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////////////////////////////////////////////////////////////
//
// SFML - Simple and Fast Multimedia Library
// Copyright (C) 2007-2018 Laurent Gomila (laurent@sfml-dev.org)
//
// This software is provided 'as-is', without any express or implied warranty.
// In no event will the authors be held liable for any damages arising from the use of this software.
//
// Permission is granted to anyone to use this software for any purpose,
// including commercial applications, and to alter it and redistribute it freely,
// subject to the following restrictions:
//
// 1. The origin of this software must not be misrepresented;
// you must not claim that you wrote the original software.
// If you use this software in a product, an acknowledgment
// in the product documentation would be appreciated but is not required.
//
// 2. Altered source versions must be plainly marked as such,
// and must not be misrepresented as being the original software.
//
// 3. This notice may not be removed or altered from any source distribution.
//
////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////
// Headers
////////////////////////////////////////////////////////////
#include <SFML/System/Win32/ClockImpl.hpp>
#include <SFML/System/Mutex.hpp>
#include <SFML/System/Lock.hpp>
#include <windows.h>
namespace
{
LARGE_INTEGER getFrequency()
{
LARGE_INTEGER frequency;
QueryPerformanceFrequency(&frequency);
return frequency;
}
bool isWindowsXpOrOlder()
{
// Windows XP was the last 5.x version of Windows
return static_cast<DWORD>(LOBYTE(LOWORD(GetVersion()))) < 6;
}
}
namespace sf
{
namespace priv
{
////////////////////////////////////////////////////////////
Time ClockImpl::getCurrentTime()
{
// Get the frequency of the performance counter
// (it is constant across the program lifetime)
static LARGE_INTEGER frequency = getFrequency();
// Detect if we are on Windows XP or older
static bool oldWindows = isWindowsXpOrOlder();
LARGE_INTEGER time;
if (oldWindows)
{
static sf::Mutex oldWindowsMutex;
// Acquire a lock (CRITICAL_SECTION) to prevent travelling back in time
Lock lock(oldWindowsMutex);
// Get the current time
QueryPerformanceCounter(&time);
}
else
{
// Get the current time
QueryPerformanceCounter(&time);
}
// Return the current time as microseconds
return sf::microseconds(1000000 * time.QuadPart / frequency.QuadPart);
}
} // namespace priv
} // namespace sf
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