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#ifndef BOOST_BASIC_TIMED_MUTEX_WIN32_HPP
#define BOOST_BASIC_TIMED_MUTEX_WIN32_HPP
// basic_timed_mutex_win32.hpp
//
// (C) Copyright 2006-8 Anthony Williams
//
// 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)
#include <boost/assert.hpp>
#include "thread_primitives.hpp"
#include "interlocked_read.hpp"
#include <boost/thread/thread_time.hpp>
#include <boost/thread/xtime.hpp>
#include <boost/detail/interlocked.hpp>
#include <boost/config/abi_prefix.hpp>
namespace boost
{
namespace detail
{
struct basic_timed_mutex
{
BOOST_STATIC_CONSTANT(unsigned char,lock_flag_bit=31);
BOOST_STATIC_CONSTANT(unsigned char,event_set_flag_bit=30);
BOOST_STATIC_CONSTANT(long,lock_flag_value=1<<lock_flag_bit);
BOOST_STATIC_CONSTANT(long,event_set_flag_value=1<<event_set_flag_bit);
long active_count;
void* event;
void initialize()
{
active_count=0;
event=0;
}
void destroy()
{
#ifdef BOOST_MSVC
#pragma warning(push)
#pragma warning(disable:4312)
#endif
void* const old_event=BOOST_INTERLOCKED_EXCHANGE_POINTER(&event,0);
#ifdef BOOST_MSVC
#pragma warning(pop)
#endif
if(old_event)
{
win32::CloseHandle(old_event);
}
}
bool try_lock()
{
return !win32::interlocked_bit_test_and_set(&active_count,lock_flag_bit);
}
void lock()
{
if(try_lock())
{
return;
}
long old_count=active_count;
mark_waiting_and_try_lock(old_count);
if(old_count&lock_flag_value)
{
bool lock_acquired=false;
void* const sem=get_event();
do
{
BOOST_VERIFY(win32::WaitForSingleObject(
sem,::boost::detail::win32::infinite)==0);
clear_waiting_and_try_lock(old_count);
lock_acquired=!(old_count&lock_flag_value);
}
while(!lock_acquired);
}
}
void mark_waiting_and_try_lock(long& old_count)
{
for(;;)
{
long const new_count=(old_count&lock_flag_value)?(old_count+1):(old_count|lock_flag_value);
long const current=BOOST_INTERLOCKED_COMPARE_EXCHANGE(&active_count,new_count,old_count);
if(current==old_count)
{
break;
}
old_count=current;
}
}
void clear_waiting_and_try_lock(long& old_count)
{
old_count&=~lock_flag_value;
old_count|=event_set_flag_value;
for(;;)
{
long const new_count=((old_count&lock_flag_value)?old_count:((old_count-1)|lock_flag_value))&~event_set_flag_value;
long const current=BOOST_INTERLOCKED_COMPARE_EXCHANGE(&active_count,new_count,old_count);
if(current==old_count)
{
break;
}
old_count=current;
}
}
bool timed_lock(::boost::system_time const& wait_until)
{
if(try_lock())
{
return true;
}
long old_count=active_count;
mark_waiting_and_try_lock(old_count);
if(old_count&lock_flag_value)
{
bool lock_acquired=false;
void* const sem=get_event();
do
{
if(win32::WaitForSingleObject(sem,::boost::detail::get_milliseconds_until(wait_until))!=0)
{
BOOST_INTERLOCKED_DECREMENT(&active_count);
return false;
}
clear_waiting_and_try_lock(old_count);
lock_acquired=!(old_count&lock_flag_value);
}
while(!lock_acquired);
}
return true;
}
template<typename Duration>
bool timed_lock(Duration const& timeout)
{
return timed_lock(get_system_time()+timeout);
}
bool timed_lock(boost::xtime const& timeout)
{
return timed_lock(system_time(timeout));
}
void unlock()
{
long const offset=lock_flag_value;
long const old_count=BOOST_INTERLOCKED_EXCHANGE_ADD(&active_count,lock_flag_value);
if(!(old_count&event_set_flag_value) && (old_count>offset))
{
if(!win32::interlocked_bit_test_and_set(&active_count,event_set_flag_bit))
{
win32::SetEvent(get_event());
}
}
}
private:
void* get_event()
{
void* current_event=::boost::detail::interlocked_read_acquire(&event);
if(!current_event)
{
void* const new_event=win32::create_anonymous_event(win32::auto_reset_event,win32::event_initially_reset);
#ifdef BOOST_MSVC
#pragma warning(push)
#pragma warning(disable:4311)
#pragma warning(disable:4312)
#endif
void* const old_event=BOOST_INTERLOCKED_COMPARE_EXCHANGE_POINTER(&event,new_event,0);
#ifdef BOOST_MSVC
#pragma warning(pop)
#endif
if(old_event!=0)
{
win32::CloseHandle(new_event);
return old_event;
}
else
{
return new_event;
}
}
return current_event;
}
};
}
}
#define BOOST_BASIC_TIMED_MUTEX_INITIALIZER {0}
#include <boost/config/abi_suffix.hpp>
#endif
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Swift