/Src/Dependencies/Boost/boost/interprocess/sync/emulation/mutex.hpp
http://hadesmem.googlecode.com/ · C++ Header · 114 lines · 78 code · 20 blank · 16 comment · 13 complexity · 31337534ff1fe5a0844afef718f46eee MD5 · raw file
- //////////////////////////////////////////////////////////////////////////////
- //
- // (C) Copyright Ion Gaztanaga 2005-2009. Distributed under the Boost
- // Software License, Version 1.0. (See accompanying file
- // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
- //
- // See http://www.boost.org/libs/interprocess for documentation.
- //
- //////////////////////////////////////////////////////////////////////////////
- #ifndef BOOST_INTERPROCESS_DETAIL_EMULATION_MUTEX_HPP
- #define BOOST_INTERPROCESS_DETAIL_EMULATION_MUTEX_HPP
- #if (defined _MSC_VER) && (_MSC_VER >= 1200)
- # pragma once
- #endif
- #include <boost/interprocess/detail/config_begin.hpp>
- #include <boost/interprocess/detail/workaround.hpp>
- #include <boost/interprocess/detail/posix_time_types_wrk.hpp>
- #include <boost/assert.hpp>
- #include <boost/interprocess/detail/atomic.hpp>
- #include <boost/cstdint.hpp>
- #include <boost/interprocess/detail/os_thread_functions.hpp>
- namespace boost {
- namespace interprocess {
- namespace detail {
- class emulation_mutex
- {
- emulation_mutex(const emulation_mutex &);
- emulation_mutex &operator=(const emulation_mutex &);
- public:
- emulation_mutex();
- ~emulation_mutex();
- void lock();
- bool try_lock();
- bool timed_lock(const boost::posix_time::ptime &abs_time);
- void unlock();
- void take_ownership(){};
- private:
- volatile boost::uint32_t m_s;
- };
- inline emulation_mutex::emulation_mutex()
- : m_s(0)
- {
- //Note that this class is initialized to zero.
- //So zeroed memory can be interpreted as an
- //initialized mutex
- }
- inline emulation_mutex::~emulation_mutex()
- {
- //Trivial destructor
- }
- inline void emulation_mutex::lock(void)
- {
- do{
- boost::uint32_t prev_s = detail::atomic_cas32(const_cast<boost::uint32_t*>(&m_s), 1, 0);
- if (m_s == 1 && prev_s == 0){
- break;
- }
- // relinquish current timeslice
- detail::thread_yield();
- }while (true);
- }
- inline bool emulation_mutex::try_lock(void)
- {
- boost::uint32_t prev_s = detail::atomic_cas32(const_cast<boost::uint32_t*>(&m_s), 1, 0);
- return m_s == 1 && prev_s == 0;
- }
- inline bool emulation_mutex::timed_lock(const boost::posix_time::ptime &abs_time)
- {
- if(abs_time == boost::posix_time::pos_infin){
- this->lock();
- return true;
- }
- //Obtain current count and target time
- boost::posix_time::ptime now = microsec_clock::universal_time();
- if(now >= abs_time) return false;
- do{
- if(this->try_lock()){
- break;
- }
- now = microsec_clock::universal_time();
- if(now >= abs_time){
- return false;
- }
- // relinquish current time slice
- detail::thread_yield();
- }while (true);
- return true;
- }
- inline void emulation_mutex::unlock(void)
- { detail::atomic_cas32(const_cast<boost::uint32_t*>(&m_s), 0, 1); }
- } //namespace detail {
- } //namespace interprocess {
- } //namespace boost {
- #endif //BOOST_INTERPROCESS_DETAIL_EMULATION_MUTEX_HPP