1 files changed, 212 insertions, 0 deletions
diff --git a/MdePkg/Library/UefiDevicePathLib/UefiDevicePathLib.c b/MdePkg/Library/UefiDevicePathLib/UefiDevicePathLib.c
index 43966fc239..be49ba4042 100644
--- a/MdePkg/Library/UefiDevicePathLib/UefiDevicePathLib.c
+++ b/MdePkg/Library/UefiDevicePathLib/UefiDevicePathLib.c
@@ -44,6 +44,218 @@ GLOBAL_REMOVE_IF_UNREFERENCED CONST EFI_DEVICE_PATH_PROTOCOL  mUefiDevicePathLib
 };
 
 /**
+  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
+DevicePathType (
+  IN CONST VOID  *Node
+  )
+{
+  ASSERT (Node != NULL);
+  return ((EFI_DEVICE_PATH_PROTOCOL *)(Node))->Type;
+}
+
+/**
+  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
+DevicePathSubType (
+  IN CONST VOID  *Node
+  )
+{
+  ASSERT (Node != NULL);
+  return ((EFI_DEVICE_PATH_PROTOCOL *)(Node))->SubType;
+}
+
+/**
+  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
+DevicePathNodeLength (
+  IN CONST VOID  *Node
+  )
+{
+  ASSERT (Node != NULL);
+  return ReadUnaligned16 ((UINT16 *)&((EFI_DEVICE_PATH_PROTOCOL *)(Node))->Length[0]);
+}
+
+/**
+  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 *
+NextDevicePathNode (
+  IN CONST VOID  *Node
+  )
+{
+  ASSERT (Node != NULL);
+  return (EFI_DEVICE_PATH_PROTOCOL *)((UINT8 *)(Node) + DevicePathNodeLength(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
+IsDevicePathEndType (
+  IN CONST VOID  *Node
+  )
+{
+  ASSERT (Node != NULL);
+  return ((DevicePathType (Node) & 0x7f) == END_DEVICE_PATH_TYPE);
+}
+
+/**
+  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
+IsDevicePathEnd (
+  IN CONST VOID  *Node
+  )
+{
+  ASSERT (Node != NULL);
+  return (IsDevicePathEndType (Node) && DevicePathSubType(Node) == END_ENTIRE_DEVICE_PATH_SUBTYPE);
+}
+
+/**
+  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
+IsDevicePathEndInstance (
+  IN CONST VOID  *Node
+  )
+{
+  ASSERT (Node != NULL);
+  return (IsDevicePathEndType (Node) && DevicePathSubType(Node) == END_INSTANCE_DEVICE_PATH_SUBTYPE);
+}
+
+/**
+  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().
+
+  @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
+SetDevicePathNodeLength (
+  IN VOID   *Node,
+  IN UINTN  NodeLength
+  )
+{
+  ASSERT (Node != NULL);
+  ASSERT (NodeLength < 0x10000);
+  return WriteUnaligned16 ((UINT16 *)&((EFI_DEVICE_PATH_PROTOCOL *)(Node))->Length[0], (UINT16)(NodeLength));
+}
+
+/**
+  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
+SetDevicePathEndNode (
+  IN VOID  *Node
+  )
+{
+  ASSERT (Node != NULL);
+  CopyMem (Node, &mUefiDevicePathLibEndDevicePath, sizeof (mUefiDevicePathLibEndDevicePath));
+}
+
+/**
   Returns the size of a device path in bytes.
 
   This function returns the size, in bytes, of the device path data structure specified by