563 lines
12 KiB
C
563 lines
12 KiB
C
/*
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splay_tree.c -- splay tree and linked list convenience
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Copyright (C) 2004-2006 Guus Sliepen <guus@tinc-vpn.org>
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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$Id: splay_tree.c 1374 2004-03-21 14:21:22Z guus $
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*/
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#include "system.h"
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#include "splay_tree.h"
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#include "xalloc.h"
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/* Splay operation */
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static splay_node_t *splay_top_down(splay_tree_t *tree, const void *data, int *result) {
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splay_node_t left = {0}, right = {0};
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splay_node_t *leftbottom = &left, *rightbottom = &right, *child, *grandchild;
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splay_node_t *root = tree->root;
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int c;
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if(!root) {
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if(result)
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*result = 0;
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return NULL;
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}
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while((c = tree->compare(data, root->data))) {
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if(c < 0 && (child = root->left)) {
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c = tree->compare(data, child->data);
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if(c < 0 && (grandchild = child->left)) {
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rightbottom->left = child;
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child->parent = rightbottom;
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rightbottom = child;
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if((root->left = child->right))
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child->right->parent = root;
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child->right = root;
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root->parent = child;
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child->left = NULL;
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grandchild->parent = NULL;
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root = grandchild;
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} else if (c > 0 && (grandchild = child->right)) {
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leftbottom->right = child;
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child->parent = leftbottom;
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leftbottom = child;
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child->right = NULL;
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grandchild->parent = NULL;
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rightbottom->left = root;
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root->parent = rightbottom;
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rightbottom = root;
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root->left = NULL;
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root = grandchild;
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} else {
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rightbottom->left = root;
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root->parent = rightbottom;
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rightbottom = root;
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root->left = NULL;
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child->parent = NULL;
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root = child;
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break;
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}
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} else if(c > 0 && (child = root->right)) {
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c = tree->compare(data, child->data);
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if(c > 0 && (grandchild = child->right)) {
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leftbottom->right = child;
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child->parent = leftbottom;
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leftbottom = child;
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if((root->right = child->left))
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child->left->parent = root;
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child->left = root;
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root->parent = child;
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child->right = NULL;
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grandchild->parent = NULL;
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root = grandchild;
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} else if (c < 0 && (grandchild = child->left)) {
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rightbottom->left = child;
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child->parent = rightbottom;
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rightbottom = child;
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child->left = NULL;
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grandchild->parent = NULL;
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leftbottom->right = root;
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root->parent = leftbottom;
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leftbottom = root;
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root->right = NULL;
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root = grandchild;
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} else {
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leftbottom->right = root;
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root->parent = leftbottom;
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leftbottom = root;
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root->right = NULL;
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child->parent = NULL;
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root = child;
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break;
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}
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} else {
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break;
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}
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}
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/* Merge trees */
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if(left.right) {
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if(root->left) {
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leftbottom->right = root->left;
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root->left->parent = leftbottom;
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}
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root->left = left.right;
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left.right->parent = root;
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}
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if(right.left) {
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if(root->right) {
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rightbottom->left = root->right;
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root->right->parent = rightbottom;
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}
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root->right = right.left;
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right.left->parent = root;
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}
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/* Return result */
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tree->root = root;
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if(result)
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*result = c;
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return tree->root;
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}
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static void splay_bottom_up(splay_tree_t *tree, splay_node_t *node) {
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splay_node_t *parent, *grandparent, *greatgrandparent;
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while((parent = node->parent)) {
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if(!(grandparent = parent->parent)) { /* zig */
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if(node == parent->left) {
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if((parent->left = node->right))
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parent->left->parent = parent;
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node->right = parent;
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} else {
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if((parent->right = node->left))
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parent->right->parent = parent;
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node->left = parent;
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}
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parent->parent = node;
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node->parent = NULL;
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} else {
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greatgrandparent = grandparent->parent;
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if(node == parent->left && parent == grandparent->left) { /* left zig-zig */
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if((grandparent->left = parent->right))
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grandparent->left->parent = grandparent;
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parent->right = grandparent;
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grandparent->parent = parent;
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if((parent->left = node->right))
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parent->left->parent = parent;
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node->right = parent;
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parent->parent = node;
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} else if(node == parent->right && parent == grandparent->right) { /* right zig-zig */
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if((grandparent->right = parent->left))
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grandparent->right->parent = grandparent;
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parent->left = grandparent;
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grandparent->parent = parent;
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if((parent->right = node->left))
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parent->right->parent = parent;
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node->left = parent;
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parent->parent = node;
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} else if(node == parent->right && parent == grandparent->left) { /* left-right zig-zag */
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if((parent->right = node->left))
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parent->right->parent = parent;
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node->left = parent;
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parent->parent = node;
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if((grandparent->left = node->right))
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grandparent->left->parent = grandparent;
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node->right = grandparent;
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grandparent->parent = node;
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} else { /* right-left zig-zag */
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if((parent->left = node->right))
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parent->left->parent = parent;
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node->right = parent;
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parent->parent = node;
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if((grandparent->right = node->left))
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grandparent->right->parent = grandparent;
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node->left = grandparent;
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grandparent->parent = node;
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}
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if((node->parent = greatgrandparent)) {
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if(grandparent == greatgrandparent->left)
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greatgrandparent->left = node;
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else
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greatgrandparent->right = node;
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}
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}
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}
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tree->root = node;
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}
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/* (De)constructors */
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splay_tree_t *splay_alloc_tree(splay_compare_t compare, splay_action_t delete) {
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splay_tree_t *tree;
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tree = xmalloc_and_zero(sizeof(splay_tree_t));
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tree->compare = compare;
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tree->delete = delete;
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return tree;
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}
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void splay_free_tree(splay_tree_t *tree) {
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free(tree);
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}
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splay_node_t *splay_alloc_node(void) {
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return xmalloc_and_zero(sizeof(splay_node_t));
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}
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void splay_free_node(splay_tree_t *tree, splay_node_t *node) {
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if(node->data && tree->delete)
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tree->delete(node->data);
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free(node);
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}
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/* Searching */
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void *splay_search(splay_tree_t *tree, const void *data) {
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splay_node_t *node;
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node = splay_search_node(tree, data);
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return node ? node->data : NULL;
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}
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void *splay_search_closest(splay_tree_t *tree, const void *data, int *result) {
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splay_node_t *node;
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node = splay_search_closest_node(tree, data, result);
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return node ? node->data : NULL;
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}
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void *splay_search_closest_smaller(splay_tree_t *tree, const void *data) {
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splay_node_t *node;
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node = splay_search_closest_smaller_node(tree, data);
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return node ? node->data : NULL;
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}
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void *splay_search_closest_greater(splay_tree_t *tree, const void *data) {
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splay_node_t *node;
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node = splay_search_closest_greater_node(tree, data);
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return node ? node->data : NULL;
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}
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splay_node_t *splay_search_node(splay_tree_t *tree, const void *data) {
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splay_node_t *node;
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int result;
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node = splay_search_closest_node(tree, data, &result);
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return result ? NULL : node;
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}
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splay_node_t *splay_search_closest_node_nosplay(const splay_tree_t *tree, const void *data, int *result) {
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splay_node_t *node;
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int c;
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node = tree->root;
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if(!node) {
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if(result)
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*result = 0;
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return NULL;
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}
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for(;;) {
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c = tree->compare(data, node->data);
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if(c < 0) {
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if(node->left)
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node = node->left;
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else
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break;
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} else if(c > 0) {
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if(node->right)
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node = node->right;
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else
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break;
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} else {
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break;
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}
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}
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if(result)
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*result = c;
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return node;
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}
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splay_node_t *splay_search_closest_node(splay_tree_t *tree, const void *data, int *result) {
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return splay_top_down(tree, data, result);
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}
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splay_node_t *splay_search_closest_smaller_node(splay_tree_t *tree, const void *data) {
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splay_node_t *node;
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int result;
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node = splay_search_closest_node(tree, data, &result);
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if(result < 0)
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node = node->prev;
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return node;
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}
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splay_node_t *splay_search_closest_greater_node(splay_tree_t *tree, const void *data) {
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splay_node_t *node;
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int result;
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node = splay_search_closest_node(tree, data, &result);
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if(result > 0)
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node = node->next;
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return node;
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}
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/* Insertion and deletion */
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splay_node_t *splay_insert(splay_tree_t *tree, void *data) {
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splay_node_t *closest, *new;
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int result;
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if(!tree->root) {
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new = splay_alloc_node();
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new->data = data;
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splay_insert_top(tree, new);
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} else {
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closest = splay_search_closest_node(tree, data, &result);
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if(!result)
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return NULL;
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new = splay_alloc_node();
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new->data = data;
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if(result < 0)
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splay_insert_before(tree, closest, new);
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else
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splay_insert_after(tree, closest, new);
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}
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return new;
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}
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splay_node_t *splay_insert_node(splay_tree_t *tree, splay_node_t *node) {
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splay_node_t *closest;
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int result;
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if(!tree->root)
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splay_insert_top(tree, node);
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else {
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closest = splay_search_closest_node(tree, node->data, &result);
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if(!result)
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return NULL;
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if(result < 0)
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splay_insert_before(tree, closest, node);
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else
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splay_insert_after(tree, closest, node);
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}
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return node;
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}
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void splay_insert_top(splay_tree_t *tree, splay_node_t *node) {
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node->prev = node->next = node->left = node->right = node->parent = NULL;
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tree->head = tree->tail = tree->root = node;
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}
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void splay_insert_before(splay_tree_t *tree, splay_node_t *before, splay_node_t *node) {
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if(!before) {
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if(tree->tail)
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splay_insert_after(tree, tree->tail, node);
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else
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splay_insert_top(tree, node);
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return;
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}
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node->next = before;
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if((node->prev = before->prev))
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before->prev->next = node;
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else
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tree->head = node;
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before->prev = node;
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splay_bottom_up(tree, before);
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node->right = before;
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before->parent = node;
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if((node->left = before->left))
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before->left->parent = node;
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before->left = NULL;
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node->parent = NULL;
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tree->root = node;
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}
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void splay_insert_after(splay_tree_t *tree, splay_node_t *after, splay_node_t *node) {
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if(!after) {
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if(tree->head)
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splay_insert_before(tree, tree->head, node);
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else
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splay_insert_top(tree, node);
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return;
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}
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node->prev = after;
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if((node->next = after->next))
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after->next->prev = node;
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else
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tree->tail = node;
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after->next = node;
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splay_bottom_up(tree, after);
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node->left = after;
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after->parent = node;
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if((node->right = after->right))
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after->right->parent = node;
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after->right = NULL;
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node->parent = NULL;
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tree->root = node;
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}
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splay_node_t *splay_unlink(splay_tree_t *tree, void *data) {
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splay_node_t *node;
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node = splay_search_node(tree, data);
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if(node)
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splay_unlink_node(tree, node);
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return node;
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}
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void splay_unlink_node(splay_tree_t *tree, splay_node_t *node) {
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if(node->prev)
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node->prev->next = node->next;
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else
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tree->head = node->next;
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if(node->next)
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node->next->prev = node->prev;
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else
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tree->tail = node->prev;
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splay_bottom_up(tree, node);
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if(node->prev) {
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node->left->parent = NULL;
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tree->root = node->left;
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if((node->prev->right = node->right))
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node->right->parent = node->prev;
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} else if(node->next) {
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tree->root = node->right;
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node->right->parent = NULL;
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} else {
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tree->root = NULL;
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}
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}
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void splay_delete_node(splay_tree_t *tree, splay_node_t *node) {
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splay_unlink_node(tree, node);
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splay_free_node(tree, node);
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}
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void splay_delete(splay_tree_t *tree, void *data) {
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splay_node_t *node;
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node = splay_search_node(tree, data);
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if(node)
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splay_delete_node(tree, node);
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}
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/* Fast tree cleanup */
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void splay_delete_tree(splay_tree_t *tree) {
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splay_node_t *node, *next;
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for(node = tree->root; node; node = next) {
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next = node->next;
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splay_free_node(tree, node);
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}
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splay_free_tree(tree);
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}
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/* Tree walking */
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void splay_foreach(const splay_tree_t *tree, splay_action_t action) {
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splay_node_t *node, *next;
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for(node = tree->head; node; node = next) {
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next = node->next;
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action(node->data);
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}
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}
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void splay_foreach_node(const splay_tree_t *tree, splay_action_t action) {
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splay_node_t *node, *next;
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for(node = tree->head; node; node = next) {
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next = node->next;
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action(node);
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}
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}
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