Chris@102: //////////////////////////////////////////////////////////////////////////////
Chris@102: //
Chris@102: // (C) Copyright Ion Gaztanaga 2012-2013. Distributed under the Boost
Chris@102: // Software License, Version 1.0. (See accompanying file
Chris@102: // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
Chris@102: //
Chris@102: // See http://www.boost.org/libs/interprocess for documentation.
Chris@102: //
Chris@102: //////////////////////////////////////////////////////////////////////////////
Chris@102: 
Chris@102: #ifndef BOOST_INTERPROCESS_SYNC_DETAIL_COMMON_ALGORITHMS_HPP
Chris@102: #define BOOST_INTERPROCESS_SYNC_DETAIL_COMMON_ALGORITHMS_HPP
Chris@102: 
Chris@102: #ifndef BOOST_CONFIG_HPP
Chris@102: #  include <boost/config.hpp>
Chris@102: #endif
Chris@102: #
Chris@102: #if defined(BOOST_HAS_PRAGMA_ONCE)
Chris@102: #  pragma once
Chris@102: #endif
Chris@102: 
Chris@102: #include <boost/interprocess/detail/config_begin.hpp>
Chris@102: #include <boost/interprocess/detail/workaround.hpp>
Chris@102: 
Chris@102: #include <boost/interprocess/sync/spin/wait.hpp>
Chris@102: 
Chris@102: namespace boost {
Chris@102: namespace interprocess {
Chris@102: namespace ipcdetail {
Chris@102: 
Chris@102: template<class MutexType>
Chris@102: bool try_based_timed_lock(MutexType &m, const boost::posix_time::ptime &abs_time)
Chris@102: {
Chris@102:    //Same as lock()
Chris@102:    if(abs_time == boost::posix_time::pos_infin){
Chris@102:       m.lock();
Chris@102:       return true;
Chris@102:    }
Chris@102:    //Always try to lock to achieve POSIX guarantees:
Chris@102:    // "Under no circumstance shall the function fail with a timeout if the mutex
Chris@102:    //  can be locked immediately. The validity of the abs_timeout parameter need not
Chris@102:    //  be checked if the mutex can be locked immediately."
Chris@102:    else if(m.try_lock()){
Chris@102:       return true;
Chris@102:    }
Chris@102:    else{
Chris@102:       spin_wait swait;
Chris@102:       while(microsec_clock::universal_time() < abs_time){
Chris@102:          if(m.try_lock()){
Chris@102:             return true;
Chris@102:          }
Chris@102:          swait.yield();
Chris@102:       }
Chris@102:       return false;
Chris@102:    }
Chris@102: }
Chris@102: 
Chris@102: template<class MutexType>
Chris@102: void try_based_lock(MutexType &m)
Chris@102: {
Chris@102:    if(!m.try_lock()){
Chris@102:       spin_wait swait;
Chris@102:       do{
Chris@102:          if(m.try_lock()){
Chris@102:             break;
Chris@102:          }
Chris@102:          else{
Chris@102:             swait.yield();
Chris@102:          }
Chris@102:       }
Chris@102:       while(1);
Chris@102:    }
Chris@102: }
Chris@102: 
Chris@102: }  //namespace ipcdetail
Chris@102: }  //namespace interprocess
Chris@102: }  //namespace boost
Chris@102: 
Chris@102: #include <boost/interprocess/detail/config_end.hpp>
Chris@102: 
Chris@102: #endif   //BOOST_INTERPROCESS_SYNC_DETAIL_COMMON_ALGORITHMS_HPP