9aa049d971
git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@6718 6f19259b-4bc3-4df7-8a09-765794883524
476 lines
14 KiB
C
476 lines
14 KiB
C
/** @file
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Linked List Library Functions.
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Copyright (c) 2006 - 2008, Intel Corporation<BR>
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All rights reserved. This program and the accompanying materials
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are licensed and made available under the terms and conditions of the BSD License
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which accompanies this distribution. The full text of the license may be found at
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http://opensource.org/licenses/bsd-license.php
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THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
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WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
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**/
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#include "BaseLibInternals.h"
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/**
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Worker function that locates the Node in the List
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By searching the List, finds the location of the Node in List. At the same time,
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verifies the validity of this list.
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If List is NULL, then ASSERT().
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If List->ForwardLink is NULL, then ASSERT().
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If List->BackLink is NULL, then ASSERT().
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If Node is NULL, then ASSERT();
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If PcdMaximumLinkedListLenth is not zero, and prior to insertion the number
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of nodes in ListHead, including the ListHead node, is greater than or
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equal to PcdMaximumLinkedListLength, then ASSERT().
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@param List A pointer to a node in a linked list.
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@param Node A pointer to one nod.
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@retval TRUE Node is in List
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@retval FALSE Node isn't in List, or List is invalid
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**/
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BOOLEAN
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EFIAPI
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IsNodeInList (
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IN CONST LIST_ENTRY *List,
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IN CONST LIST_ENTRY *Node
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)
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{
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UINTN Count;
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CONST LIST_ENTRY *Ptr;
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BOOLEAN Found;
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//
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// Test the validity of List and Node
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//
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ASSERT (List != NULL);
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ASSERT (List->ForwardLink != NULL);
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ASSERT (List->BackLink != NULL);
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ASSERT (Node != NULL);
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Count = PcdGet32 (PcdMaximumLinkedListLength);
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Ptr = List;
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do {
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Ptr = Ptr->ForwardLink;
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Count--;
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} while ((Ptr != List) && (Ptr != Node) && (Count > 0));
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Found = (BOOLEAN)(Ptr == Node);
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if (PcdGet32 (PcdMaximumLinkedListLength) > 0) {
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while ((Count > 0) && (Ptr != List)) {
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Ptr = Ptr->ForwardLink;
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Count--;
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}
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ASSERT (Count > 0);
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}
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return Found;
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}
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/**
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Initializes the head node of a doubly linked list, and returns the pointer to
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the head node of the doubly linked list.
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Initializes the forward and backward links of a new linked list. After
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initializing a linked list with this function, the other linked list
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functions may be used to add and remove nodes from the linked list. It is up
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to the caller of this function to allocate the memory for ListHead.
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If ListHead is NULL, then ASSERT().
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@param ListHead A pointer to the head node of a new doubly linked list.
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@return ListHead
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**/
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LIST_ENTRY *
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EFIAPI
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InitializeListHead (
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IN OUT LIST_ENTRY *List
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)
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{
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ASSERT (List != NULL);
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List->ForwardLink = List;
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List->BackLink = List;
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return List;
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}
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/**
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Adds a node to the beginning of a doubly linked list, and returns the pointer
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to the head node of the doubly linked list.
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Adds the node Entry at the beginning of the doubly linked list denoted by
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ListHead, and returns ListHead.
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If ListHead is NULL, then ASSERT().
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If Entry is NULL, then ASSERT().
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If ListHead was not initialized with INTIALIZE_LIST_HEAD_VARIABLE() or
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InitializeListHead(), then ASSERT().
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If PcdMaximumLinkedListLenth is not zero, and prior to insertion the number
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of nodes in ListHead, including the ListHead node, is greater than or
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equal to PcdMaximumLinkedListLength, then ASSERT().
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@param ListHead A pointer to the head node of a doubly linked list.
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@param Entry A pointer to a node that is to be inserted at the beginning
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of a doubly linked list.
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@return ListHead
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**/
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LIST_ENTRY *
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EFIAPI
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InsertHeadList (
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IN OUT LIST_ENTRY *List,
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IN OUT LIST_ENTRY *Entry
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)
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{
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//
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// ASSERT List not too long and Entry is not one of the nodes of List
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//
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ASSERT (!IsNodeInList (List, Entry));
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Entry->ForwardLink = List->ForwardLink;
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Entry->BackLink = List;
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Entry->ForwardLink->BackLink = Entry;
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List->ForwardLink = Entry;
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return List;
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}
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/**
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Adds a node to the end of a doubly linked list, and returns the pointer to
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the head node of the doubly linked list.
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Adds the node Entry to the end of the doubly linked list denoted by ListHead,
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and returns ListHead.
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If ListHead is NULL, then ASSERT().
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If Entry is NULL, then ASSERT().
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If ListHead was not initialized with INTIALIZE_LIST_HEAD_VARIABLE() or
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InitializeListHead(), then ASSERT().
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If PcdMaximumLinkedListLenth is not zero, and prior to insertion the number
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of nodes in ListHead, including the ListHead node, is greater than or
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equal to PcdMaximumLinkedListLength, then ASSERT().
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@param ListHead A pointer to the head node of a doubly linked list.
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@param Entry A pointer to a node that is to be added at the end of the
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doubly linked list.
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@return ListHead
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**/
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LIST_ENTRY *
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EFIAPI
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InsertTailList (
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IN OUT LIST_ENTRY *List,
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IN OUT LIST_ENTRY *Entry
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)
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{
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//
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// ASSERT List not too long and Entry is not one of the nodes of List
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//
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ASSERT (!IsNodeInList (List, Entry));
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Entry->ForwardLink = List;
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Entry->BackLink = List->BackLink;
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Entry->BackLink->ForwardLink = Entry;
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List->BackLink = Entry;
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return List;
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}
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/**
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Retrieves the first node of a doubly linked list.
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Returns the first node of a doubly linked list. List must have been
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initialized with INTIALIZE_LIST_HEAD_VARIABLE() or InitializeListHead().
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If List is empty, then List is returned.
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If List is NULL, then ASSERT().
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If List was not initialized with INTIALIZE_LIST_HEAD_VARIABLE() or
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InitializeListHead(), then ASSERT().
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If PcdMaximumLinkedListLenth is not zero, and the number of nodes
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in List, including the List node, is greater than or equal to
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PcdMaximumLinkedListLength, then ASSERT().
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@param List A pointer to the head node of a doubly linked list.
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@return The first node of a doubly linked list.
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@retval NULL The list is empty.
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**/
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LIST_ENTRY *
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EFIAPI
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GetFirstNode (
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IN CONST LIST_ENTRY *List
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)
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{
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//
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// ASSERT List not too long
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//
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ASSERT (IsNodeInList (List, List));
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return List->ForwardLink;
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}
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/**
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Retrieves the next node of a doubly linked list.
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Returns the node of a doubly linked list that follows Node.
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List must have been initialized with INTIALIZE_LIST_HEAD_VARIABLE()
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or InitializeListHead(). If List is empty, then List is returned.
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If List is NULL, then ASSERT().
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If Node is NULL, then ASSERT().
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If List was not initialized with INTIALIZE_LIST_HEAD_VARIABLE() or
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InitializeListHead(), then ASSERT().
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If PcdMaximumLinkedListLenth is not zero, and List contains more than
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PcdMaximumLinkedListLenth nodes, then ASSERT().
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If Node is not a node in List, then ASSERT().
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@param List A pointer to the head node of a doubly linked list.
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@param Node A pointer to a node in the doubly linked list.
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@return Pointer to the next node if one exists. Otherwise a null value which
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is actually List is returned.
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**/
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LIST_ENTRY *
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EFIAPI
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GetNextNode (
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IN CONST LIST_ENTRY *List,
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IN CONST LIST_ENTRY *Node
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)
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{
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//
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// ASSERT List not too long and Node is one of the nodes of List
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//
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ASSERT (IsNodeInList (List, Node));
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return Node->ForwardLink;
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}
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/**
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Checks to see if a doubly linked list is empty or not.
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Checks to see if the doubly linked list is empty. If the linked list contains
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zero nodes, this function returns TRUE. Otherwise, it returns FALSE.
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If ListHead is NULL, then ASSERT().
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If ListHead was not initialized with INTIALIZE_LIST_HEAD_VARIABLE() or
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InitializeListHead(), then ASSERT().
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If PcdMaximumLinkedListLenth is not zero, and the number of nodes
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in List, including the List node, is greater than or equal to
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PcdMaximumLinkedListLength, then ASSERT().
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@param ListHead A pointer to the head node of a doubly linked list.
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@retval TRUE The linked list is empty.
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@retval FALSE The linked list is not empty.
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**/
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BOOLEAN
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EFIAPI
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IsListEmpty (
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IN CONST LIST_ENTRY *List
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)
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{
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//
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// ASSERT List not too long
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//
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ASSERT (IsNodeInList (List, List));
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return (BOOLEAN)(List->ForwardLink == List);
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}
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/**
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Determines if a node in a doubly linked list is the head node of a the same
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doubly linked list. This function is typically used to terminate a loop that
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traverses all the nodes in a doubly linked list starting with the head node.
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Returns TRUE if Node is equal to List. Returns FALSE if Node is one of the
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nodes in the doubly linked list specified by List. List must have been
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initialized with INTIALIZE_LIST_HEAD_VARIABLE() or InitializeListHead().
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If List is NULL, then ASSERT().
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If Node is NULL, then ASSERT().
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If List was not initialized with INTIALIZE_LIST_HEAD_VARIABLE() or InitializeListHead(),
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then ASSERT().
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If PcdMaximumLinkedListLenth is not zero, and the number of nodes
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in List, including the List node, is greater than or equal to
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PcdMaximumLinkedListLength, then ASSERT().
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If Node is not a node in List and Node is not equal to List, then ASSERT().
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@param List A pointer to the head node of a doubly linked list.
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@param Node A pointer to a node in the doubly linked list.
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@retval TRUE Node is one of the nodes in the doubly linked list.
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@retval FALSE Node is not one of the nodes in the doubly linked list.
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**/
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BOOLEAN
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EFIAPI
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IsNull (
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IN CONST LIST_ENTRY *List,
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IN CONST LIST_ENTRY *Node
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)
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{
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//
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// ASSERT List not too long and Node is one of the nodes of List
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//
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ASSERT (IsNodeInList (List, Node));
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return (BOOLEAN)(Node == List);
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}
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/**
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Determines if a node the last node in a doubly linked list.
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Returns TRUE if Node is the last node in the doubly linked list specified by
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List. Otherwise, FALSE is returned. List must have been initialized with
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INTIALIZE_LIST_HEAD_VARIABLE() or InitializeListHead().
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If List is NULL, then ASSERT().
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If Node is NULL, then ASSERT().
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If List was not initialized with INTIALIZE_LIST_HEAD_VARIABLE() or
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InitializeListHead(), then ASSERT().
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If PcdMaximumLinkedListLenth is not zero, and the number of nodes
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in List, including the List node, is greater than or equal to
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PcdMaximumLinkedListLength, then ASSERT().
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If Node is not a node in List, then ASSERT().
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@param List A pointer to the head node of a doubly linked list.
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@param Node A pointer to a node in the doubly linked list.
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@retval TRUE Node is the last node in the linked list.
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@retval FALSE Node is not the last node in the linked list.
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**/
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BOOLEAN
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EFIAPI
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IsNodeAtEnd (
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IN CONST LIST_ENTRY *List,
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IN CONST LIST_ENTRY *Node
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)
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{
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//
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// ASSERT List not too long and Node is one of the nodes of List
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//
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ASSERT (IsNodeInList (List, Node));
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return (BOOLEAN)(!IsNull (List, Node) && List->BackLink == Node);
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}
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/**
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Swaps the location of two nodes in a doubly linked list, and returns the
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first node after the swap.
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If FirstEntry is identical to SecondEntry, then SecondEntry is returned.
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Otherwise, the location of the FirstEntry node is swapped with the location
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of the SecondEntry node in a doubly linked list. SecondEntry must be in the
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same double linked list as FirstEntry and that double linked list must have
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been initialized with INTIALIZE_LIST_HEAD_VARIABLE() or InitializeListHead().
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SecondEntry is returned after the nodes are swapped.
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If FirstEntry is NULL, then ASSERT().
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If SecondEntry is NULL, then ASSERT().
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If SecondEntry and FirstEntry are not in the same linked list, then ASSERT().
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If PcdMaximumLinkedListLength is not zero, and the number of nodes in the
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linked list containing the FirstEntry and SecondEntry nodes, including
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the FirstEntry and SecondEntry nodes, is greater than or equal to
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PcdMaximumLinkedListLength, then ASSERT().
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@param FirstEntry A pointer to a node in a linked list.
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@param SecondEntry A pointer to another node in the same linked list.
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@return SecondEntry.
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**/
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LIST_ENTRY *
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EFIAPI
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SwapListEntries (
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IN OUT LIST_ENTRY *FirstEntry,
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IN OUT LIST_ENTRY *SecondEntry
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)
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{
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LIST_ENTRY *Ptr;
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if (FirstEntry == SecondEntry) {
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return SecondEntry;
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}
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//
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// ASSERT Entry1 and Entry2 are in the same linked list
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//
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ASSERT (IsNodeInList (FirstEntry, SecondEntry));
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//
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// Ptr is the node pointed to by FirstEntry->ForwardLink
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//
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Ptr = RemoveEntryList (FirstEntry);
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//
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// If FirstEntry immediately follows SecondEntry, FirstEntry will be placed
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// immediately in front of SecondEntry
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//
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if (Ptr->BackLink == SecondEntry) {
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return InsertTailList (SecondEntry, FirstEntry);
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}
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//
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// Ptr == SecondEntry means SecondEntry immediately follows FirstEntry,
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// then there are no further steps necessary
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//
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if (Ptr == InsertHeadList (SecondEntry, FirstEntry)) {
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return Ptr;
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}
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//
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// Move SecondEntry to the front of Ptr
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//
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RemoveEntryList (SecondEntry);
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InsertTailList (Ptr, SecondEntry);
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return SecondEntry;
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}
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/**
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Removes a node from a doubly linked list, and returns the node that follows
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the removed node.
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Removes the node Entry from a doubly linked list. It is up to the caller of
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this function to release the memory used by this node if that is required. On
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exit, the node following Entry in the doubly linked list is returned. If
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Entry is the only node in the linked list, then the head node of the linked
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list is returned.
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If Entry is NULL, then ASSERT().
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If Entry is the head node of an empty list, then ASSERT().
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If PcdMaximumLinkedListLength is not zero, and the number of nodes in the
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linked list containing Entry, including the Entry node, is greater than
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or equal to PcdMaximumLinkedListLength, then ASSERT().
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@param Entry A pointer to a node in a linked list.
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@return Entry.
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**/
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LIST_ENTRY *
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EFIAPI
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RemoveEntryList (
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IN CONST LIST_ENTRY *Entry
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)
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{
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ASSERT (!IsListEmpty (Entry));
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Entry->ForwardLink->BackLink = Entry->BackLink;
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Entry->BackLink->ForwardLink = Entry->ForwardLink;
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return Entry->ForwardLink;
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}
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