MdePkg BaseLib: Fix GCC build break

[mirror_edk2.git] / MdePkg / Library / BaseLib / LinkedList.c

diff --git a/MdePkg/Library/BaseLib/LinkedList.c b/MdePkg/Library/BaseLib/LinkedList.c
index 3ff582a978c706276d3c540ea560517a8c21bb7e..f3e57702a641670dfc270b07bdd173190707c19d 100644 (file)
--- a/MdePkg/Library/BaseLib/LinkedList.c
+++ b/MdePkg/Library/BaseLib/LinkedList.c
@@ -1,8 +1,8 @@
 /** @file\r
   Linked List Library Functions.\r
 \r
-  Copyright (c) 2006 - 2008, Intel Corporation<BR>\r
-  All rights reserved. This program and the accompanying materials\r
+  Copyright (c) 2006 - 2008, Intel Corporation. All rights reserved.<BR>\r
+  This program and the accompanying materials\r
   are licensed and made available under the terms and conditions of the BSD License\r
   which accompanies this distribution.  The full text of the license may be found at\r
   http://opensource.org/licenses/bsd-license.php\r
@@ -276,8 +276,7 @@ GetFirstNode (
   @param  List  A pointer to the head node of a doubly linked list.\r
   @param  Node  A pointer to a node in the doubly linked list.\r
 \r
-  @return Pointer to the next node if one exists. Otherwise a null value which\r
-          is actually List is returned.\r
+  @return Pointer to the next node if one exists. Otherwise List is returned.\r
 \r
 **/\r
 LIST_ENTRY *\r
@@ -295,6 +294,42 @@ GetNextNode (
   return Node->ForwardLink;\r
 }\r
 \r
+/**\r
+  Retrieves the previous node of a doubly linked list.\r
+ \r
+  Returns the node of a doubly linked list that precedes Node.  \r
+  List must have been initialized with INTIALIZE_LIST_HEAD_VARIABLE()\r
+  or InitializeListHead().  If List is empty, then List is returned.\r
+ \r
+  If List is NULL, then ASSERT().\r
+  If Node is NULL, then ASSERT().\r
+  If List was not initialized with INTIALIZE_LIST_HEAD_VARIABLE() or \r
+  InitializeListHead(), then ASSERT().\r
+  If PcdMaximumLinkedListLenth is not zero, and List contains more than\r
+  PcdMaximumLinkedListLenth nodes, then ASSERT().\r
+  If PcdVerifyNodeInList is TRUE and Node is not a node in List, then ASSERT().\r
+ \r
+  @param  List  A pointer to the head node of a doubly linked list.\r
+  @param  Node  A pointer to a node in the doubly linked list.\r
+ \r
+  @return Pointer to the previous node if one exists. Otherwise List is returned.\r
+ \r
+**/\r
+LIST_ENTRY *\r
+EFIAPI\r
+GetPreviousNode (\r
+  IN      CONST LIST_ENTRY          *List,\r
+  IN      CONST LIST_ENTRY          *Node\r
+  )\r
+{\r
+  //\r
+  // ASSERT List not too long and Node is one of the nodes of List\r
+  //\r
+  ASSERT (InternalBaseLibIsNodeInList (List, Node, TRUE));\r
+ \r
+  return Node->BackLink;\r
+}\r
+\r
 /**\r
   Checks to see if a doubly linked list is empty or not.\r
 \r