2 rbtree - simple balanced binary search tree (red-black tree) library.
3 Copyright (C) 2011-2014 John Tsiombikas <nuclear@member.fsf.org>
5 rbtree is free software, feel free to use, modify, and redistribute it, under
6 the terms of the 3-clause BSD license. See COPYING for details.
14 #define INT2PTR(x) ((void*)(intptr_t)(x))
15 #define PTR2INT(x) ((int)(intptr_t)(x))
20 rb_alloc_func_t alloc;
27 struct rbnode *rstack, *iter;
30 static int cmpaddr(const void *ap, const void *bp);
31 static int cmpint(const void *ap, const void *bp);
33 static int count_nodes(struct rbnode *node);
34 static void del_tree(struct rbnode *node, void (*delfunc)(struct rbnode*, void*), void *cls);
35 static struct rbnode *insert(struct rbtree *rb, struct rbnode *tree, void *key, void *data);
36 static struct rbnode *delete(struct rbtree *rb, struct rbnode *tree, void *key);
37 /*static struct rbnode *find(struct rbtree *rb, struct rbnode *node, void *key);*/
38 static void traverse(struct rbnode *node, void (*func)(struct rbnode*, void*), void *cls);
40 struct rbtree *rb_create(rb_cmp_func_t cmp_func)
44 if(!(rb = malloc(sizeof *rb))) {
47 if(rb_init(rb, cmp_func) == -1) {
54 void rb_free(struct rbtree *rb)
63 int rb_init(struct rbtree *rb, rb_cmp_func_t cmp_func)
65 memset(rb, 0, sizeof *rb);
69 } else if(cmp_func == RB_KEY_INT) {
71 } else if(cmp_func == RB_KEY_STRING) {
72 rb->cmp = (rb_cmp_func_t)strcmp;
82 void rb_destroy(struct rbtree *rb)
84 del_tree(rb->root, rb->del, rb->del_cls);
87 void rb_set_allocator(struct rbtree *rb, rb_alloc_func_t alloc, rb_free_func_t free)
94 void rb_set_compare_func(struct rbtree *rb, rb_cmp_func_t func)
99 void rb_set_delete_func(struct rbtree *rb, rb_del_func_t func, void *cls)
106 void rb_clear(struct rbtree *rb)
108 del_tree(rb->root, rb->del, rb->del_cls);
112 int rb_copy(struct rbtree *dest, struct rbtree *src)
118 while((node = rb_next(src))) {
119 if(rb_insert(dest, node->key, node->data) == -1) {
126 int rb_size(struct rbtree *rb)
128 return count_nodes(rb->root);
131 int rb_insert(struct rbtree *rb, void *key, void *data)
133 rb->root = insert(rb, rb->root, key, data);
138 int rb_inserti(struct rbtree *rb, int key, void *data)
140 rb->root = insert(rb, rb->root, INT2PTR(key), data);
146 int rb_delete(struct rbtree *rb, void *key)
148 if((rb->root = delete(rb, rb->root, key))) {
154 int rb_deletei(struct rbtree *rb, int key)
156 if((rb->root = delete(rb, rb->root, INT2PTR(key)))) {
163 struct rbnode *rb_find(struct rbtree *rb, void *key)
165 struct rbnode *node = rb->root;
168 int cmp = rb->cmp(key, node->key);
172 node = cmp < 0 ? node->left : node->right;
177 struct rbnode *rb_findi(struct rbtree *rb, int key)
179 return rb_find(rb, INT2PTR(key));
183 void rb_foreach(struct rbtree *rb, void (*func)(struct rbnode*, void*), void *cls)
185 traverse(rb->root, func, cls);
189 struct rbnode *rb_root(struct rbtree *rb)
194 void rb_begin(struct rbtree *rb)
200 #define push(sp, x) ((x)->next = (sp), (sp) = (x))
201 #define pop(sp) ((sp) = (sp)->next)
204 struct rbnode *rb_next(struct rbtree *rb)
206 struct rbnode *res = 0;
208 while(rb->rstack || rb->iter) {
210 push(rb->rstack, rb->iter);
211 rb->iter = rb->iter->left;
213 rb->iter = top(rb->rstack);
216 rb->iter = rb->iter->right;
223 void *rb_node_key(struct rbnode *node)
225 return node ? node->key : 0;
228 int rb_node_keyi(struct rbnode *node)
230 return node ? PTR2INT(node->key) : 0;
233 void *rb_node_data(struct rbnode *node)
235 return node ? node->data : 0;
238 static int cmpaddr(const void *ap, const void *bp)
240 return ap < bp ? -1 : (ap > bp ? 1 : 0);
243 static int cmpint(const void *ap, const void *bp)
245 return PTR2INT(ap) - PTR2INT(bp);
249 /* ---- left-leaning 2-3 red-black implementation ---- */
251 /* helper prototypes */
252 static int is_red(struct rbnode *tree);
253 static void color_flip(struct rbnode *tree);
254 static struct rbnode *rot_left(struct rbnode *a);
255 static struct rbnode *rot_right(struct rbnode *a);
256 static struct rbnode *find_min(struct rbnode *tree);
257 static struct rbnode *del_min(struct rbtree *rb, struct rbnode *tree);
258 /*static struct rbnode *move_red_right(struct rbnode *tree);*/
259 static struct rbnode *move_red_left(struct rbnode *tree);
260 static struct rbnode *fix_up(struct rbnode *tree);
262 static int count_nodes(struct rbnode *node)
267 return 1 + count_nodes(node->left) + count_nodes(node->right);
270 static void del_tree(struct rbnode *node, rb_del_func_t delfunc, void *cls)
275 del_tree(node->left, delfunc, cls);
276 del_tree(node->right, delfunc, cls);
284 static struct rbnode *insert(struct rbtree *rb, struct rbnode *tree, void *key, void *data)
289 struct rbnode *node = rb->alloc(sizeof *node);
293 node->left = node->right = 0;
297 cmp = rb->cmp(key, tree->key);
300 tree->left = insert(rb, tree->left, key, data);
302 tree->right = insert(rb, tree->right, key, data);
307 /* fix right-leaning reds */
308 if(is_red(tree->right)) {
309 tree = rot_left(tree);
311 /* fix two reds in a row */
312 if(is_red(tree->left) && is_red(tree->left->left)) {
313 tree = rot_right(tree);
316 /* if 4-node, split it by color inversion */
317 if(is_red(tree->left) && is_red(tree->right)) {
324 static struct rbnode *delete(struct rbtree *rb, struct rbnode *tree, void *key)
332 cmp = rb->cmp(key, tree->key);
335 if(!is_red(tree->left) && !is_red(tree->left->left)) {
336 tree = move_red_left(tree);
338 tree->left = delete(rb, tree->left, key);
340 /* need reds on the right */
341 if(is_red(tree->left)) {
342 tree = rot_right(tree);
345 /* found it at the bottom (XXX what certifies left is null?) */
346 if(cmp == 0 && !tree->right) {
348 rb->del(tree, rb->del_cls);
354 if(!is_red(tree->right) && !is_red(tree->right->left)) {
355 tree = move_red_left(tree);
358 if(key == tree->key) {
359 struct rbnode *rmin = find_min(tree->right);
360 tree->key = rmin->key;
361 tree->data = rmin->data;
362 tree->right = del_min(rb, tree->right);
364 tree->right = delete(rb, tree->right, key);
371 /*static struct rbnode *find(struct rbtree *rb, struct rbnode *node, void *key)
378 if((cmp = rb->cmp(key, node->key)) == 0) {
381 return find(rb, cmp < 0 ? node->left : node->right, key);
384 static void traverse(struct rbnode *node, void (*func)(struct rbnode*, void*), void *cls)
389 traverse(node->left, func, cls);
391 traverse(node->right, func, cls);
396 static int is_red(struct rbnode *tree)
398 return tree && tree->red;
401 static void color_flip(struct rbnode *tree)
403 tree->red = !tree->red;
404 tree->left->red = !tree->left->red;
405 tree->right->red = !tree->right->red;
408 static struct rbnode *rot_left(struct rbnode *a)
410 struct rbnode *b = a->right;
418 static struct rbnode *rot_right(struct rbnode *a)
420 struct rbnode *b = a->left;
428 static struct rbnode *find_min(struct rbnode *tree)
439 static struct rbnode *del_min(struct rbtree *rb, struct rbnode *tree)
443 rb->del(tree->left, rb->del_cls);
445 rb->free(tree->left);
449 /* make sure we've got red (3/4-nodes) at the left side so we can delete at the bottom */
450 if(!is_red(tree->left) && !is_red(tree->left->left)) {
451 tree = move_red_left(tree);
453 tree->left = del_min(rb, tree->left);
455 /* fix right-reds, red-reds, and split 4-nodes on the way up */
460 /* push a red link on this node to the right */
461 static struct rbnode *move_red_right(struct rbnode *tree)
463 /* flipping it makes both children go red, so we have a red to the right */
466 /* if after the flip we've got a red-red situation to the left, fix it */
467 if(is_red(tree->left->left)) {
468 tree = rot_right(tree);
475 /* push a red link on this node to the left */
476 static struct rbnode *move_red_left(struct rbnode *tree)
478 /* flipping it makes both children go red, so we have a red to the left */
481 /* if after the flip we've got a red-red on the right-left, fix it */
482 if(is_red(tree->right->left)) {
483 tree->right = rot_right(tree->right);
484 tree = rot_left(tree);
490 static struct rbnode *fix_up(struct rbnode *tree)
492 /* fix right-leaning */
493 if(is_red(tree->right)) {
494 tree = rot_left(tree);
496 /* change invalid red-red pairs into a proper 4-node */
497 if(is_red(tree->left) && is_red(tree->left->left)) {
498 tree = rot_right(tree);
501 if(is_red(tree->left) && is_red(tree->right)) {