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/* Copyright (C) 2010 Wildfire Games.
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be included
* in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
/*
* Timer implementation using timeGetTime
*/
// note: WinMM is delay-loaded to avoid dragging it in when this timer
// implementation isn't used. (this is relevant because its startup is
// fairly slow)
#include "precompiled.h"
#include "lib/sysdep/os/win/whrt/tgt.h"
#include "lib/sysdep/os/win/whrt/counter.h"
#include "lib/sysdep/os/win/win.h"
#include <mmsystem.h>
#if MSC_VERSION
#pragma comment(lib, "winmm.lib")
#endif
// "Guidelines For Providing Multimedia Timer Support" claims that
// speeding the timer up to 2 ms has little impact, while 1 ms
// causes significant slowdown.
static const UINT PERIOD_MS = 2;
class CounterTGT : public ICounter
{
public:
virtual const char* Name() const
{
return "TGT";
}
Status Activate()
{
// note: timeGetTime is always available and cannot fail.
MMRESULT ret = timeBeginPeriod(PERIOD_MS);
ENSURE(ret == TIMERR_NOERROR);
return INFO::OK;
}
void Shutdown()
{
timeEndPeriod(PERIOD_MS);
}
bool IsSafe() const
{
// the only point of criticism is the possibility of falling behind
// due to lost interrupts. this can happen to any interrupt-based timer
// and some systems may lack a counter-based timer, so consider TGT
// 'safe'. note that it is still only chosen when all other timers fail.
return true;
}
u64 Counter() const
{
return timeGetTime();
}
size_t CounterBits() const
{
return 32;
}
double NominalFrequency() const
{
return 1000.0;
}
double Resolution() const
{
return PERIOD_MS*1e-3;
}
};
ICounter* CreateCounterTGT(void* address, size_t size)
{
ENSURE(sizeof(CounterTGT) <= size);
return new(address) CounterTGT();
}
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