ShellPkg/Library/UefiDpLib/DpUtilities.c - third_party/edk2 - Git at Google

 /** @file
   Utility functions used by the Dp application.

   Copyright (c) 2009 - 2013, Intel Corporation. All rights reserved.
   This program and the accompanying materials
   are licensed and made available under the terms and conditions of the BSD License
   which accompanies this distribution.  The full text of the license may be found at
   http://opensource.org/licenses/bsd-license.php

   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
 **/

 #include <Library/BaseLib.h>
 #include <Library/BaseMemoryLib.h>
 #include <Library/MemoryAllocationLib.h>
 #include <Library/DebugLib.h>
 #include <Library/UefiBootServicesTableLib.h>
 #include <Library/TimerLib.h>
 #include <Library/PeCoffGetEntryPointLib.h>
 #include <Library/PrintLib.h>
 #include <Library/HiiLib.h>
 #include <Library/PcdLib.h>
 #include <Library/UefiLib.h>
 #include <Library/DevicePathLib.h>
 #include <Library/HandleParsingLib.h>

 #include <Pi/PiFirmwareFile.h>
 #include <Library/DxeServicesLib.h>

 #include <Protocol/LoadedImage.h>
 #include <Protocol/DriverBinding.h>
 #include <Protocol/ComponentName2.h>
 #include <Protocol/DevicePath.h>

 #include <Guid/Performance.h>

 #include "Dp.h"
 #include "Literals.h"
 #include "DpInternal.h"

 /**
   Calculate an event's duration in timer ticks.

   Given the count direction and the event's start and end timer values,
   calculate the duration of the event in timer ticks.  Information for
   the current measurement is pointed to by the parameter.

   If the measurement's start time is 1, it indicates that the developer
   is indicating that the measurement began at the release of reset.
   The start time is adjusted to the timer's starting count before performing
   the elapsed time calculation.

   The calculated duration, in ticks, is the absolute difference between
   the measurement's ending and starting counts.

   @param Measurement   Pointer to a MEASUREMENT_RECORD structure containing
                        data for the current measurement.

   @return              The 64-bit duration of the event.
 **/
 UINT64
 GetDuration (
   IN OUT MEASUREMENT_RECORD   *Measurement
   )
 {
   UINT64    Duration;
   BOOLEAN   Error;

   // PERF_START macros are called with a value of 1 to indicate
   // the beginning of time.  So, adjust the start ticker value
   // to the real beginning of time.
   // Assumes no wraparound.  Even then, there is a very low probability
   // of having a valid StartTicker value of 1.
   if (Measurement->StartTimeStamp == 1) {
     Measurement->StartTimeStamp = TimerInfo.StartCount;
   }
   if (TimerInfo.CountUp) {
     Duration = Measurement->EndTimeStamp - Measurement->StartTimeStamp;
     Error = (BOOLEAN)(Duration > Measurement->EndTimeStamp);
   }
   else {
     Duration = Measurement->StartTimeStamp - Measurement->EndTimeStamp;
     Error = (BOOLEAN)(Duration > Measurement->StartTimeStamp);
   }

   if (Error) {
     DEBUG ((EFI_D_ERROR, ALit_TimerLibError));
     Duration = 0;
   }
   return Duration;
 }

 /**
   Determine whether the Measurement record is for an EFI Phase.

   The Token and Module members of the measurement record are checked.
   Module must be empty and Token must be one of SEC, PEI, DXE, BDS, or SHELL.

   @param[in]  Measurement A pointer to the Measurement record to test.

   @retval     TRUE        The measurement record is for an EFI Phase.
   @retval     FALSE       The measurement record is NOT for an EFI Phase.
 **/
 BOOLEAN
 IsPhase(
   IN MEASUREMENT_RECORD        *Measurement
   )
 {
   BOOLEAN   RetVal;

   RetVal = (BOOLEAN)( ( *Measurement->Module == '\0')                               &&
             ((AsciiStrnCmp (Measurement->Token, ALit_SEC, PERF_TOKEN_LENGTH) == 0)    ||
              (AsciiStrnCmp (Measurement->Token, ALit_PEI, PERF_TOKEN_LENGTH) == 0)    ||
              (AsciiStrnCmp (Measurement->Token, ALit_DXE, PERF_TOKEN_LENGTH) == 0)    ||
              (AsciiStrnCmp (Measurement->Token, ALit_BDS, PERF_TOKEN_LENGTH) == 0))
             );
   return RetVal;
 }

 /**
   Get the file name portion of the Pdb File Name.

   The portion of the Pdb File Name between the last backslash and
   either a following period or the end of the string is converted
   to Unicode and copied into UnicodeBuffer.  The name is truncated,
   if necessary, to ensure that UnicodeBuffer is not overrun.

   @param[in]  PdbFileName     Pdb file name.
   @param[out] UnicodeBuffer   The resultant Unicode File Name.

 **/
 VOID
 GetShortPdbFileName (
   IN  CHAR8     *PdbFileName,
   OUT CHAR16    *UnicodeBuffer
   )
 {
   UINTN IndexA;     // Current work location within an ASCII string.
   UINTN IndexU;     // Current work location within a Unicode string.
   UINTN StartIndex;
   UINTN EndIndex;

   ZeroMem (UnicodeBuffer, DXE_PERFORMANCE_STRING_LENGTH * sizeof (CHAR16));

   if (PdbFileName == NULL) {
     StrCpy (UnicodeBuffer, L" ");
   } else {
     StartIndex = 0;
     for (EndIndex = 0; PdbFileName[EndIndex] != 0; EndIndex++)
       ;
     for (IndexA = 0; PdbFileName[IndexA] != 0; IndexA++) {
       if (PdbFileName[IndexA] == '\\') {
         StartIndex = IndexA + 1;
       }

       if (PdbFileName[IndexA] == '.') {
         EndIndex = IndexA;
       }
     }

     IndexU = 0;
     for (IndexA = StartIndex; IndexA < EndIndex; IndexA++) {
       UnicodeBuffer[IndexU] = (CHAR16) PdbFileName[IndexA];
       IndexU++;
       if (IndexU >= DXE_PERFORMANCE_STRING_LENGTH) {
         UnicodeBuffer[DXE_PERFORMANCE_STRING_LENGTH] = 0;
         break;
       }
     }
   }
 }

 /**
   Get a human readable name for an image handle.
   The following methods will be tried orderly:
     1. Image PDB
     2. ComponentName2 protocol
     3. FFS UI section
     4. Image GUID
     5. Image DevicePath
     6. Unknown Driver Name

   @param[in]    Handle

   @post   The resulting Unicode name string is stored in the
           mGaugeString global array.

 **/
 VOID
 GetNameFromHandle (
   IN EFI_HANDLE   Handle
   )
 {
   EFI_STATUS                  Status;
   EFI_LOADED_IMAGE_PROTOCOL   *Image;
   CHAR8                       *PdbFileName;
   EFI_DRIVER_BINDING_PROTOCOL *DriverBinding;
   EFI_STRING                  StringPtr;
   EFI_DEVICE_PATH_PROTOCOL    *LoadedImageDevicePath;
   EFI_DEVICE_PATH_PROTOCOL    *DevicePath;
   EFI_GUID                    *NameGuid;
   CHAR16                      *NameString;
   UINTN                       StringSize;
   CHAR8                       *PlatformLanguage;
   EFI_COMPONENT_NAME2_PROTOCOL      *ComponentName2;

   //
   // Method 1: Get the name string from image PDB
   //
   Status = gBS->HandleProtocol (
                   Handle,
                   &gEfiLoadedImageProtocolGuid,
                   (VOID **) &Image
                   );

   if (EFI_ERROR (Status)) {
     Status = gBS->OpenProtocol (
                     Handle,
                     &gEfiDriverBindingProtocolGuid,
                     (VOID **) &DriverBinding,
                     NULL,
                     NULL,
                     EFI_OPEN_PROTOCOL_GET_PROTOCOL
                     );
     if (!EFI_ERROR (Status)) {
       Status = gBS->HandleProtocol (
                       DriverBinding->ImageHandle,
                       &gEfiLoadedImageProtocolGuid,
                       (VOID **) &Image
                       );
     }
   }

   if (!EFI_ERROR (Status)) {
     PdbFileName = PeCoffLoaderGetPdbPointer (Image->ImageBase);

     if (PdbFileName != NULL) {
       GetShortPdbFileName (PdbFileName, mGaugeString);
       return;
     }
   }

   //
   // Method 2: Get the name string from ComponentName2 protocol
   //
   Status = gBS->HandleProtocol (
                   Handle,
                   &gEfiComponentName2ProtocolGuid,
                   (VOID **) &ComponentName2
                   );
   if (!EFI_ERROR (Status)) {
     //
     // Get the current platform language setting
     //
     PlatformLanguage = GetBestLanguageForDriver(ComponentName2->SupportedLanguages, NULL, FALSE);
     Status = ComponentName2->GetDriverName (
                                ComponentName2,
                                PlatformLanguage != NULL ? PlatformLanguage : "en-US",
                                &StringPtr
                                );
     if (!EFI_ERROR (Status)) {
       SHELL_FREE_NON_NULL (PlatformLanguage);
       StrnCpy (mGaugeString, StringPtr, DP_GAUGE_STRING_LENGTH);
       mGaugeString[DP_GAUGE_STRING_LENGTH] = 0;
       return;
     }
   }

   Status = gBS->HandleProtocol (
                   Handle,
                   &gEfiLoadedImageDevicePathProtocolGuid,
                   (VOID **) &LoadedImageDevicePath
                   );
   if (!EFI_ERROR (Status) && (LoadedImageDevicePath != NULL)) {
     DevicePath = LoadedImageDevicePath;

     //
     // Try to get image GUID from LoadedImageDevicePath protocol
     //
     NameGuid = NULL;
     while (!IsDevicePathEndType (DevicePath)) {
       NameGuid = EfiGetNameGuidFromFwVolDevicePathNode ((MEDIA_FW_VOL_FILEPATH_DEVICE_PATH *) DevicePath);
       if (NameGuid != NULL) {
         break;
       }
       DevicePath = NextDevicePathNode (DevicePath);
     }

     if (NameGuid != NULL) {
       //
       // Try to get the image's FFS UI section by image GUID
       //
       NameString = NULL;
       StringSize = 0;
       Status = GetSectionFromAnyFv (
                 NameGuid,
                 EFI_SECTION_USER_INTERFACE,
                 0,
                 (VOID **) &NameString,
                 &StringSize
                 );

       if (!EFI_ERROR (Status)) {
         //
         // Method 3. Get the name string from FFS UI section
         //
         StrnCpy (mGaugeString, NameString, DP_GAUGE_STRING_LENGTH);
         mGaugeString[DP_GAUGE_STRING_LENGTH] = 0;
         FreePool (NameString);
       } else {
         //
         // Method 4: Get the name string from image GUID
         //
         UnicodeSPrint (mGaugeString, sizeof (mGaugeString), L"%g", NameGuid);
       }
       return;
     } else {
       //
       // Method 5: Get the name string from image DevicePath
       //
       NameString = ConvertDevicePathToText (LoadedImageDevicePath, TRUE, FALSE);
       if (NameString != NULL) {
         StrnCpy (mGaugeString, NameString, DP_GAUGE_STRING_LENGTH);
         mGaugeString[DP_GAUGE_STRING_LENGTH] = 0;
         FreePool (NameString);
         return;
       }
     }
   }

   //
   // Method 6: Unknown Driver Name
   //
   StringPtr = HiiGetString (gDpHiiHandle, STRING_TOKEN (STR_DP_ERROR_NAME), NULL);
   ASSERT (StringPtr != NULL);
   StrCpy (mGaugeString, StringPtr);
   FreePool (StringPtr);
 }

 /**
   Calculate the Duration in microseconds.

   Duration is multiplied by 1000, instead of Frequency being divided by 1000 or
   multiplying the result by 1000, in order to maintain precision.  Since Duration is
   a 64-bit value, multiplying it by 1000 is unlikely to produce an overflow.

   The time is calculated as (Duration * 1000) / Timer_Frequency.

   @param[in]  Duration   The event duration in timer ticks.

   @return     A 64-bit value which is the Elapsed time in microseconds.
 **/
 UINT64
 DurationInMicroSeconds (
   IN UINT64 Duration
   )
 {
   UINT64 Temp;

   Temp = MultU64x32 (Duration, 1000);
   return DivU64x32 (Temp, TimerInfo.Frequency);
 }

 /**
   Get index of Measurement Record's match in the CumData array.

   If the Measurement's Token value matches a Token in one of the CumData
   records, the index of the matching record is returned.  The returned
   index is a signed value so that negative values can indicate that
   the Measurement didn't match any entry in the CumData array.

   @param[in]  Measurement A pointer to a Measurement Record to match against the CumData array.

   @retval     <0    Token is not in the CumData array.
   @retval     >=0   Return value is the index into CumData where Token is found.
 **/
 INTN
 GetCumulativeItem(
   IN MEASUREMENT_RECORD   *Measurement
   )
 {
   INTN    Index;

   for( Index = 0; Index < (INTN)NumCum; ++Index) {
     if (AsciiStrnCmp (Measurement->Token, CumData[Index].Name, PERF_TOKEN_LENGTH) == 0) {
       return Index;  // Exit, we found a match
     }
   }
   // If the for loop exits, Token was not found.
   return -1;   // Indicate failure
 }
	/** @file
	Utility functions used by the Dp application.

	Copyright (c) 2009 - 2013, Intel Corporation. All rights reserved.
	This program and the accompanying materials
	are licensed and made available under the terms and conditions of the BSD License
	which accompanies this distribution. The full text of the license may be found at
	http://opensource.org/licenses/bsd-license.php

	THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
	WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
	**/

	#include <Library/BaseLib.h>
	#include <Library/BaseMemoryLib.h>
	#include <Library/MemoryAllocationLib.h>
	#include <Library/DebugLib.h>
	#include <Library/UefiBootServicesTableLib.h>
	#include <Library/TimerLib.h>
	#include <Library/PeCoffGetEntryPointLib.h>
	#include <Library/PrintLib.h>
	#include <Library/HiiLib.h>
	#include <Library/PcdLib.h>
	#include <Library/UefiLib.h>
	#include <Library/DevicePathLib.h>
	#include <Library/HandleParsingLib.h>

	#include <Pi/PiFirmwareFile.h>
	#include <Library/DxeServicesLib.h>

	#include <Protocol/LoadedImage.h>
	#include <Protocol/DriverBinding.h>
	#include <Protocol/ComponentName2.h>
	#include <Protocol/DevicePath.h>

	#include <Guid/Performance.h>

	#include "Dp.h"
	#include "Literals.h"
	#include "DpInternal.h"

	/**
	Calculate an event's duration in timer ticks.

	Given the count direction and the event's start and end timer values,
	calculate the duration of the event in timer ticks. Information for
	the current measurement is pointed to by the parameter.

	If the measurement's start time is 1, it indicates that the developer
	is indicating that the measurement began at the release of reset.
	The start time is adjusted to the timer's starting count before performing
	the elapsed time calculation.

	The calculated duration, in ticks, is the absolute difference between
	the measurement's ending and starting counts.

	@param Measurement Pointer to a MEASUREMENT_RECORD structure containing
	data for the current measurement.

	@return The 64-bit duration of the event.
	**/
	UINT64
	GetDuration (
	IN OUT MEASUREMENT_RECORD *Measurement
	)
	{
	UINT64 Duration;
	BOOLEAN Error;

	// PERF_START macros are called with a value of 1 to indicate
	// the beginning of time. So, adjust the start ticker value
	// to the real beginning of time.
	// Assumes no wraparound. Even then, there is a very low probability
	// of having a valid StartTicker value of 1.
	if (Measurement->StartTimeStamp == 1) {
	Measurement->StartTimeStamp = TimerInfo.StartCount;
	}
	if (TimerInfo.CountUp) {
	Duration = Measurement->EndTimeStamp - Measurement->StartTimeStamp;
	Error = (BOOLEAN)(Duration > Measurement->EndTimeStamp);
	}
	else {
	Duration = Measurement->StartTimeStamp - Measurement->EndTimeStamp;
	Error = (BOOLEAN)(Duration > Measurement->StartTimeStamp);
	}

	if (Error) {
	DEBUG ((EFI_D_ERROR, ALit_TimerLibError));
	Duration = 0;
	}
	return Duration;
	}

	/**
	Determine whether the Measurement record is for an EFI Phase.

	The Token and Module members of the measurement record are checked.
	Module must be empty and Token must be one of SEC, PEI, DXE, BDS, or SHELL.

	@param[in] Measurement A pointer to the Measurement record to test.

	@retval TRUE The measurement record is for an EFI Phase.
	@retval FALSE The measurement record is NOT for an EFI Phase.
	**/
	BOOLEAN
	IsPhase(
	IN MEASUREMENT_RECORD *Measurement
	)
	{
	BOOLEAN RetVal;

	RetVal = (BOOLEAN)( ( *Measurement->Module == '\0') &&
	((AsciiStrnCmp (Measurement->Token, ALit_SEC, PERF_TOKEN_LENGTH) == 0) \|\|
	(AsciiStrnCmp (Measurement->Token, ALit_PEI, PERF_TOKEN_LENGTH) == 0) \|\|
	(AsciiStrnCmp (Measurement->Token, ALit_DXE, PERF_TOKEN_LENGTH) == 0) \|\|
	(AsciiStrnCmp (Measurement->Token, ALit_BDS, PERF_TOKEN_LENGTH) == 0))
	);
	return RetVal;
	}

	/**
	Get the file name portion of the Pdb File Name.

	The portion of the Pdb File Name between the last backslash and
	either a following period or the end of the string is converted
	to Unicode and copied into UnicodeBuffer. The name is truncated,
	if necessary, to ensure that UnicodeBuffer is not overrun.

	@param[in] PdbFileName Pdb file name.
	@param[out] UnicodeBuffer The resultant Unicode File Name.

	**/
	VOID
	GetShortPdbFileName (
	IN CHAR8 *PdbFileName,
	OUT CHAR16 *UnicodeBuffer
	)
	{
	UINTN IndexA; // Current work location within an ASCII string.
	UINTN IndexU; // Current work location within a Unicode string.
	UINTN StartIndex;
	UINTN EndIndex;

	ZeroMem (UnicodeBuffer, DXE_PERFORMANCE_STRING_LENGTH * sizeof (CHAR16));

	if (PdbFileName == NULL) {
	StrCpy (UnicodeBuffer, L" ");
	} else {
	StartIndex = 0;
	for (EndIndex = 0; PdbFileName[EndIndex] != 0; EndIndex++)
	;
	for (IndexA = 0; PdbFileName[IndexA] != 0; IndexA++) {
	if (PdbFileName[IndexA] == '\\') {
	StartIndex = IndexA + 1;
	}

	if (PdbFileName[IndexA] == '.') {
	EndIndex = IndexA;
	}
	}

	IndexU = 0;
	for (IndexA = StartIndex; IndexA < EndIndex; IndexA++) {
	UnicodeBuffer[IndexU] = (CHAR16) PdbFileName[IndexA];
	IndexU++;
	if (IndexU >= DXE_PERFORMANCE_STRING_LENGTH) {
	UnicodeBuffer[DXE_PERFORMANCE_STRING_LENGTH] = 0;
	break;
	}
	}
	}
	}

	/**
	Get a human readable name for an image handle.
	The following methods will be tried orderly:
	1. Image PDB
	2. ComponentName2 protocol
	3. FFS UI section
	4. Image GUID
	5. Image DevicePath
	6. Unknown Driver Name

	@param[in] Handle

	@post The resulting Unicode name string is stored in the
	mGaugeString global array.

	**/
	VOID
	GetNameFromHandle (
	IN EFI_HANDLE Handle
	)
	{
	EFI_STATUS Status;
	EFI_LOADED_IMAGE_PROTOCOL *Image;
	CHAR8 *PdbFileName;
	EFI_DRIVER_BINDING_PROTOCOL *DriverBinding;
	EFI_STRING StringPtr;
	EFI_DEVICE_PATH_PROTOCOL *LoadedImageDevicePath;
	EFI_DEVICE_PATH_PROTOCOL *DevicePath;
	EFI_GUID *NameGuid;
	CHAR16 *NameString;
	UINTN StringSize;
	CHAR8 *PlatformLanguage;
	EFI_COMPONENT_NAME2_PROTOCOL *ComponentName2;

	//
	// Method 1: Get the name string from image PDB
	//
	Status = gBS->HandleProtocol (
	Handle,
	&gEfiLoadedImageProtocolGuid,
	(VOID **) &Image
	);

	if (EFI_ERROR (Status)) {
	Status = gBS->OpenProtocol (
	Handle,
	&gEfiDriverBindingProtocolGuid,
	(VOID **) &DriverBinding,
	NULL,
	NULL,
	EFI_OPEN_PROTOCOL_GET_PROTOCOL
	);
	if (!EFI_ERROR (Status)) {
	Status = gBS->HandleProtocol (
	DriverBinding->ImageHandle,
	&gEfiLoadedImageProtocolGuid,
	(VOID **) &Image
	);
	}
	}

	if (!EFI_ERROR (Status)) {
	PdbFileName = PeCoffLoaderGetPdbPointer (Image->ImageBase);

	if (PdbFileName != NULL) {
	GetShortPdbFileName (PdbFileName, mGaugeString);
	return;
	}
	}

	//
	// Method 2: Get the name string from ComponentName2 protocol
	//
	Status = gBS->HandleProtocol (
	Handle,
	&gEfiComponentName2ProtocolGuid,
	(VOID **) &ComponentName2
	);
	if (!EFI_ERROR (Status)) {
	//
	// Get the current platform language setting
	//
	PlatformLanguage = GetBestLanguageForDriver(ComponentName2->SupportedLanguages, NULL, FALSE);
	Status = ComponentName2->GetDriverName (
	ComponentName2,
	PlatformLanguage != NULL ? PlatformLanguage : "en-US",
	&StringPtr
	);
	if (!EFI_ERROR (Status)) {
	SHELL_FREE_NON_NULL (PlatformLanguage);
	StrnCpy (mGaugeString, StringPtr, DP_GAUGE_STRING_LENGTH);
	mGaugeString[DP_GAUGE_STRING_LENGTH] = 0;
	return;
	}
	}

	Status = gBS->HandleProtocol (
	Handle,
	&gEfiLoadedImageDevicePathProtocolGuid,
	(VOID **) &LoadedImageDevicePath
	);
	if (!EFI_ERROR (Status) && (LoadedImageDevicePath != NULL)) {
	DevicePath = LoadedImageDevicePath;

	//
	// Try to get image GUID from LoadedImageDevicePath protocol
	//
	NameGuid = NULL;
	while (!IsDevicePathEndType (DevicePath)) {
	NameGuid = EfiGetNameGuidFromFwVolDevicePathNode ((MEDIA_FW_VOL_FILEPATH_DEVICE_PATH *) DevicePath);
	if (NameGuid != NULL) {
	break;
	}
	DevicePath = NextDevicePathNode (DevicePath);
	}

	if (NameGuid != NULL) {
	//
	// Try to get the image's FFS UI section by image GUID
	//
	NameString = NULL;
	StringSize = 0;
	Status = GetSectionFromAnyFv (
	NameGuid,
	EFI_SECTION_USER_INTERFACE,
	0,
	(VOID **) &NameString,
	&StringSize
	);

	if (!EFI_ERROR (Status)) {
	//
	// Method 3. Get the name string from FFS UI section
	//
	StrnCpy (mGaugeString, NameString, DP_GAUGE_STRING_LENGTH);
	mGaugeString[DP_GAUGE_STRING_LENGTH] = 0;
	FreePool (NameString);
	} else {
	//
	// Method 4: Get the name string from image GUID
	//
	UnicodeSPrint (mGaugeString, sizeof (mGaugeString), L"%g", NameGuid);
	}
	return;
	} else {
	//
	// Method 5: Get the name string from image DevicePath
	//
	NameString = ConvertDevicePathToText (LoadedImageDevicePath, TRUE, FALSE);
	if (NameString != NULL) {
	StrnCpy (mGaugeString, NameString, DP_GAUGE_STRING_LENGTH);
	mGaugeString[DP_GAUGE_STRING_LENGTH] = 0;
	FreePool (NameString);
	return;
	}
	}
	}

	//
	// Method 6: Unknown Driver Name
	//
	StringPtr = HiiGetString (gDpHiiHandle, STRING_TOKEN (STR_DP_ERROR_NAME), NULL);
	ASSERT (StringPtr != NULL);
	StrCpy (mGaugeString, StringPtr);
	FreePool (StringPtr);
	}

	/**
	Calculate the Duration in microseconds.

	Duration is multiplied by 1000, instead of Frequency being divided by 1000 or
	multiplying the result by 1000, in order to maintain precision. Since Duration is
	a 64-bit value, multiplying it by 1000 is unlikely to produce an overflow.

	The time is calculated as (Duration * 1000) / Timer_Frequency.

	@param[in] Duration The event duration in timer ticks.

	@return A 64-bit value which is the Elapsed time in microseconds.
	**/
	UINT64
	DurationInMicroSeconds (
	IN UINT64 Duration
	)
	{
	UINT64 Temp;

	Temp = MultU64x32 (Duration, 1000);
	return DivU64x32 (Temp, TimerInfo.Frequency);
	}

	/**
	Get index of Measurement Record's match in the CumData array.

	If the Measurement's Token value matches a Token in one of the CumData
	records, the index of the matching record is returned. The returned
	index is a signed value so that negative values can indicate that
	the Measurement didn't match any entry in the CumData array.

	@param[in] Measurement A pointer to a Measurement Record to match against the CumData array.

	@retval <0 Token is not in the CumData array.
	@retval >=0 Return value is the index into CumData where Token is found.
	**/
	INTN
	GetCumulativeItem(
	IN MEASUREMENT_RECORD *Measurement
	)
	{
	INTN Index;

	for( Index = 0; Index < (INTN)NumCum; ++Index) {
	if (AsciiStrnCmp (Measurement->Token, CumData[Index].Name, PERF_TOKEN_LENGTH) == 0) {
	return Index; // Exit, we found a match
	}
	}
	// If the for loop exits, Token was not found.
	return -1; // Indicate failure
	}