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
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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;
102 * Finds a node in an avl-tree with a certain key
103 * @param tree pointer to avl-tree
104 * @param key pointer to key
105 * @return pointer to avl-node with key, NULL if no node with
109 avl_find(const struct avl_tree *tree, const void *key)
111 struct avl_node *node;
114 if (tree->root == NULL)
117 node = avl_find_rec(tree->root, key, tree->comp, tree->cmp_ptr, &diff);
119 return diff == 0 ? node : NULL;
123 * Finds the last node in an avl-tree with a key less or equal
124 * than the specified key
125 * @param tree pointer to avl-tree
126 * @param key pointer to specified key
127 * @return pointer to avl-node, NULL if no node with
128 * key less or equal specified key exists.
131 avl_find_lessequal(const struct avl_tree *tree, const void *key) {
132 struct avl_node *node, *next;
135 if (tree->root == NULL)
138 node = avl_find_rec(tree->root, key, tree->comp, tree->cmp_ptr, &diff);
140 /* go left as long as key<node.key */
142 if (list_is_first(&node->list, &tree->list_head)) {
146 node = (struct avl_node *)node->list.prev;
147 diff = (*tree->comp) (key, node->key, tree->cmp_ptr);
150 /* go right as long as key>=next_node.key */
154 if (list_is_last(&node->list, &tree->list_head)) {
158 next = (struct avl_node *)node->list.next;
159 diff = (*tree->comp) (key, next->key, tree->cmp_ptr);
165 * Finds the first node in an avl-tree with a key greater or equal
166 * than the specified key
167 * @param tree pointer to avl-tree
168 * @param key pointer to specified key
169 * @return pointer to avl-node, NULL if no node with
170 * key greater or equal specified key exists.
173 avl_find_greaterequal(const struct avl_tree *tree, const void *key) {
174 struct avl_node *node, *next;
177 if (tree->root == NULL)
180 node = avl_find_rec(tree->root, key, tree->comp, tree->cmp_ptr, &diff);
182 /* go right as long as key>node.key */
184 if (list_is_last(&node->list, &tree->list_head)) {
188 node = (struct avl_node *)node->list.next;
189 diff = (*tree->comp) (key, node->key, tree->cmp_ptr);
192 /* go left as long as key<=next_node.key */
196 if (list_is_first(&node->list, &tree->list_head)) {
200 next = (struct avl_node *)node->list.prev;
201 diff = (*tree->comp) (key, next->key, tree->cmp_ptr);
207 * Inserts an avl_node into a tree
208 * @param tree pointer to tree
209 * @param new pointer to node
210 * @return 0 if node was inserted successfully, -1 if it was not inserted
211 * because of a key collision
214 avl_insert(struct avl_tree *tree, struct avl_node *new)
216 struct avl_node *node, *next, *last;
227 if (tree->root == NULL) {
228 list_add_head(&tree->list_head, &new->list);
234 node = avl_find_rec(tree->root, new->key, tree->comp, tree->cmp_ptr, &diff);
238 while (!list_is_last(&last->list, &tree->list_head)) {
239 next = list_next_element(last, list);
246 diff = (*tree->comp) (new->key, node->key, tree->cmp_ptr);
249 if (!tree->allow_dups)
254 avl_insert_after(tree, last, new);
258 if (node->balance == 1) {
259 avl_insert_before(tree, node, new);
267 if (node->balance == -1) {
268 avl_insert_after(tree, last, new);
277 avl_insert_before(tree, node, new);
282 post_insert(tree, node);
286 avl_insert_after(tree, last, new);
291 post_insert(tree, node);
296 * Remove a node from an avl tree
297 * @param tree pointer to tree
298 * @param node pointer to node
301 avl_delete(struct avl_tree *tree, struct avl_node *node)
303 struct avl_node *next;
304 struct avl_node *parent;
305 struct avl_node *left;
306 struct avl_node *right;
309 && !list_is_last(&node->list, &tree->list_head)
310 && !(next = list_next_element(node, list))->leader) {
312 next->balance = node->balance;
314 parent = node->parent;
318 next->parent = parent;
326 if (node == parent->left)
330 parent->right = next;
337 right->parent = next;
341 avl_delete_worker(tree, node);
344 avl_remove(tree, node);
347 static struct avl_node *
348 avl_find_rec(struct avl_node *node, const void *key, avl_tree_comp comp, void *cmp_ptr, int *cmp_result)
352 diff = (*comp) (key, node->key, cmp_ptr);
356 if (node->left != NULL)
357 return avl_find_rec(node->left, key, comp, cmp_ptr, cmp_result);
363 if (node->right != NULL)
364 return avl_find_rec(node->right, key, comp, cmp_ptr, cmp_result);
373 avl_rotate_right(struct avl_tree *tree, struct avl_node *node)
375 struct avl_node *left, *parent;
378 parent = node->parent;
380 left->parent = parent;
387 if (parent->left == node)
391 parent->right = left;
394 node->left = left->right;
397 if (node->left != NULL)
398 node->left->parent = node;
400 node->balance += 1 - avl_min(left->balance, 0);
401 left->balance += 1 + avl_max(node->balance, 0);
405 avl_rotate_left(struct avl_tree *tree, struct avl_node *node)
407 struct avl_node *right, *parent;
410 parent = node->parent;
412 right->parent = parent;
413 node->parent = right;
419 if (parent->left == node)
420 parent->left = right;
423 parent->right = right;
426 node->right = right->left;
429 if (node->right != NULL)
430 node->right->parent = node;
432 node->balance -= 1 + avl_max(right->balance, 0);
433 right->balance -= 1 - avl_min(node->balance, 0);
437 post_insert(struct avl_tree *tree, struct avl_node *node)
439 struct avl_node *parent = node->parent;
444 if (node == parent->left) {
447 if (parent->balance == 0)
450 if (parent->balance == -1) {
451 post_insert(tree, parent);
455 if (node->balance == -1) {
456 avl_rotate_right(tree, parent);
460 avl_rotate_left(tree, node);
461 avl_rotate_right(tree, node->parent->parent);
467 if (parent->balance == 0)
470 if (parent->balance == 1) {
471 post_insert(tree, parent);
475 if (node->balance == 1) {
476 avl_rotate_left(tree, parent);
480 avl_rotate_right(tree, node);
481 avl_rotate_left(tree, node->parent->parent);
485 avl_insert_before(struct avl_tree *tree, struct avl_node *pos_node, struct avl_node *node)
487 list_add_before(&pos_node->list, &node->list);
492 avl_insert_after(struct avl_tree *tree, struct avl_node *pos_node, struct avl_node *node)
494 list_add_after(&pos_node->list, &node->list);
499 avl_remove(struct avl_tree *tree, struct avl_node *node)
501 list_remove(&node->list);
506 avl_post_delete(struct avl_tree *tree, struct avl_node *node)
508 struct avl_node *parent;
510 if ((parent = node->parent) == NULL)
513 if (node == parent->left) {
516 if (parent->balance == 0) {
517 avl_post_delete(tree, parent);
521 if (parent->balance == 1)
524 if (parent->right->balance == 0) {
525 avl_rotate_left(tree, parent);
529 if (parent->right->balance == 1) {
530 avl_rotate_left(tree, parent);
531 avl_post_delete(tree, parent->parent);
535 avl_rotate_right(tree, parent->right);
536 avl_rotate_left(tree, parent);
537 avl_post_delete(tree, parent->parent);
543 if (parent->balance == 0) {
544 avl_post_delete(tree, parent);
548 if (parent->balance == -1)
551 if (parent->left->balance == 0) {
552 avl_rotate_right(tree, parent);
556 if (parent->left->balance == -1) {
557 avl_rotate_right(tree, parent);
558 avl_post_delete(tree, parent->parent);
562 avl_rotate_left(tree, parent->left);
563 avl_rotate_right(tree, parent);
564 avl_post_delete(tree, parent->parent);
567 static struct avl_node *
568 avl_local_min(struct avl_node *node)
570 while (node->left != NULL)
577 static struct avl_node *
578 avl_local_max(struct avl_node *node)
580 while (node->right != NULL)
588 avl_delete_worker(struct avl_tree *tree, struct avl_node *node)
590 struct avl_node *parent, *min;
592 parent = node->parent;
594 if (node->left == NULL && node->right == NULL) {
595 if (parent == NULL) {
600 if (parent->left == node) {
604 if (parent->balance == 1)
607 if (parent->balance == 0) {
608 avl_post_delete(tree, parent);
612 if (parent->right->balance == 0) {
613 avl_rotate_left(tree, parent);
617 if (parent->right->balance == 1) {
618 avl_rotate_left(tree, parent);
619 avl_post_delete(tree, parent->parent);
623 avl_rotate_right(tree, parent->right);
624 avl_rotate_left(tree, parent);
625 avl_post_delete(tree, parent->parent);
629 if (parent->right == node) {
630 parent->right = NULL;
633 if (parent->balance == -1)
636 if (parent->balance == 0) {
637 avl_post_delete(tree, parent);
641 if (parent->left->balance == 0) {
642 avl_rotate_right(tree, parent);
646 if (parent->left->balance == -1) {
647 avl_rotate_right(tree, parent);
648 avl_post_delete(tree, parent->parent);
652 avl_rotate_left(tree, parent->left);
653 avl_rotate_right(tree, parent);
654 avl_post_delete(tree, parent->parent);
659 if (node->left == NULL) {
660 if (parent == NULL) {
661 tree->root = node->right;
662 node->right->parent = NULL;
666 node->right->parent = parent;
668 if (parent->left == node)
669 parent->left = node->right;
672 parent->right = node->right;
674 avl_post_delete(tree, node->right);
678 if (node->right == NULL) {
679 if (parent == NULL) {
680 tree->root = node->left;
681 node->left->parent = NULL;
685 node->left->parent = parent;
687 if (parent->left == node)
688 parent->left = node->left;
691 parent->right = node->left;
693 avl_post_delete(tree, node->left);
697 min = avl_local_min(node->right);
698 avl_delete_worker(tree, min);
699 parent = node->parent;
701 min->balance = node->balance;
702 min->parent = parent;
703 min->left = node->left;
704 min->right = node->right;
706 if (min->left != NULL)
707 min->left->parent = min;
709 if (min->right != NULL)
710 min->right->parent = min;
712 if (parent == NULL) {
717 if (parent->left == node) {
728 * indent-tabs-mode: nil