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source: vbox/trunk/include/iprt/list.h@ 91991

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1/** @file
2 * IPRT - Generic Doubly Linked List.
3 */
4
5/*
6 * Copyright (C) 2010-2020 Oracle Corporation
7 *
8 * This file is part of VirtualBox Open Source Edition (OSE), as
9 * available from http://www.virtualbox.org. This file is free software;
10 * you can redistribute it and/or modify it under the terms of the GNU
11 * General Public License (GPL) as published by the Free Software
12 * Foundation, in version 2 as it comes in the "COPYING" file of the
13 * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
14 * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
15 *
16 * The contents of this file may alternatively be used under the terms
17 * of the Common Development and Distribution License Version 1.0
18 * (CDDL) only, as it comes in the "COPYING.CDDL" file of the
19 * VirtualBox OSE distribution, in which case the provisions of the
20 * CDDL are applicable instead of those of the GPL.
21 *
22 * You may elect to license modified versions of this file under the
23 * terms and conditions of either the GPL or the CDDL or both.
24 */
25
26#ifndef IPRT_INCLUDED_list_h
27#define IPRT_INCLUDED_list_h
28#ifndef RT_WITHOUT_PRAGMA_ONCE
29# pragma once
30#endif
31
32#include <iprt/types.h>
33
34/** @defgroup grp_rt_list RTList - Generic Doubly Linked List
35 * @ingroup grp_rt
36 *
37 * The list implementation is circular without any type wise distintion between
38 * the list and its nodes. This can be confusing since the list head usually
39 * resides in a different structure than the nodes, so care must be taken when
40 * walking the list.
41 *
42 * @{
43 */
44
45RT_C_DECLS_BEGIN
46
47/**
48 * A list node of a doubly linked list.
49 */
50typedef struct RTLISTNODE
51{
52 /** Pointer to the next list node. */
53 struct RTLISTNODE *pNext;
54 /** Pointer to the previous list node. */
55 struct RTLISTNODE *pPrev;
56} RTLISTNODE;
57/** Pointer to a list node. */
58typedef RTLISTNODE *PRTLISTNODE;
59/** Pointer to a const list node. */
60typedef RTLISTNODE const *PCRTLISTNODE;
61/** Pointer to a list node pointer. */
62typedef PRTLISTNODE *PPRTLISTNODE;
63
64/** The anchor (head/tail) of a doubly linked list.
65 *
66 * @remarks Please use this instead of RTLISTNODE to indicate a list
67 * head/tail. It makes the code so much easier to read. Also,
68 * always mention the actual list node type(s) in the comment. */
69typedef RTLISTNODE RTLISTANCHOR;
70/** Pointer to a doubly linked list anchor. */
71typedef RTLISTANCHOR *PRTLISTANCHOR;
72/** Pointer to a const doubly linked list anchor. */
73typedef RTLISTANCHOR const *PCRTLISTANCHOR;
74
75/** Version of RTLISTNODE for holding a ring-3 only list in data which gets
76 * shared between multiple contexts. */
77#ifdef IN_RING3
78typedef RTLISTNODE RTLISTNODER3;
79#else
80typedef struct { RTR3PTR aOffLimits[2]; } RTLISTNODER3;
81#endif
82/** Version of RTLISTANCHOR for holding a ring-3 only list in data which gets
83 * shared between multiple contexts. */
84typedef RTLISTNODER3 RTLISTANCHORR3;
85
86/** Version of RTLISTNODE for holding a ring-0 only list in data which gets
87 * shared between multiple contexts. */
88#ifdef IN_RING0
89typedef RTLISTNODE RTLISTNODER0;
90#else
91typedef struct { RTR0PTR aOffLimits[2]; } RTLISTNODER0;
92#endif
93/** Version of RTLISTANCHOR for holding a ring-0 only list in data which gets
94 * shared between multiple contexts. */
95typedef RTLISTNODER0 RTLISTANCHORR0;
96
97
98/**
99 * Initialize a list.
100 *
101 * @param pList Pointer to an unitialised list.
102 */
103DECLINLINE(void) RTListInit(PRTLISTNODE pList)
104{
105 pList->pNext = pList;
106 pList->pPrev = pList;
107}
108
109/**
110 * Append a node to the end of the list.
111 *
112 * @param pList The list to append the node to.
113 * @param pNode The node to append.
114 */
115DECLINLINE(void) RTListAppend(PRTLISTNODE pList, PRTLISTNODE pNode)
116{
117 pList->pPrev->pNext = pNode;
118 pNode->pPrev = pList->pPrev;
119 pNode->pNext = pList;
120 pList->pPrev = pNode;
121}
122
123/**
124 * Add a node as the first element of the list.
125 *
126 * @param pList The list to prepend the node to.
127 * @param pNode The node to prepend.
128 */
129DECLINLINE(void) RTListPrepend(PRTLISTNODE pList, PRTLISTNODE pNode)
130{
131 pList->pNext->pPrev = pNode;
132 pNode->pNext = pList->pNext;
133 pNode->pPrev = pList;
134 pList->pNext = pNode;
135}
136
137/**
138 * Inserts a node after the specified one.
139 *
140 * @param pCurNode The current node.
141 * @param pNewNode The node to insert.
142 */
143DECLINLINE(void) RTListNodeInsertAfter(PRTLISTNODE pCurNode, PRTLISTNODE pNewNode)
144{
145 RTListPrepend(pCurNode, pNewNode);
146}
147
148/**
149 * Inserts a node before the specified one.
150 *
151 * @param pCurNode The current node.
152 * @param pNewNode The node to insert.
153 */
154DECLINLINE(void) RTListNodeInsertBefore(PRTLISTNODE pCurNode, PRTLISTNODE pNewNode)
155{
156 RTListAppend(pCurNode, pNewNode);
157}
158
159/**
160 * Remove a node from a list.
161 *
162 * @param pNode The node to remove.
163 */
164DECLINLINE(void) RTListNodeRemove(PRTLISTNODE pNode)
165{
166 PRTLISTNODE pPrev = pNode->pPrev;
167 PRTLISTNODE pNext = pNode->pNext;
168
169 pPrev->pNext = pNext;
170 pNext->pPrev = pPrev;
171
172 /* poison */
173 pNode->pNext = NULL;
174 pNode->pPrev = NULL;
175}
176
177
178/**
179 * Remove a node from a list, returns value.
180 *
181 * @returns pNode
182 * @param pNode The node to remove.
183 */
184DECLINLINE(PRTLISTNODE) RTListNodeRemoveRet(PRTLISTNODE pNode)
185{
186 PRTLISTNODE pPrev = pNode->pPrev;
187 PRTLISTNODE pNext = pNode->pNext;
188
189 pPrev->pNext = pNext;
190 pNext->pPrev = pPrev;
191
192 /* poison */
193 pNode->pNext = NULL;
194 pNode->pPrev = NULL;
195
196 return pNode;
197}
198
199/**
200 * Checks if a node is the last element in the list.
201 *
202 * @retval true if the node is the last element in the list.
203 * @retval false otherwise
204 *
205 * @param pList The list.
206 * @param pNode The node to check.
207 */
208#define RTListNodeIsLast(pList, pNode) ((pNode)->pNext == (pList))
209
210/**
211 * Checks if a node is the first element in the list.
212 *
213 * @retval true if the node is the first element in the list.
214 * @retval false otherwise.
215 *
216 * @param pList The list.
217 * @param pNode The node to check.
218 */
219#define RTListNodeIsFirst(pList, pNode) ((pNode)->pPrev == (pList))
220
221/**
222 * Checks if a type converted node is actually the dummy element (@a pList).
223 *
224 * @retval true if the node is the dummy element in the list.
225 * @retval false otherwise.
226 *
227 * @param pList The list.
228 * @param pNode The node structure to check. Typically
229 * something obtained from RTListNodeGetNext() or
230 * RTListNodeGetPrev(). This is NOT a PRTLISTNODE
231 * but something that contains a RTLISTNODE member!
232 * @param Type Structure the list node is a member of.
233 * @param Member The list node member.
234 */
235#define RTListNodeIsDummy(pList, pNode, Type, Member) \
236 ( (pNode) == RT_FROM_MEMBER((pList), Type, Member) )
237/** @copydoc RTListNodeIsDummy */
238#define RTListNodeIsDummyCpp(pList, pNode, Type, Member) \
239 ( (pNode) == RT_FROM_CPP_MEMBER((pList), Type, Member) )
240
241/**
242 * Checks if a list is empty.
243 *
244 * @retval true if the list is empty.
245 * @retval false otherwise.
246 *
247 * @param pList The list to check.
248 */
249#define RTListIsEmpty(pList) ((pList)->pPrev == (pList))
250
251/**
252 * Returns the next node in the list.
253 *
254 * @returns The next node.
255 *
256 * @param pCurNode The current node.
257 * @param Type Structure the list node is a member of.
258 * @param Member The list node member.
259 */
260#define RTListNodeGetNext(pCurNode, Type, Member) \
261 RT_FROM_MEMBER((pCurNode)->pNext, Type, Member)
262/** @copydoc RTListNodeGetNext */
263#define RTListNodeGetNextCpp(pCurNode, Type, Member) \
264 RT_FROM_CPP_MEMBER((pCurNode)->pNext, Type, Member)
265
266/**
267 * Returns the previous node in the list.
268 *
269 * @returns The previous node.
270 *
271 * @param pCurNode The current node.
272 * @param Type Structure the list node is a member of.
273 * @param Member The list node member.
274 */
275#define RTListNodeGetPrev(pCurNode, Type, Member) \
276 RT_FROM_MEMBER((pCurNode)->pPrev, Type, Member)
277/** @copydoc RTListNodeGetPrev */
278#define RTListNodeGetPrevCpp(pCurNode, Type, Member) \
279 RT_FROM_CPP_MEMBER((pCurNode)->pPrev, Type, Member)
280
281/**
282 * Returns the first element in the list (checks for empty list).
283 *
284 * @returns Pointer to the first list element, or NULL if empty list.
285 *
286 * @param pList List to get the first element from.
287 * @param Type Structure the list node is a member of.
288 * @param Member The list node member.
289 */
290#define RTListGetFirst(pList, Type, Member) \
291 (!RTListIsEmpty(pList) ? RTListNodeGetNext(pList, Type, Member) : NULL)
292/** @copydoc RTListGetFirst */
293#define RTListGetFirstCpp(pList, Type, Member) \
294 (!RTListIsEmpty(pList) ? RTListNodeGetNextCpp(pList, Type, Member) : NULL)
295
296/**
297 * Returns the last element in the list (checks for empty list).
298 *
299 * @returns Pointer to the last list element, or NULL if empty list.
300 *
301 * @param pList List to get the last element from.
302 * @param Type Structure the list node is a member of.
303 * @param Member The list node member.
304 */
305#define RTListGetLast(pList, Type, Member) \
306 (!RTListIsEmpty(pList) ? RTListNodeGetPrev(pList, Type, Member) : NULL)
307/** @copydoc RTListGetLast */
308#define RTListGetLastCpp(pList, Type, Member) \
309 (!RTListIsEmpty(pList) ? RTListNodeGetPrevCpp(pList, Type, Member) : NULL)
310
311/**
312 * Returns the next node in the list or NULL if the end has been reached.
313 *
314 * @returns The next node, or NULL if end of list.
315 *
316 * @param pList The list @a pCurNode is linked on.
317 * @param pCurNode The current node, of type @a Type.
318 * @param Type Structure the list node is a member of.
319 * @param Member The list node member.
320 */
321#define RTListGetNext(pList, pCurNode, Type, Member) \
322 ( (pCurNode)->Member.pNext != (pList) ? RT_FROM_MEMBER((pCurNode)->Member.pNext, Type, Member) : NULL )
323/** @copydoc RTListGetNext */
324#define RTListGetNextCpp(pList, pCurNode, Type, Member) \
325 ( (pCurNode)->Member.pNext != (pList) ? RT_FROM_CPP_MEMBER((pCurNode)->Member.pNext, Type, Member) : NULL )
326
327/**
328 * Returns the previous node in the list or NULL if the start has been reached.
329 *
330 * @returns The previous node, or NULL if end of list.
331 *
332 * @param pList The list @a pCurNode is linked on.
333 * @param pCurNode The current node, of type @a Type.
334 * @param Type Structure the list node is a member of.
335 * @param Member The list node member.
336 */
337#define RTListGetPrev(pList, pCurNode, Type, Member) \
338 ( (pCurNode)->Member.pPrev != (pList) ? RT_FROM_MEMBER((pCurNode)->Member.pPrev, Type, Member) : NULL )
339/** @copydoc RTListGetPrev */
340#define RTListGetPrevCpp(pList, pCurNode, Type, Member) \
341 ( (pCurNode)->Member.pPrev != (pList) ? RT_FROM_CPP_MEMBER((pCurNode)->Member.pPrev, Type, Member) : NULL )
342
343
344/**
345 * Removes and returns the first element in the list (checks for empty list).
346 *
347 * @returns Pointer to the first list element, or NULL if empty list.
348 *
349 * @param pList List to get the first element from.
350 * @param Type Structure the list node is a member of.
351 * @param Member The list node member.
352 */
353#define RTListRemoveFirst(pList, Type, Member) \
354 (!RTListIsEmpty(pList) ? RT_FROM_MEMBER(RTListNodeRemoveRet((pList)->pNext), Type, Member) : NULL)
355/** @copydoc RTListRemoveFirst */
356#define RTListRemoveFirstCpp(pList, Type, Member) \
357 (!RTListIsEmpty(pList) ? RT_FROM_CPP_MEMBER(RTListNodeRemoveRet((pList)->pNext), Type, Member) : NULL)
358
359/**
360 * Removes and returns the last element in the list (checks for empty list).
361 *
362 * @returns Pointer to the last list element, or NULL if empty list.
363 *
364 * @param pList List to get the last element from.
365 * @param Type Structure the list node is a member of.
366 * @param Member The list node member.
367 */
368#define RTListRemoveLast(pList, Type, Member) \
369 (!RTListIsEmpty(pList) ? RT_FROM_MEMBER(RTListNodeRemoveRet((pList)->pPrev), Type, Member) : NULL)
370/** @copydoc RTListRemoveLast */
371#define RTListRemoveLastCpp(pList, Type, Member) \
372 (!RTListIsEmpty(pList) ? RT_FROM_CPP_MEMBER(RTListNodeRemoveRet((pList)->pPrev), Type, Member) : NULL)
373
374/**
375 * Removes and returns the next node in the list or NULL if the end has been
376 * reached.
377 *
378 * @returns The next node, or NULL if end of list.
379 *
380 * @param pList The list @a pCurNode is linked on.
381 * @param pCurNode The current node, of type @a Type.
382 * @param Type Structure the list node is a member of.
383 * @param Member The list node member.
384 */
385#define RTListRemoveNext(pList, pCurNode, Type, Member) \
386 ( (pCurNode)->Member.pNext != (pList) ? RT_FROM_MEMBER(RTListNodeRemoveRet((pCurNode)->Member.pNext), Type, Member) : NULL )
387/** @copydoc RTListRemoveNext */
388#define RTListRemoveNextCpp(pList, pCurNode, Type, Member) \
389 ( (pCurNode)->Member.pNext != (pList) ? RT_FROM_CPP_MEMBER(RTListNodeRemoveRet((pCurNode)->Member.pNext), Type, Member) : NULL )
390
391/**
392 * Removes and returns the previous node in the list or NULL if the start has
393 * been reached.
394 *
395 * @returns The previous node, or NULL if end of list.
396 *
397 * @param pList The list @a pCurNode is linked on.
398 * @param pCurNode The current node, of type @a Type.
399 * @param Type Structure the list node is a member of.
400 * @param Member The list node member.
401 */
402#define RTListRemovePrev(pList, pCurNode, Type, Member) \
403 ( (pCurNode)->Member.pNext != (pList) ? RT_FROM_MEMBER(RTListNodeRemoveRet((pCurNode)->Member.pPrev), Type, Member) : NULL )
404/** @copydoc RTListRemovePrev */
405#define RTListRemovePrevCpp(pList, pCurNode, Type, Member) \
406 ( (pCurNode)->Member.pNext != (pList) ? RT_FROM_CPP_MEMBER(RTListNodeRemoveRet((pCurNode)->Member.pPrev), Type, Member) : NULL )
407
408
409/**
410 * Enumerate the list in head to tail order.
411 *
412 * @param pList List to enumerate.
413 * @param pIterator The iterator variable name.
414 * @param Type Structure the list node is a member of.
415 * @param Member The list node member name.
416 */
417#define RTListForEach(pList, pIterator, Type, Member) \
418 for (pIterator = RTListNodeGetNext(pList, Type, Member); \
419 !RTListNodeIsDummy(pList, pIterator, Type, Member); \
420 pIterator = RT_FROM_MEMBER((pIterator)->Member.pNext, Type, Member) )
421/** @copydoc RTListForEach */
422#define RTListForEachCpp(pList, pIterator, Type, Member) \
423 for (pIterator = RTListNodeGetNextCpp(pList, Type, Member); \
424 !RTListNodeIsDummyCpp(pList, pIterator, Type, Member); \
425 pIterator = RT_FROM_CPP_MEMBER((pIterator)->Member.pNext, Type, Member) )
426
427
428/**
429 * Enumerate the list in head to tail order, safe against removal of the
430 * current node.
431 *
432 * @param pList List to enumerate.
433 * @param pIterator The iterator variable name.
434 * @param pIterNext The name of the variable saving the pointer to
435 * the next element.
436 * @param Type Structure the list node is a member of.
437 * @param Member The list node member name.
438 */
439#define RTListForEachSafe(pList, pIterator, pIterNext, Type, Member) \
440 for (pIterator = RTListNodeGetNext(pList, Type, Member), \
441 pIterNext = RT_FROM_MEMBER((pIterator)->Member.pNext, Type, Member); \
442 !RTListNodeIsDummy(pList, pIterator, Type, Member); \
443 pIterator = pIterNext, \
444 pIterNext = RT_FROM_MEMBER((pIterator)->Member.pNext, Type, Member) )
445/** @copydoc RTListForEachSafe */
446#define RTListForEachSafeCpp(pList, pIterator, pIterNext, Type, Member) \
447 for (pIterator = RTListNodeGetNextCpp(pList, Type, Member), \
448 pIterNext = RT_FROM_CPP_MEMBER((pIterator)->Member.pNext, Type, Member); \
449 !RTListNodeIsDummyCpp(pList, pIterator, Type, Member); \
450 pIterator = pIterNext, \
451 pIterNext = RT_FROM_CPP_MEMBER((pIterator)->Member.pNext, Type, Member) )
452
453
454/**
455 * Enumerate the list in reverse order (tail to head).
456 *
457 * @param pList List to enumerate.
458 * @param pIterator The iterator variable name.
459 * @param Type Structure the list node is a member of.
460 * @param Member The list node member name.
461 */
462#define RTListForEachReverse(pList, pIterator, Type, Member) \
463 for (pIterator = RTListNodeGetPrev(pList, Type, Member); \
464 !RTListNodeIsDummy(pList, pIterator, Type, Member); \
465 pIterator = RT_FROM_MEMBER((pIterator)->Member.pPrev, Type, Member) )
466/** @copydoc RTListForEachReverse */
467#define RTListForEachReverseCpp(pList, pIterator, Type, Member) \
468 for (pIterator = RTListNodeGetPrevCpp(pList, Type, Member); \
469 !RTListNodeIsDummyCpp(pList, pIterator, Type, Member); \
470 pIterator = RT_FROM_CPP_MEMBER((pIterator)->Member.pPrev, Type, Member) )
471
472
473/**
474 * Enumerate the list in reverse order (tail to head).
475 *
476 * @param pList List to enumerate.
477 * @param pIterator The iterator variable name.
478 * @param pIterPrev The name of the variable saving the pointer to
479 * the previous element.
480 * @param Type Structure the list node is a member of.
481 * @param Member The list node member name.
482 */
483#define RTListForEachReverseSafe(pList, pIterator, pIterPrev, Type, Member) \
484 for (pIterator = RTListNodeGetPrev(pList, Type, Member), \
485 pIterPrev = RT_FROM_MEMBER((pIterator)->Member.pPrev, Type, Member); \
486 !RTListNodeIsDummy(pList, pIterator, Type, Member); \
487 pIterator = pIterPrev, \
488 pIterPrev = RT_FROM_MEMBER((pIterator)->Member.pPrev, Type, Member) )
489/** @copydoc RTListForEachReverseSafe */
490#define RTListForEachReverseSafeCpp(pList, pIterator, pIterPrev, Type, Member) \
491 for (pIterator = RTListNodeGetPrevCpp(pList, Type, Member), \
492 pIterPrev = RT_FROM_CPP_MEMBER((pIterator)->Member.pPrev, Type, Member); \
493 !RTListNodeIsDummyCpp(pList, pIterator, Type, Member); \
494 pIterator = pIterPrev, \
495 pIterPrev = RT_FROM_CPP_MEMBER((pIterator)->Member.pPrev, Type, Member) )
496
497
498/**
499 * Move the given list to a new list header.
500 *
501 * @param pListDst The new list.
502 * @param pListSrc The list to move.
503 */
504DECLINLINE(void) RTListMove(PRTLISTNODE pListDst, PRTLISTNODE pListSrc)
505{
506 if (!RTListIsEmpty(pListSrc))
507 {
508 pListDst->pNext = pListSrc->pNext;
509 pListDst->pPrev = pListSrc->pPrev;
510
511 /* Adjust the first and last element links */
512 pListDst->pNext->pPrev = pListDst;
513 pListDst->pPrev->pNext = pListDst;
514
515 /* Finally remove the elements from the source list */
516 RTListInit(pListSrc);
517 }
518 else
519 RTListInit(pListDst);
520}
521
522/**
523 * List concatenation.
524 *
525 * @returns nothing.
526 * @param pListDst The destination list.
527 * @param pListSrc The source list to concatenate.
528 */
529DECLINLINE(void) RTListConcatenate(PRTLISTANCHOR pListDst, PRTLISTANCHOR pListSrc)
530{
531 if (!RTListIsEmpty(pListSrc))
532 {
533 PRTLISTNODE pFirst = pListSrc->pNext;
534 PRTLISTNODE pLast = pListSrc->pPrev;
535
536 pListDst->pPrev->pNext = pFirst;
537 pFirst->pPrev = pListDst->pPrev;
538 pLast->pNext = pListDst;
539 pListDst->pPrev = pLast;
540
541 /* Finally remove the elements from the source list */
542 RTListInit(pListSrc);
543 }
544}
545
546RT_C_DECLS_END
547
548/** @} */
549
550#endif /* !IPRT_INCLUDED_list_h */
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