-/*
- splay_tree.c -- splay tree and linked list convenience
- Copyright (C) 2004-2006 Guus Sliepen <guus@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.
-*/
-
-#include "system.h"
-
-#include "splay_tree.h"
-#include "xalloc.h"
-
-/* Splay operation */
-
-static splay_node_t *splay_top_down(splay_tree_t *tree, const void *data, int *result) {
- splay_node_t left = {0}, right = {0};
- splay_node_t *leftbottom = &left, *rightbottom = &right, *child, *grandchild;
- splay_node_t *root = tree->root;
- int c;
-
- if(!root) {
- if(result)
- *result = 0;
- return NULL;
- }
-
- while((c = tree->compare(data, root->data))) {
- if(c < 0 && (child = root->left)) {
- c = tree->compare(data, child->data);
-
- if(c < 0 && (grandchild = child->left)) {
- rightbottom->left = child;
- child->parent = rightbottom;
- rightbottom = child;
-
- if((root->left = child->right))
- child->right->parent = root;
-
- child->right = root;
- root->parent = child;
-
- child->left = NULL;
- grandchild->parent = NULL;
-
- root = grandchild;
- } else if (c > 0 && (grandchild = child->right)) {
- leftbottom->right = child;
- child->parent = leftbottom;
- leftbottom = child;
-
- child->right = NULL;
- grandchild->parent = NULL;
-
- rightbottom->left = root;
- root->parent = rightbottom;
- rightbottom = root;
-
- root->left = NULL;
-
- root = grandchild;
- } else {
- rightbottom->left = root;
- root->parent = rightbottom;
- rightbottom = root;
-
- root->left = NULL;
- child->parent = NULL;
-
- root = child;
- break;
- }
- } else if(c > 0 && (child = root->right)) {
- c = tree->compare(data, child->data);
-
- if(c > 0 && (grandchild = child->right)) {
- leftbottom->right = child;
- child->parent = leftbottom;
- leftbottom = child;
-
- if((root->right = child->left))
- child->left->parent = root;
-
- child->left = root;
- root->parent = child;
-
- child->right = NULL;
- grandchild->parent = NULL;
-
- root = grandchild;
- } else if (c < 0 && (grandchild = child->left)) {
- rightbottom->left = child;
- child->parent = rightbottom;
- rightbottom = child;
-
- child->left = NULL;
- grandchild->parent = NULL;
-
- leftbottom->right = root;
- root->parent = leftbottom;
- leftbottom = root;
-
- root->right = NULL;
-
- root = grandchild;
- } else {
- leftbottom->right = root;
- root->parent = leftbottom;
- leftbottom = root;
-
- root->right = NULL;
- child->parent = NULL;
-
- root = child;
- break;
- }
- } else {
- break;
- }
- }
-
- /* Merge trees */
-
- if(left.right) {
- if(root->left) {
- leftbottom->right = root->left;
- root->left->parent = leftbottom;
- }
- root->left = left.right;
- left.right->parent = root;
- }
-
- if(right.left) {
- if(root->right) {
- rightbottom->left = root->right;
- root->right->parent = rightbottom;
- }
- root->right = right.left;
- right.left->parent = root;
- }
-
- /* Return result */
-
- tree->root = root;
- if(result)
- *result = c;
-
- return tree->root;
-}
-
-static void splay_bottom_up(splay_tree_t *tree, splay_node_t *node) {
- splay_node_t *parent, *grandparent, *greatgrandparent;
-
- while((parent = node->parent)) {
- if(!(grandparent = parent->parent)) { /* zig */
- if(node == parent->left) {
- if((parent->left = node->right))
- parent->left->parent = parent;
- node->right = parent;
- } else {
- if((parent->right = node->left))
- parent->right->parent = parent;
- node->left = parent;
- }
-
- parent->parent = node;
- node->parent = NULL;
- } else {
- greatgrandparent = grandparent->parent;
-
- if(node == parent->left && parent == grandparent->left) { /* left zig-zig */
- if((grandparent->left = parent->right))
- grandparent->left->parent = grandparent;
- parent->right = grandparent;
- grandparent->parent = parent;
-
- if((parent->left = node->right))
- parent->left->parent = parent;
- node->right = parent;
- parent->parent = node;
- } else if(node == parent->right && parent == grandparent->right) { /* right zig-zig */
- if((grandparent->right = parent->left))
- grandparent->right->parent = grandparent;
- parent->left = grandparent;
- grandparent->parent = parent;
-
- if((parent->right = node->left))
- parent->right->parent = parent;
- node->left = parent;
- parent->parent = node;
- } else if(node == parent->right && parent == grandparent->left) { /* left-right zig-zag */
- if((parent->right = node->left))
- parent->right->parent = parent;
- node->left = parent;
- parent->parent = node;
-
- if((grandparent->left = node->right))
- grandparent->left->parent = grandparent;
- node->right = grandparent;
- grandparent->parent = node;
- } else { /* right-left zig-zag */
- if((parent->left = node->right))
- parent->left->parent = parent;
- node->right = parent;
- parent->parent = node;
-
- if((grandparent->right = node->left))
- grandparent->right->parent = grandparent;
- node->left = grandparent;
- grandparent->parent = node;
- }
-
- if((node->parent = greatgrandparent)) {
- if(grandparent == greatgrandparent->left)
- greatgrandparent->left = node;
- else
- greatgrandparent->right = node;
- }
- }
- }
-
- tree->root = node;
-}
-
-/* (De)constructors */
-
-splay_tree_t *splay_alloc_tree(splay_compare_t compare, splay_action_t delete) {
- splay_tree_t *tree;
-
- tree = xmalloc_and_zero(sizeof(splay_tree_t));
- tree->compare = compare;
- tree->delete = delete;
-
- return tree;
-}
-
-void splay_free_tree(splay_tree_t *tree) {
- free(tree);
-}
-
-splay_node_t *splay_alloc_node(void) {
- return xmalloc_and_zero(sizeof(splay_node_t));
-}
-
-void splay_free_node(splay_tree_t *tree, splay_node_t *node) {
- if(node->data && tree->delete)
- tree->delete(node->data);
-
- free(node);
-}
-
-/* Searching */
-
-void *splay_search(splay_tree_t *tree, const void *data) {
- splay_node_t *node;
-
- node = splay_search_node(tree, data);
-
- return node ? node->data : NULL;
-}
-
-void *splay_search_closest(splay_tree_t *tree, const void *data, int *result) {
- splay_node_t *node;
-
- node = splay_search_closest_node(tree, data, result);
-
- return node ? node->data : NULL;
-}
-
-void *splay_search_closest_smaller(splay_tree_t *tree, const void *data) {
- splay_node_t *node;
-
- node = splay_search_closest_smaller_node(tree, data);
-
- return node ? node->data : NULL;
-}
-
-void *splay_search_closest_greater(splay_tree_t *tree, const void *data) {
- splay_node_t *node;
-
- node = splay_search_closest_greater_node(tree, data);
-
- return node ? node->data : NULL;
-}
-
-splay_node_t *splay_search_node(splay_tree_t *tree, const void *data) {
- splay_node_t *node;
- int result;
-
- node = splay_search_closest_node(tree, data, &result);
-
- return result ? NULL : node;
-}
-
-splay_node_t *splay_search_closest_node_nosplay(const splay_tree_t *tree, const void *data, int *result) {
- splay_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
- break;
- } else if(c > 0) {
- if(node->right)
- node = node->right;
- else
- break;
- } else {
- break;
- }
- }
-
- if(result)
- *result = c;
- return node;
-}
-
-splay_node_t *splay_search_closest_node(splay_tree_t *tree, const void *data, int *result) {
- return splay_top_down(tree, data, result);
-}
-
-splay_node_t *splay_search_closest_smaller_node(splay_tree_t *tree, const void *data) {
- splay_node_t *node;
- int result;
-
- node = splay_search_closest_node(tree, data, &result);
-
- if(result < 0)
- node = node->prev;
-
- return node;
-}
-
-splay_node_t *splay_search_closest_greater_node(splay_tree_t *tree, const void *data) {
- splay_node_t *node;
- int result;
-
- node = splay_search_closest_node(tree, data, &result);
-
- if(result > 0)
- node = node->next;
-
- return node;
-}
-
-/* Insertion and deletion */
-
-splay_node_t *splay_insert(splay_tree_t *tree, void *data) {
- splay_node_t *closest, *new;
- int result;
-
- if(!tree->root) {
- new = splay_alloc_node();
- new->data = data;
- splay_insert_top(tree, new);
- } else {
- closest = splay_search_closest_node(tree, data, &result);
-
- if(!result)
- return NULL;
-
- new = splay_alloc_node();
- new->data = data;
-
- if(result < 0)
- splay_insert_before(tree, closest, new);
- else
- splay_insert_after(tree, closest, new);
- }
-
- return new;
-}
-
-splay_node_t *splay_insert_node(splay_tree_t *tree, splay_node_t *node) {
- splay_node_t *closest;
- int result;
-
- if(!tree->root)
- splay_insert_top(tree, node);
- else {
- closest = splay_search_closest_node(tree, node->data, &result);
-
- if(!result)
- return NULL;
-
- if(result < 0)
- splay_insert_before(tree, closest, node);
- else
- splay_insert_after(tree, closest, node);
- }
-
- return node;
-}
-
-void splay_insert_top(splay_tree_t *tree, splay_node_t *node) {
- node->prev = node->next = node->left = node->right = node->parent = NULL;
- tree->head = tree->tail = tree->root = node;
-}
-
-void splay_insert_before(splay_tree_t *tree, splay_node_t *before, splay_node_t *node) {
- if(!before) {
- if(tree->tail)
- splay_insert_after(tree, tree->tail, node);
- else
- splay_insert_top(tree, node);
- return;
- }
-
- node->next = before;
- if((node->prev = before->prev))
- before->prev->next = node;
- else
- tree->head = node;
- before->prev = node;
-
- splay_bottom_up(tree, before);
-
- node->right = before;
- before->parent = node;
- if((node->left = before->left))
- before->left->parent = node;
- before->left = NULL;
-
- node->parent = NULL;
- tree->root = node;
-}
-
-void splay_insert_after(splay_tree_t *tree, splay_node_t *after, splay_node_t *node) {
- if(!after) {
- if(tree->head)
- splay_insert_before(tree, tree->head, node);
- else
- splay_insert_top(tree, node);
- return;
- }
-
- node->prev = after;
- if((node->next = after->next))
- after->next->prev = node;
- else
- tree->tail = node;
- after->next = node;
-
- splay_bottom_up(tree, after);
-
- node->left = after;
- after->parent = node;
- if((node->right = after->right))
- after->right->parent = node;
- after->right = NULL;
-
- node->parent = NULL;
- tree->root = node;
-}
-
-splay_node_t *splay_unlink(splay_tree_t *tree, void *data) {
- splay_node_t *node;
-
- node = splay_search_node(tree, data);
-
- if(node)
- splay_unlink_node(tree, node);
-
- return node;
-}
-
-void splay_unlink_node(splay_tree_t *tree, splay_node_t *node) {
- 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;
-
- splay_bottom_up(tree, node);
-
- if(node->prev) {
- node->left->parent = NULL;
- tree->root = node->left;
- if((node->prev->right = node->right))
- node->right->parent = node->prev;
- } else if(node->next) {
- tree->root = node->right;
- node->right->parent = NULL;
- } else {
- tree->root = NULL;
- }
-}
-
-void splay_delete_node(splay_tree_t *tree, splay_node_t *node) {
- splay_unlink_node(tree, node);
- splay_free_node(tree, node);
-}
-
-void splay_delete(splay_tree_t *tree, void *data) {
- splay_node_t *node;
-
- node = splay_search_node(tree, data);
-
- if(node)
- splay_delete_node(tree, node);
-}
-
-/* Fast tree cleanup */
-
-void splay_delete_tree(splay_tree_t *tree) {
- splay_node_t *node, *next;
-
- for(node = tree->head; node; node = next) {
- next = node->next;
- splay_free_node(tree, node);
- }
-
- splay_free_tree(tree);
-}
-
-/* Tree walking */
-
-void splay_foreach(const splay_tree_t *tree, splay_action_t action) {
- splay_node_t *node, *next;
-
- for(node = tree->head; node; node = next) {
- next = node->next;
- action(node->data);
- }
-}
-
-void splay_foreach_node(const splay_tree_t *tree, splay_action_t action) {
- splay_node_t *node, *next;
-
- for(node = tree->head; node; node = next) {
- next = node->next;
- action(node);
- }
-}
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