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1 | /** @file\r | |
2 | Linked List Library Functions.\r | |
3 | \r | |
4 | Copyright (c) 2006 - 2018, Intel Corporation. All rights reserved.<BR>\r | |
5 | This program and the accompanying materials\r | |
6 | are licensed and made available under the terms and conditions of the BSD License\r | |
7 | which accompanies this distribution. The full text of the license may be found at\r | |
8 | http://opensource.org/licenses/bsd-license.php.\r | |
9 | \r | |
10 | THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r | |
11 | WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r | |
12 | \r | |
13 | **/\r | |
14 | \r | |
15 | #include "BaseLibInternals.h"\r | |
16 | \r | |
17 | /**\r | |
18 | If PcdVerifyNodeInList is TRUE, ASSERTs when SecondEntry is or is not part of\r | |
19 | the same doubly-linked list as FirstEntry depending on the value of InList.\r | |
20 | Independent of PcdVerifyNodeInList, ASSERTs when FirstEntry is not part of a\r | |
21 | valid list.\r | |
22 | \r | |
23 | If FirstEntry is NULL, then ASSERT().\r | |
24 | If FirstEntry->ForwardLink is NULL, then ASSERT().\r | |
25 | If FirstEntry->BackLink is NULL, then ASSERT().\r | |
26 | If PcdMaximumLinkedListLength is not zero, and List contains more than\r | |
27 | PcdMaximumLinkedListLength nodes, then ASSERT().\r | |
28 | If PcdVerifyNodeInList is TRUE and SecondEntry is NULL, then ASSERT().\r | |
29 | \r | |
30 | @param FirstEntry A pointer to a node in a linked list.\r | |
31 | @param SecondEntry A pointer to the node to locate.\r | |
32 | @param InList Defines whether to check if SecondEntry is or is not part\r | |
33 | of the same doubly-linked list as FirstEntry.\r | |
34 | \r | |
35 | **/\r | |
36 | #if !defined (MDEPKG_NDEBUG)\r | |
37 | #define ASSERT_VERIFY_NODE_IN_VALID_LIST(FirstEntry, SecondEntry, InList) \\r | |
38 | do { \\r | |
39 | if (FeaturePcdGet (PcdVerifyNodeInList)) { \\r | |
40 | ASSERT (InList == IsNodeInList ((FirstEntry), (SecondEntry))); \\r | |
41 | } else { \\r | |
42 | ASSERT (InternalBaseLibIsListValid (FirstEntry)); \\r | |
43 | } \\r | |
44 | } while (FALSE)\r | |
45 | #else\r | |
46 | #define ASSERT_VERIFY_NODE_IN_VALID_LIST(FirstEntry, SecondEntry, InList)\r | |
47 | #endif\r | |
48 | \r | |
49 | /**\r | |
50 | Worker function that verifies the validity of this list.\r | |
51 | \r | |
52 | If List is NULL, then ASSERT().\r | |
53 | If List->ForwardLink is NULL, then ASSERT().\r | |
54 | If List->BackLink is NULL, then ASSERT().\r | |
55 | If PcdMaximumLinkedListLength is not zero, and List contains more than\r | |
56 | PcdMaximumLinkedListLength nodes, then ASSERT().\r | |
57 | \r | |
58 | @param List A pointer to a node in a linked list.\r | |
59 | \r | |
60 | @retval TRUE if PcdVerifyNodeInList is FALSE\r | |
61 | @retval TRUE if DoMembershipCheck is FALSE\r | |
62 | @retval TRUE if PcdVerifyNodeInList is TRUE and DoMembershipCheck is TRUE\r | |
63 | and Node is a member of List.\r | |
64 | @retval FALSE if PcdVerifyNodeInList is TRUE and DoMembershipCheck is TRUE\r | |
65 | and Node is in not a member of List.\r | |
66 | \r | |
67 | **/\r | |
68 | BOOLEAN\r | |
69 | EFIAPI\r | |
70 | InternalBaseLibIsListValid (\r | |
71 | IN CONST LIST_ENTRY *List\r | |
72 | )\r | |
73 | {\r | |
74 | UINTN Count;\r | |
75 | CONST LIST_ENTRY *Ptr;\r | |
76 | \r | |
77 | //\r | |
78 | // Test the validity of List and Node\r | |
79 | //\r | |
80 | ASSERT (List != NULL);\r | |
81 | ASSERT (List->ForwardLink != NULL);\r | |
82 | ASSERT (List->BackLink != NULL);\r | |
83 | \r | |
84 | if (PcdGet32 (PcdMaximumLinkedListLength) > 0) {\r | |
85 | Count = 0;\r | |
86 | Ptr = List;\r | |
87 | \r | |
88 | //\r | |
89 | // Count the total number of nodes in List.\r | |
90 | // Exit early if the number of nodes in List >= PcdMaximumLinkedListLength\r | |
91 | //\r | |
92 | do {\r | |
93 | Ptr = Ptr->ForwardLink;\r | |
94 | Count++;\r | |
95 | } while ((Ptr != List) && (Count < PcdGet32 (PcdMaximumLinkedListLength)));\r | |
96 | \r | |
97 | //\r | |
98 | // return whether linked list is too long\r | |
99 | //\r | |
100 | return (BOOLEAN)(Count < PcdGet32 (PcdMaximumLinkedListLength));\r | |
101 | }\r | |
102 | \r | |
103 | return TRUE;\r | |
104 | }\r | |
105 | \r | |
106 | /**\r | |
107 | Checks whether FirstEntry and SecondEntry are part of the same doubly-linked\r | |
108 | list.\r | |
109 | \r | |
110 | If FirstEntry is NULL, then ASSERT().\r | |
111 | If FirstEntry->ForwardLink is NULL, then ASSERT().\r | |
112 | If FirstEntry->BackLink is NULL, then ASSERT().\r | |
113 | If SecondEntry is NULL, then ASSERT();\r | |
114 | If PcdMaximumLinkedListLength is not zero, and List contains more than\r | |
115 | PcdMaximumLinkedListLength nodes, then ASSERT().\r | |
116 | \r | |
117 | @param FirstEntry A pointer to a node in a linked list.\r | |
118 | @param SecondEntry A pointer to the node to locate.\r | |
119 | \r | |
120 | @retval TRUE SecondEntry is in the same doubly-linked list as FirstEntry.\r | |
121 | @retval FALSE SecondEntry isn't in the same doubly-linked list as FirstEntry,\r | |
122 | or FirstEntry is invalid.\r | |
123 | \r | |
124 | **/\r | |
125 | BOOLEAN\r | |
126 | EFIAPI\r | |
127 | IsNodeInList (\r | |
128 | IN CONST LIST_ENTRY *FirstEntry,\r | |
129 | IN CONST LIST_ENTRY *SecondEntry\r | |
130 | )\r | |
131 | {\r | |
132 | UINTN Count;\r | |
133 | CONST LIST_ENTRY *Ptr;\r | |
134 | \r | |
135 | //\r | |
136 | // ASSERT List not too long\r | |
137 | //\r | |
138 | ASSERT (InternalBaseLibIsListValid (FirstEntry));\r | |
139 | \r | |
140 | ASSERT (SecondEntry != NULL);\r | |
141 | \r | |
142 | Count = 0;\r | |
143 | Ptr = FirstEntry;\r | |
144 | \r | |
145 | //\r | |
146 | // Check to see if SecondEntry is a member of FirstEntry.\r | |
147 | // Exit early if the number of nodes in List >= PcdMaximumLinkedListLength\r | |
148 | //\r | |
149 | do {\r | |
150 | Ptr = Ptr->ForwardLink;\r | |
151 | if (PcdGet32 (PcdMaximumLinkedListLength) > 0) {\r | |
152 | Count++;\r | |
153 | \r | |
154 | //\r | |
155 | // Return if the linked list is too long\r | |
156 | //\r | |
157 | if (Count == PcdGet32 (PcdMaximumLinkedListLength)) {\r | |
158 | return (BOOLEAN)(Ptr == SecondEntry);\r | |
159 | }\r | |
160 | }\r | |
161 | \r | |
162 | if (Ptr == SecondEntry) {\r | |
163 | return TRUE;\r | |
164 | }\r | |
165 | } while (Ptr != FirstEntry);\r | |
166 | \r | |
167 | return FALSE;\r | |
168 | }\r | |
169 | \r | |
170 | /**\r | |
171 | Initializes the head node of a doubly-linked list, and returns the pointer to\r | |
172 | the head node of the doubly-linked list.\r | |
173 | \r | |
174 | Initializes the forward and backward links of a new linked list. After\r | |
175 | initializing a linked list with this function, the other linked list\r | |
176 | functions may be used to add and remove nodes from the linked list. It is up\r | |
177 | to the caller of this function to allocate the memory for ListHead.\r | |
178 | \r | |
179 | If ListHead is NULL, then ASSERT().\r | |
180 | \r | |
181 | @param ListHead A pointer to the head node of a new doubly-linked list.\r | |
182 | \r | |
183 | @return ListHead\r | |
184 | \r | |
185 | **/\r | |
186 | LIST_ENTRY *\r | |
187 | EFIAPI\r | |
188 | InitializeListHead (\r | |
189 | IN OUT LIST_ENTRY *ListHead\r | |
190 | )\r | |
191 | \r | |
192 | {\r | |
193 | ASSERT (ListHead != NULL);\r | |
194 | \r | |
195 | ListHead->ForwardLink = ListHead;\r | |
196 | ListHead->BackLink = ListHead;\r | |
197 | return ListHead;\r | |
198 | }\r | |
199 | \r | |
200 | /**\r | |
201 | Adds a node to the beginning of a doubly-linked list, and returns the pointer\r | |
202 | to the head node of the doubly-linked list.\r | |
203 | \r | |
204 | Adds the node Entry at the beginning of the doubly-linked list denoted by\r | |
205 | ListHead, and returns ListHead.\r | |
206 | \r | |
207 | If ListHead is NULL, then ASSERT().\r | |
208 | If Entry is NULL, then ASSERT().\r | |
209 | If ListHead was not initialized with INTIALIZE_LIST_HEAD_VARIABLE() or\r | |
210 | InitializeListHead(), then ASSERT().\r | |
211 | If PcdMaximumLinkedListLength is not zero, and prior to insertion the number\r | |
212 | of nodes in ListHead, including the ListHead node, is greater than or\r | |
213 | equal to PcdMaximumLinkedListLength, then ASSERT().\r | |
214 | \r | |
215 | @param ListHead A pointer to the head node of a doubly-linked list.\r | |
216 | @param Entry A pointer to a node that is to be inserted at the beginning\r | |
217 | of a doubly-linked list.\r | |
218 | \r | |
219 | @return ListHead\r | |
220 | \r | |
221 | **/\r | |
222 | LIST_ENTRY *\r | |
223 | EFIAPI\r | |
224 | InsertHeadList (\r | |
225 | IN OUT LIST_ENTRY *ListHead,\r | |
226 | IN OUT LIST_ENTRY *Entry\r | |
227 | )\r | |
228 | {\r | |
229 | //\r | |
230 | // ASSERT List not too long and Entry is not one of the nodes of List\r | |
231 | //\r | |
232 | ASSERT_VERIFY_NODE_IN_VALID_LIST (ListHead, Entry, FALSE);\r | |
233 | \r | |
234 | Entry->ForwardLink = ListHead->ForwardLink;\r | |
235 | Entry->BackLink = ListHead;\r | |
236 | Entry->ForwardLink->BackLink = Entry;\r | |
237 | ListHead->ForwardLink = Entry;\r | |
238 | return ListHead;\r | |
239 | }\r | |
240 | \r | |
241 | /**\r | |
242 | Adds a node to the end of a doubly-linked list, and returns the pointer to\r | |
243 | the head node of the doubly-linked list.\r | |
244 | \r | |
245 | Adds the node Entry to the end of the doubly-linked list denoted by ListHead,\r | |
246 | and returns ListHead.\r | |
247 | \r | |
248 | If ListHead is NULL, then ASSERT().\r | |
249 | If Entry is NULL, then ASSERT().\r | |
250 | If ListHead was not initialized with INTIALIZE_LIST_HEAD_VARIABLE() or\r | |
251 | InitializeListHead(), then ASSERT().\r | |
252 | If PcdMaximumLinkedListLength is not zero, and prior to insertion the number\r | |
253 | of nodes in ListHead, including the ListHead node, is greater than or\r | |
254 | equal to PcdMaximumLinkedListLength, then ASSERT().\r | |
255 | \r | |
256 | @param ListHead A pointer to the head node of a doubly-linked list.\r | |
257 | @param Entry A pointer to a node that is to be added at the end of the\r | |
258 | doubly-linked list.\r | |
259 | \r | |
260 | @return ListHead\r | |
261 | \r | |
262 | **/\r | |
263 | LIST_ENTRY *\r | |
264 | EFIAPI\r | |
265 | InsertTailList (\r | |
266 | IN OUT LIST_ENTRY *ListHead,\r | |
267 | IN OUT LIST_ENTRY *Entry\r | |
268 | )\r | |
269 | {\r | |
270 | //\r | |
271 | // ASSERT List not too long and Entry is not one of the nodes of List\r | |
272 | //\r | |
273 | ASSERT_VERIFY_NODE_IN_VALID_LIST (ListHead, Entry, FALSE);\r | |
274 | \r | |
275 | Entry->ForwardLink = ListHead;\r | |
276 | Entry->BackLink = ListHead->BackLink;\r | |
277 | Entry->BackLink->ForwardLink = Entry;\r | |
278 | ListHead->BackLink = Entry;\r | |
279 | return ListHead;\r | |
280 | }\r | |
281 | \r | |
282 | /**\r | |
283 | Retrieves the first node of a doubly-linked list.\r | |
284 | \r | |
285 | Returns the first node of a doubly-linked list. List must have been\r | |
286 | initialized with INTIALIZE_LIST_HEAD_VARIABLE() or InitializeListHead().\r | |
287 | If List is empty, then List is returned.\r | |
288 | \r | |
289 | If List is NULL, then ASSERT().\r | |
290 | If List was not initialized with INTIALIZE_LIST_HEAD_VARIABLE() or\r | |
291 | InitializeListHead(), then ASSERT().\r | |
292 | If PcdMaximumLinkedListLength is not zero, and the number of nodes\r | |
293 | in List, including the List node, is greater than or equal to\r | |
294 | PcdMaximumLinkedListLength, then ASSERT().\r | |
295 | \r | |
296 | @param List A pointer to the head node of a doubly-linked list.\r | |
297 | \r | |
298 | @return The first node of a doubly-linked list.\r | |
299 | @retval List The list is empty.\r | |
300 | \r | |
301 | **/\r | |
302 | LIST_ENTRY *\r | |
303 | EFIAPI\r | |
304 | GetFirstNode (\r | |
305 | IN CONST LIST_ENTRY *List\r | |
306 | )\r | |
307 | {\r | |
308 | //\r | |
309 | // ASSERT List not too long\r | |
310 | //\r | |
311 | ASSERT (InternalBaseLibIsListValid (List));\r | |
312 | \r | |
313 | return List->ForwardLink;\r | |
314 | }\r | |
315 | \r | |
316 | /**\r | |
317 | Retrieves the next node of a doubly-linked list.\r | |
318 | \r | |
319 | Returns the node of a doubly-linked list that follows Node.\r | |
320 | List must have been initialized with INTIALIZE_LIST_HEAD_VARIABLE()\r | |
321 | or InitializeListHead(). If List is empty, then List is returned.\r | |
322 | \r | |
323 | If List is NULL, then ASSERT().\r | |
324 | If Node is NULL, then ASSERT().\r | |
325 | If List was not initialized with INTIALIZE_LIST_HEAD_VARIABLE() or\r | |
326 | InitializeListHead(), then ASSERT().\r | |
327 | If PcdMaximumLinkedListLength is not zero, and List contains more than\r | |
328 | PcdMaximumLinkedListLength nodes, then ASSERT().\r | |
329 | If PcdVerifyNodeInList is TRUE and Node is not a node in List, then ASSERT().\r | |
330 | \r | |
331 | @param List A pointer to the head node of a doubly-linked list.\r | |
332 | @param Node A pointer to a node in the doubly-linked list.\r | |
333 | \r | |
334 | @return A pointer to the next node if one exists. Otherwise List is returned.\r | |
335 | \r | |
336 | **/\r | |
337 | LIST_ENTRY *\r | |
338 | EFIAPI\r | |
339 | GetNextNode (\r | |
340 | IN CONST LIST_ENTRY *List,\r | |
341 | IN CONST LIST_ENTRY *Node\r | |
342 | )\r | |
343 | {\r | |
344 | //\r | |
345 | // ASSERT List not too long and Node is one of the nodes of List\r | |
346 | //\r | |
347 | ASSERT_VERIFY_NODE_IN_VALID_LIST (List, Node, TRUE);\r | |
348 | \r | |
349 | return Node->ForwardLink;\r | |
350 | }\r | |
351 | \r | |
352 | /**\r | |
353 | Retrieves the previous node of a doubly-linked list.\r | |
354 | \r | |
355 | Returns the node of a doubly-linked list that precedes Node.\r | |
356 | List must have been initialized with INTIALIZE_LIST_HEAD_VARIABLE()\r | |
357 | or InitializeListHead(). If List is empty, then List is returned.\r | |
358 | \r | |
359 | If List is NULL, then ASSERT().\r | |
360 | If Node is NULL, then ASSERT().\r | |
361 | If List was not initialized with INTIALIZE_LIST_HEAD_VARIABLE() or\r | |
362 | InitializeListHead(), then ASSERT().\r | |
363 | If PcdMaximumLinkedListLength is not zero, and List contains more than\r | |
364 | PcdMaximumLinkedListLength nodes, then ASSERT().\r | |
365 | If PcdVerifyNodeInList is TRUE and Node is not a node in List, then ASSERT().\r | |
366 | \r | |
367 | @param List A pointer to the head node of a doubly-linked list.\r | |
368 | @param Node A pointer to a node in the doubly-linked list.\r | |
369 | \r | |
370 | @return A pointer to the previous node if one exists. Otherwise List is returned.\r | |
371 | \r | |
372 | **/\r | |
373 | LIST_ENTRY *\r | |
374 | EFIAPI\r | |
375 | GetPreviousNode (\r | |
376 | IN CONST LIST_ENTRY *List,\r | |
377 | IN CONST LIST_ENTRY *Node\r | |
378 | )\r | |
379 | {\r | |
380 | //\r | |
381 | // ASSERT List not too long and Node is one of the nodes of List\r | |
382 | //\r | |
383 | ASSERT_VERIFY_NODE_IN_VALID_LIST (List, Node, TRUE);\r | |
384 | \r | |
385 | return Node->BackLink;\r | |
386 | }\r | |
387 | \r | |
388 | /**\r | |
389 | Checks to see if a doubly-linked list is empty or not.\r | |
390 | \r | |
391 | Checks to see if the doubly-linked list is empty. If the linked list contains\r | |
392 | zero nodes, this function returns TRUE. Otherwise, it returns FALSE.\r | |
393 | \r | |
394 | If ListHead is NULL, then ASSERT().\r | |
395 | If ListHead was not initialized with INTIALIZE_LIST_HEAD_VARIABLE() or\r | |
396 | InitializeListHead(), then ASSERT().\r | |
397 | If PcdMaximumLinkedListLength is not zero, and the number of nodes\r | |
398 | in List, including the List node, is greater than or equal to\r | |
399 | PcdMaximumLinkedListLength, then ASSERT().\r | |
400 | \r | |
401 | @param ListHead A pointer to the head node of a doubly-linked list.\r | |
402 | \r | |
403 | @retval TRUE The linked list is empty.\r | |
404 | @retval FALSE The linked list is not empty.\r | |
405 | \r | |
406 | **/\r | |
407 | BOOLEAN\r | |
408 | EFIAPI\r | |
409 | IsListEmpty (\r | |
410 | IN CONST LIST_ENTRY *ListHead\r | |
411 | )\r | |
412 | {\r | |
413 | //\r | |
414 | // ASSERT List not too long\r | |
415 | //\r | |
416 | ASSERT (InternalBaseLibIsListValid (ListHead));\r | |
417 | \r | |
418 | return (BOOLEAN)(ListHead->ForwardLink == ListHead);\r | |
419 | }\r | |
420 | \r | |
421 | /**\r | |
422 | Determines if a node in a doubly-linked list is the head node of a the same\r | |
423 | doubly-linked list. This function is typically used to terminate a loop that\r | |
424 | traverses all the nodes in a doubly-linked list starting with the head node.\r | |
425 | \r | |
426 | Returns TRUE if Node is equal to List. Returns FALSE if Node is one of the\r | |
427 | nodes in the doubly-linked list specified by List. List must have been\r | |
428 | initialized with INTIALIZE_LIST_HEAD_VARIABLE() or InitializeListHead().\r | |
429 | \r | |
430 | If List is NULL, then ASSERT().\r | |
431 | If Node is NULL, then ASSERT().\r | |
432 | If List was not initialized with INTIALIZE_LIST_HEAD_VARIABLE() or InitializeListHead(),\r | |
433 | then ASSERT().\r | |
434 | If PcdMaximumLinkedListLength is not zero, and the number of nodes\r | |
435 | in List, including the List node, is greater than or equal to\r | |
436 | PcdMaximumLinkedListLength, then ASSERT().\r | |
437 | If PcdVerifyNodeInList is TRUE and Node is not a node in List and Node is not\r | |
438 | equal to List, then ASSERT().\r | |
439 | \r | |
440 | @param List A pointer to the head node of a doubly-linked list.\r | |
441 | @param Node A pointer to a node in the doubly-linked list.\r | |
442 | \r | |
443 | @retval TRUE Node is the head of the doubly-linked list pointed by List.\r | |
444 | @retval FALSE Node is not the head of the doubly-linked list pointed by List.\r | |
445 | \r | |
446 | **/\r | |
447 | BOOLEAN\r | |
448 | EFIAPI\r | |
449 | IsNull (\r | |
450 | IN CONST LIST_ENTRY *List,\r | |
451 | IN CONST LIST_ENTRY *Node\r | |
452 | )\r | |
453 | {\r | |
454 | //\r | |
455 | // ASSERT List not too long and Node is one of the nodes of List\r | |
456 | //\r | |
457 | ASSERT_VERIFY_NODE_IN_VALID_LIST (List, Node, TRUE);\r | |
458 | \r | |
459 | return (BOOLEAN)(Node == List);\r | |
460 | }\r | |
461 | \r | |
462 | /**\r | |
463 | Determines if a node the last node in a doubly-linked list.\r | |
464 | \r | |
465 | Returns TRUE if Node is the last node in the doubly-linked list specified by\r | |
466 | List. Otherwise, FALSE is returned. List must have been initialized with\r | |
467 | INTIALIZE_LIST_HEAD_VARIABLE() or InitializeListHead().\r | |
468 | \r | |
469 | If List is NULL, then ASSERT().\r | |
470 | If Node is NULL, then ASSERT().\r | |
471 | If List was not initialized with INTIALIZE_LIST_HEAD_VARIABLE() or\r | |
472 | InitializeListHead(), then ASSERT().\r | |
473 | If PcdMaximumLinkedListLength is not zero, and the number of nodes\r | |
474 | in List, including the List node, is greater than or equal to\r | |
475 | PcdMaximumLinkedListLength, then ASSERT().\r | |
476 | If PcdVerifyNodeInList is TRUE and Node is not a node in List, then ASSERT().\r | |
477 | \r | |
478 | @param List A pointer to the head node of a doubly-linked list.\r | |
479 | @param Node A pointer to a node in the doubly-linked list.\r | |
480 | \r | |
481 | @retval TRUE Node is the last node in the linked list.\r | |
482 | @retval FALSE Node is not the last node in the linked list.\r | |
483 | \r | |
484 | **/\r | |
485 | BOOLEAN\r | |
486 | EFIAPI\r | |
487 | IsNodeAtEnd (\r | |
488 | IN CONST LIST_ENTRY *List,\r | |
489 | IN CONST LIST_ENTRY *Node\r | |
490 | )\r | |
491 | {\r | |
492 | //\r | |
493 | // ASSERT List not too long and Node is one of the nodes of List\r | |
494 | //\r | |
495 | ASSERT_VERIFY_NODE_IN_VALID_LIST (List, Node, TRUE);\r | |
496 | \r | |
497 | return (BOOLEAN)(!IsNull (List, Node) && List->BackLink == Node);\r | |
498 | }\r | |
499 | \r | |
500 | /**\r | |
501 | Swaps the location of two nodes in a doubly-linked list, and returns the\r | |
502 | first node after the swap.\r | |
503 | \r | |
504 | If FirstEntry is identical to SecondEntry, then SecondEntry is returned.\r | |
505 | Otherwise, the location of the FirstEntry node is swapped with the location\r | |
506 | of the SecondEntry node in a doubly-linked list. SecondEntry must be in the\r | |
507 | same double linked list as FirstEntry and that double linked list must have\r | |
508 | been initialized with INTIALIZE_LIST_HEAD_VARIABLE() or InitializeListHead().\r | |
509 | SecondEntry is returned after the nodes are swapped.\r | |
510 | \r | |
511 | If FirstEntry is NULL, then ASSERT().\r | |
512 | If SecondEntry is NULL, then ASSERT().\r | |
513 | If PcdVerifyNodeInList is TRUE and SecondEntry and FirstEntry are not in the\r | |
514 | same linked list, then ASSERT().\r | |
515 | If PcdMaximumLinkedListLength is not zero, and the number of nodes in the\r | |
516 | linked list containing the FirstEntry and SecondEntry nodes, including\r | |
517 | the FirstEntry and SecondEntry nodes, is greater than or equal to\r | |
518 | PcdMaximumLinkedListLength, then ASSERT().\r | |
519 | \r | |
520 | @param FirstEntry A pointer to a node in a linked list.\r | |
521 | @param SecondEntry A pointer to another node in the same linked list.\r | |
522 | \r | |
523 | @return SecondEntry.\r | |
524 | \r | |
525 | **/\r | |
526 | LIST_ENTRY *\r | |
527 | EFIAPI\r | |
528 | SwapListEntries (\r | |
529 | IN OUT LIST_ENTRY *FirstEntry,\r | |
530 | IN OUT LIST_ENTRY *SecondEntry\r | |
531 | )\r | |
532 | {\r | |
533 | LIST_ENTRY *Ptr;\r | |
534 | \r | |
535 | if (FirstEntry == SecondEntry) {\r | |
536 | return SecondEntry;\r | |
537 | }\r | |
538 | \r | |
539 | //\r | |
540 | // ASSERT Entry1 and Entry2 are in the same linked list\r | |
541 | //\r | |
542 | ASSERT_VERIFY_NODE_IN_VALID_LIST (FirstEntry, SecondEntry, TRUE);\r | |
543 | \r | |
544 | //\r | |
545 | // Ptr is the node pointed to by FirstEntry->ForwardLink\r | |
546 | //\r | |
547 | Ptr = RemoveEntryList (FirstEntry);\r | |
548 | \r | |
549 | //\r | |
550 | // If FirstEntry immediately follows SecondEntry, FirstEntry will be placed\r | |
551 | // immediately in front of SecondEntry\r | |
552 | //\r | |
553 | if (Ptr->BackLink == SecondEntry) {\r | |
554 | return InsertTailList (SecondEntry, FirstEntry);\r | |
555 | }\r | |
556 | \r | |
557 | //\r | |
558 | // Ptr == SecondEntry means SecondEntry immediately follows FirstEntry,\r | |
559 | // then there are no further steps necessary\r | |
560 | //\r | |
561 | if (Ptr == InsertHeadList (SecondEntry, FirstEntry)) {\r | |
562 | return Ptr;\r | |
563 | }\r | |
564 | \r | |
565 | //\r | |
566 | // Move SecondEntry to the front of Ptr\r | |
567 | //\r | |
568 | RemoveEntryList (SecondEntry);\r | |
569 | InsertTailList (Ptr, SecondEntry);\r | |
570 | return SecondEntry;\r | |
571 | }\r | |
572 | \r | |
573 | /**\r | |
574 | Removes a node from a doubly-linked list, and returns the node that follows\r | |
575 | the removed node.\r | |
576 | \r | |
577 | Removes the node Entry from a doubly-linked list. It is up to the caller of\r | |
578 | this function to release the memory used by this node if that is required. On\r | |
579 | exit, the node following Entry in the doubly-linked list is returned. If\r | |
580 | Entry is the only node in the linked list, then the head node of the linked\r | |
581 | list is returned.\r | |
582 | \r | |
583 | If Entry is NULL, then ASSERT().\r | |
584 | If Entry is the head node of an empty list, then ASSERT().\r | |
585 | If PcdMaximumLinkedListLength is not zero, and the number of nodes in the\r | |
586 | linked list containing Entry, including the Entry node, is greater than\r | |
587 | or equal to PcdMaximumLinkedListLength, then ASSERT().\r | |
588 | \r | |
589 | @param Entry A pointer to a node in a linked list.\r | |
590 | \r | |
591 | @return Entry.\r | |
592 | \r | |
593 | **/\r | |
594 | LIST_ENTRY *\r | |
595 | EFIAPI\r | |
596 | RemoveEntryList (\r | |
597 | IN CONST LIST_ENTRY *Entry\r | |
598 | )\r | |
599 | {\r | |
600 | ASSERT (!IsListEmpty (Entry));\r | |
601 | \r | |
602 | Entry->ForwardLink->BackLink = Entry->BackLink;\r | |
603 | Entry->BackLink->ForwardLink = Entry->ForwardLink;\r | |
604 | return Entry->ForwardLink;\r | |
605 | }\r |