2 * PacketBB handler library (see RFC 5444)
3 * Copyright (c) 2010 Henning Rogge <hrogge@googlemail.com>
4 * Original OLSRd implementation by Hannes Gredler <hannes@gredler.at>
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
11 * * Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * * Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in
15 * the documentation and/or other materials provided with the
17 * * Neither the name of olsr.org, olsrd nor the names of its
18 * contributors may be used to endorse or promote products derived
19 * from this software without specific prior written permission.
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22 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
24 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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34 * Visit http://www.olsr.org/git for more information.
36 * If you find this software useful feel free to make a donation
37 * to the project. For more information see the website or contact
38 * the copyright holders.
51 * internal type save inline function to calculate the maximum of
52 * to integers without macro implementation.
54 * @param x first parameter of maximum function
55 * @param y second parameter of maximum function
56 * @return largest integer of both parameters
58 static inline int avl_max(int x
, int y
) {
63 * internal type save inline function to calculate the minimum of
64 * to integers without macro implementation.
66 * @param x first parameter of minimum function
67 * @param y second parameter of minimum function
68 * @return smallest integer of both parameters
70 static inline int avl_min(int x
, int y
) {
74 static struct avl_node
*
75 avl_find_rec(struct avl_node
*node
, const void *key
, avl_tree_comp comp
, void *ptr
, int *cmp_result
);
76 static void avl_insert_before(struct avl_tree
*tree
, struct avl_node
*pos_node
, struct avl_node
*node
);
77 static void avl_insert_after(struct avl_tree
*tree
, struct avl_node
*pos_node
, struct avl_node
*node
);
78 static void post_insert(struct avl_tree
*tree
, struct avl_node
*node
);
79 static void avl_delete_worker(struct avl_tree
*tree
, struct avl_node
*node
);
80 static void avl_remove(struct avl_tree
*tree
, struct avl_node
*node
);
83 * Initialize a new avl_tree struct
84 * @param tree pointer to avl-tree
85 * @param comp pointer to comparator for the tree
86 * @param allow_dups true if the tree allows multiple
87 * elements with the same
88 * @param ptr custom parameter for comparator
91 avl_init(struct avl_tree
*tree
, avl_tree_comp comp
, bool allow_dups
, void *ptr
)
93 INIT_LIST_HEAD(&tree
->list_head
);
97 tree
->allow_dups
= allow_dups
;
101 static inline struct avl_node
*avl_next(struct avl_node
*node
)
103 return list_entry(node
->list
.next
, struct avl_node
, list
);
107 * Finds a node in an avl-tree with a certain key
108 * @param tree pointer to avl-tree
109 * @param key pointer to key
110 * @return pointer to avl-node with key, NULL if no node with
114 avl_find(const struct avl_tree
*tree
, const void *key
)
116 struct avl_node
*node
;
119 if (tree
->root
== NULL
)
122 node
= avl_find_rec(tree
->root
, key
, tree
->comp
, tree
->cmp_ptr
, &diff
);
124 return diff
== 0 ? node
: NULL
;
128 * Finds the last node in an avl-tree with a key less or equal
129 * than the specified key
130 * @param tree pointer to avl-tree
131 * @param key pointer to specified key
132 * @return pointer to avl-node, NULL if no node with
133 * key less or equal specified key exists.
136 avl_find_lessequal(const struct avl_tree
*tree
, const void *key
) {
137 struct avl_node
*node
, *next
;
140 if (tree
->root
== NULL
)
143 node
= avl_find_rec(tree
->root
, key
, tree
->comp
, tree
->cmp_ptr
, &diff
);
145 /* go left as long as key<node.key */
147 if (list_is_first(&node
->list
, &tree
->list_head
)) {
151 node
= (struct avl_node
*)node
->list
.prev
;
152 diff
= (*tree
->comp
) (key
, node
->key
, tree
->cmp_ptr
);
155 /* go right as long as key>=next_node.key */
159 if (list_is_last(&node
->list
, &tree
->list_head
)) {
163 next
= (struct avl_node
*)node
->list
.next
;
164 diff
= (*tree
->comp
) (key
, next
->key
, tree
->cmp_ptr
);
170 * Finds the first node in an avl-tree with a key greater or equal
171 * than the specified key
172 * @param tree pointer to avl-tree
173 * @param key pointer to specified key
174 * @return pointer to avl-node, NULL if no node with
175 * key greater or equal specified key exists.
178 avl_find_greaterequal(const struct avl_tree
*tree
, const void *key
) {
179 struct avl_node
*node
, *next
;
182 if (tree
->root
== NULL
)
185 node
= avl_find_rec(tree
->root
, key
, tree
->comp
, tree
->cmp_ptr
, &diff
);
187 /* go right as long as key>node.key */
189 if (list_is_last(&node
->list
, &tree
->list_head
)) {
193 node
= (struct avl_node
*)node
->list
.next
;
194 diff
= (*tree
->comp
) (key
, node
->key
, tree
->cmp_ptr
);
197 /* go left as long as key<=next_node.key */
201 if (list_is_first(&node
->list
, &tree
->list_head
)) {
205 next
= (struct avl_node
*)node
->list
.prev
;
206 diff
= (*tree
->comp
) (key
, next
->key
, tree
->cmp_ptr
);
212 * Inserts an avl_node into a tree
213 * @param tree pointer to tree
214 * @param new pointer to node
215 * @return 0 if node was inserted successfully, -1 if it was not inserted
216 * because of a key collision
219 avl_insert(struct avl_tree
*tree
, struct avl_node
*new)
221 struct avl_node
*node
, *next
, *last
;
232 if (tree
->root
== NULL
) {
233 list_add(&new->list
, &tree
->list_head
);
239 node
= avl_find_rec(tree
->root
, new->key
, tree
->comp
, tree
->cmp_ptr
, &diff
);
243 while (!list_is_last(&last
->list
, &tree
->list_head
)) {
244 next
= avl_next(last
);
251 diff
= (*tree
->comp
) (new->key
, node
->key
, tree
->cmp_ptr
);
254 if (!tree
->allow_dups
)
259 avl_insert_after(tree
, last
, new);
263 if (node
->balance
== 1) {
264 avl_insert_before(tree
, node
, new);
272 if (node
->balance
== -1) {
273 avl_insert_after(tree
, last
, new);
282 avl_insert_before(tree
, node
, new);
287 post_insert(tree
, node
);
291 avl_insert_after(tree
, last
, new);
296 post_insert(tree
, node
);
301 * Remove a node from an avl tree
302 * @param tree pointer to tree
303 * @param node pointer to node
306 avl_delete(struct avl_tree
*tree
, struct avl_node
*node
)
308 struct avl_node
*next
;
309 struct avl_node
*parent
;
310 struct avl_node
*left
;
311 struct avl_node
*right
;
314 && !list_is_last(&node
->list
, &tree
->list_head
)
315 && !(next
= avl_next(node
))->leader
) {
317 next
->balance
= node
->balance
;
319 parent
= node
->parent
;
323 next
->parent
= parent
;
331 if (node
== parent
->left
)
335 parent
->right
= next
;
342 right
->parent
= next
;
346 avl_delete_worker(tree
, node
);
349 avl_remove(tree
, node
);
352 static struct avl_node
*
353 avl_find_rec(struct avl_node
*node
, const void *key
, avl_tree_comp comp
, void *cmp_ptr
, int *cmp_result
)
357 diff
= (*comp
) (key
, node
->key
, cmp_ptr
);
361 if (node
->left
!= NULL
)
362 return avl_find_rec(node
->left
, key
, comp
, cmp_ptr
, cmp_result
);
368 if (node
->right
!= NULL
)
369 return avl_find_rec(node
->right
, key
, comp
, cmp_ptr
, cmp_result
);
378 avl_rotate_right(struct avl_tree
*tree
, struct avl_node
*node
)
380 struct avl_node
*left
, *parent
;
383 parent
= node
->parent
;
385 left
->parent
= parent
;
392 if (parent
->left
== node
)
396 parent
->right
= left
;
399 node
->left
= left
->right
;
402 if (node
->left
!= NULL
)
403 node
->left
->parent
= node
;
405 node
->balance
+= 1 - avl_min(left
->balance
, 0);
406 left
->balance
+= 1 + avl_max(node
->balance
, 0);
410 avl_rotate_left(struct avl_tree
*tree
, struct avl_node
*node
)
412 struct avl_node
*right
, *parent
;
415 parent
= node
->parent
;
417 right
->parent
= parent
;
418 node
->parent
= right
;
424 if (parent
->left
== node
)
425 parent
->left
= right
;
428 parent
->right
= right
;
431 node
->right
= right
->left
;
434 if (node
->right
!= NULL
)
435 node
->right
->parent
= node
;
437 node
->balance
-= 1 + avl_max(right
->balance
, 0);
438 right
->balance
-= 1 - avl_min(node
->balance
, 0);
442 post_insert(struct avl_tree
*tree
, struct avl_node
*node
)
444 struct avl_node
*parent
= node
->parent
;
449 if (node
== parent
->left
) {
452 if (parent
->balance
== 0)
455 if (parent
->balance
== -1) {
456 post_insert(tree
, parent
);
460 if (node
->balance
== -1) {
461 avl_rotate_right(tree
, parent
);
465 avl_rotate_left(tree
, node
);
466 avl_rotate_right(tree
, node
->parent
->parent
);
472 if (parent
->balance
== 0)
475 if (parent
->balance
== 1) {
476 post_insert(tree
, parent
);
480 if (node
->balance
== 1) {
481 avl_rotate_left(tree
, parent
);
485 avl_rotate_right(tree
, node
);
486 avl_rotate_left(tree
, node
->parent
->parent
);
490 avl_insert_before(struct avl_tree
*tree
, struct avl_node
*pos_node
, struct avl_node
*node
)
492 list_add_tail(&node
->list
, &pos_node
->list
);
497 avl_insert_after(struct avl_tree
*tree
, struct avl_node
*pos_node
, struct avl_node
*node
)
499 list_add(&node
->list
, &pos_node
->list
);
504 avl_remove(struct avl_tree
*tree
, struct avl_node
*node
)
506 list_del(&node
->list
);
511 avl_post_delete(struct avl_tree
*tree
, struct avl_node
*node
)
513 struct avl_node
*parent
;
515 if ((parent
= node
->parent
) == NULL
)
518 if (node
== parent
->left
) {
521 if (parent
->balance
== 0) {
522 avl_post_delete(tree
, parent
);
526 if (parent
->balance
== 1)
529 if (parent
->right
->balance
== 0) {
530 avl_rotate_left(tree
, parent
);
534 if (parent
->right
->balance
== 1) {
535 avl_rotate_left(tree
, parent
);
536 avl_post_delete(tree
, parent
->parent
);
540 avl_rotate_right(tree
, parent
->right
);
541 avl_rotate_left(tree
, parent
);
542 avl_post_delete(tree
, parent
->parent
);
548 if (parent
->balance
== 0) {
549 avl_post_delete(tree
, parent
);
553 if (parent
->balance
== -1)
556 if (parent
->left
->balance
== 0) {
557 avl_rotate_right(tree
, parent
);
561 if (parent
->left
->balance
== -1) {
562 avl_rotate_right(tree
, parent
);
563 avl_post_delete(tree
, parent
->parent
);
567 avl_rotate_left(tree
, parent
->left
);
568 avl_rotate_right(tree
, parent
);
569 avl_post_delete(tree
, parent
->parent
);
572 static struct avl_node
*
573 avl_local_min(struct avl_node
*node
)
575 while (node
->left
!= NULL
)
582 static struct avl_node
*
583 avl_local_max(struct avl_node
*node
)
585 while (node
->right
!= NULL
)
593 avl_delete_worker(struct avl_tree
*tree
, struct avl_node
*node
)
595 struct avl_node
*parent
, *min
;
597 parent
= node
->parent
;
599 if (node
->left
== NULL
&& node
->right
== NULL
) {
600 if (parent
== NULL
) {
605 if (parent
->left
== node
) {
609 if (parent
->balance
== 1)
612 if (parent
->balance
== 0) {
613 avl_post_delete(tree
, parent
);
617 if (parent
->right
->balance
== 0) {
618 avl_rotate_left(tree
, parent
);
622 if (parent
->right
->balance
== 1) {
623 avl_rotate_left(tree
, parent
);
624 avl_post_delete(tree
, parent
->parent
);
628 avl_rotate_right(tree
, parent
->right
);
629 avl_rotate_left(tree
, parent
);
630 avl_post_delete(tree
, parent
->parent
);
634 if (parent
->right
== node
) {
635 parent
->right
= NULL
;
638 if (parent
->balance
== -1)
641 if (parent
->balance
== 0) {
642 avl_post_delete(tree
, parent
);
646 if (parent
->left
->balance
== 0) {
647 avl_rotate_right(tree
, parent
);
651 if (parent
->left
->balance
== -1) {
652 avl_rotate_right(tree
, parent
);
653 avl_post_delete(tree
, parent
->parent
);
657 avl_rotate_left(tree
, parent
->left
);
658 avl_rotate_right(tree
, parent
);
659 avl_post_delete(tree
, parent
->parent
);
664 if (node
->left
== NULL
) {
665 if (parent
== NULL
) {
666 tree
->root
= node
->right
;
667 node
->right
->parent
= NULL
;
671 node
->right
->parent
= parent
;
673 if (parent
->left
== node
)
674 parent
->left
= node
->right
;
677 parent
->right
= node
->right
;
679 avl_post_delete(tree
, node
->right
);
683 if (node
->right
== NULL
) {
684 if (parent
== NULL
) {
685 tree
->root
= node
->left
;
686 node
->left
->parent
= NULL
;
690 node
->left
->parent
= parent
;
692 if (parent
->left
== node
)
693 parent
->left
= node
->left
;
696 parent
->right
= node
->left
;
698 avl_post_delete(tree
, node
->left
);
702 min
= avl_local_min(node
->right
);
703 avl_delete_worker(tree
, min
);
704 parent
= node
->parent
;
706 min
->balance
= node
->balance
;
707 min
->parent
= parent
;
708 min
->left
= node
->left
;
709 min
->right
= node
->right
;
711 if (min
->left
!= NULL
)
712 min
->left
->parent
= min
;
714 if (min
->right
!= NULL
)
715 min
->right
->parent
= min
;
717 if (parent
== NULL
) {
722 if (parent
->left
== node
) {
733 * indent-tabs-mode: nil