Tcl Source Code

{
    Tcl_WideInt now;

    if (tclGetTimeProcPtr != NativeGetTime) {
	Tcl_Time time;

	tclGetTimeProcPtr(&time, tclTimeClientData);
	now = ((Tcl_WideInt)time.sec)*1000000 + time.usec;
    } else {
#ifdef MAC_OSX_TCL
	now = (Tcl_WideInt) (mach_absolute_time() & INT64_MAX);
#else
#error Wide high-resolution clicks not implemented on this platform
#endif
    }

 */

static void
NativeGetTime(
    Tcl_Time *timePtr,
    ClientData clientData)
{




    /*
     * Initialize static storage on the first trip through.
     *
     * Note: Outer check for 'initialized' is a performance win since it
     * avoids an extra mutex lock in the common case.
     */

    if (timeInfo.perfCounterAvailable && timeInfo.curCounterFreq.QuadPart!=0) {
	/*
	 * Query the performance counter and use it to calculate the current
	 * time.
	 */

	ULARGE_INTEGER fileTimeLastCall;
	LARGE_INTEGER perfCounterLastCall, curCounterFreq;
				/* Copy with current data of calibration cycle */

	LARGE_INTEGER curCounter;
				/* Current performance counter. */
	Tcl_WideInt curFileTime;/* Current estimated time, expressed as 100-ns
				 * ticks since the Windows epoch. */
	static LARGE_INTEGER posixEpoch;
				/* Posix epoch expressed as 100-ns ticks since
				 * the windows epoch. */
	Tcl_WideInt usecSincePosixEpoch;
				/* Current microseconds since Posix epoch. */

	posixEpoch.LowPart = 0xD53E8000;
	posixEpoch.HighPart = 0x019DB1DE;

	QueryPerformanceCounter(&curCounter);

	/* 
	 * Hold time section locked as short as possible
	 */
	EnterCriticalSection(&timeInfo.cs);

	fileTimeLastCall.QuadPart = timeInfo.fileTimeLastCall.QuadPart;
	perfCounterLastCall.QuadPart = timeInfo.perfCounterLastCall.QuadPart;
	curCounterFreq.QuadPart = timeInfo.curCounterFreq.QuadPart;

	LeaveCriticalSection(&timeInfo.cs);

	/*
	 * If calibration cycle occurred after we get curCounter
	 */
	if (curCounter.QuadPart <= perfCounterLastCall.QuadPart) {
	    usecSincePosixEpoch = 
		(fileTimeLastCall.QuadPart - posixEpoch.QuadPart) / 10;
	    timePtr->sec = (long) (usecSincePosixEpoch / 1000000);
	    timePtr->usec = (unsigned long) (usecSincePosixEpoch % 1000000);
	    return;
	}

	/*
	 * If it appears to be more than 1.1 seconds since the last trip
	 * through the calibration loop, the performance counter may have
	 * jumped forward. (See MSDN Knowledge Base article Q274323 for a
	 * description of the hardware problem that makes this test
	 * necessary.) If the counter jumps, we don't want to use it directly.
	 * Instead, we must return system time. Eventually, the calibration
	 * loop should recover.
	 */

	if (curCounter.QuadPart - perfCounterLastCall.QuadPart <
		11 * curCounterFreq.QuadPart / 10
	) {
	    curFileTime = fileTimeLastCall.QuadPart +
		 ((curCounter.QuadPart - perfCounterLastCall.QuadPart)
		    * 10000000 / curCounterFreq.QuadPart);


	    usecSincePosixEpoch = (curFileTime - posixEpoch.QuadPart) / 10;
	    timePtr->sec = (long) (usecSincePosixEpoch / 1000000);
	    timePtr->usec = (unsigned long) (usecSincePosixEpoch % 1000000);
	    return;
	}
    }


    do {

	/*
	 * High resolution timer is not available. Just use ftime.
	 */
	struct _timeb t;

	_ftime(&t);
	timePtr->sec = (long)t.time;
	timePtr->usec = t.millitm * 1000;

    } while(0);
}

/*
 *----------------------------------------------------------------------
 *
 * StopCalibration --
 *