--- /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
projects / tinc / blobdiff