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// license:BSD-3-Clause
// copyright-holders:Olivier Galibert, R. Belmont
//============================================================
//
// osdsync.h - Core synchronization functions
//
//============================================================
#ifndef MAME_OSD_OSDSYNC_H
#define MAME_OSD_OSDSYNC_H
#pragma once
// C++ headers
#include <mutex>
#include <atomic>
#include <condition_variable>
#include "osdcore.h"
/***************************************************************************
SYNCHRONIZATION INTERFACES - Events
***************************************************************************/
#define OSD_EVENT_WAIT_INFINITE (~(osd_ticks_t)0)
/* osd_event is an opaque type which represents a setable/resettable event */
class osd_event
{
public:
/*-----------------------------------------------------------------------------
constructor: allocate a new event
Parameters:
manualreset - boolean. If true, the event will be automatically set
to non-signalled after a thread successfully waited for
it.
initialstate - boolean. If true, the event is signalled initially.
Return value:
A pointer to the allocated event.
-----------------------------------------------------------------------------*/
osd_event(int manualreset, int initialstate)
{
m_signalled = initialstate;
m_autoreset = !manualreset;
}
~osd_event()
{
}
/*-----------------------------------------------------------------------------
wait: wait for an event to be signalled
If the event is in signalled state, the
function returns immediately. If not it will wait for the event
to become signalled.
Parameters:
timeout - timeout in osd_ticks
Return value:
true: The event was signalled
false: A timeout occurred
-----------------------------------------------------------------------------*/
bool wait(osd_ticks_t timeout)
{
if (timeout == OSD_EVENT_WAIT_INFINITE)
timeout = osd_ticks_per_second() * (osd_ticks_t)10000;
std::unique_lock<std::mutex> lock(m_mutex);
if (!timeout)
{
if (!m_signalled)
{
return false;
}
}
else
{
if (!m_signalled)
{
uint64_t msec = timeout * 1000 / osd_ticks_per_second();
do {
if (m_cond.wait_for(lock, std::chrono::milliseconds(msec)) == std::cv_status::timeout)
{
if (!m_signalled)
{
return false;
}
else
break;
} else
break;
} while (true);
}
}
if (m_autoreset)
m_signalled = 0;
return true;
}
/*-----------------------------------------------------------------------------
osd_event_reset: reset an event to non-signalled state
Parameters:
None
Return value:
None
-----------------------------------------------------------------------------*/
void reset()
{
m_mutex.lock();
m_signalled = false;
m_mutex.unlock();
}
/*-----------------------------------------------------------------------------
osd_event_set: set an event to signalled state
Parameters:
None
Return value:
Whether or not the event was actually signalled (false if the event had already been signalled)
Notes:
All threads waiting for the event will be signalled.
-----------------------------------------------------------------------------*/
bool set()
{
m_mutex.lock();
bool needs_signal = !m_signalled;
if (needs_signal)
{
m_signalled = true;
if (m_autoreset)
m_cond.notify_one();
else
m_cond.notify_all();
}
m_mutex.unlock();
return needs_signal;
}
private:
std::mutex m_mutex;
std::condition_variable m_cond;
int32_t m_autoreset;
int32_t m_signalled;
};
#endif // MAME_OSD_OSDSYNC_H
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