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603 lines
20 KiB
603 lines
20 KiB
#ifndef BOOST_THREAD_WIN32_SHARED_MUTEX_HPP |
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#define BOOST_THREAD_WIN32_SHARED_MUTEX_HPP |
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// (C) Copyright 2006-8 Anthony Williams |
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// |
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// Distributed under the Boost Software License, Version 1.0. (See |
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// accompanying file LICENSE_1_0.txt or copy at |
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// http://www.boost.org/LICENSE_1_0.txt) |
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#include <boost/assert.hpp> |
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#include <boost/detail/interlocked.hpp> |
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#include <boost/thread/win32/thread_primitives.hpp> |
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#include <boost/static_assert.hpp> |
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#include <limits.h> |
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#include <boost/utility.hpp> |
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#include <boost/thread/thread_time.hpp> |
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#include <boost/config/abi_prefix.hpp> |
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namespace boost |
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{ |
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class shared_mutex |
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{ |
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private: |
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shared_mutex(shared_mutex const&); |
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shared_mutex& operator=(shared_mutex const&); |
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private: |
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struct state_data |
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{ |
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unsigned shared_count:11, |
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shared_waiting:11, |
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exclusive:1, |
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upgrade:1, |
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exclusive_waiting:7, |
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exclusive_waiting_blocked:1; |
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friend bool operator==(state_data const& lhs,state_data const& rhs) |
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{ |
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return *reinterpret_cast<unsigned const*>(&lhs)==*reinterpret_cast<unsigned const*>(&rhs); |
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} |
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}; |
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template<typename T> |
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T interlocked_compare_exchange(T* target,T new_value,T comparand) |
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{ |
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BOOST_STATIC_ASSERT(sizeof(T)==sizeof(long)); |
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long const res=BOOST_INTERLOCKED_COMPARE_EXCHANGE(reinterpret_cast<long*>(target), |
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*reinterpret_cast<long*>(&new_value), |
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*reinterpret_cast<long*>(&comparand)); |
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return *reinterpret_cast<T const*>(&res); |
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} |
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enum |
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{ |
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unlock_sem = 0, |
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exclusive_sem = 1 |
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}; |
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state_data state; |
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detail::win32::handle semaphores[2]; |
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detail::win32::handle upgrade_sem; |
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void release_waiters(state_data old_state) |
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{ |
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if(old_state.exclusive_waiting) |
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{ |
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BOOST_VERIFY(detail::win32::ReleaseSemaphore(semaphores[exclusive_sem],1,0)!=0); |
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} |
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if(old_state.shared_waiting || old_state.exclusive_waiting) |
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{ |
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BOOST_VERIFY(detail::win32::ReleaseSemaphore(semaphores[unlock_sem],old_state.shared_waiting + (old_state.exclusive_waiting?1:0),0)!=0); |
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} |
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} |
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public: |
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shared_mutex() |
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{ |
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semaphores[unlock_sem]=detail::win32::create_anonymous_semaphore(0,LONG_MAX); |
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semaphores[exclusive_sem]=detail::win32::create_anonymous_semaphore(0,LONG_MAX); |
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upgrade_sem=detail::win32::create_anonymous_semaphore(0,LONG_MAX); |
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state_data state_={0}; |
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state=state_; |
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} |
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~shared_mutex() |
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{ |
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detail::win32::CloseHandle(upgrade_sem); |
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detail::win32::CloseHandle(semaphores[unlock_sem]); |
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detail::win32::CloseHandle(semaphores[exclusive_sem]); |
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} |
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bool try_lock_shared() |
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{ |
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state_data old_state=state; |
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for(;;) |
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{ |
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state_data new_state=old_state; |
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if(!new_state.exclusive && !new_state.exclusive_waiting_blocked) |
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{ |
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++new_state.shared_count; |
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if(!new_state.shared_count) |
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{ |
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return false; |
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} |
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} |
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state_data const current_state=interlocked_compare_exchange(&state,new_state,old_state); |
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if(current_state==old_state) |
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{ |
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break; |
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} |
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old_state=current_state; |
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} |
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return !(old_state.exclusive| old_state.exclusive_waiting_blocked); |
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} |
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void lock_shared() |
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{ |
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BOOST_VERIFY(timed_lock_shared(::boost::detail::get_system_time_sentinel())); |
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} |
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template<typename TimeDuration> |
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bool timed_lock_shared(TimeDuration const & relative_time) |
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{ |
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return timed_lock_shared(get_system_time()+relative_time); |
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} |
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bool timed_lock_shared(boost::system_time const& wait_until) |
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{ |
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for(;;) |
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{ |
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state_data old_state=state; |
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for(;;) |
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{ |
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state_data new_state=old_state; |
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if(new_state.exclusive || new_state.exclusive_waiting_blocked) |
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{ |
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++new_state.shared_waiting; |
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if(!new_state.shared_waiting) |
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{ |
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boost::throw_exception(boost::lock_error()); |
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} |
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} |
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else |
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{ |
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++new_state.shared_count; |
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if(!new_state.shared_count) |
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{ |
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boost::throw_exception(boost::lock_error()); |
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} |
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} |
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state_data const current_state=interlocked_compare_exchange(&state,new_state,old_state); |
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if(current_state==old_state) |
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{ |
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break; |
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} |
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old_state=current_state; |
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} |
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if(!(old_state.exclusive| old_state.exclusive_waiting_blocked)) |
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{ |
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return true; |
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} |
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unsigned long const res=detail::win32::WaitForSingleObject(semaphores[unlock_sem],::boost::detail::get_milliseconds_until(wait_until)); |
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if(res==detail::win32::timeout) |
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{ |
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for(;;) |
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{ |
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state_data new_state=old_state; |
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if(new_state.exclusive || new_state.exclusive_waiting_blocked) |
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{ |
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if(new_state.shared_waiting) |
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{ |
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--new_state.shared_waiting; |
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} |
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} |
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else |
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{ |
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++new_state.shared_count; |
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if(!new_state.shared_count) |
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{ |
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return false; |
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} |
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} |
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state_data const current_state=interlocked_compare_exchange(&state,new_state,old_state); |
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if(current_state==old_state) |
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{ |
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break; |
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} |
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old_state=current_state; |
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} |
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if(!(old_state.exclusive| old_state.exclusive_waiting_blocked)) |
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{ |
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return true; |
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} |
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return false; |
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} |
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BOOST_ASSERT(res==0); |
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} |
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} |
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void unlock_shared() |
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{ |
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state_data old_state=state; |
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for(;;) |
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{ |
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state_data new_state=old_state; |
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bool const last_reader=!--new_state.shared_count; |
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if(last_reader) |
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{ |
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if(new_state.upgrade) |
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{ |
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new_state.upgrade=false; |
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new_state.exclusive=true; |
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} |
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else |
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{ |
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if(new_state.exclusive_waiting) |
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{ |
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--new_state.exclusive_waiting; |
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new_state.exclusive_waiting_blocked=false; |
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} |
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new_state.shared_waiting=0; |
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} |
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} |
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state_data const current_state=interlocked_compare_exchange(&state,new_state,old_state); |
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if(current_state==old_state) |
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{ |
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if(last_reader) |
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{ |
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if(old_state.upgrade) |
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{ |
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BOOST_VERIFY(detail::win32::ReleaseSemaphore(upgrade_sem,1,0)!=0); |
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} |
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else |
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{ |
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release_waiters(old_state); |
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} |
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} |
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break; |
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} |
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old_state=current_state; |
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} |
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} |
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void lock() |
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{ |
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BOOST_VERIFY(timed_lock(::boost::detail::get_system_time_sentinel())); |
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} |
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template<typename TimeDuration> |
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bool timed_lock(TimeDuration const & relative_time) |
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{ |
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return timed_lock(get_system_time()+relative_time); |
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} |
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bool try_lock() |
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{ |
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state_data old_state=state; |
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for(;;) |
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{ |
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state_data new_state=old_state; |
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if(new_state.shared_count || new_state.exclusive) |
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{ |
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return false; |
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} |
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else |
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{ |
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new_state.exclusive=true; |
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} |
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state_data const current_state=interlocked_compare_exchange(&state,new_state,old_state); |
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if(current_state==old_state) |
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{ |
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break; |
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} |
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old_state=current_state; |
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} |
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return true; |
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} |
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bool timed_lock(boost::system_time const& wait_until) |
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{ |
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for(;;) |
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{ |
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state_data old_state=state; |
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for(;;) |
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{ |
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state_data new_state=old_state; |
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if(new_state.shared_count || new_state.exclusive) |
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{ |
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++new_state.exclusive_waiting; |
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if(!new_state.exclusive_waiting) |
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{ |
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boost::throw_exception(boost::lock_error()); |
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} |
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new_state.exclusive_waiting_blocked=true; |
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} |
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else |
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{ |
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new_state.exclusive=true; |
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} |
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state_data const current_state=interlocked_compare_exchange(&state,new_state,old_state); |
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if(current_state==old_state) |
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{ |
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break; |
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} |
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old_state=current_state; |
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} |
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if(!old_state.shared_count && !old_state.exclusive) |
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{ |
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return true; |
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} |
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unsigned long const wait_res=detail::win32::WaitForMultipleObjects(2,semaphores,true,::boost::detail::get_milliseconds_until(wait_until)); |
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if(wait_res==detail::win32::timeout) |
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{ |
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for(;;) |
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{ |
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state_data new_state=old_state; |
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if(new_state.shared_count || new_state.exclusive) |
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{ |
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if(new_state.exclusive_waiting) |
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{ |
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if(!--new_state.exclusive_waiting) |
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{ |
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new_state.exclusive_waiting_blocked=false; |
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} |
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} |
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} |
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else |
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{ |
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new_state.exclusive=true; |
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} |
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state_data const current_state=interlocked_compare_exchange(&state,new_state,old_state); |
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if(current_state==old_state) |
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{ |
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break; |
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} |
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old_state=current_state; |
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} |
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if(!old_state.shared_count && !old_state.exclusive) |
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{ |
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return true; |
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} |
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return false; |
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} |
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BOOST_ASSERT(wait_res<2); |
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} |
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} |
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void unlock() |
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{ |
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state_data old_state=state; |
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for(;;) |
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{ |
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state_data new_state=old_state; |
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new_state.exclusive=false; |
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if(new_state.exclusive_waiting) |
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{ |
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--new_state.exclusive_waiting; |
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new_state.exclusive_waiting_blocked=false; |
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} |
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new_state.shared_waiting=0; |
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state_data const current_state=interlocked_compare_exchange(&state,new_state,old_state); |
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if(current_state==old_state) |
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{ |
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break; |
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} |
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old_state=current_state; |
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} |
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release_waiters(old_state); |
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} |
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void lock_upgrade() |
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{ |
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for(;;) |
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{ |
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state_data old_state=state; |
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for(;;) |
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{ |
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state_data new_state=old_state; |
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if(new_state.exclusive || new_state.exclusive_waiting_blocked || new_state.upgrade) |
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{ |
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++new_state.shared_waiting; |
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if(!new_state.shared_waiting) |
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{ |
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boost::throw_exception(boost::lock_error()); |
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} |
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} |
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else |
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{ |
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++new_state.shared_count; |
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if(!new_state.shared_count) |
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{ |
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boost::throw_exception(boost::lock_error()); |
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} |
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new_state.upgrade=true; |
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} |
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state_data const current_state=interlocked_compare_exchange(&state,new_state,old_state); |
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if(current_state==old_state) |
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{ |
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break; |
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} |
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old_state=current_state; |
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} |
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if(!(old_state.exclusive|| old_state.exclusive_waiting_blocked|| old_state.upgrade)) |
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{ |
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return; |
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} |
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BOOST_VERIFY(!detail::win32::WaitForSingleObject(semaphores[unlock_sem],detail::win32::infinite)); |
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} |
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} |
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bool try_lock_upgrade() |
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{ |
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state_data old_state=state; |
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for(;;) |
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{ |
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state_data new_state=old_state; |
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if(new_state.exclusive || new_state.exclusive_waiting_blocked || new_state.upgrade) |
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{ |
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return false; |
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} |
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else |
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{ |
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++new_state.shared_count; |
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if(!new_state.shared_count) |
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{ |
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return false; |
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} |
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new_state.upgrade=true; |
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} |
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state_data const current_state=interlocked_compare_exchange(&state,new_state,old_state); |
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if(current_state==old_state) |
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{ |
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break; |
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} |
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old_state=current_state; |
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} |
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return true; |
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} |
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void unlock_upgrade() |
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{ |
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state_data old_state=state; |
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for(;;) |
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{ |
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state_data new_state=old_state; |
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new_state.upgrade=false; |
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bool const last_reader=!--new_state.shared_count; |
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if(last_reader) |
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{ |
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if(new_state.exclusive_waiting) |
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{ |
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--new_state.exclusive_waiting; |
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new_state.exclusive_waiting_blocked=false; |
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} |
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new_state.shared_waiting=0; |
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} |
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state_data const current_state=interlocked_compare_exchange(&state,new_state,old_state); |
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if(current_state==old_state) |
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{ |
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if(last_reader) |
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{ |
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release_waiters(old_state); |
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} |
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break; |
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} |
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old_state=current_state; |
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} |
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} |
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void unlock_upgrade_and_lock() |
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{ |
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state_data old_state=state; |
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for(;;) |
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{ |
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state_data new_state=old_state; |
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bool const last_reader=!--new_state.shared_count; |
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if(last_reader) |
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{ |
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new_state.upgrade=false; |
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new_state.exclusive=true; |
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} |
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state_data const current_state=interlocked_compare_exchange(&state,new_state,old_state); |
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if(current_state==old_state) |
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{ |
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if(!last_reader) |
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{ |
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BOOST_VERIFY(!detail::win32::WaitForSingleObject(upgrade_sem,detail::win32::infinite)); |
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} |
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break; |
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} |
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old_state=current_state; |
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} |
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} |
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void unlock_and_lock_upgrade() |
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{ |
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state_data old_state=state; |
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for(;;) |
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{ |
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state_data new_state=old_state; |
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new_state.exclusive=false; |
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new_state.upgrade=true; |
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++new_state.shared_count; |
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if(new_state.exclusive_waiting) |
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{ |
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--new_state.exclusive_waiting; |
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new_state.exclusive_waiting_blocked=false; |
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} |
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new_state.shared_waiting=0; |
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state_data const current_state=interlocked_compare_exchange(&state,new_state,old_state); |
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if(current_state==old_state) |
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{ |
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break; |
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} |
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old_state=current_state; |
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} |
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release_waiters(old_state); |
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} |
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void unlock_and_lock_shared() |
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{ |
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state_data old_state=state; |
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for(;;) |
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{ |
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state_data new_state=old_state; |
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new_state.exclusive=false; |
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++new_state.shared_count; |
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if(new_state.exclusive_waiting) |
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{ |
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--new_state.exclusive_waiting; |
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new_state.exclusive_waiting_blocked=false; |
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} |
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new_state.shared_waiting=0; |
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state_data const current_state=interlocked_compare_exchange(&state,new_state,old_state); |
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if(current_state==old_state) |
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{ |
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break; |
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} |
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old_state=current_state; |
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} |
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release_waiters(old_state); |
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} |
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void unlock_upgrade_and_lock_shared() |
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{ |
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state_data old_state=state; |
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for(;;) |
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{ |
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state_data new_state=old_state; |
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new_state.upgrade=false; |
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if(new_state.exclusive_waiting) |
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{ |
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--new_state.exclusive_waiting; |
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new_state.exclusive_waiting_blocked=false; |
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} |
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new_state.shared_waiting=0; |
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state_data const current_state=interlocked_compare_exchange(&state,new_state,old_state); |
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if(current_state==old_state) |
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{ |
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break; |
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} |
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old_state=current_state; |
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} |
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release_waiters(old_state); |
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} |
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}; |
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} |
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#include <boost/config/abi_suffix.hpp> |
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#endif
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