Mercurial > hg > vamp-build-and-test
diff DEPENDENCIES/generic/include/boost/interprocess/sync/spin/mutex.hpp @ 16:2665513ce2d3
Add boost headers
author | Chris Cannam |
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date | Tue, 05 Aug 2014 11:11:38 +0100 |
parents | |
children | c530137014c0 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/DEPENDENCIES/generic/include/boost/interprocess/sync/spin/mutex.hpp Tue Aug 05 11:11:38 2014 +0100 @@ -0,0 +1,117 @@ +////////////////////////////////////////////////////////////////////////////// +// +// (C) Copyright Ion Gaztanaga 2005-2012. 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_SPIN_MUTEX_HPP +#define BOOST_INTERPROCESS_DETAIL_SPIN_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> +#include <boost/interprocess/sync/spin/wait.hpp> + +namespace boost { +namespace interprocess { +namespace ipcdetail { + +class spin_mutex +{ + spin_mutex(const spin_mutex &); + spin_mutex &operator=(const spin_mutex &); + public: + + spin_mutex(); + ~spin_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 spin_mutex::spin_mutex() + : m_s(0) +{ + //Note that this class is initialized to zero. + //So zeroed memory can be interpreted as an + //initialized mutex +} + +inline spin_mutex::~spin_mutex() +{ + //Trivial destructor +} + +inline void spin_mutex::lock(void) +{ + spin_wait swait; + do{ + boost::uint32_t prev_s = ipcdetail::atomic_cas32(const_cast<boost::uint32_t*>(&m_s), 1, 0); + + if (m_s == 1 && prev_s == 0){ + break; + } + // relinquish current timeslice + swait.yield(); + }while (true); +} + +inline bool spin_mutex::try_lock(void) +{ + boost::uint32_t prev_s = ipcdetail::atomic_cas32(const_cast<boost::uint32_t*>(&m_s), 1, 0); + return m_s == 1 && prev_s == 0; +} + +inline bool spin_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(); + + spin_wait swait; + do{ + if(this->try_lock()){ + break; + } + now = microsec_clock::universal_time(); + + if(now >= abs_time){ + return false; + } + // relinquish current time slice + swait.yield(); + }while (true); + + return true; +} + +inline void spin_mutex::unlock(void) +{ ipcdetail::atomic_cas32(const_cast<boost::uint32_t*>(&m_s), 0, 1); } + +} //namespace ipcdetail { +} //namespace interprocess { +} //namespace boost { + +#include <boost/interprocess/detail/config_end.hpp> + +#endif //BOOST_INTERPROCESS_DETAIL_SPIN_MUTEX_HPP