ceph/src/boost/boost/interprocess/sync/spin/semaphore.hpp

   1 //////////////////////////////////////////////////////////////////////////////
   2 //
   3 // (C) Copyright Ion Gaztanaga 2005-2012. Distributed under the Boost
   4 // Software License, Version 1.0. (See accompanying file
   5 // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   6 //
   7 // See http://www.boost.org/libs/interprocess for documentation.
   8 //
   9 //////////////////////////////////////////////////////////////////////////////
  10
  11 #ifndef BOOST_INTERPROCESS_DETAIL_SPIN_SEMAPHORE_HPP
  12 #define BOOST_INTERPROCESS_DETAIL_SPIN_SEMAPHORE_HPP
  13
  14 #ifndef BOOST_CONFIG_HPP
  15 #  include <boost/config.hpp>
  16 #endif
  17 #
  18 #if defined(BOOST_HAS_PRAGMA_ONCE)
  19 #  pragma once
  20 #endif
  21
  22 #include <boost/interprocess/detail/config_begin.hpp>
  23 #include <boost/interprocess/detail/workaround.hpp>
  24 #include <boost/interprocess/detail/atomic.hpp>
  25 #include <boost/interprocess/detail/os_thread_functions.hpp>
  26 #include <boost/interprocess/sync/detail/common_algorithms.hpp>
  27 #include <boost/interprocess/sync/detail/locks.hpp>
  28 #include <boost/cstdint.hpp>
  29
  30 namespace boost {
  31 namespace interprocess {
  32 namespace ipcdetail {
  33
  34 class spin_semaphore
  35 {
  36    spin_semaphore(const spin_semaphore &);
  37    spin_semaphore &operator=(const spin_semaphore &);
  38
  39    public:
  40    spin_semaphore(unsigned int initialCount);
  41    ~spin_semaphore();
  42
  43    void post();
  44    void wait();
  45    bool try_wait();
  46    template<class TimePoint> bool timed_wait(const TimePoint &abs_time);
  47
  48 //   int get_count() const;
  49    private:
  50    volatile boost::uint32_t m_count;
  51 };
  52
  53
  54 inline spin_semaphore::~spin_semaphore()
  55 {}
  56
  57 inline spin_semaphore::spin_semaphore(unsigned int initialCount)
  58 {  ipcdetail::atomic_write32(&this->m_count, boost::uint32_t(initialCount));  }
  59
  60 inline void spin_semaphore::post()
  61 {
  62    ipcdetail::atomic_inc32(&m_count);
  63 }
  64
  65 inline void spin_semaphore::wait()
  66 {
  67    ipcdetail::lock_to_wait<spin_semaphore> lw(*this);
  68    return ipcdetail::try_based_lock(lw);
  69 }
  70
  71 inline bool spin_semaphore::try_wait()
  72 {
  73    return ipcdetail::atomic_add_unless32(&m_count, boost::uint32_t(-1), boost::uint32_t(0));
  74 }
  75
  76 template<class TimePoint>
  77 inline bool spin_semaphore::timed_wait(const TimePoint &abs_time)
  78 {
  79    ipcdetail::lock_to_wait<spin_semaphore> lw(*this);
  80    return ipcdetail::try_based_timed_lock(lw, abs_time);
  81 }
  82
  83 //inline int spin_semaphore::get_count() const
  84 //{
  85    //return (int)ipcdetail::atomic_read32(&m_count);
  86 //}
  87
  88 }  //namespace ipcdetail {
  89 }  //namespace interprocess {
  90 }  //namespace boost {
  91
  92 #include <boost/interprocess/detail/config_end.hpp>
  93
  94 #endif   //BOOST_INTERPROCESS_DETAIL_SPIN_SEMAPHORE_HPP