sync/spin/semaphore.hpp

0001 //////////////////////////////////////////////////////////////////////////////
0002 //
0003 // (C) Copyright Ion Gaztanaga 2005-2012. Distributed under the Boost
0004 // Software License, Version 1.0. (See accompanying file
0005 // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
0006 //
0007 // See http://www.boost.org/libs/interprocess for documentation.
0008 //
0009 //////////////////////////////////////////////////////////////////////////////
0010
0011 #ifndef BOOST_INTERPROCESS_DETAIL_SPIN_SEMAPHORE_HPP
0012 #define BOOST_INTERPROCESS_DETAIL_SPIN_SEMAPHORE_HPP
0013
0014 #ifndef BOOST_CONFIG_HPP
0015 #  include <boost/config.hpp>
0016 #endif
0017 #
0018 #if defined(BOOST_HAS_PRAGMA_ONCE)
0019 #  pragma once
0020 #endif
0021
0022 #include <boost/interprocess/detail/config_begin.hpp>
0023 #include <boost/interprocess/detail/workaround.hpp>
0024 #include <boost/interprocess/detail/atomic.hpp>
0025 #include <boost/interprocess/detail/os_thread_functions.hpp>
0026 #include <boost/interprocess/sync/detail/common_algorithms.hpp>
0027 #include <boost/interprocess/sync/detail/locks.hpp>
0028 #include <boost/cstdint.hpp>
0029
0030 namespace boost {
0031 namespace interprocess {
0032 namespace ipcdetail {
0033
0034 class spin_semaphore
0035 {
0036    spin_semaphore(const spin_semaphore &);
0037    spin_semaphore &operator=(const spin_semaphore &);
0038
0039    public:
0040    spin_semaphore(unsigned int initialCount);
0041    ~spin_semaphore();
0042
0043    void post();
0044    void wait();
0045    bool try_wait();
0046    template<class TimePoint> bool timed_wait(const TimePoint &abs_time);
0047
0048 //   int get_count() const;
0049    private:
0050    volatile boost::uint32_t m_count;
0051 };
0052
0053
0054 inline spin_semaphore::~spin_semaphore()
0055 {}
0056
0057 inline spin_semaphore::spin_semaphore(unsigned int initialCount)
0058 {  ipcdetail::atomic_write32(&this->m_count, boost::uint32_t(initialCount));  }
0059
0060 inline void spin_semaphore::post()
0061 {
0062    ipcdetail::atomic_inc32(&m_count);
0063 }
0064
0065 inline void spin_semaphore::wait()
0066 {
0067    ipcdetail::lock_to_wait<spin_semaphore> lw(*this);
0068    return ipcdetail::try_based_lock(lw);
0069 }
0070
0071 inline bool spin_semaphore::try_wait()
0072 {
0073    return ipcdetail::atomic_add_unless32(&m_count, boost::uint32_t(-1), boost::uint32_t(0));
0074 }
0075
0076 template<class TimePoint>
0077 inline bool spin_semaphore::timed_wait(const TimePoint &abs_time)
0078 {
0079    ipcdetail::lock_to_wait<spin_semaphore> lw(*this);
0080    return ipcdetail::try_based_timed_lock(lw, abs_time);
0081 }
0082
0083 //inline int spin_semaphore::get_count() const
0084 //{
0085    //return (int)ipcdetail::atomic_read32(&m_count);
0086 //}
0087
0088 }  //namespace ipcdetail {
0089 }  //namespace interprocess {
0090 }  //namespace boost {
0091
0092 #include <boost/interprocess/detail/config_end.hpp>
0093
0094 #endif   //BOOST_INTERPROCESS_DETAIL_SPIN_SEMAPHORE_HPP