#include <limits.h>
#ifdef WIN32
#include <time.h>
#include <tchar.h>
#endif
#include "_osdef.h"
#include "Tick.h"
#include "Lock.h"

using namespace wylib::time::tick64;
static TICKCOUNT64 UserSetTick = 0;

#ifndef WIN32
unsigned int timeGetTime()  
{  
	unsigned int uptime = 0;  
	struct timespec on;  
	if(clock_gettime(CLOCK_MONOTONIC, &on) == 0)  
		uptime = on.tv_sec*1000 + on.tv_nsec/1000000;  
	return uptime;  
}
#endif

/***
 实际测试的性能表明，基于timeGetTime实现的GetTickCount64具有较高的性能，
 而基于QueryPerformanceCounter的实现则是timeGetTime版本时间消耗的300倍
***/

//static LONG			dwAtomLock		= 0;
#ifdef WIN32
static MMRESULT		mmPeriod		= timeBeginPeriod(1);
#endif
static TICKCOUNT64	llTickBase		= 0;
static TICKCOUNT64	llStartTick		= timeGetTime();
static DWORD		dwLastShortTick = timeGetTime();

TICKCOUNT64	wylib::time::tick64::GetTickCount64()
{
	if (UserSetTick)
		return UserSetTick;
	
	/*
	  此处需要将dwLastShortTick导致保存为局部变量并尝试通过保存的值以锁总线的方式改变dwLastShortTick的值。
	      由于在检测并修改dwLastShortTick的值的期间，当前线程可能由于进程调度而使得线程被挂起。当前线程被挂
	  起的期间如果其他线程也执行了此函数则该线程会先于此线程修改dwLastShortTick的值。当本线程在恢复后再修改
	  dwLastShortTick的值将导致错误的结果并会错误的判断为进入了一个49天的循环并修改llTickBase的值，从而导
	  致所有后续调用的返回值全部错误的问题！
		  为尽量降低数据同步的开销，不能使用临界区等方式来同步数据，故必须使用原子加锁操作指令代替。
	*/
	DWORD dwLastTick = dwLastShortTick;
	DWORD dwTick = timeGetTime();
#ifdef WIN32
	if (InterlockedCompareExchange((volatile long*)&dwLastShortTick, (long)dwTick, (long)dwLastTick) == dwLastTick)
#else
	if (__sync_val_compare_and_swap((volatile long*)&dwLastShortTick, (long)dwLastTick, (long)dwTick) == dwLastTick)
#endif
	{
		if (dwTick < dwLastTick)
		{
#ifdef WIN32
			if (IsDebuggerPresent())
			{
				//请手动确认此处是否未发生BUG，而是系统真正的经过了49天的循环，并按继续键……
				OutputDebugString(_T("请手动确认此处是否未发生BUG，而是系统真正的经过了49天的循环"));
				DebugBreak();
			}
			llTickBase += 0x1UI64 << 32;
#else
			llTickBase += 0x1LL << 32;
#endif
		}
	}

	return llTickBase + dwTick - llStartTick;
}

/*
TICKCOUNT64	wylib::time::tick64::GetTickCount64()
{
	if (UserSetTick)
		return UserSetTick;

	static LARGE_INTEGER Frequency;
	static BOOL boSuportPerformanceTick = QueryPerformanceFrequency(&Frequency);
	
	LARGE_INTEGER tick;
	TICKCOUNT64 sec, milpart;

	if ( !boSuportPerformanceTick )
	{
		return timeGetTime();
	}

	QueryPerformanceCounter( &tick );

	sec = tick.QuadPart / Frequency.QuadPart;
	milpart = tick.QuadPart - (sec * Frequency.QuadPart);
	return sec * 1000 + milpart * 1000 / Frequency.QuadPart;
}
*/

TICKCOUNT64 wylib::time::tick64::SetTickCount64(TICKCOUNT64 llValue)
{
	//TICKCOUNT64 lOldTick = UserSetTick;
	UserSetTick = llValue;
	return UserSetTick;
}

TICKCOUNT32 wylib::time::tick64::GetTickCount32()
{
	return timeGetTime();
}

TICKCOUNT32 wylib::time::tick64::SetTickCount32(TICKCOUNT32 dwTick)
{
	return (TICKCOUNT32)SetTickCount64(dwTick);
}