPP
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#if (defined _MSC_VER) && (_MSC_VER >= 1200)
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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/atomic.hpp>
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#include <boost/interprocess/detail/os_thread_functions.hpp>
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#include <boost/interprocess/detail/posix_time_types_wrk.hpp>
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#include <boost/interprocess/sync/spin/wait.hpp>
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#include <boost/cstdint.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_semaphore
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{
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spin_semaphore(const spin_semaphore &);
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spin_semaphore &operator=(const spin_semaphore &);
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public:
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spin_semaphore(unsigned int initialCount);
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~spin_semaphore();
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void post();
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void wait();
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bool try_wait();
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bool timed_wait(const boost::posix_time::ptime &abs_time);
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// int get_count() const;
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private:
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volatile boost::uint32_t m_count;
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};
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inline spin_semaphore::~spin_semaphore()
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{}
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inline spin_semaphore::spin_semaphore(unsigned int initialCount)
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{ ipcdetail::atomic_write32(&this->m_count, boost::uint32_t(initialCount)); }
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inline void spin_semaphore::post()
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{
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ipcdetail::atomic_inc32(&m_count);
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}
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inline void spin_semaphore::wait()
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{
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spin_wait swait;
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while(!ipcdetail::atomic_add_unless32(&m_count, boost::uint32_t(-1), boost::uint32_t(0))){
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swait.yield();
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}
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}
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inline bool spin_semaphore::try_wait()
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{
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return ipcdetail::atomic_add_unless32(&m_count, boost::uint32_t(-1), boost::uint32_t(0));
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}
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inline bool spin_semaphore::timed_wait(const boost::posix_time::ptime &abs_time)
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{
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if(abs_time == boost::posix_time::pos_infin){
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this->wait();
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return true;
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}
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//Obtain current count and target time
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boost::posix_time::ptime now(microsec_clock::universal_time());
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spin_wait swait;
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do{
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if(this->try_wait()){
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break;
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}
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now = microsec_clock::universal_time();
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if(now >= abs_time){
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return this->try_wait();
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}
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// relinquish current time slice
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swait.yield();
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}while (true);
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return true;
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}
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//inline int spin_semaphore::get_count() const
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//{
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//return (int)ipcdetail::atomic_read32(&m_count);
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//}
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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_SEMAPHORE_HPP
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