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1 /* $OpenBSD: tree.h,v 1.14 2015/05/25 03:07:49 deraadt Exp $ */
2 /*
3 * Copyright 2002 Niels Provos <provos@citi.umich.edu>
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27 #ifndef _SYS_TREE_H_
28 #define _SYS_TREE_H_
29
30 #ifdef __cplusplus
31 extern "C" {
32 #endif
33
34 /*
35 * This file defines data structures for different types of trees:
36 * splay trees and red-black trees.
37 *
38 * A splay tree is a self-organizing data structure. Every operation
39 * on the tree causes a splay to happen. The splay moves the requested
40 * node to the root of the tree and partly rebalances it.
41 *
42 * This has the benefit that request locality causes faster lookups as
43 * the requested nodes move to the top of the tree. On the other hand,
44 * every lookup causes memory writes.
45 *
46 * The Balance Theorem bounds the total access time for m operations
47 * and n inserts on an initially empty tree as O((m + n)lg n). The
48 * amortized cost for a sequence of m accesses to a splay tree is O(lg n);
49 *
50 * A red-black tree is a binary search tree with the node color as an
51 * extra attribute. It fulfills a set of conditions:
52 * - every search path from the root to a leaf consists of the
53 * same number of black nodes,
54 * - each red node (except for the root) has a black parent,
55 * - each leaf node is black.
56 *
57 * Every operation on a red-black tree is bounded as O(lg n).
58 * The maximum height of a red-black tree is 2lg (n+1).
59 */
60
61 #define SPLAY_HEAD(name, type) \
62 struct name { \
63 struct type *sph_root; /* root of the tree */ \
64 }
65
66 #define SPLAY_INITIALIZER(root) \
67 { \
68 NULL \
69 }
70
71 #define SPLAY_INIT(root) \
72 do { \
73 (root)->sph_root = NULL; \
74 } while (0)
75
76 #define SPLAY_ENTRY(type) \
77 struct { \
78 struct type *spe_left; /* left element */ \
79 struct type *spe_right; /* right element */ \
80 }
81
82 #define SPLAY_LEFT(elm, field) (elm)->field.spe_left
83 #define SPLAY_RIGHT(elm, field) (elm)->field.spe_right
84 #define SPLAY_ROOT(head) (head)->sph_root
85 #define SPLAY_EMPTY(head) (SPLAY_ROOT(head) == NULL)
86
87 /* SPLAY_ROTATE_{LEFT,RIGHT} expect that tmp hold SPLAY_{RIGHT,LEFT} */
88 #define SPLAY_ROTATE_RIGHT(head, tmp, field) \
89 do { \
90 SPLAY_LEFT((head)->sph_root, field) = SPLAY_RIGHT(tmp, field); \
91 SPLAY_RIGHT(tmp, field) = (head)->sph_root; \
92 (head)->sph_root = tmp; \
93 } while (0)
94
95 #define SPLAY_ROTATE_LEFT(head, tmp, field) \
96 do { \
97 SPLAY_RIGHT((head)->sph_root, field) = SPLAY_LEFT(tmp, field); \
98 SPLAY_LEFT(tmp, field) = (head)->sph_root; \
99 (head)->sph_root = tmp; \
100 } while (0)
101
102 #define SPLAY_LINKLEFT(head, tmp, field) \
103 do { \
104 SPLAY_LEFT(tmp, field) = (head)->sph_root; \
105 tmp = (head)->sph_root; \
106 (head)->sph_root = SPLAY_LEFT((head)->sph_root, field); \
107 } while (0)
108
109 #define SPLAY_LINKRIGHT(head, tmp, field) \
110 do { \
111 SPLAY_RIGHT(tmp, field) = (head)->sph_root; \
112 tmp = (head)->sph_root; \
113 (head)->sph_root = SPLAY_RIGHT((head)->sph_root, field); \
114 } while (0)
115
116 #define SPLAY_ASSEMBLE(head, node, left, right, field) \
117 do { \
118 SPLAY_RIGHT(left, field) = \
119 SPLAY_LEFT((head)->sph_root, field); \
120 SPLAY_LEFT(right, field) = \
121 SPLAY_RIGHT((head)->sph_root, field); \
122 SPLAY_LEFT((head)->sph_root, field) = \
123 SPLAY_RIGHT(node, field); \
124 SPLAY_RIGHT((head)->sph_root, field) = \
125 SPLAY_LEFT(node, field); \
126 } while (0)
127
128 /* Generates prototypes and inline functions */
129
130 #define SPLAY_PROTOTYPE(name, type, field, cmp) \
131 void name##_SPLAY(struct name *, struct type *); \
132 void name##_SPLAY_MINMAX(struct name *, int); \
133 struct type *name##_SPLAY_INSERT(struct name *, struct type *); \
134 struct type *name##_SPLAY_REMOVE(struct name *, struct type *); \
135 \
136 /* Finds the node with the same key as elm */ \
137 static __inline struct type *name##_SPLAY_FIND(struct name *head, \
138 struct type *elm) \
139 { \
140 if (SPLAY_EMPTY(head)) \
141 return (NULL); \
142 name##_SPLAY(head, elm); \
143 if ((cmp)(elm, (head)->sph_root) == 0) \
144 return (head->sph_root); \
145 return (NULL); \
146 } \
147 \
148 static __inline struct type *name##_SPLAY_NEXT(struct name *head, \
149 struct type *elm) \
150 { \
151 name##_SPLAY(head, elm); \
152 if (SPLAY_RIGHT(elm, field) != NULL) { \
153 elm = SPLAY_RIGHT(elm, field); \
154 while (SPLAY_LEFT(elm, field) != NULL) { \
155 elm = SPLAY_LEFT(elm, field); \
156 } \
157 } else \
158 elm = NULL; \
159 return (elm); \
160 } \
161 \
162 static __inline struct type *name##_SPLAY_MIN_MAX(struct name *head, \
163 int val) \
164 { \
165 name##_SPLAY_MINMAX(head, val); \
166 return (SPLAY_ROOT(head)); \
167 }
168
169 /* Main splay operation.
170 * Moves node close to the key of elm to top
171 */
172 #define SPLAY_GENERATE(name, type, field, cmp) \
173 struct type *name##_SPLAY_INSERT(struct name *head, struct type *elm) \
174 { \
175 if (SPLAY_EMPTY(head)) { \
176 SPLAY_LEFT(elm, field) = SPLAY_RIGHT(elm, field) = \
177 NULL; \
178 } else { \
179 int __comp; \
180 name##_SPLAY(head, elm); \
181 __comp = (cmp)(elm, (head)->sph_root); \
182 if (__comp < 0) { \
183 SPLAY_LEFT(elm, field) = \
184 SPLAY_LEFT((head)->sph_root, field); \
185 SPLAY_RIGHT(elm, field) = (head)->sph_root; \
186 SPLAY_LEFT((head)->sph_root, field) = NULL; \
187 } else if (__comp > 0) { \
188 SPLAY_RIGHT(elm, field) = \
189 SPLAY_RIGHT((head)->sph_root, field); \
190 SPLAY_LEFT(elm, field) = (head)->sph_root; \
191 SPLAY_RIGHT((head)->sph_root, field) = NULL; \
192 } else \
193 return ((head)->sph_root); \
194 } \
195 (head)->sph_root = (elm); \
196 return (NULL); \
197 } \
198 \
199 struct type *name##_SPLAY_REMOVE(struct name *head, struct type *elm) \
200 { \
201 struct type *__tmp; \
202 if (SPLAY_EMPTY(head)) \
203 return (NULL); \
204 name##_SPLAY(head, elm); \
205 if ((cmp)(elm, (head)->sph_root) == 0) { \
206 if (SPLAY_LEFT((head)->sph_root, field) == NULL) { \
207 (head)->sph_root = \
208 SPLAY_RIGHT((head)->sph_root, field); \
209 } else { \
210 __tmp = SPLAY_RIGHT((head)->sph_root, field); \
211 (head)->sph_root = \
212 SPLAY_LEFT((head)->sph_root, field); \
213 name##_SPLAY(head, elm); \
214 SPLAY_RIGHT((head)->sph_root, field) = __tmp; \
215 } \
216 return (elm); \
217 } \
218 return (NULL); \
219 } \
220 \
221 void name##_SPLAY(struct name *head, struct type *elm) \
222 { \
223 struct type __node, *__left, *__right, *__tmp; \
224 int __comp; \
225 \
226 SPLAY_LEFT(&__node, field) = SPLAY_RIGHT(&__node, field) = \
227 NULL; \
228 __left = __right = &__node; \
229 \
230 while ((__comp = (cmp)(elm, (head)->sph_root))) { \
231 if (__comp < 0) { \
232 __tmp = SPLAY_LEFT((head)->sph_root, field); \
233 if (__tmp == NULL) \
234 break; \
235 if ((cmp)(elm, __tmp) < 0) { \
236 SPLAY_ROTATE_RIGHT(head, __tmp, \
237 field); \
238 if (SPLAY_LEFT((head)->sph_root, \
239 field) \
240 == NULL) \
241 break; \
242 } \
243 SPLAY_LINKLEFT(head, __right, field); \
244 } else if (__comp > 0) { \
245 __tmp = SPLAY_RIGHT((head)->sph_root, field); \
246 if (__tmp == NULL) \
247 break; \
248 if ((cmp)(elm, __tmp) > 0) { \
249 SPLAY_ROTATE_LEFT(head, __tmp, field); \
250 if (SPLAY_RIGHT((head)->sph_root, \
251 field) \
252 == NULL) \
253 break; \
254 } \
255 SPLAY_LINKRIGHT(head, __left, field); \
256 } \
257 } \
258 SPLAY_ASSEMBLE(head, &__node, __left, __right, field); \
259 } \
260 \
261 /* Splay with either the minimum or the maximum element \
262 * Used to find minimum or maximum element in tree. \
263 */ \
264 void name##_SPLAY_MINMAX(struct name *head, int __comp) \
265 { \
266 struct type __node, *__left, *__right, *__tmp; \
267 \
268 SPLAY_LEFT(&__node, field) = SPLAY_RIGHT(&__node, field) = \
269 NULL; \
270 __left = __right = &__node; \
271 \
272 while (1) { \
273 if (__comp < 0) { \
274 __tmp = SPLAY_LEFT((head)->sph_root, field); \
275 if (__tmp == NULL) \
276 break; \
277 if (__comp < 0) { \
278 SPLAY_ROTATE_RIGHT(head, __tmp, \
279 field); \
280 if (SPLAY_LEFT((head)->sph_root, \
281 field) \
282 == NULL) \
283 break; \
284 } \
285 SPLAY_LINKLEFT(head, __right, field); \
286 } else if (__comp > 0) { \
287 __tmp = SPLAY_RIGHT((head)->sph_root, field); \
288 if (__tmp == NULL) \
289 break; \
290 if (__comp > 0) { \
291 SPLAY_ROTATE_LEFT(head, __tmp, field); \
292 if (SPLAY_RIGHT((head)->sph_root, \
293 field) \
294 == NULL) \
295 break; \
296 } \
297 SPLAY_LINKRIGHT(head, __left, field); \
298 } \
299 } \
300 SPLAY_ASSEMBLE(head, &__node, __left, __right, field); \
301 }
302
303 #define SPLAY_NEGINF -1
304 #define SPLAY_INF 1
305
306 #define SPLAY_INSERT(name, x, y) name##_SPLAY_INSERT(x, y)
307 #define SPLAY_REMOVE(name, x, y) name##_SPLAY_REMOVE(x, y)
308 #define SPLAY_FIND(name, x, y) name##_SPLAY_FIND(x, y)
309 #define SPLAY_NEXT(name, x, y) name##_SPLAY_NEXT(x, y)
310 #define SPLAY_MIN(name, x) \
311 (SPLAY_EMPTY(x) ? NULL : name##_SPLAY_MIN_MAX(x, SPLAY_NEGINF))
312 #define SPLAY_MAX(name, x) \
313 (SPLAY_EMPTY(x) ? NULL : name##_SPLAY_MIN_MAX(x, SPLAY_INF))
314
315 #define SPLAY_FOREACH(x, name, head) \
316 for ((x) = SPLAY_MIN(name, head); (x) != NULL; \
317 (x) = SPLAY_NEXT(name, head, x))
318
319 /*
320 * Copyright (c) 2016 David Gwynne <dlg@openbsd.org>
321 *
322 * Permission to use, copy, modify, and distribute this software for any
323 * purpose with or without fee is hereby granted, provided that the above
324 * copyright notice and this permission notice appear in all copies.
325 *
326 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
327 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
328 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
329 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
330 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
331 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
332 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
333 */
334
335 #define RB_BLACK 0
336 #define RB_RED 1
337
338 struct rb_type {
339 int (*t_compare)(const void *, const void *);
340 void (*t_augment)(void *);
341 unsigned int t_offset; /* offset of rb_entry in type */
342 };
343
344 struct rbt_tree {
345 struct rb_entry *rbt_root;
346 };
347
348 struct rb_entry {
349 struct rb_entry *rbt_parent;
350 struct rb_entry *rbt_left;
351 struct rb_entry *rbt_right;
352 unsigned int rbt_color;
353 };
354
355 #define RB_HEAD(_name, _type) \
356 struct _name { \
357 struct rbt_tree rbh_root; \
358 }
359
360 #define RB_ENTRY(_type) struct rb_entry
361
362 static inline void _rb_init(struct rbt_tree *rbt)
363 {
364 rbt->rbt_root = NULL;
365 }
366
367 static inline int _rb_empty(struct rbt_tree *rbt)
368 {
369 return (rbt->rbt_root == NULL);
370 }
371
372 void *_rb_insert(const struct rb_type *, struct rbt_tree *, void *);
373 void *_rb_remove(const struct rb_type *, struct rbt_tree *, void *);
374 void *_rb_find(const struct rb_type *, struct rbt_tree *, const void *);
375 void *_rb_nfind(const struct rb_type *, struct rbt_tree *, const void *);
376 void *_rb_root(const struct rb_type *, struct rbt_tree *);
377 void *_rb_min(const struct rb_type *, struct rbt_tree *);
378 void *_rb_max(const struct rb_type *, struct rbt_tree *);
379 void *_rb_next(const struct rb_type *, void *);
380 void *_rb_prev(const struct rb_type *, void *);
381 void *_rb_left(const struct rb_type *, void *);
382 void *_rb_right(const struct rb_type *, void *);
383 void *_rb_parent(const struct rb_type *, void *);
384 void _rb_set_left(const struct rb_type *, void *, void *);
385 void _rb_set_right(const struct rb_type *, void *, void *);
386 void _rb_set_parent(const struct rb_type *, void *, void *);
387 void _rb_poison(const struct rb_type *, void *, unsigned long);
388 int _rb_check(const struct rb_type *, void *, unsigned long);
389
390 #define RB_INITIALIZER(_head) { { NULL } }
391
392 #define RB_PROTOTYPE(_name, _type, _field, _cmp) \
393 extern const struct rb_type *const _name##_RB_TYPE; \
394 \
395 __attribute__((__unused__)) static inline void _name##_RB_INIT( \
396 struct _name *head) \
397 { \
398 _rb_init(&head->rbh_root); \
399 } \
400 \
401 __attribute__((__unused__)) static inline struct _type \
402 *_name##_RB_INSERT(struct _name *head, struct _type *elm) \
403 { \
404 return (struct _type *)_rb_insert( \
405 _name##_RB_TYPE, &head->rbh_root, elm); \
406 } \
407 \
408 __attribute__((__unused__)) static inline struct _type \
409 *_name##_RB_REMOVE(struct _name *head, struct _type *elm) \
410 { \
411 return (struct _type *)_rb_remove( \
412 _name##_RB_TYPE, &head->rbh_root, elm); \
413 } \
414 \
415 __attribute__((__unused__)) static inline struct _type \
416 *_name##_RB_FIND(struct _name *head, const struct _type *key) \
417 { \
418 return (struct _type *)_rb_find( \
419 _name##_RB_TYPE, &head->rbh_root, key); \
420 } \
421 \
422 __attribute__((__unused__)) static inline struct _type \
423 *_name##_RB_NFIND(struct _name *head, const struct _type *key) \
424 { \
425 return (struct _type *)_rb_nfind( \
426 _name##_RB_TYPE, &head->rbh_root, key); \
427 } \
428 \
429 __attribute__((__unused__)) static inline struct _type \
430 *_name##_RB_ROOT(struct _name *head) \
431 { \
432 return (struct _type *)_rb_root( \
433 _name##_RB_TYPE, &head->rbh_root); \
434 } \
435 \
436 __attribute__((__unused__)) static inline int _name##_RB_EMPTY( \
437 struct _name *head) \
438 { \
439 return _rb_empty(&head->rbh_root); \
440 } \
441 \
442 __attribute__((__unused__)) static inline struct _type \
443 *_name##_RB_MIN(struct _name *head) \
444 { \
445 return (struct _type *)_rb_min( \
446 _name##_RB_TYPE, &head->rbh_root); \
447 } \
448 \
449 __attribute__((__unused__)) static inline struct _type \
450 *_name##_RB_MAX(struct _name *head) \
451 { \
452 return (struct _type *)_rb_max( \
453 _name##_RB_TYPE, &head->rbh_root); \
454 } \
455 \
456 __attribute__((__unused__)) static inline struct _type \
457 *_name##_RB_NEXT(struct _type *elm) \
458 { \
459 return (struct _type *)_rb_next(_name##_RB_TYPE, elm); \
460 } \
461 \
462 __attribute__((__unused__)) static inline struct _type \
463 *_name##_RB_PREV(struct _type *elm) \
464 { \
465 return (struct _type *)_rb_prev(_name##_RB_TYPE, elm); \
466 } \
467 \
468 __attribute__((__unused__)) static inline struct _type \
469 *_name##_RB_LEFT(struct _type *elm) \
470 { \
471 return (struct _type *)_rb_left(_name##_RB_TYPE, elm); \
472 } \
473 \
474 __attribute__((__unused__)) static inline struct _type \
475 *_name##_RB_RIGHT(struct _type *elm) \
476 { \
477 return (struct _type *)_rb_right(_name##_RB_TYPE, elm); \
478 } \
479 \
480 __attribute__((__unused__)) static inline struct _type \
481 *_name##_RB_PARENT(struct _type *elm) \
482 { \
483 return (struct _type *)_rb_parent(_name##_RB_TYPE, elm); \
484 } \
485 \
486 __attribute__((__unused__)) static inline void _name##_RB_SET_LEFT( \
487 struct _type *elm, struct _type *left) \
488 { \
489 _rb_set_left(_name##_RB_TYPE, elm, left); \
490 } \
491 \
492 __attribute__((__unused__)) static inline void _name##_RB_SET_RIGHT( \
493 struct _type *elm, struct _type *right) \
494 { \
495 _rb_set_right(_name##_RB_TYPE, elm, right); \
496 } \
497 \
498 __attribute__((__unused__)) static inline void _name##_RB_SET_PARENT( \
499 struct _type *elm, struct _type *parent) \
500 { \
501 _rb_set_parent(_name##_RB_TYPE, elm, parent); \
502 } \
503 \
504 __attribute__((__unused__)) static inline void _name##_RB_POISON( \
505 struct _type *elm, unsigned long poison) \
506 { \
507 _rb_poison(_name##_RB_TYPE, elm, poison); \
508 } \
509 \
510 __attribute__((__unused__)) static inline int _name##_RB_CHECK( \
511 struct _type *elm, unsigned long poison) \
512 { \
513 return _rb_check(_name##_RB_TYPE, elm, poison); \
514 }
515
516 #define RB_GENERATE_INTERNAL(_name, _type, _field, _cmp, _aug) \
517 static int _name##_RB_COMPARE(const void *lptr, const void *rptr) \
518 { \
519 const struct _type *l = lptr, *r = rptr; \
520 return _cmp(l, r); \
521 } \
522 static const struct rb_type _name##_RB_INFO = { \
523 _name##_RB_COMPARE, _aug, offsetof(struct _type, _field), \
524 }; \
525 const struct rb_type *const _name##_RB_TYPE = &_name##_RB_INFO;
526
527 #define RB_GENERATE_AUGMENT(_name, _type, _field, _cmp, _aug) \
528 static void _name##_RB_AUGMENT(void *ptr) \
529 { \
530 struct _type *p = ptr; \
531 return _aug(p); \
532 } \
533 RB_GENERATE_INTERNAL(_name, _type, _field, _cmp, _name##_RB_AUGMENT)
534
535 #define RB_GENERATE(_name, _type, _field, _cmp) \
536 RB_GENERATE_INTERNAL(_name, _type, _field, _cmp, NULL)
537
538 #define RB_INIT(_name, _head) _name##_RB_INIT(_head)
539 #define RB_INSERT(_name, _head, _elm) _name##_RB_INSERT(_head, _elm)
540 #define RB_REMOVE(_name, _head, _elm) _name##_RB_REMOVE(_head, _elm)
541 #define RB_FIND(_name, _head, _key) _name##_RB_FIND(_head, _key)
542 #define RB_NFIND(_name, _head, _key) _name##_RB_NFIND(_head, _key)
543 #define RB_ROOT(_name, _head) _name##_RB_ROOT(_head)
544 #define RB_EMPTY(_name, _head) _name##_RB_EMPTY(_head)
545 #define RB_MIN(_name, _head) _name##_RB_MIN(_head)
546 #define RB_MAX(_name, _head) _name##_RB_MAX(_head)
547 #define RB_NEXT(_name, _elm) _name##_RB_NEXT(_elm)
548 #define RB_PREV(_name, _elm) _name##_RB_PREV(_elm)
549 #define RB_LEFT(_name, _elm) _name##_RB_LEFT(_elm)
550 #define RB_RIGHT(_name, _elm) _name##_RB_RIGHT(_elm)
551 #define RB_PARENT(_name, _elm) _name##_RB_PARENT(_elm)
552 #define RB_SET_LEFT(_name, _elm, _l) _name##_RB_SET_LEFT(_elm, _l)
553 #define RB_SET_RIGHT(_name, _elm, _r) _name##_RB_SET_RIGHT(_elm, _r)
554 #define RB_SET_PARENT(_name, _elm, _p) _name##_RB_SET_PARENT(_elm, _p)
555 #define RB_POISON(_name, _elm, _p) _name##_RB_POISON(_elm, _p)
556 #define RB_CHECK(_name, _elm, _p) _name##_RB_CHECK(_elm, _p)
557
558 #define RB_FOREACH(_e, _name, _head) \
559 for ((_e) = RB_MIN(_name, (_head)); (_e) != NULL; \
560 (_e) = RB_NEXT(_name, (_e)))
561
562 #define RB_FOREACH_SAFE(_e, _name, _head, _n) \
563 for ((_e) = RB_MIN(_name, (_head)); \
564 (_e) != NULL && ((_n) = RB_NEXT(_name, (_e)), 1); (_e) = (_n))
565
566 #define RB_FOREACH_REVERSE(_e, _name, _head) \
567 for ((_e) = RB_MAX(_name, (_head)); (_e) != NULL; \
568 (_e) = RB_PREV(_name, (_e)))
569
570 #define RB_FOREACH_REVERSE_SAFE(_e, _name, _head, _n) \
571 for ((_e) = RB_MAX(_name, (_head)); \
572 (_e) != NULL && ((_n) = RB_PREV(_name, (_e)), 1); (_e) = (_n))
573
574 #ifdef __cplusplus
575 }
576 #endif
577
578 #endif /* _SYS_TREE_H_ */