+++ /dev/null
-/*
- avl_tree.c -- avl_ tree and linked list convenience
- Copyright (C) 1998 Michael H. Buselli
- 2000-2005 Ivo Timmermans,
- 2000-2006 Guus Sliepen <guus@tinc-vpn.org>
- 2000-2005 Wessel Dankers <wsl@tinc-vpn.org>
-
- This program is free software; you can redistribute it and/or modify
- it under the terms of the GNU General Public License as published by
- the Free Software Foundation; either version 2 of the License, or
- (at your option) any later version.
-
- This program is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- GNU General Public License for more details.
-
- You should have received a copy of the GNU General Public License along
- with this program; if not, write to the Free Software Foundation, Inc.,
- 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
-
- Original AVL tree library by Michael H. Buselli <cosine@cosine.org>.
-
- Modified 2000-11-28 by Wessel Dankers <wsl@tinc-vpn.org> to use counts
- instead of depths, to add the ->next and ->prev and to generally obfuscate
- the code. Mail me if you found a bug.
-
- Cleaned up and incorporated some of the ideas from the red-black tree
- library for inclusion into tinc (http://www.tinc-vpn.org/) by
- Guus Sliepen <guus@tinc-vpn.org>.
-*/
-
-#include "system.h"
-
-#include "avl_tree.h"
-#include "xalloc.h"
-
-#ifdef AVL_COUNT
-#define AVL_NODE_COUNT(n) ((n) ? (n)->count : 0)
-#define AVL_L_COUNT(n) (AVL_NODE_COUNT((n)->left))
-#define AVL_R_COUNT(n) (AVL_NODE_COUNT((n)->right))
-#define AVL_CALC_COUNT(n) (AVL_L_COUNT(n) + AVL_R_COUNT(n) + 1)
-#endif
-
-#ifdef AVL_DEPTH
-#define AVL_NODE_DEPTH(n) ((n) ? (n)->depth : 0)
-#define L_AVL_DEPTH(n) (AVL_NODE_DEPTH((n)->left))
-#define R_AVL_DEPTH(n) (AVL_NODE_DEPTH((n)->right))
-#define AVL_CALC_DEPTH(n) ((L_AVL_DEPTH(n)>R_AVL_DEPTH(n)?L_AVL_DEPTH(n):R_AVL_DEPTH(n)) + 1)
-#endif
-
-#ifndef AVL_DEPTH
-static int lg(unsigned int u) __attribute__ ((__const__));
-
-static int lg(unsigned int u)
-{
- int r = 1;
-
- if(!u)
- return 0;
-
- if(u & 0xffff0000) {
- u >>= 16;
- r += 16;
- }
-
- if(u & 0x0000ff00) {
- u >>= 8;
- r += 8;
- }
-
- if(u & 0x000000f0) {
- u >>= 4;
- r += 4;
- }
-
- if(u & 0x0000000c) {
- u >>= 2;
- r += 2;
- }
-
- if(u & 0x00000002)
- r++;
-
- return r;
-}
-#endif
-
-/* Internal helper functions */
-
-static int avl_check_balance(const avl_node_t *node)
-{
-#ifdef AVL_DEPTH
- int d;
-
- d = R_AVL_DEPTH(node) - L_AVL_DEPTH(node);
-
- return d < -1 ? -1 : d > 1 ? 1 : 0;
-#else
-/* int d;
- * d = lg(AVL_R_COUNT(node)) - lg(AVL_L_COUNT(node));
- * d = d<-1?-1:d>1?1:0;
- */
- int pl, r;
-
- pl = lg(AVL_L_COUNT(node));
- r = AVL_R_COUNT(node);
-
- if(r >> pl + 1)
- return 1;
-
- if(pl < 2 || r >> pl - 2)
- return 0;
-
- return -1;
-#endif
-}
-
-static void avl_rebalance(avl_tree_t *tree, avl_node_t *node)
-{
- avl_node_t *child;
- avl_node_t *gchild;
- avl_node_t *parent;
- avl_node_t **superparent;
-
- parent = node;
-
- while(node) {
- parent = node->parent;
-
- superparent =
- parent ? node ==
- parent->left ? &parent->left : &parent->right : &tree->root;
-
- switch (avl_check_balance(node)) {
- case -1:
- child = node->left;
-#ifdef AVL_DEPTH
- if(L_AVL_DEPTH(child) >= R_AVL_DEPTH(child)) {
-#else
- if(AVL_L_COUNT(child) >= AVL_R_COUNT(child)) {
-#endif
- node->left = child->right;
- if(node->left)
- node->left->parent = node;
-
- child->right = node;
- node->parent = child;
- *superparent = child;
- child->parent = parent;
-#ifdef AVL_COUNT
- node->count = AVL_CALC_COUNT(node);
- child->count = AVL_CALC_COUNT(child);
-#endif
-#ifdef AVL_DEPTH
- node->depth = AVL_CALC_DEPTH(node);
- child->depth = AVL_CALC_DEPTH(child);
-#endif
- } else {
- gchild = child->right;
- node->left = gchild->right;
-
- if(node->left)
- node->left->parent = node;
- child->right = gchild->left;
-
- if(child->right)
- child->right->parent = child;
- gchild->right = node;
-
- if(gchild->right)
- gchild->right->parent = gchild;
- gchild->left = child;
-
- if(gchild->left)
- gchild->left->parent = gchild;
- *superparent = gchild;
-
- gchild->parent = parent;
-#ifdef AVL_COUNT
- node->count = AVL_CALC_COUNT(node);
- child->count = AVL_CALC_COUNT(child);
- gchild->count = AVL_CALC_COUNT(gchild);
-#endif
-#ifdef AVL_DEPTH
- node->depth = AVL_CALC_DEPTH(node);
- child->depth = AVL_CALC_DEPTH(child);
- gchild->depth = AVL_CALC_DEPTH(gchild);
-#endif
- }
- break;
-
- case 1:
- child = node->right;
-#ifdef AVL_DEPTH
- if(R_AVL_DEPTH(child) >= L_AVL_DEPTH(child)) {
-#else
- if(AVL_R_COUNT(child) >= AVL_L_COUNT(child)) {
-#endif
- node->right = child->left;
- if(node->right)
- node->right->parent = node;
- child->left = node;
- node->parent = child;
- *superparent = child;
- child->parent = parent;
-#ifdef AVL_COUNT
- node->count = AVL_CALC_COUNT(node);
- child->count = AVL_CALC_COUNT(child);
-#endif
-#ifdef AVL_DEPTH
- node->depth = AVL_CALC_DEPTH(node);
- child->depth = AVL_CALC_DEPTH(child);
-#endif
- } else {
- gchild = child->left;
- node->right = gchild->left;
-
- if(node->right)
- node->right->parent = node;
- child->left = gchild->right;
-
- if(child->left)
- child->left->parent = child;
- gchild->left = node;
-
- if(gchild->left)
- gchild->left->parent = gchild;
- gchild->right = child;
-
- if(gchild->right)
- gchild->right->parent = gchild;
-
- *superparent = gchild;
- gchild->parent = parent;
-#ifdef AVL_COUNT
- node->count = AVL_CALC_COUNT(node);
- child->count = AVL_CALC_COUNT(child);
- gchild->count = AVL_CALC_COUNT(gchild);
-#endif
-#ifdef AVL_DEPTH
- node->depth = AVL_CALC_DEPTH(node);
- child->depth = AVL_CALC_DEPTH(child);
- gchild->depth = AVL_CALC_DEPTH(gchild);
-#endif
- }
- break;
-
- default:
-#ifdef AVL_COUNT
- node->count = AVL_CALC_COUNT(node);
-#endif
-#ifdef AVL_DEPTH
- node->depth = AVL_CALC_DEPTH(node);
-#endif
- }
- node = parent;
- }
-}
-
-/* (De)constructors */
-
-avl_tree_t *avl_alloc_tree(avl_compare_t compare, avl_action_t delete)
-{
- avl_tree_t *tree;
-
- tree = xmalloc_and_zero(sizeof(avl_tree_t));
- tree->compare = compare;
- tree->delete = delete;
-
- return tree;
-}
-
-void avl_free_tree(avl_tree_t *tree)
-{
- free(tree);
-}
-
-avl_node_t *avl_alloc_node(void)
-{
- return xmalloc_and_zero(sizeof(avl_node_t));
-}
-
-void avl_free_node(avl_tree_t *tree, avl_node_t *node)
-{
- if(node->data && tree->delete)
- tree->delete(node->data);
-
- free(node);
-}
-
-/* Searching */
-
-void *avl_search(const avl_tree_t *tree, const void *data)
-{
- avl_node_t *node;
-
- node = avl_search_node(tree, data);
-
- return node ? node->data : NULL;
-}
-
-void *avl_search_closest(const avl_tree_t *tree, const void *data, int *result)
-{
- avl_node_t *node;
-
- node = avl_search_closest_node(tree, data, result);
-
- return node ? node->data : NULL;
-}
-
-void *avl_search_closest_smaller(const avl_tree_t *tree, const void *data)
-{
- avl_node_t *node;
-
- node = avl_search_closest_smaller_node(tree, data);
-
- return node ? node->data : NULL;
-}
-
-void *avl_search_closest_greater(const avl_tree_t *tree, const void *data)
-{
- avl_node_t *node;
-
- node = avl_search_closest_greater_node(tree, data);
-
- return node ? node->data : NULL;
-}
-
-avl_node_t *avl_search_node(const avl_tree_t *tree, const void *data)
-{
- avl_node_t *node;
- int result;
-
- node = avl_search_closest_node(tree, data, &result);
-
- return result ? NULL : node;
-}
-
-avl_node_t *avl_search_closest_node(const avl_tree_t *tree, const void *data,
- int *result)
-{
- avl_node_t *node;
- int c;
-
- node = tree->root;
-
- if(!node) {
- if(result)
- *result = 0;
- return NULL;
- }
-
- for(;;) {
- c = tree->compare(data, node->data);
-
- if(c < 0) {
- if(node->left)
- node = node->left;
- else {
- if(result)
- *result = -1;
- break;
- }
- } else if(c > 0) {
- if(node->right)
- node = node->right;
- else {
- if(result)
- *result = 1;
- break;
- }
- } else {
- if(result)
- *result = 0;
- break;
- }
- }
-
- return node;
-}
-
-avl_node_t *avl_search_closest_smaller_node(const avl_tree_t *tree,
- const void *data)
-{
- avl_node_t *node;
- int result;
-
- node = avl_search_closest_node(tree, data, &result);
-
- if(result < 0)
- node = node->prev;
-
- return node;
-}
-
-avl_node_t *avl_search_closest_greater_node(const avl_tree_t *tree,
- const void *data)
-{
- avl_node_t *node;
- int result;
-
- node = avl_search_closest_node(tree, data, &result);
-
- if(result > 0)
- node = node->next;
-
- return node;
-}
-
-/* Insertion and deletion */
-
-avl_node_t *avl_insert(avl_tree_t *tree, void *data)
-{
- avl_node_t *closest, *new;
- int result;
-
- if(!tree->root) {
- new = avl_alloc_node();
- new->data = data;
- avl_insert_top(tree, new);
- } else {
- closest = avl_search_closest_node(tree, data, &result);
-
- switch (result) {
- case -1:
- new = avl_alloc_node();
- new->data = data;
- avl_insert_before(tree, closest, new);
- break;
-
- case 1:
- new = avl_alloc_node();
- new->data = data;
- avl_insert_after(tree, closest, new);
- break;
-
- default:
- return NULL;
- }
- }
-
-#ifdef AVL_COUNT
- new->count = 1;
-#endif
-#ifdef AVL_DEPTH
- new->depth = 1;
-#endif
-
- return new;
-}
-
-avl_node_t *avl_insert_node(avl_tree_t *tree, avl_node_t *node)
-{
- avl_node_t *closest;
- int result;
-
- if(!tree->root)
- avl_insert_top(tree, node);
- else {
- closest = avl_search_closest_node(tree, node->data, &result);
-
- switch (result) {
- case -1:
- avl_insert_before(tree, closest, node);
- break;
-
- case 1:
- avl_insert_after(tree, closest, node);
- break;
-
- case 0:
- return NULL;
- }
- }
-
-#ifdef AVL_COUNT
- node->count = 1;
-#endif
-#ifdef AVL_DEPTH
- node->depth = 1;
-#endif
-
- return node;
-}
-
-void avl_insert_top(avl_tree_t *tree, avl_node_t *node)
-{
- node->prev = node->next = node->parent = NULL;
- tree->head = tree->tail = tree->root = node;
-}
-
-void avl_insert_before(avl_tree_t *tree, avl_node_t *before,
- avl_node_t *node)
-{
- if(!before) {
- if(tree->tail)
- avl_insert_after(tree, tree->tail, node);
- else
- avl_insert_top(tree, node);
- return;
- }
-
- node->next = before;
- node->parent = before;
- node->prev = before->prev;
-
- if(before->left) {
- avl_insert_after(tree, before->prev, node);
- return;
- }
-
- if(before->prev)
- before->prev->next = node;
- else
- tree->head = node;
-
- before->prev = node;
- before->left = node;
-
- avl_rebalance(tree, before);
-}
-
-void avl_insert_after(avl_tree_t *tree, avl_node_t *after, avl_node_t *node)
-{
- if(!after) {
- if(tree->head)
- avl_insert_before(tree, tree->head, node);
- else
- avl_insert_top(tree, node);
- return;
- }
-
- if(after->right) {
- avl_insert_before(tree, after->next, node);
- return;
- }
-
- node->prev = after;
- node->parent = after;
- node->next = after->next;
-
- if(after->next)
- after->next->prev = node;
- else
- tree->tail = node;
-
- after->next = node;
- after->right = node;
-
- avl_rebalance(tree, after);
-}
-
-avl_node_t *avl_unlink(avl_tree_t *tree, void *data)
-{
- avl_node_t *node;
-
- node = avl_search_node(tree, data);
-
- if(node)
- avl_unlink_node(tree, node);
-
- return node;
-}
-
-void avl_unlink_node(avl_tree_t *tree, avl_node_t *node)
-{
- avl_node_t *parent;
- avl_node_t **superparent;
- avl_node_t *subst, *left, *right;
- avl_node_t *balnode;
-
- if(node->prev)
- node->prev->next = node->next;
- else
- tree->head = node->next;
- if(node->next)
- node->next->prev = node->prev;
- else
- tree->tail = node->prev;
-
- parent = node->parent;
-
- superparent =
- parent ? node ==
- parent->left ? &parent->left : &parent->right : &tree->root;
-
- left = node->left;
- right = node->right;
- if(!left) {
- *superparent = right;
-
- if(right)
- right->parent = parent;
-
- balnode = parent;
- } else if(!right) {
- *superparent = left;
- left->parent = parent;
- balnode = parent;
- } else {
- subst = node->prev;
-
- if(subst == left) {
- balnode = subst;
- } else {
- balnode = subst->parent;
- balnode->right = subst->left;
-
- if(balnode->right)
- balnode->right->parent = balnode;
-
- subst->left = left;
- left->parent = subst;
- }
-
- subst->right = right;
- subst->parent = parent;
- right->parent = subst;
- *superparent = subst;
- }
-
- avl_rebalance(tree, balnode);
-
- node->next = node->prev = node->parent = node->left = node->right = NULL;
-
-#ifdef AVL_COUNT
- node->count = 0;
-#endif
-#ifdef AVL_DEPTH
- node->depth = 0;
-#endif
-}
-
-void avl_delete_node(avl_tree_t *tree, avl_node_t *node)
-{
- avl_unlink_node(tree, node);
- avl_free_node(tree, node);
-}
-
-void avl_delete(avl_tree_t *tree, void *data)
-{
- avl_node_t *node;
-
- node = avl_search_node(tree, data);
-
- if(node)
- avl_delete_node(tree, node);
-}
-
-/* Fast tree cleanup */
-
-void avl_delete_tree(avl_tree_t *tree)
-{
- avl_node_t *node, *next;
-
- for(node = tree->head; node; node = next) {
- next = node->next;
- avl_free_node(tree, node);
- }
-
- avl_free_tree(tree);
-}
-
-/* Tree walking */
-
-void avl_foreach(const avl_tree_t *tree, avl_action_t action)
-{
- avl_node_t *node, *next;
-
- for(node = tree->head; node; node = next) {
- next = node->next;
- action(node->data);
- }
-}
-
-void avl_foreach_node(const avl_tree_t *tree, avl_action_t action)
-{
- avl_node_t *node, *next;
-
- for(node = tree->head; node; node = next) {
- next = node->next;
- action(node);
- }
-}
-
-/* Indexing */
-
-#ifdef AVL_COUNT
-unsigned int avl_count(const avl_tree_t *tree)
-{
- return AVL_NODE_COUNT(tree->root);
-}
-
-avl_node_t *avl_get_node(const avl_tree_t *tree, unsigned int index)
-{
- avl_node_t *node;
- unsigned int c;
-
- node = tree->root;
-
- while(node) {
- c = AVL_L_COUNT(node);
-
- if(index < c) {
- node = node->left;
- } else if(index > c) {
- node = node->right;
- index -= c + 1;
- } else {
- return node;
- }
- }
-
- return NULL;
-}
-
-unsigned int avl_index(const avl_node_t *node)
-{
- avl_node_t *next;
- unsigned int index;
-
- index = AVL_L_COUNT(node);
-
- while((next = node->parent)) {
- if(node == next->right)
- index += AVL_L_COUNT(next) + 1;
- node = next;
- }
-
- return index;
-}
-#endif
-#ifdef AVL_DEPTH
-unsigned int avl_depth(const avl_tree_t *tree)
-{
- return AVL_NODE_DEPTH(tree->root);
-}
-#endif
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