text: /** @file
    Provides library functions to construct and parse UEFI Device Paths.
  
    This library provides defines, macros, and functions to help create and parse
    EFI_DEVICE_PATH_PROTOCOL structures.
  
  Copyright (c) 2006 - 2013, 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 that 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.
  
  **/
  
  #ifndef __DEVICE_PATH_LIB_H__
  #define __DEVICE_PATH_LIB_H__
  
  #define END_DEVICE_PATH_LENGTH               (sizeof (EFI_DEVICE_PATH_PROTOCOL))
  
  /**
    Determine whether a given device path is valid.
    If DevicePath is NULL, then ASSERT().
  
    @param  DevicePath  A pointer to a device path data structure.
    @param  MaxSize     The maximum size of the device path data structure.
  
    @retval TRUE        DevicePath is valid.
    @retval FALSE       The length of any node node in the DevicePath is less
                        than sizeof (EFI_DEVICE_PATH_PROTOCOL).
    @retval FALSE       If MaxSize is not zero, the size of the DevicePath
                        exceeds MaxSize.
    @retval FALSE       If PcdMaximumDevicePathNodeCount is not zero, the node
                        count of the DevicePath exceeds PcdMaximumDevicePathNodeCount.
  **/
  BOOLEAN
  EFIAPI
  IsDevicePathValid (
    IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath,
    IN       UINTN                    MaxSize
    );
  
  /**
    Returns the Type field of a device path node.
  
    Returns the Type field of the device path node specified by Node.
  
    If Node is NULL, then ASSERT().
  
    @param  Node      A pointer to a device path node data structure.
  
    @return The Type field of the device path node specified by Node.
  
  **/
  UINT8
  EFIAPI
  DevicePathType (
    IN CONST VOID  *Node
    );
  
  /**
    Returns the SubType field of a device path node.
  
    Returns the SubType field of the device path node specified by Node.
  
    If Node is NULL, then ASSERT().
  
    @param  Node      A pointer to a device path node data structure.
  
    @return The SubType field of the device path node specified by Node.
  
  **/
  UINT8
  EFIAPI
  DevicePathSubType (
    IN CONST VOID  *Node
    );
  
  /**
    Returns the 16-bit Length field of a device path node.
  
    Returns the 16-bit Length field of the device path node specified by Node.
    Node is not required to be aligned on a 16-bit boundary, so it is recommended
    that a function such as ReadUnaligned16() be used to extract the contents of
    the Length field.
  
    If Node is NULL, then ASSERT().
  
    @param  Node      A pointer to a device path node data structure.
  
    @return The 16-bit Length field of the device path node specified by Node.
  
  **/
  UINTN
  EFIAPI
  DevicePathNodeLength (
    IN CONST VOID  *Node
    );
  
  /**
    Returns a pointer to the next node in a device path.
  
    Returns a pointer to the device path node that follows the device path node specified by Node.
  
    If Node is NULL, then ASSERT().
  
    @param  Node      A pointer to a device path node data structure.
  
    @return a pointer to the device path node that follows the device path node specified by Node.
  
  **/
  EFI_DEVICE_PATH_PROTOCOL *
  EFIAPI
  NextDevicePathNode (
    IN CONST VOID  *Node
    );
  
  /**
    Determines if a device path node is an end node of a device path.
    This includes nodes that are the end of a device path instance and nodes that
    are the end of an entire device path.
  
    Determines if the device path node specified by Node is an end node of a device path.
    This includes nodes that are the end of a device path instance and nodes that are the
    end of an entire device path.  If Node represents an end node of a device path,
    then TRUE is returned.  Otherwise, FALSE is returned.
  
    If Node is NULL, then ASSERT().
  
    @param  Node      A pointer to a device path node data structure.
  
    @retval TRUE      The device path node specified by Node is an end node of a device path.
    @retval FALSE     The device path node specified by Node is not an end node of a device path.
  
  **/
  BOOLEAN
  EFIAPI
  IsDevicePathEndType (
    IN CONST VOID  *Node
    );
  
  /**
    Determines if a device path node is an end node of an entire device path.
  
    Determines if a device path node specified by Node is an end node of an entire device path.
    If Node represents the end of an entire device path, then TRUE is returned.
    Otherwise, FALSE is returned.
  
    If Node is NULL, then ASSERT().
  
    @param  Node      A pointer to a device path node data structure.
  
    @retval TRUE      The device path node specified by Node is the end of an entire device path.
    @retval FALSE     The device path node specified by Node is not the end of an entire device path.
  
  **/
  BOOLEAN
  EFIAPI
  IsDevicePathEnd (
    IN CONST VOID  *Node
    );
  
  /**
    Determines if a device path node is an end node of a device path instance.
  
    Determines if a device path node specified by Node is an end node of a device path instance.
    If Node represents the end of a device path instance, then TRUE is returned.
    Otherwise, FALSE is returned.
  
    If Node is NULL, then ASSERT().
  
    @param  Node      A pointer to a device path node data structure.
  
    @retval TRUE      The device path node specified by Node is the end of a device path instance.
    @retval FALSE     The device path node specified by Node is not the end of a device path instance.
  
  **/
  BOOLEAN
  EFIAPI
  IsDevicePathEndInstance (
    IN CONST VOID  *Node
    );
  
  /**
    Sets the length, in bytes, of a device path node.
  
    Sets the length of the device path node specified by Node to the value specified
    by NodeLength.  NodeLength is returned.  Node is not required to be aligned on
    a 16-bit boundary, so it is recommended that a function such as WriteUnaligned16()
    be used to set the contents of the Length field.
  
    If Node is NULL, then ASSERT().
    If NodeLength >= 0x10000, then ASSERT().
    If NodeLength < sizeof (EFI_DEVICE_PATH_PROTOCOL), then ASSERT().
  
    @param  Node      A pointer to a device path node data structure.
    @param  Length    The length, in bytes, of the device path node.
  
    @return Length
  
  **/
  UINT16
  EFIAPI
  SetDevicePathNodeLength (
    IN OUT VOID  *Node,
    IN UINTN     Length
    );
  
  /**
    Fills in all the fields of a device path node that is the end of an entire device path.
  
    Fills in all the fields of a device path node specified by Node so Node represents
    the end of an entire device path.  The Type field of Node is set to
    END_DEVICE_PATH_TYPE, the SubType field of Node is set to
    END_ENTIRE_DEVICE_PATH_SUBTYPE, and the Length field of Node is set to
    END_DEVICE_PATH_LENGTH.  Node is not required to be aligned on a 16-bit boundary,
    so it is recommended that a function such as WriteUnaligned16() be used to set
    the contents of the Length field.
  
    If Node is NULL, then ASSERT().
  
    @param  Node      A pointer to a device path node data structure.
  
  **/
  VOID
  EFIAPI
  SetDevicePathEndNode (
    OUT VOID  *Node
    );
  
  /**
    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
    );
  
  /**
    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
    );
  
  /**
    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
    );
  
  /**
    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      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
    );
  
  /**
    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 secified 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
    );
  
  /**
    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
    );
  
  /**
    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
    );
  
  /**
    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
    );
  
  /**
    Retrieves the device path protocol from a handle.
  
    This function returns the device path protocol from the handle specified by Handle.  If Handle is
    NULL or Handle does not contain a device path protocol, then NULL is returned.
  
    @param  Handle                     The handle from which to retrieve the device path protocol.
  
    @return The device path protocol from the handle specified by Handle.
  
  **/
  EFI_DEVICE_PATH_PROTOCOL *
  EFIAPI
  DevicePathFromHandle (
    IN EFI_HANDLE                      Handle
    );
  
  /**
    Allocates a device path for a file and appends it to an existing device path.
  
    If Device is a valid device handle that contains a device path protocol, then a device path for
    the file specified by FileName  is allocated and appended to the device path associated with the
    handle Device.  The allocated device path is returned.  If Device is NULL or Device is a handle
    that does not support the device path protocol, then a device path containing a single device
    path node for the file specified by FileName is allocated and 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.
  
    If FileName is NULL, then ASSERT().
    If FileName is not aligned on a 16-bit boundary, then ASSERT().
  
    @param  Device                     A pointer to a device handle.  This parameter is optional and
                                       may be NULL.
    @param  FileName                   A pointer to a Null-terminated Unicode string.
  
    @return The allocated device path.
  
  **/
  EFI_DEVICE_PATH_PROTOCOL *
  EFIAPI
  FileDevicePath (
    IN EFI_HANDLE                      Device,     OPTIONAL
    IN CONST CHAR16                    *FileName
    );
  
  /**
    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
    );
  
  /**
    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
    );
  
  /**
    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
    );
  
  /**
    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
    );
  
  #endif
  