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-rw-r--r--win/tclWinTime.c42
1 files changed, 29 insertions, 13 deletions
diff --git a/win/tclWinTime.c b/win/tclWinTime.c
index 70ab93d..63da982 100644
--- a/win/tclWinTime.c
+++ b/win/tclWinTime.c
@@ -9,7 +9,7 @@
* See the file "license.terms" for information on usage and redistribution
* of this file, and for a DISCLAIMER OF ALL WARRANTIES.
*
- * RCS: @(#) $Id: tclWinTime.c,v 1.13 2003/01/27 02:19:57 mdejong Exp $
+ * RCS: @(#) $Id: tclWinTime.c,v 1.14 2003/02/14 22:16:27 kennykb Exp $
*/
#include "tclWinInt.h"
@@ -252,6 +252,10 @@ Tcl_GetTime(timePtr)
struct timeb t;
+ int useFtime = 1; /* Flag == TRUE if we need to fall back
+ * on ftime rather than using the perf
+ * counter */
+
/* Initialize static storage on the first trip through. */
/*
@@ -360,22 +364,34 @@ Tcl_GetTime(timePtr)
EnterCriticalSection( &timeInfo.cs );
QueryPerformanceCounter( &curCounter );
- curFileTime = timeInfo.lastFileTime.QuadPart
- + ( ( curCounter.QuadPart - timeInfo.lastCounter.QuadPart )
- * 10000000 / timeInfo.curCounterFreq.QuadPart );
- timeInfo.lastFileTime.QuadPart = curFileTime;
- timeInfo.lastCounter.QuadPart = curCounter.QuadPart;
- usecSincePosixEpoch = ( curFileTime - posixEpoch.QuadPart ) / 10;
- timePtr->sec = (time_t) ( usecSincePosixEpoch / 1000000 );
- timePtr->usec = (unsigned long ) ( usecSincePosixEpoch % 1000000 );
-
- LeaveCriticalSection( &timeInfo.cs );
+ /*
+ * If it appears to be more than 1.1 seconds since the last trip
+ * through the calibration loop, the performance counter may
+ * have jumped. Discard it. See MSDN Knowledge Base article
+ * Q274323 for a description of the hardware problem that makes
+ * this test necessary.
+ */
+ if ( curCounter.QuadPart - timeInfo.lastPerfCounter
+ < 11 * timeInfo.estPerfCounterFreq / 10 ) {
+
+ curFileTime = timeInfo.lastFileTime.QuadPart
+ + ( ( curCounter.QuadPart - timeInfo.lastCounter.QuadPart )
+ * 10000000 / timeInfo.curCounterFreq.QuadPart );
+ timeInfo.lastFileTime.QuadPart = curFileTime;
+ timeInfo.lastCounter.QuadPart = curCounter.QuadPart;
+ usecSincePosixEpoch = ( curFileTime - posixEpoch.QuadPart ) / 10;
+ timePtr->sec = (time_t) ( usecSincePosixEpoch / 1000000 );
+ timePtr->usec = (unsigned long ) ( usecSincePosixEpoch % 1000000 );
+ useFtime = 0;
+ }
+ LeaveCriticalSection( &timeInfo.cs );
+ }
- } else {
+ if ( useFtime ) {
/* High resolution timer is not available. Just use ftime */
-
+
ftime(&t);
timePtr->sec = t.time;
timePtr->usec = t.millitm * 1000;