Tcl Source Code

	 * to be replaced.
	 */
	Tcl_SetObjResult(interp, objv[1]);
    } else {
	Tcl_Obj *resultPtr;

	/*
	 * We are re-fetching in case the string argument is same value as 
	 * an index argument, and shimmering cost us our ustring.
	 */

	ustring = Tcl_GetUnicodeFromObj(objv[1], &length);
	end = length-1;

	if (first < 0) {
................................................................................
 
/*
 *----------------------------------------------------------------------
 *
 * Tcl_TimeRateObjCmd --
 *
 *	This object-based procedure is invoked to process the "timerate" Tcl
 *	command. 
 *	This is similar to command "time", except the execution limited by 
 *	given time (in milliseconds) instead of repetition count.
 *
 * Example:
 *	timerate {after 5} 1000 ; # equivalent for `time {after 5} [expr 1000/5]`
 *
 * Results:
 *	A standard Tcl object result.
................................................................................
int
Tcl_TimeRateObjCmd(
    ClientData dummy,		/* Not used. */
    Tcl_Interp *interp,		/* Current interpreter. */
    int objc,			/* Number of arguments. */
    Tcl_Obj *const objv[])	/* Argument objects. */
{
    static 
    double measureOverhead = 0; /* global measure-overhead */
    double overhead = -1;	/* given measure-overhead */
    register Tcl_Obj *objPtr;
    register int result, i;
    Tcl_Obj *calibrate = NULL, *direct = NULL;
    Tcl_WideUInt count = 0;	/* Holds repetition count */
    Tcl_WideInt  maxms  = WIDE_MIN;
				/* Maximal running time (in milliseconds) */
................................................................................
    if (calibrate) {

	/* if no time specified for the calibration */
	if (maxms == WIDE_MIN) {
	    Tcl_Obj *clobjv[6];
	    Tcl_WideInt maxCalTime = 5000;
	    double lastMeasureOverhead = measureOverhead;
	    
	    clobjv[0] = objv[0]; 
	    i = 1;
	    if (direct) {
	    	clobjv[i++] = direct;
	    }
	    clobjv[i++] = objPtr; 

	    /* reset last measurement overhead */
	    measureOverhead = (double)0;

	    /* self-call with 100 milliseconds to warm-up,
	     * before entering the calibration cycle */
	    TclNewLongObj(clobjv[i], 100);
................................................................................
	    Tcl_DecrRefCount(clobjv[i]);
	    if (result != TCL_OK) {
		return result;
	    }

	    i--;
	    clobjv[i++] = calibrate;
	    clobjv[i++] = objPtr; 

	    /* set last measurement overhead to max */
	    measureOverhead = (double)UWIDE_MAX;

	    /* calibration cycle until it'll be preciser */
	    maxms = -1000;
	    do {
................................................................................
		goto done;
	    }
	    /* force stop immediately */
	    threshold = 1;
	    maxcnt = 0;
	    result = TCL_OK;
	}
	
	/* don't check time up to threshold */
	if (--threshold > 0) continue;

	/* check stop time reached, estimate new threshold */
    #ifdef TCL_WIDE_CLICKS
	middle = TclpGetWideClicks();
    #else
................................................................................

	/* if not calibrate */
	if (!calibrate) {
	    /* minimize influence of measurement overhead */
	    if (overhead > 0) {
		/* estimate the time of overhead (microsecs) */
		Tcl_WideUInt curOverhead = overhead * count;
		if (middle > curOverhead) {
		    middle -= curOverhead;
		} else {
		    middle = 0;
		}
	    }
	} else {
	    /* calibration - obtaining new measurement overhead */
................................................................................
	    if (val < 1000)  { fmt = "%.3f"; } else
	    if (val < 10000) { fmt = "%.2f"; } else
			     { fmt = "%.1f"; };
	    objs[0] = Tcl_ObjPrintf(fmt, ((double)middle)/count);
	}

	objs[2] = Tcl_NewWideIntObj(count); /* iterations */
	
	/* calculate speed as rate (count) per sec */
	if (!middle) middle++; /* +1 ms, just to avoid divide by zero */
	if (count < (WIDE_MAX / 1000000)) {
	    val = (count * 1000000) / middle;
	    if (val < 100000) {
		if (val < 100)	{ fmt = "%.3f"; } else
		if (val < 1000) { fmt = "%.2f"; } else

	 * to be replaced.
	 */
	Tcl_SetObjResult(interp, objv[1]);
    } else {
	Tcl_Obj *resultPtr;

	/*
	 * We are re-fetching in case the string argument is same value as
	 * an index argument, and shimmering cost us our ustring.
	 */

	ustring = Tcl_GetUnicodeFromObj(objv[1], &length);
	end = length-1;

	if (first < 0) {
................................................................................
 
/*
 *----------------------------------------------------------------------
 *
 * Tcl_TimeRateObjCmd --
 *
 *	This object-based procedure is invoked to process the "timerate" Tcl
 *	command.
 *	This is similar to command "time", except the execution limited by
 *	given time (in milliseconds) instead of repetition count.
 *
 * Example:
 *	timerate {after 5} 1000 ; # equivalent for `time {after 5} [expr 1000/5]`
 *
 * Results:
 *	A standard Tcl object result.
................................................................................
int
Tcl_TimeRateObjCmd(
    ClientData dummy,		/* Not used. */
    Tcl_Interp *interp,		/* Current interpreter. */
    int objc,			/* Number of arguments. */
    Tcl_Obj *const objv[])	/* Argument objects. */
{

    static double measureOverhead = 0; /* global measure-overhead */
    double overhead = -1;	/* given measure-overhead */
    register Tcl_Obj *objPtr;
    register int result, i;
    Tcl_Obj *calibrate = NULL, *direct = NULL;
    Tcl_WideUInt count = 0;	/* Holds repetition count */
    Tcl_WideInt  maxms  = WIDE_MIN;
				/* Maximal running time (in milliseconds) */
................................................................................
    if (calibrate) {

	/* if no time specified for the calibration */
	if (maxms == WIDE_MIN) {
	    Tcl_Obj *clobjv[6];
	    Tcl_WideInt maxCalTime = 5000;
	    double lastMeasureOverhead = measureOverhead;

	    clobjv[0] = objv[0];
	    i = 1;
	    if (direct) {
	    	clobjv[i++] = direct;
	    }
	    clobjv[i++] = objPtr;

	    /* reset last measurement overhead */
	    measureOverhead = (double)0;

	    /* self-call with 100 milliseconds to warm-up,
	     * before entering the calibration cycle */
	    TclNewLongObj(clobjv[i], 100);
................................................................................
	    Tcl_DecrRefCount(clobjv[i]);
	    if (result != TCL_OK) {
		return result;
	    }

	    i--;
	    clobjv[i++] = calibrate;
	    clobjv[i++] = objPtr;

	    /* set last measurement overhead to max */
	    measureOverhead = (double)UWIDE_MAX;

	    /* calibration cycle until it'll be preciser */
	    maxms = -1000;
	    do {
................................................................................
		goto done;
	    }
	    /* force stop immediately */
	    threshold = 1;
	    maxcnt = 0;
	    result = TCL_OK;
	}

	/* don't check time up to threshold */
	if (--threshold > 0) continue;

	/* check stop time reached, estimate new threshold */
    #ifdef TCL_WIDE_CLICKS
	middle = TclpGetWideClicks();
    #else
................................................................................

	/* if not calibrate */
	if (!calibrate) {
	    /* minimize influence of measurement overhead */
	    if (overhead > 0) {
		/* estimate the time of overhead (microsecs) */
		Tcl_WideUInt curOverhead = overhead * count;
		if ((Tcl_WideUInt)middle > curOverhead) {
		    middle -= curOverhead;
		} else {
		    middle = 0;
		}
	    }
	} else {
	    /* calibration - obtaining new measurement overhead */
................................................................................
	    if (val < 1000)  { fmt = "%.3f"; } else
	    if (val < 10000) { fmt = "%.2f"; } else
			     { fmt = "%.1f"; };
	    objs[0] = Tcl_ObjPrintf(fmt, ((double)middle)/count);
	}

	objs[2] = Tcl_NewWideIntObj(count); /* iterations */

	/* calculate speed as rate (count) per sec */
	if (!middle) middle++; /* +1 ms, just to avoid divide by zero */
	if (count < (WIDE_MAX / 1000000)) {
	    val = (count * 1000000) / middle;
	    if (val < 100000) {
		if (val < 100)	{ fmt = "%.3f"; } else
		if (val < 1000) { fmt = "%.2f"; } else

}
 
/*
 *----------------------------------------------------------------------
 *
 * TclpWideClickInMicrosec --
 *
 *	This procedure return scale to convert click values from the 
 *	TclpGetWideClicks native resolution to microsecond resolution
 *	and back.
 *
 * Results:
 * 	1 click in microseconds as double.
 *
 * Side effects:

}
 
/*
 *----------------------------------------------------------------------
 *
 * TclpWideClickInMicrosec --
 *
 *	This procedure return scale to convert click values from the
 *	TclpGetWideClicks native resolution to microsecond resolution
 *	and back.
 *
 * Results:
 * 	1 click in microseconds as double.
 *
 * Side effects:

    fclose(fp);
    return 0;
}
 
BOOL FileExists(LPCTSTR szPath)
{
#ifndef INVALID_FILE_ATTRIBUTES
    #define INVALID_FILE_ATTRIBUTES ((DWORD)-1) 
#endif
    DWORD pathAttr = GetFileAttributes(szPath);
    return (pathAttr != INVALID_FILE_ATTRIBUTES && 
	    !(pathAttr & FILE_ATTRIBUTE_DIRECTORY));
}
 

/*
 * QualifyPath --
 *
................................................................................
    strncpy(path, dir, dirlen);
    strncpy(path+dirlen, "\\*", 3);	/* Including terminating \0 */
    keylen = strlen(keypath);

#if 0 /* This function is not available in Visual C++ 6 */
    /*
     * Use numerics 0 -> FindExInfoStandard,
     * 1 -> FindExSearchLimitToDirectories, 
     * as these are not defined in Visual C++ 6
     */
    hSearch = FindFirstFileEx(path, 0, &finfo, 1, NULL, 0);
#else
    hSearch = FindFirstFile(path, &finfo);
#endif
    if (hSearch == INVALID_HANDLE_VALUE)
................................................................................
	return 1; /* Not found */

    /* Loop through all subdirs checking if the keypath is under there */
    ret = 1; /* Assume not found */
    do {
	int sublen;
	/*
	 * We need to check it is a directory despite the 
	 * FindExSearchLimitToDirectories in the above call. See SDK docs
	 */
	if ((finfo.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) == 0)
	    continue;
	sublen = strlen(finfo.cFileName);
	if ((dirlen+1+sublen+1+keylen+1) > sizeof(path))
	    continue;		/* Path does not fit, assume not matched */
................................................................................
 * LocateDependency --
 *
 *	Locates a dependency for a package.
 *        keypath - a relative path within the package directory
 *          that is used to confirm it is the correct directory.
 *	The search path for the package directory is currently only
 *      the parent and grandparent of the current working directory.
 *      If found, the command prints 
 *         name_DIRPATH=<full path of located directory>
 *      and returns 0. If not found, does not print anything and returns 1.
 */
static int LocateDependency(const char *keypath)
{
    int i, ret;
    static char *paths[] = {"..", "..\\..", "..\\..\\.."};
    
    for (i = 0; i < (sizeof(paths)/sizeof(paths[0])); ++i) {
	ret = LocateDependencyHelper(paths[i], keypath);
	if (ret == 0)
	    return ret;
    }
    return ret;
}

    fclose(fp);
    return 0;
}
 
BOOL FileExists(LPCTSTR szPath)
{
#ifndef INVALID_FILE_ATTRIBUTES
    #define INVALID_FILE_ATTRIBUTES ((DWORD)-1)
#endif
    DWORD pathAttr = GetFileAttributes(szPath);
    return (pathAttr != INVALID_FILE_ATTRIBUTES &&
	    !(pathAttr & FILE_ATTRIBUTE_DIRECTORY));
}
 

/*
 * QualifyPath --
 *
................................................................................
    strncpy(path, dir, dirlen);
    strncpy(path+dirlen, "\\*", 3);	/* Including terminating \0 */
    keylen = strlen(keypath);

#if 0 /* This function is not available in Visual C++ 6 */
    /*
     * Use numerics 0 -> FindExInfoStandard,
     * 1 -> FindExSearchLimitToDirectories,
     * as these are not defined in Visual C++ 6
     */
    hSearch = FindFirstFileEx(path, 0, &finfo, 1, NULL, 0);
#else
    hSearch = FindFirstFile(path, &finfo);
#endif
    if (hSearch == INVALID_HANDLE_VALUE)
................................................................................
	return 1; /* Not found */

    /* Loop through all subdirs checking if the keypath is under there */
    ret = 1; /* Assume not found */
    do {
	int sublen;
	/*
	 * We need to check it is a directory despite the
	 * FindExSearchLimitToDirectories in the above call. See SDK docs
	 */
	if ((finfo.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) == 0)
	    continue;
	sublen = strlen(finfo.cFileName);
	if ((dirlen+1+sublen+1+keylen+1) > sizeof(path))
	    continue;		/* Path does not fit, assume not matched */
................................................................................
 * LocateDependency --
 *
 *	Locates a dependency for a package.
 *        keypath - a relative path within the package directory
 *          that is used to confirm it is the correct directory.
 *	The search path for the package directory is currently only
 *      the parent and grandparent of the current working directory.
 *      If found, the command prints
 *         name_DIRPATH=<full path of located directory>
 *      and returns 0. If not found, does not print anything and returns 1.
 */
static int LocateDependency(const char *keypath)
{
    int i, ret;
    static const char *paths[] = {"..", "..\\..", "..\\..\\.."};

    for (i = 0; i < (sizeof(paths)/sizeof(paths[0])); ++i) {
	ret = LocateDependencyHelper(paths[i], keypath);
	if (ret == 0)
	    return ret;
    }
    return ret;
}

    Tcl_DStringInit(bufferPtr);

    wDomain = NULL;
    domain = Tcl_UtfFindFirst(name, '@');
    if (domain == NULL) {
	const char *ptr;
	
	/* no domain - firstly check it's the current user */
	if ( (ptr = TclpGetUserName(&ds)) != NULL 
	  && strcasecmp(name, ptr) == 0
	) {
	    /* try safest and fastest way to get current user home */
	    ptr = TclGetEnv("HOME", &ds);
	    if (ptr != NULL) {
		Tcl_JoinPath(1, &ptr, bufferPtr);
		rc = 1;
................................................................................
	Tcl_DStringFree(&ds);
	nameLen = domain - name;
    }
    if (rc == 0) {
	Tcl_DStringInit(&ds);
	wName = Tcl_UtfToUniCharDString(name, nameLen, &ds);
	while (NetUserGetInfo(wDomain, wName, 1, (LPBYTE *) &uiPtr) != 0) {
	    /* 
	     * user does not exists - if domain was not specified,
	     * try again using current domain.
	     */
	    rc = 1;
	    if (domain != NULL) break;
	    /* get current domain */
	    rc = NetGetDCName(NULL, NULL, (LPBYTE *) &wDomain);
................................................................................
	/*
	 * File exists, nothing else to check.
	 */

	return 0;
    }

    /* 
     * If it's not a directory (assume file), do several fast checks:
     */
    if (!(attr & FILE_ATTRIBUTE_DIRECTORY)) {
	/*
	 * If the attributes say this is not writable at all.  The file is a
	 * regular file (i.e., not a directory), then the file is not
	 * writable, full stop.	 For directories, the read-only bit is
................................................................................
     * in wish by default). However the subsequent GetFileInformationByHandle
     * will fail. We do a WinIsReserved to see if it is one of the special
     * names, and if successful, mock up a BY_HANDLE_FILE_INFORMATION
     * structure.
     */

    fileHandle = CreateFile(nativePath, GENERIC_READ,
	    FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE, 
	    NULL, OPEN_EXISTING,
	    FILE_FLAG_BACKUP_SEMANTICS | FILE_FLAG_OPEN_REPARSE_POINT, NULL);

    if (fileHandle != INVALID_HANDLE_VALUE) {
	BY_HANDLE_FILE_INFORMATION data;

	if (GetFileInformationByHandle(fileHandle,&data) != TRUE) {

    Tcl_DStringInit(bufferPtr);

    wDomain = NULL;
    domain = Tcl_UtfFindFirst(name, '@');
    if (domain == NULL) {
	const char *ptr;

	/* no domain - firstly check it's the current user */
	if ( (ptr = TclpGetUserName(&ds)) != NULL
	  && strcasecmp(name, ptr) == 0
	) {
	    /* try safest and fastest way to get current user home */
	    ptr = TclGetEnv("HOME", &ds);
	    if (ptr != NULL) {
		Tcl_JoinPath(1, &ptr, bufferPtr);
		rc = 1;
................................................................................
	Tcl_DStringFree(&ds);
	nameLen = domain - name;
    }
    if (rc == 0) {
	Tcl_DStringInit(&ds);
	wName = Tcl_UtfToUniCharDString(name, nameLen, &ds);
	while (NetUserGetInfo(wDomain, wName, 1, (LPBYTE *) &uiPtr) != 0) {
	    /*
	     * user does not exists - if domain was not specified,
	     * try again using current domain.
	     */
	    rc = 1;
	    if (domain != NULL) break;
	    /* get current domain */
	    rc = NetGetDCName(NULL, NULL, (LPBYTE *) &wDomain);
................................................................................
	/*
	 * File exists, nothing else to check.
	 */

	return 0;
    }

    /*
     * If it's not a directory (assume file), do several fast checks:
     */
    if (!(attr & FILE_ATTRIBUTE_DIRECTORY)) {
	/*
	 * If the attributes say this is not writable at all.  The file is a
	 * regular file (i.e., not a directory), then the file is not
	 * writable, full stop.	 For directories, the read-only bit is
................................................................................
     * in wish by default). However the subsequent GetFileInformationByHandle
     * will fail. We do a WinIsReserved to see if it is one of the special
     * names, and if successful, mock up a BY_HANDLE_FILE_INFORMATION
     * structure.
     */

    fileHandle = CreateFile(nativePath, GENERIC_READ,
	    FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
	    NULL, OPEN_EXISTING,
	    FILE_FLAG_BACKUP_SEMANTICS | FILE_FLAG_OPEN_REPARSE_POINT, NULL);

    if (fileHandle != INVALID_HANDLE_VALUE) {
	BY_HANDLE_FILE_INFORMATION data;

	if (GetFileInformationByHandle(fileHandle,&data) != TRUE) {

	 * Let the OS loader examine the binary search path for whatever
	 * string the user gave us which hopefully refers to a file on the
	 * binary path.
	 */

	Tcl_DString ds;

        /* 
         * Remember the first error on load attempt to be used if the
         * second load attempt below also fails.
        */
        firstError = (nativeName == NULL) ?
		ERROR_MOD_NOT_FOUND : GetLastError();

	nativeName = Tcl_WinUtfToTChar(Tcl_GetString(pathPtr), -1, &ds);

	 * Let the OS loader examine the binary search path for whatever
	 * string the user gave us which hopefully refers to a file on the
	 * binary path.
	 */

	Tcl_DString ds;

        /*
         * Remember the first error on load attempt to be used if the
         * second load attempt below also fails.
        */
        firstError = (nativeName == NULL) ?
		ERROR_MOD_NOT_FOUND : GetLastError();

	nativeName = Tcl_WinUtfToTChar(Tcl_GetString(pathPtr), -1, &ds);

    /*
     * Apply the new ACL. Note PROTECTED_DACL_SECURITY_INFORMATION can be used
     * to remove inherited ACL (we need to overwrite the default ACL's in this case)
     */

    if (set_readOnly == acl_readOnly_found || SetNamedSecurityInfoA(
	    (LPSTR) nativePath, SE_FILE_OBJECT, 
	    DACL_SECURITY_INFORMATION /*| PROTECTED_DACL_SECURITY_INFORMATION*/,
	    NULL, NULL, newAcl, NULL) == ERROR_SUCCESS) {
	res = 0;
    }

  done:
    if (secDesc) {

    /*
     * Apply the new ACL. Note PROTECTED_DACL_SECURITY_INFORMATION can be used
     * to remove inherited ACL (we need to overwrite the default ACL's in this case)
     */

    if (set_readOnly == acl_readOnly_found || SetNamedSecurityInfoA(
	    (LPSTR) nativePath, SE_FILE_OBJECT,
	    DACL_SECURITY_INFORMATION /*| PROTECTED_DACL_SECURITY_INFORMATION*/,
	    NULL, NULL, newAcl, NULL) == ERROR_SUCCESS) {
	res = 0;
    }

  done:
    if (secDesc) {

    LARGE_INTEGER curCounter;

    if (!wideClick.initialized) {
	LARGE_INTEGER perfCounterFreq;

	/*
	 * The frequency of the performance counter is fixed at system boot and
	 * is consistent across all processors. Therefore, the frequency need 
	 * only be queried upon application initialization.
	 */
	if (QueryPerformanceFrequency(&perfCounterFreq)) {
	    wideClick.perfCounter = 1;
	    wideClick.microsecsScale = 1000000.0 / perfCounterFreq.QuadPart;
	} else {
	    /* fallback using microseconds */
	    wideClick.perfCounter = 0;
	    wideClick.microsecsScale = 1;
	}
	
	wideClick.initialized = 1;
    }
    if (wideClick.perfCounter) {
	if (QueryPerformanceCounter(&curCounter)) {
	    return (Tcl_WideInt)curCounter.QuadPart;
	}
	/* fallback using microseconds */
................................................................................
}
 
/*
 *----------------------------------------------------------------------
 *
 * TclpWideClickInMicrosec --
 *
 *	This procedure return scale to convert wide click values from the 
 *	TclpGetWideClicks native resolution to microsecond resolution
 *	and back.
 *
 * Results:
 * 	1 click in microseconds as double.
 *
 * Side effects:
................................................................................
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

Tcl_WideInt 
TclpGetMicroseconds(void)
{
    Tcl_WideInt usecSincePosixEpoch;

    /* Try to use high resolution timer */
    if ( tclGetTimeProcPtr == NativeGetTime
      && (usecSincePosixEpoch = NativeGetMicroseconds())
................................................................................
static inline Tcl_WideInt
NativeCalc100NsTicks(
    ULONGLONG fileTimeLastCall,
    LONGLONG perfCounterLastCall,
    LONGLONG curCounterFreq,
    LONGLONG curCounter
) {
    return fileTimeLastCall + 
	((curCounter - perfCounterLastCall) * 10000000 / curCounterFreq);
}

static Tcl_WideInt
NativeGetMicroseconds(void)
{
    /*
................................................................................
      && curFileTime.QuadPart < lastFileTime.QuadPart +
      				    (timeInfo.calibrationInterv * 10000000)
    ) {
    	/* again in next one second */
	return;
    }
    QueryPerformanceCounter(&curPerfCounter);
    
    lastFileTime.QuadPart = curFileTime.QuadPart;

    /*
     * We devide by timeInfo.curCounterFreq.QuadPart in several places. That
     * value should always be positive on a correctly functioning system. But
     * it is good to be defensive about such matters. So if something goes
     * wrong and the value does goes to zero, we clear the
................................................................................
    if (tdiff > 10000000 || tdiff < -10000000) {
    	/* jump to current system time, use curent estimated frequency */
    	vt0 = curFileTime.QuadPart;
    } else {
    	/* calculate new frequency and estimate drift to the next second */
	vt1 = 20000000 + curFileTime.QuadPart;
	driftFreq = (estFreq * 20000000 / (vt1 - vt0));
	/* 
	 * Avoid too large drifts (only half of the current difference),
	 * that allows also be more accurate (aspire to the smallest tdiff),
	 * so then we can prolong calibration interval by tdiff < 100000
	 */
	driftFreq = timeInfo.curCounterFreq.QuadPart +
		(driftFreq - timeInfo.curCounterFreq.QuadPart) / 2;

	/* 
	 * Average between estimated, 2 current and 5 drifted frequencies,
	 * (do the soft drifting as possible)
	 */
	estFreq = (estFreq + 2 * timeInfo.curCounterFreq.QuadPart + 5 * driftFreq) / 8;
    }
    
    /* Avoid too large discrepancy from nominal frequency */
    if (estFreq > 1003*timeInfo.nominalFreq.QuadPart/1000) {
	estFreq = 1003*timeInfo.nominalFreq.QuadPart/1000;
	vt0 = curFileTime.QuadPart;
    } else if (estFreq < 997*timeInfo.nominalFreq.QuadPart/1000) {
	estFreq = 997*timeInfo.nominalFreq.QuadPart/1000;
	vt0 = curFileTime.QuadPart;
    } else if (vt0 != curFileTime.QuadPart) {
	/* 
	 * Be sure the clock ticks never backwards (avoid it by negative drifting)
	 * just compare native time (in 100-ns) before and hereafter using 
	 * new calibrated values) and do a small adjustment (short time freeze)
	 */
	LARGE_INTEGER newPerfCounter;
	Tcl_WideInt nt0, nt1;

	QueryPerformanceCounter(&newPerfCounter);
	nt0 = NativeCalc100NsTicks(timeInfo.fileTimeLastCall.QuadPart,

    LARGE_INTEGER curCounter;

    if (!wideClick.initialized) {
	LARGE_INTEGER perfCounterFreq;

	/*
	 * The frequency of the performance counter is fixed at system boot and
	 * is consistent across all processors. Therefore, the frequency need
	 * only be queried upon application initialization.
	 */
	if (QueryPerformanceFrequency(&perfCounterFreq)) {
	    wideClick.perfCounter = 1;
	    wideClick.microsecsScale = 1000000.0 / perfCounterFreq.QuadPart;
	} else {
	    /* fallback using microseconds */
	    wideClick.perfCounter = 0;
	    wideClick.microsecsScale = 1;
	}

	wideClick.initialized = 1;
    }
    if (wideClick.perfCounter) {
	if (QueryPerformanceCounter(&curCounter)) {
	    return (Tcl_WideInt)curCounter.QuadPart;
	}
	/* fallback using microseconds */
................................................................................
}
 
/*
 *----------------------------------------------------------------------
 *
 * TclpWideClickInMicrosec --
 *
 *	This procedure return scale to convert wide click values from the
 *	TclpGetWideClicks native resolution to microsecond resolution
 *	and back.
 *
 * Results:
 * 	1 click in microseconds as double.
 *
 * Side effects:
................................................................................
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

Tcl_WideInt
TclpGetMicroseconds(void)
{
    Tcl_WideInt usecSincePosixEpoch;

    /* Try to use high resolution timer */
    if ( tclGetTimeProcPtr == NativeGetTime
      && (usecSincePosixEpoch = NativeGetMicroseconds())
................................................................................
static inline Tcl_WideInt
NativeCalc100NsTicks(
    ULONGLONG fileTimeLastCall,
    LONGLONG perfCounterLastCall,
    LONGLONG curCounterFreq,
    LONGLONG curCounter
) {
    return fileTimeLastCall +
	((curCounter - perfCounterLastCall) * 10000000 / curCounterFreq);
}

static Tcl_WideInt
NativeGetMicroseconds(void)
{
    /*
................................................................................
      && curFileTime.QuadPart < lastFileTime.QuadPart +
      				    (timeInfo.calibrationInterv * 10000000)
    ) {
    	/* again in next one second */
	return;
    }
    QueryPerformanceCounter(&curPerfCounter);

    lastFileTime.QuadPart = curFileTime.QuadPart;

    /*
     * We devide by timeInfo.curCounterFreq.QuadPart in several places. That
     * value should always be positive on a correctly functioning system. But
     * it is good to be defensive about such matters. So if something goes
     * wrong and the value does goes to zero, we clear the
................................................................................
    if (tdiff > 10000000 || tdiff < -10000000) {
    	/* jump to current system time, use curent estimated frequency */
    	vt0 = curFileTime.QuadPart;
    } else {
    	/* calculate new frequency and estimate drift to the next second */
	vt1 = 20000000 + curFileTime.QuadPart;
	driftFreq = (estFreq * 20000000 / (vt1 - vt0));
	/*
	 * Avoid too large drifts (only half of the current difference),
	 * that allows also be more accurate (aspire to the smallest tdiff),
	 * so then we can prolong calibration interval by tdiff < 100000
	 */
	driftFreq = timeInfo.curCounterFreq.QuadPart +
		(driftFreq - timeInfo.curCounterFreq.QuadPart) / 2;

	/*
	 * Average between estimated, 2 current and 5 drifted frequencies,
	 * (do the soft drifting as possible)
	 */
	estFreq = (estFreq + 2 * timeInfo.curCounterFreq.QuadPart + 5 * driftFreq) / 8;
    }

    /* Avoid too large discrepancy from nominal frequency */
    if (estFreq > 1003*timeInfo.nominalFreq.QuadPart/1000) {
	estFreq = 1003*timeInfo.nominalFreq.QuadPart/1000;
	vt0 = curFileTime.QuadPart;
    } else if (estFreq < 997*timeInfo.nominalFreq.QuadPart/1000) {
	estFreq = 997*timeInfo.nominalFreq.QuadPart/1000;
	vt0 = curFileTime.QuadPart;
    } else if (vt0 != curFileTime.QuadPart) {
	/*
	 * Be sure the clock ticks never backwards (avoid it by negative drifting)
	 * just compare native time (in 100-ns) before and hereafter using
	 * new calibrated values) and do a small adjustment (short time freeze)
	 */
	LARGE_INTEGER newPerfCounter;
	Tcl_WideInt nt0, nt1;

	QueryPerformanceCounter(&newPerfCounter);
	nt0 = NativeCalc100NsTicks(timeInfo.fileTimeLastCall.QuadPart,