MdePkg/Library/UefiDevicePathLib/UefiDevicePathLibOptionalDevicePathProtocol.c - third_party/edk2 - Git at Google

 /** @file
   Device Path services. The thing to remember is device paths are built out of
   nodes. The device path is terminated by an end node that is length
   sizeof(EFI_DEVICE_PATH_PROTOCOL). That would be why there is sizeof(EFI_DEVICE_PATH_PROTOCOL)
   all over this file.

   The only place where multi-instance device paths are supported is in
   environment varibles. Multi-instance device paths should never be placed
   on a Handle.

   Copyright (c) 2013 - 2018, Intel Corporation. All rights reserved.<BR>
   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 "UefiDevicePathLib.h"

 GLOBAL_REMOVE_IF_UNREFERENCED EFI_DEVICE_PATH_UTILITIES_PROTOCOL *mDevicePathLibDevicePathUtilities = NULL;
 GLOBAL_REMOVE_IF_UNREFERENCED EFI_DEVICE_PATH_TO_TEXT_PROTOCOL   *mDevicePathLibDevicePathToText    = NULL;
 GLOBAL_REMOVE_IF_UNREFERENCED EFI_DEVICE_PATH_FROM_TEXT_PROTOCOL *mDevicePathLibDevicePathFromText  = NULL;

 /**
   The constructor function caches the pointer to DevicePathUtilites protocol,
   DevicePathToText protocol and DevicePathFromText protocol.

   The constructor function locates these three protocols from protocol database.
   It will caches the pointer to local protocol instance if that operation fails
   and it will always return EFI_SUCCESS.

   @param  ImageHandle   The firmware allocated handle for the EFI image.
   @param  SystemTable   A pointer to the EFI System Table.

   @retval EFI_SUCCESS   The constructor always returns EFI_SUCCESS.

 **/
 EFI_STATUS
 EFIAPI
 UefiDevicePathLibOptionalDevicePathProtocolConstructor (
   IN      EFI_HANDLE                ImageHandle,
   IN      EFI_SYSTEM_TABLE          *SystemTable
   )
 {
   EFI_STATUS                        Status;

   Status = gBS->LocateProtocol (
                   &gEfiDevicePathUtilitiesProtocolGuid,
                   NULL,
                   (VOID**) &mDevicePathLibDevicePathUtilities
                   );
   ASSERT_EFI_ERROR (Status);
   ASSERT (mDevicePathLibDevicePathUtilities != NULL);
   return Status;
 }

 /**
   Returns the size of a device path in bytes.

   This function returns the size, in bytes, of the device path data structure
   specified by DevicePath including the end of device path node.
   If DevicePath is NULL or invalid, then 0 is returned.

   @param  DevicePath  A pointer to a device path data structure.

   @retval 0           If DevicePath is NULL or invalid.
   @retval Others      The size of a device path in bytes.

 **/
 UINTN
 EFIAPI
 GetDevicePathSize (
   IN CONST EFI_DEVICE_PATH_PROTOCOL  *DevicePath
   )
 {
   if (mDevicePathLibDevicePathUtilities != NULL) {
     return mDevicePathLibDevicePathUtilities->GetDevicePathSize (DevicePath);
   } else {
     return UefiDevicePathLibGetDevicePathSize (DevicePath);
   }
 }

 /**
   Creates a new copy of an existing device path.

   This function allocates space for a new copy of the device path specified by DevicePath.
   If DevicePath is NULL, then NULL is returned.  If the memory is successfully
   allocated, then the contents of DevicePath are copied to the newly allocated
   buffer, and a pointer to that buffer is returned.  Otherwise, NULL is returned.
   The memory for the new device path is allocated from EFI boot services memory.
   It is the responsibility of the caller to free the memory allocated.

   @param  DevicePath    A pointer to a device path data structure.

   @retval NULL          DevicePath is NULL or invalid.
   @retval Others        A pointer to the duplicated device path.

 **/
 EFI_DEVICE_PATH_PROTOCOL *
 EFIAPI
 DuplicateDevicePath (
   IN CONST EFI_DEVICE_PATH_PROTOCOL  *DevicePath
   )
 {
   if (mDevicePathLibDevicePathUtilities != NULL) {
     return mDevicePathLibDevicePathUtilities->DuplicateDevicePath (DevicePath);
   } else {
     return UefiDevicePathLibDuplicateDevicePath (DevicePath);
   }
 }

 /**
   Creates a new device path by appending a second device path to a first device path.

   This function creates a new device path by appending a copy of SecondDevicePath
   to a copy of FirstDevicePath in a newly allocated buffer.  Only the end-of-device-path
   device node from SecondDevicePath is retained. The newly created device path is
   returned. If FirstDevicePath is NULL, then it is ignored, and a duplicate of
   SecondDevicePath is returned.  If SecondDevicePath is NULL, then it is ignored,
   and a duplicate of FirstDevicePath is returned. If both FirstDevicePath and
   SecondDevicePath are NULL, then a copy of an end-of-device-path is returned.

   If there is not enough memory for the newly allocated buffer, then NULL is returned.
   The memory for the new device path is allocated from EFI boot services memory.
   It is the responsibility of the caller to free the memory allocated.

   @param  FirstDevicePath            A pointer to a device path data structure.
   @param  SecondDevicePath           A pointer to a device path data structure.

   @retval NULL      If there is not enough memory for the newly allocated buffer.
   @retval NULL      If FirstDevicePath or SecondDevicePath is invalid.
   @retval Others    A pointer to the new device path if success.
                     Or a copy an end-of-device-path if both FirstDevicePath and SecondDevicePath are NULL.

 **/
 EFI_DEVICE_PATH_PROTOCOL *
 EFIAPI
 AppendDevicePath (
   IN CONST EFI_DEVICE_PATH_PROTOCOL  *FirstDevicePath,  OPTIONAL
   IN CONST EFI_DEVICE_PATH_PROTOCOL  *SecondDevicePath  OPTIONAL
   )
 {
   if (mDevicePathLibDevicePathUtilities != NULL) {
     return mDevicePathLibDevicePathUtilities->AppendDevicePath (FirstDevicePath, SecondDevicePath);
   } else {
     return UefiDevicePathLibAppendDevicePath (FirstDevicePath, SecondDevicePath);
   }
 }

 /**
   Creates a new path by appending the device node to the device path.

   This function creates a new device path by appending a copy of the device node
   specified by DevicePathNode to a copy of the device path specified by DevicePath
   in an allocated buffer. The end-of-device-path device node is moved after the
   end of the appended device node.
   If DevicePathNode is NULL then a copy of DevicePath is returned.
   If DevicePath is NULL then a copy of DevicePathNode, followed by an end-of-device
   path device node is returned.
   If both DevicePathNode and DevicePath are NULL then a copy of an end-of-device-path
   device node is returned.
   If there is not enough memory to allocate space for the new device path, then
   NULL is returned.
   The memory is allocated from EFI boot services memory. It is the responsibility
   of the caller to free the memory allocated.

   @param  DevicePath                 A pointer to a device path data structure.
   @param  DevicePathNode             A pointer to a single device path node.

   @retval NULL      If there is not enough memory for the new device path.
   @retval Others    A pointer to the new device path if success.
                     A copy of DevicePathNode followed by an end-of-device-path node
                     if both FirstDevicePath and SecondDevicePath are NULL.
                     A copy of an end-of-device-path node if both FirstDevicePath
                     and SecondDevicePath are NULL.

 **/
 EFI_DEVICE_PATH_PROTOCOL *
 EFIAPI
 AppendDevicePathNode (
   IN CONST EFI_DEVICE_PATH_PROTOCOL  *DevicePath,     OPTIONAL
   IN CONST EFI_DEVICE_PATH_PROTOCOL  *DevicePathNode  OPTIONAL
   )
 {
   if (mDevicePathLibDevicePathUtilities != NULL) {
     return mDevicePathLibDevicePathUtilities->AppendDeviceNode (DevicePath, DevicePathNode);
   } else {
     return UefiDevicePathLibAppendDevicePathNode (DevicePath, DevicePathNode);
   }
 }

 /**
   Creates a new device path by appending the specified device path instance to the specified device
   path.

   This function creates a new device path by appending a copy of the device path
   instance specified by DevicePathInstance to a copy of the device path specified
   by DevicePath in a allocated buffer.
   The end-of-device-path device node is moved after the end of the appended device
   path instance and a new end-of-device-path-instance node is inserted between.
   If DevicePath is NULL, then a copy if DevicePathInstance is returned.
   If DevicePathInstance is NULL, then NULL is returned.
   If DevicePath or DevicePathInstance is invalid, then NULL is returned.
   If there is not enough memory to allocate space for the new device path, then
   NULL is returned.
   The memory is allocated from EFI boot services memory. It is the responsibility
   of the caller to free the memory allocated.

   @param  DevicePath                 A pointer to a device path data structure.
   @param  DevicePathInstance         A pointer to a device path instance.

   @return A pointer to the new device path.

 **/
 EFI_DEVICE_PATH_PROTOCOL *
 EFIAPI
 AppendDevicePathInstance (
   IN CONST EFI_DEVICE_PATH_PROTOCOL  *DevicePath,        OPTIONAL
   IN CONST EFI_DEVICE_PATH_PROTOCOL  *DevicePathInstance OPTIONAL
   )
 {
   if (mDevicePathLibDevicePathUtilities != NULL) {
     return mDevicePathLibDevicePathUtilities->AppendDevicePathInstance (DevicePath, DevicePathInstance);
   } else {
     return UefiDevicePathLibAppendDevicePathInstance (DevicePath, DevicePathInstance);
   }
 }

 /**
   Creates a copy of the current device path instance and returns a pointer to the next device path
   instance.

   This function creates a copy of the current device path instance. It also updates
   DevicePath to point to the next device path instance in the device path (or NULL
   if no more) and updates Size to hold the size of the device path instance copy.
   If DevicePath is NULL, then NULL is returned.
   If DevicePath points to a invalid device path, then NULL is returned.
   If there is not enough memory to allocate space for the new device path, then
   NULL is returned.
   The memory is allocated from EFI boot services memory. It is the responsibility
   of the caller to free the memory allocated.
   If Size is NULL, then ASSERT().

   @param  DevicePath                 On input, this holds the pointer to the current
                                      device path instance. On output, this holds
                                      the pointer to the next device path instance
                                      or NULL if there are no more device path
                                      instances in the device path pointer to a
                                      device path data structure.
   @param  Size                       On output, this holds the size of the device
                                      path instance, in bytes or zero, if DevicePath
                                      is NULL.

   @return A pointer to the current device path instance.

 **/
 EFI_DEVICE_PATH_PROTOCOL *
 EFIAPI
 GetNextDevicePathInstance (
   IN OUT EFI_DEVICE_PATH_PROTOCOL    **DevicePath,
   OUT UINTN                          *Size
   )
 {
   if (mDevicePathLibDevicePathUtilities != NULL) {
     return mDevicePathLibDevicePathUtilities->GetNextDevicePathInstance (DevicePath, Size);
   } else {
     return UefiDevicePathLibGetNextDevicePathInstance (DevicePath, Size);
   }
 }

 /**
   Creates a device node.

   This function creates a new device node in a newly allocated buffer of size
   NodeLength and initializes the device path node header with NodeType and NodeSubType.
   The new device path node is returned.
   If NodeLength is smaller than a device path header, then NULL is returned.
   If there is not enough memory to allocate space for the new device path, then
   NULL is returned.
   The memory is allocated from EFI boot services memory. It is the responsibility
   of the caller to free the memory allocated.

   @param  NodeType                   The device node type for the new device node.
   @param  NodeSubType                The device node sub-type for the new device node.
   @param  NodeLength                 The length of the new device node.

   @return The new device path.

 **/
 EFI_DEVICE_PATH_PROTOCOL *
 EFIAPI
 CreateDeviceNode (
   IN UINT8                           NodeType,
   IN UINT8                           NodeSubType,
   IN UINT16                          NodeLength
   )
 {
   if (mDevicePathLibDevicePathUtilities != NULL) {
     return mDevicePathLibDevicePathUtilities->CreateDeviceNode (NodeType, NodeSubType, NodeLength);
   } else {
     return UefiDevicePathLibCreateDeviceNode (NodeType, NodeSubType, NodeLength);
   }
 }

 /**
   Determines if a device path is single or multi-instance.

   This function returns TRUE if the device path specified by DevicePath is
   multi-instance.
   Otherwise, FALSE is returned.
   If DevicePath is NULL or invalid, then FALSE is returned.

   @param  DevicePath                 A pointer to a device path data structure.

   @retval  TRUE                      DevicePath is multi-instance.
   @retval  FALSE                     DevicePath is not multi-instance, or DevicePath
                                      is NULL or invalid.

 **/
 BOOLEAN
 EFIAPI
 IsDevicePathMultiInstance (
   IN CONST EFI_DEVICE_PATH_PROTOCOL  *DevicePath
   )
 {
   if (mDevicePathLibDevicePathUtilities != NULL) {
     return mDevicePathLibDevicePathUtilities->IsDevicePathMultiInstance (DevicePath);
   } else {
     return UefiDevicePathLibIsDevicePathMultiInstance (DevicePath);
   }
 }

 /**
   Locate and return the protocol instance identified by the ProtocolGuid.

   @param ProtocolGuid     The GUID of the protocol.

   @return A pointer to the protocol instance or NULL when absent.
 **/
 VOID *
 UefiDevicePathLibLocateProtocol (
   EFI_GUID                         *ProtocolGuid
   )
 {
   EFI_STATUS Status;
   VOID       *Protocol;
   Status = gBS->LocateProtocol (
                   ProtocolGuid,
                   NULL,
                   (VOID**) &Protocol
                   );
   if (EFI_ERROR (Status)) {
     return NULL;
   } else {
     return Protocol;
   }
 }

 /**
   Converts a device node to its string representation.

   @param DeviceNode        A Pointer to the device node to be converted.
   @param DisplayOnly       If DisplayOnly is TRUE, then the shorter text representation
                            of the display node is used, where applicable. If DisplayOnly
                            is FALSE, then the longer text representation of the display node
                            is used.
   @param AllowShortcuts    If AllowShortcuts is TRUE, then the shortcut forms of text
                            representation for a device node can be used, where applicable.

   @return A pointer to the allocated text representation of the device node or NULL if DeviceNode
           is NULL or there was insufficient memory.

 **/
 CHAR16 *
 EFIAPI
 ConvertDeviceNodeToText (
   IN CONST EFI_DEVICE_PATH_PROTOCOL  *DeviceNode,
   IN BOOLEAN                         DisplayOnly,
   IN BOOLEAN                         AllowShortcuts
   )
 {
   if (mDevicePathLibDevicePathToText == NULL) {
     mDevicePathLibDevicePathToText = UefiDevicePathLibLocateProtocol (&gEfiDevicePathToTextProtocolGuid);
   }
   if (mDevicePathLibDevicePathToText != NULL) {
     return mDevicePathLibDevicePathToText->ConvertDeviceNodeToText (DeviceNode, DisplayOnly, AllowShortcuts);
   }

   return UefiDevicePathLibConvertDeviceNodeToText (DeviceNode, DisplayOnly, AllowShortcuts);
 }

 /**
   Converts a device path to its text representation.

   @param DevicePath      A Pointer to the device to be converted.
   @param DisplayOnly     If DisplayOnly is TRUE, then the shorter text representation
                          of the display node is used, where applicable. If DisplayOnly
                          is FALSE, then the longer text representation of the display node
                          is used.
   @param AllowShortcuts  If AllowShortcuts is TRUE, then the shortcut forms of text
                          representation for a device node can be used, where applicable.

   @return A pointer to the allocated text representation of the device path or
           NULL if DeviceNode is NULL or there was insufficient memory.

 **/
 CHAR16 *
 EFIAPI
 ConvertDevicePathToText (
   IN CONST EFI_DEVICE_PATH_PROTOCOL   *DevicePath,
   IN BOOLEAN                          DisplayOnly,
   IN BOOLEAN                          AllowShortcuts
   )
 {
   if (mDevicePathLibDevicePathToText == NULL) {
     mDevicePathLibDevicePathToText = UefiDevicePathLibLocateProtocol (&gEfiDevicePathToTextProtocolGuid);
   }
   if (mDevicePathLibDevicePathToText != NULL) {
     return mDevicePathLibDevicePathToText->ConvertDevicePathToText (DevicePath, DisplayOnly, AllowShortcuts);
   }

   return UefiDevicePathLibConvertDevicePathToText (DevicePath, DisplayOnly, AllowShortcuts);
 }

 /**
   Convert text to the binary representation of a device node.

   @param TextDeviceNode  TextDeviceNode points to the text representation of a device
                          node. Conversion starts with the first character and continues
                          until the first non-device node character.

   @return A pointer to the EFI device node or NULL if TextDeviceNode is NULL or there was
           insufficient memory or text unsupported.

 **/
 EFI_DEVICE_PATH_PROTOCOL *
 EFIAPI
 ConvertTextToDeviceNode (
   IN CONST CHAR16 *TextDeviceNode
   )
 {
   if (mDevicePathLibDevicePathFromText == NULL) {
     mDevicePathLibDevicePathFromText = UefiDevicePathLibLocateProtocol (&gEfiDevicePathFromTextProtocolGuid);
   }
   if (mDevicePathLibDevicePathFromText != NULL) {
     return mDevicePathLibDevicePathFromText->ConvertTextToDeviceNode (TextDeviceNode);
   }

   return UefiDevicePathLibConvertTextToDeviceNode (TextDeviceNode);
 }

 /**
   Convert text to the binary representation of a device path.


   @param TextDevicePath  TextDevicePath points to the text representation of a device
                          path. Conversion starts with the first character and continues
                          until the first non-device node character.

   @return A pointer to the allocated device path or NULL if TextDeviceNode is NULL or
           there was insufficient memory.

 **/
 EFI_DEVICE_PATH_PROTOCOL *
 EFIAPI
 ConvertTextToDevicePath (
   IN CONST CHAR16 *TextDevicePath
   )
 {
   if (mDevicePathLibDevicePathFromText == NULL) {
     mDevicePathLibDevicePathFromText = UefiDevicePathLibLocateProtocol (&gEfiDevicePathFromTextProtocolGuid);
   }
   if (mDevicePathLibDevicePathFromText != NULL) {
     return mDevicePathLibDevicePathFromText->ConvertTextToDevicePath (TextDevicePath);
   }

   return UefiDevicePathLibConvertTextToDevicePath (TextDevicePath);
 }
	/** @file
	Device Path services. The thing to remember is device paths are built out of
	nodes. The device path is terminated by an end node that is length
	sizeof(EFI_DEVICE_PATH_PROTOCOL). That would be why there is sizeof(EFI_DEVICE_PATH_PROTOCOL)
	all over this file.

	The only place where multi-instance device paths are supported is in
	environment varibles. Multi-instance device paths should never be placed
	on a Handle.

	Copyright (c) 2013 - 2018, Intel Corporation. All rights reserved.<BR>
	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 "UefiDevicePathLib.h"

	GLOBAL_REMOVE_IF_UNREFERENCED EFI_DEVICE_PATH_UTILITIES_PROTOCOL *mDevicePathLibDevicePathUtilities = NULL;
	GLOBAL_REMOVE_IF_UNREFERENCED EFI_DEVICE_PATH_TO_TEXT_PROTOCOL *mDevicePathLibDevicePathToText = NULL;
	GLOBAL_REMOVE_IF_UNREFERENCED EFI_DEVICE_PATH_FROM_TEXT_PROTOCOL *mDevicePathLibDevicePathFromText = NULL;

	/**
	The constructor function caches the pointer to DevicePathUtilites protocol,
	DevicePathToText protocol and DevicePathFromText protocol.

	The constructor function locates these three protocols from protocol database.
	It will caches the pointer to local protocol instance if that operation fails
	and it will always return EFI_SUCCESS.

	@param ImageHandle The firmware allocated handle for the EFI image.
	@param SystemTable A pointer to the EFI System Table.

	@retval EFI_SUCCESS The constructor always returns EFI_SUCCESS.

	**/
	EFI_STATUS
	EFIAPI
	UefiDevicePathLibOptionalDevicePathProtocolConstructor (
	IN EFI_HANDLE ImageHandle,
	IN EFI_SYSTEM_TABLE *SystemTable
	)
	{
	EFI_STATUS Status;

	Status = gBS->LocateProtocol (
	&gEfiDevicePathUtilitiesProtocolGuid,
	NULL,
	(VOID**) &mDevicePathLibDevicePathUtilities
	);
	ASSERT_EFI_ERROR (Status);
	ASSERT (mDevicePathLibDevicePathUtilities != NULL);
	return Status;
	}

	/**
	Returns the size of a device path in bytes.

	This function returns the size, in bytes, of the device path data structure
	specified by DevicePath including the end of device path node.
	If DevicePath is NULL or invalid, then 0 is returned.

	@param DevicePath A pointer to a device path data structure.

	@retval 0 If DevicePath is NULL or invalid.
	@retval Others The size of a device path in bytes.

	**/
	UINTN
	EFIAPI
	GetDevicePathSize (
	IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath
	)
	{
	if (mDevicePathLibDevicePathUtilities != NULL) {
	return mDevicePathLibDevicePathUtilities->GetDevicePathSize (DevicePath);
	} else {
	return UefiDevicePathLibGetDevicePathSize (DevicePath);
	}
	}

	/**
	Creates a new copy of an existing device path.

	This function allocates space for a new copy of the device path specified by DevicePath.
	If DevicePath is NULL, then NULL is returned. If the memory is successfully
	allocated, then the contents of DevicePath are copied to the newly allocated
	buffer, and a pointer to that buffer is returned. Otherwise, NULL is returned.
	The memory for the new device path is allocated from EFI boot services memory.
	It is the responsibility of the caller to free the memory allocated.

	@param DevicePath A pointer to a device path data structure.

	@retval NULL DevicePath is NULL or invalid.
	@retval Others A pointer to the duplicated device path.

	**/
	EFI_DEVICE_PATH_PROTOCOL *
	EFIAPI
	DuplicateDevicePath (
	IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath
	)
	{
	if (mDevicePathLibDevicePathUtilities != NULL) {
	return mDevicePathLibDevicePathUtilities->DuplicateDevicePath (DevicePath);
	} else {
	return UefiDevicePathLibDuplicateDevicePath (DevicePath);
	}
	}

	/**
	Creates a new device path by appending a second device path to a first device path.

	This function creates a new device path by appending a copy of SecondDevicePath
	to a copy of FirstDevicePath in a newly allocated buffer. Only the end-of-device-path
	device node from SecondDevicePath is retained. The newly created device path is
	returned. If FirstDevicePath is NULL, then it is ignored, and a duplicate of
	SecondDevicePath is returned. If SecondDevicePath is NULL, then it is ignored,
	and a duplicate of FirstDevicePath is returned. If both FirstDevicePath and
	SecondDevicePath are NULL, then a copy of an end-of-device-path is returned.

	If there is not enough memory for the newly allocated buffer, then NULL is returned.
	The memory for the new device path is allocated from EFI boot services memory.
	It is the responsibility of the caller to free the memory allocated.

	@param FirstDevicePath A pointer to a device path data structure.
	@param SecondDevicePath A pointer to a device path data structure.

	@retval NULL If there is not enough memory for the newly allocated buffer.
	@retval NULL If FirstDevicePath or SecondDevicePath is invalid.
	@retval Others A pointer to the new device path if success.
	Or a copy an end-of-device-path if both FirstDevicePath and SecondDevicePath are NULL.

	**/
	EFI_DEVICE_PATH_PROTOCOL *
	EFIAPI
	AppendDevicePath (
	IN CONST EFI_DEVICE_PATH_PROTOCOL *FirstDevicePath, OPTIONAL
	IN CONST EFI_DEVICE_PATH_PROTOCOL *SecondDevicePath OPTIONAL
	)
	{
	if (mDevicePathLibDevicePathUtilities != NULL) {
	return mDevicePathLibDevicePathUtilities->AppendDevicePath (FirstDevicePath, SecondDevicePath);
	} else {
	return UefiDevicePathLibAppendDevicePath (FirstDevicePath, SecondDevicePath);
	}
	}

	/**
	Creates a new path by appending the device node to the device path.

	This function creates a new device path by appending a copy of the device node
	specified by DevicePathNode to a copy of the device path specified by DevicePath
	in an allocated buffer. The end-of-device-path device node is moved after the
	end of the appended device node.
	If DevicePathNode is NULL then a copy of DevicePath is returned.
	If DevicePath is NULL then a copy of DevicePathNode, followed by an end-of-device
	path device node is returned.
	If both DevicePathNode and DevicePath are NULL then a copy of an end-of-device-path
	device node is returned.
	If there is not enough memory to allocate space for the new device path, then
	NULL is returned.
	The memory is allocated from EFI boot services memory. It is the responsibility
	of the caller to free the memory allocated.

	@param DevicePath A pointer to a device path data structure.
	@param DevicePathNode A pointer to a single device path node.

	@retval NULL If there is not enough memory for the new device path.
	@retval Others A pointer to the new device path if success.
	A copy of DevicePathNode followed by an end-of-device-path node
	if both FirstDevicePath and SecondDevicePath are NULL.
	A copy of an end-of-device-path node if both FirstDevicePath
	and SecondDevicePath are NULL.

	**/
	EFI_DEVICE_PATH_PROTOCOL *
	EFIAPI
	AppendDevicePathNode (
	IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath, OPTIONAL
	IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePathNode OPTIONAL
	)
	{
	if (mDevicePathLibDevicePathUtilities != NULL) {
	return mDevicePathLibDevicePathUtilities->AppendDeviceNode (DevicePath, DevicePathNode);
	} else {
	return UefiDevicePathLibAppendDevicePathNode (DevicePath, DevicePathNode);
	}
	}

	/**
	Creates a new device path by appending the specified device path instance to the specified device
	path.

	This function creates a new device path by appending a copy of the device path
	instance specified by DevicePathInstance to a copy of the device path specified
	by DevicePath in a allocated buffer.
	The end-of-device-path device node is moved after the end of the appended device
	path instance and a new end-of-device-path-instance node is inserted between.
	If DevicePath is NULL, then a copy if DevicePathInstance is returned.
	If DevicePathInstance is NULL, then NULL is returned.
	If DevicePath or DevicePathInstance is invalid, then NULL is returned.
	If there is not enough memory to allocate space for the new device path, then
	NULL is returned.
	The memory is allocated from EFI boot services memory. It is the responsibility
	of the caller to free the memory allocated.

	@param DevicePath A pointer to a device path data structure.
	@param DevicePathInstance A pointer to a device path instance.

	@return A pointer to the new device path.

	**/
	EFI_DEVICE_PATH_PROTOCOL *
	EFIAPI
	AppendDevicePathInstance (
	IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath, OPTIONAL
	IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePathInstance OPTIONAL
	)
	{
	if (mDevicePathLibDevicePathUtilities != NULL) {
	return mDevicePathLibDevicePathUtilities->AppendDevicePathInstance (DevicePath, DevicePathInstance);
	} else {
	return UefiDevicePathLibAppendDevicePathInstance (DevicePath, DevicePathInstance);
	}
	}

	/**
	Creates a copy of the current device path instance and returns a pointer to the next device path
	instance.

	This function creates a copy of the current device path instance. It also updates
	DevicePath to point to the next device path instance in the device path (or NULL
	if no more) and updates Size to hold the size of the device path instance copy.
	If DevicePath is NULL, then NULL is returned.
	If DevicePath points to a invalid device path, then NULL is returned.
	If there is not enough memory to allocate space for the new device path, then
	NULL is returned.
	The memory is allocated from EFI boot services memory. It is the responsibility
	of the caller to free the memory allocated.
	If Size is NULL, then ASSERT().

	@param DevicePath On input, this holds the pointer to the current
	device path instance. On output, this holds
	the pointer to the next device path instance
	or NULL if there are no more device path
	instances in the device path pointer to a
	device path data structure.
	@param Size On output, this holds the size of the device
	path instance, in bytes or zero, if DevicePath
	is NULL.

	@return A pointer to the current device path instance.

	**/
	EFI_DEVICE_PATH_PROTOCOL *
	EFIAPI
	GetNextDevicePathInstance (
	IN OUT EFI_DEVICE_PATH_PROTOCOL **DevicePath,
	OUT UINTN *Size
	)
	{
	if (mDevicePathLibDevicePathUtilities != NULL) {
	return mDevicePathLibDevicePathUtilities->GetNextDevicePathInstance (DevicePath, Size);
	} else {
	return UefiDevicePathLibGetNextDevicePathInstance (DevicePath, Size);
	}
	}

	/**
	Creates a device node.

	This function creates a new device node in a newly allocated buffer of size
	NodeLength and initializes the device path node header with NodeType and NodeSubType.
	The new device path node is returned.
	If NodeLength is smaller than a device path header, then NULL is returned.
	If there is not enough memory to allocate space for the new device path, then
	NULL is returned.
	The memory is allocated from EFI boot services memory. It is the responsibility
	of the caller to free the memory allocated.

	@param NodeType The device node type for the new device node.
	@param NodeSubType The device node sub-type for the new device node.
	@param NodeLength The length of the new device node.

	@return The new device path.

	**/
	EFI_DEVICE_PATH_PROTOCOL *
	EFIAPI
	CreateDeviceNode (
	IN UINT8 NodeType,
	IN UINT8 NodeSubType,
	IN UINT16 NodeLength
	)
	{
	if (mDevicePathLibDevicePathUtilities != NULL) {
	return mDevicePathLibDevicePathUtilities->CreateDeviceNode (NodeType, NodeSubType, NodeLength);
	} else {
	return UefiDevicePathLibCreateDeviceNode (NodeType, NodeSubType, NodeLength);
	}
	}

	/**
	Determines if a device path is single or multi-instance.

	This function returns TRUE if the device path specified by DevicePath is
	multi-instance.
	Otherwise, FALSE is returned.
	If DevicePath is NULL or invalid, then FALSE is returned.

	@param DevicePath A pointer to a device path data structure.

	@retval TRUE DevicePath is multi-instance.
	@retval FALSE DevicePath is not multi-instance, or DevicePath
	is NULL or invalid.

	**/
	BOOLEAN
	EFIAPI
	IsDevicePathMultiInstance (
	IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath
	)
	{
	if (mDevicePathLibDevicePathUtilities != NULL) {
	return mDevicePathLibDevicePathUtilities->IsDevicePathMultiInstance (DevicePath);
	} else {
	return UefiDevicePathLibIsDevicePathMultiInstance (DevicePath);
	}
	}

	/**
	Locate and return the protocol instance identified by the ProtocolGuid.

	@param ProtocolGuid The GUID of the protocol.

	@return A pointer to the protocol instance or NULL when absent.
	**/
	VOID *
	UefiDevicePathLibLocateProtocol (
	EFI_GUID *ProtocolGuid
	)
	{
	EFI_STATUS Status;
	VOID *Protocol;
	Status = gBS->LocateProtocol (
	ProtocolGuid,
	NULL,
	(VOID**) &Protocol
	);
	if (EFI_ERROR (Status)) {
	return NULL;
	} else {
	return Protocol;
	}
	}

	/**
	Converts a device node to its string representation.

	@param DeviceNode A Pointer to the device node to be converted.
	@param DisplayOnly If DisplayOnly is TRUE, then the shorter text representation
	of the display node is used, where applicable. If DisplayOnly
	is FALSE, then the longer text representation of the display node
	is used.
	@param AllowShortcuts If AllowShortcuts is TRUE, then the shortcut forms of text
	representation for a device node can be used, where applicable.

	@return A pointer to the allocated text representation of the device node or NULL if DeviceNode
	is NULL or there was insufficient memory.

	**/
	CHAR16 *
	EFIAPI
	ConvertDeviceNodeToText (
	IN CONST EFI_DEVICE_PATH_PROTOCOL *DeviceNode,
	IN BOOLEAN DisplayOnly,
	IN BOOLEAN AllowShortcuts
	)
	{
	if (mDevicePathLibDevicePathToText == NULL) {
	mDevicePathLibDevicePathToText = UefiDevicePathLibLocateProtocol (&gEfiDevicePathToTextProtocolGuid);
	}
	if (mDevicePathLibDevicePathToText != NULL) {
	return mDevicePathLibDevicePathToText->ConvertDeviceNodeToText (DeviceNode, DisplayOnly, AllowShortcuts);
	}

	return UefiDevicePathLibConvertDeviceNodeToText (DeviceNode, DisplayOnly, AllowShortcuts);
	}

	/**
	Converts a device path to its text representation.

	@param DevicePath A Pointer to the device to be converted.
	@param DisplayOnly If DisplayOnly is TRUE, then the shorter text representation
	of the display node is used, where applicable. If DisplayOnly
	is FALSE, then the longer text representation of the display node
	is used.
	@param AllowShortcuts If AllowShortcuts is TRUE, then the shortcut forms of text
	representation for a device node can be used, where applicable.

	@return A pointer to the allocated text representation of the device path or
	NULL if DeviceNode is NULL or there was insufficient memory.

	**/
	CHAR16 *
	EFIAPI
	ConvertDevicePathToText (
	IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath,
	IN BOOLEAN DisplayOnly,
	IN BOOLEAN AllowShortcuts
	)
	{
	if (mDevicePathLibDevicePathToText == NULL) {
	mDevicePathLibDevicePathToText = UefiDevicePathLibLocateProtocol (&gEfiDevicePathToTextProtocolGuid);
	}
	if (mDevicePathLibDevicePathToText != NULL) {
	return mDevicePathLibDevicePathToText->ConvertDevicePathToText (DevicePath, DisplayOnly, AllowShortcuts);
	}

	return UefiDevicePathLibConvertDevicePathToText (DevicePath, DisplayOnly, AllowShortcuts);
	}

	/**
	Convert text to the binary representation of a device node.

	@param TextDeviceNode TextDeviceNode points to the text representation of a device
	node. Conversion starts with the first character and continues
	until the first non-device node character.

	@return A pointer to the EFI device node or NULL if TextDeviceNode is NULL or there was
	insufficient memory or text unsupported.

	**/
	EFI_DEVICE_PATH_PROTOCOL *
	EFIAPI
	ConvertTextToDeviceNode (
	IN CONST CHAR16 *TextDeviceNode
	)
	{
	if (mDevicePathLibDevicePathFromText == NULL) {
	mDevicePathLibDevicePathFromText = UefiDevicePathLibLocateProtocol (&gEfiDevicePathFromTextProtocolGuid);
	}
	if (mDevicePathLibDevicePathFromText != NULL) {
	return mDevicePathLibDevicePathFromText->ConvertTextToDeviceNode (TextDeviceNode);
	}

	return UefiDevicePathLibConvertTextToDeviceNode (TextDeviceNode);
	}

	/**
	Convert text to the binary representation of a device path.


	@param TextDevicePath TextDevicePath points to the text representation of a device
	path. Conversion starts with the first character and continues
	until the first non-device node character.

	@return A pointer to the allocated device path or NULL if TextDeviceNode is NULL or
	there was insufficient memory.

	**/
	EFI_DEVICE_PATH_PROTOCOL *
	EFIAPI
	ConvertTextToDevicePath (
	IN CONST CHAR16 *TextDevicePath
	)
	{
	if (mDevicePathLibDevicePathFromText == NULL) {
	mDevicePathLibDevicePathFromText = UefiDevicePathLibLocateProtocol (&gEfiDevicePathFromTextProtocolGuid);
	}
	if (mDevicePathLibDevicePathFromText != NULL) {
	return mDevicePathLibDevicePathFromText->ConvertTextToDevicePath (TextDevicePath);
	}

	return UefiDevicePathLibConvertTextToDevicePath (TextDevicePath);
	}