Initial commit
This commit is contained in:
Henrik Hautakoski
commit
fdfefe7d55
31 changed files with 3242 additions and 0 deletions
355
src/common/rbtree.c
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355
src/common/rbtree.c
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/*
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* Modified version of Julienne Walker's implementation
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* http://www.eternallyconfuzzled.com/tuts/datastructures/jsw_tut_rbtree.aspx
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*
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* Copyright (C) 2010 Archived
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*
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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 3 of the License, or
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* (at your option) any later version.
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*
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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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*
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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, see <http://www.gnu.org/licenses/>.
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*
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* Do not touch anything in this file. it's perfect ;)
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*/
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#include <malloc.h>
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#include "debug.h"
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#include "rbtree.h"
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#define is_red(n) (n != NULL && n->color == RB_RED)
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#define swap(n,d,q) n->child[n->child[d] == q]
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#ifdef __DEBUG__
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int rb_assert(rbnode *node) {
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int rh, lh;
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rbnode *ln;
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rbnode *rn;
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if (node == NULL) {
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return 1;
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}
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ln = node->child[0];
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rn = node->child[1];
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if (is_red(node)) {
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if (is_red(ln) || is_red(rn)) {
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die("Double red");
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return 0;
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}
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}
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lh = rb_assert(ln);
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rh = rb_assert(rn);
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if ( (ln != NULL && ln->key >= node->key) &&
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(rn != NULL && rn->key <= node->key) ) {
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die("BST violation");
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return 0;
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}
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if (rh != 0 && lh != 0) {
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if (rh != lh) {
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die("Black height violation");
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return 0;
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}
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return (is_red(node)) ? lh : lh+1;
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}
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return 0;
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}
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#endif
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static rbnode* node_alloc(uint key, void *ptr) {
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rbnode *n = malloc(sizeof(rbnode));
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if (n == NULL)
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return NULL;
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n->key = key;
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n->data = ptr;
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n->color = RB_RED;
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n->child[0] = NULL;
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n->child[1] = NULL;
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return n;
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}
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static void node_dealloc(rbnode *n, void (*a)(rbnode *)) {
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if (n == NULL)
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return;
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if (a != NULL)
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a(n);
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else
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free(n->data);
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node_dealloc(n->child[0], a);
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node_dealloc(n->child[1], a);
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free(n);
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}
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static void _rbwalk(rbnode *n, void (*a)(rbnode *)) {
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if (n == NULL)
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return;
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a(n);
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_rbwalk(n->child[0], a);
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_rbwalk(n->child[1], a);
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}
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static rbnode* _rbcmp(rbnode *n, void *d, size_t l) {
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rbnode* r;
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if (n == NULL)
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return NULL;
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if (memcmp(n->data, d, l) == 0)
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return n;
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r = _rbcmp(n->child[0], d, l);
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if (r == NULL)
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r = _rbcmp(n->child[1], d, l);
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return r;
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}
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static rbnode* rotate_single(rbnode *root, unsigned char dir) {
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rbnode *save = root->child[!dir];
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root->child[!dir] = save->child[dir];
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save->child[dir] = root;
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root->color = RB_RED;
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save->color = RB_BLACK;
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return save;
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}
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static rbnode* rotate_double(rbnode *root, unsigned char dir) {
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root->child[!dir] = rotate_single(root->child[!dir], !dir);
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return rotate_single(root, dir);
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}
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int rbtree_insert(rbtree *tree, uint key, void *data) {
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rbnode head = {0};
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/* grandparent and parent */
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rbnode *g, *t;
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/* iterator and parent */
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rbnode *p, *q;
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unsigned char dir = 0, dir2, last;
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/* somewhere in here, there should be dragons */
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if (tree->root == NULL) {
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tree->root = node_alloc(key, data);
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if (tree->root == NULL)
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return 0;
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} else {
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t = &head;
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g = p = NULL;
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q = t->child[1] = tree->root;
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for(;;) {
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if (q == NULL) {
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p->child[dir] = q = node_alloc(key, data);
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if (q == NULL)
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return 0;
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} else if (is_red(q->child[0]) && is_red(q->child[1])) {
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/* color flip case */
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q->color = RB_RED;
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q->child[0]->color = RB_BLACK;
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q->child[1]->color = RB_BLACK;
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}
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/* fix red validation */
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if (is_red(q) && is_red(p)) {
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dir2 = (t->child[1] == g);
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if (q == p->child[last])
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t->child[dir2] = rotate_single(g, !last);
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else
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t->child[dir2] = rotate_double(g, !last);
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}
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if (q->key == key)
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break;
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last = dir;
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dir = q->key < key;
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if (g != NULL)
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t = g;
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g = p, p = q;
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q = q->child[dir];
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}
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tree->root = head.child[1];
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}
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/* root should be black */
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tree->root->color = RB_BLACK;
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return 1;
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}
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void* rbtree_delete(rbtree *tree, uint key) {
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rbnode head = {0};
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/* helpers*/
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rbnode *q, *p, *g, *s;
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/* found item */
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rbnode *f = NULL;
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/* pointer to the data member of the node we delete */
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void *ret = NULL;
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unsigned char dir = 1, dir2, last;
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if (rbtree_is_empty(tree))
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return NULL;
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q = &head;
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g = p = NULL;
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q->child[1] = tree->root;
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/* more dragons */
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while(q->child[dir] != NULL) {
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last = dir;
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g = p, p = q;
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q = q->child[dir];
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dir = q->key < key;
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if (q->key == key)
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f = q;
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if (!is_red(q) && !is_red(q->child[dir])) {
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if (is_red(q->child[!dir]))
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p = p->child[last] = rotate_single(q, dir);
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else if (!is_red(q->child[!dir])) {
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s = p->child[!last];
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if (s != NULL) {
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/* swap color if both child's are black */
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if (!is_red(s->child[!last]) && !is_red(s->child[last])) {
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p->color = RB_BLACK;
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s->color = q->color = RB_RED;
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} else {
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dir2 = (g->child[1] == p);
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if (is_red(s->child[last]))
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g->child[dir2] = rotate_double(p, last);
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else if (is_red(s->child[!last]))
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g->child[dir2] = rotate_single(p, last);
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q->color = g->child[dir2]->color = RB_RED;
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g->child[dir2]->child[0]->color = RB_BLACK;
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g->child[dir2]->child[1]->color = RB_BLACK;
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}
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}
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}
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}
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}
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tree->root = head.child[1];
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if (tree->root != NULL)
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tree->root->color = RB_BLACK;
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/* remove if found */
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if (f != NULL) {
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ret = q->data;
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if (q == tree->root) {
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tree->root = NULL;
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} else {
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if (f != q) {
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f->key = q->key;
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f->data = q->data;
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}
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swap(p,1,q) = swap(q, 0, NULL);
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}
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free(q);
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}
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return ret;
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}
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rbnode* rbtree_search(rbtree *tree, uint key) {
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rbnode *n;
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if (tree == NULL || tree->root == NULL)
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return NULL;
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n = tree->root;
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while(n != NULL) {
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#ifdef __DEBUG__
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printf("SEARCH: check %u\n", n->key);
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#endif
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if (n->key == key)
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break;
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n = n->child[n->key < key];
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}
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return n;
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}
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rbnode* rbtree_cmp_search(rbtree *tree, void *cmpdata, size_t len) {
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if (tree == NULL)
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return NULL;
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return _rbcmp(tree->root, cmpdata, len);
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}
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void rbtree_walk(rbtree *tree, void (*action)(rbnode *)) {
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if (tree == NULL)
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return;
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_rbwalk(tree->root, action);
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}
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void rbtree_free(rbtree *tree, void (*action)(rbnode *)) {
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if (tree == NULL)
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return;
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node_dealloc(tree->root, action);
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tree->root = NULL;
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}
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inline int rbtree_is_empty(rbtree *tree) {
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return tree == NULL || tree->root == NULL;
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}
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