rbtree

annotate src/rbtree.c @ 0:6621337b6378

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red-black tree lib
author John Tsiombikas <nuclear@mutantstargoat.com>
date Sun, 09 Oct 2011 07:48:14 +0300
parents
children 53afe96233f2
rev   line source
nuclear@0 1 #include <stdio.h>
nuclear@0 2 #include <stdlib.h>
nuclear@0 3 #include <string.h>
nuclear@0 4 #include "rbtree.h"
nuclear@0 5
nuclear@0 6 #define INT2PTR(x) ((void*)(x))
nuclear@0 7 #define PTR2INT(x) ((int)(x))
nuclear@0 8
nuclear@0 9 struct rbtree {
nuclear@0 10 struct rbnode *root;
nuclear@0 11
nuclear@0 12 rb_alloc_func_t alloc;
nuclear@0 13 rb_free_func_t free;
nuclear@0 14
nuclear@0 15 rb_cmp_func_t cmp;
nuclear@0 16 rb_del_func_t del;
nuclear@0 17 void *del_cls;
nuclear@0 18
nuclear@0 19 struct rbnode *rstack, *iter;
nuclear@0 20 };
nuclear@0 21
nuclear@0 22 static int cmpaddr(void *ap, void *bp);
nuclear@0 23 static int cmpint(void *ap, void *bp);
nuclear@0 24
nuclear@0 25 static int count_nodes(struct rbnode *node);
nuclear@0 26 static void del_tree(struct rbnode *node, void (*delfunc)(struct rbnode*, void*), void *cls);
nuclear@0 27 static struct rbnode *insert(struct rbtree *rb, struct rbnode *tree, void *key, void *data);
nuclear@0 28 static struct rbnode *delete(struct rbtree *rb, struct rbnode *tree, void *key);
nuclear@0 29 static struct rbnode *find(struct rbtree *rb, struct rbnode *node, void *key);
nuclear@0 30 static void traverse(struct rbnode *node, void (*func)(struct rbnode*, void*), void *cls);
nuclear@0 31
nuclear@0 32 struct rbtree *rb_create(rb_cmp_func_t cmp_func)
nuclear@0 33 {
nuclear@0 34 struct rbtree *rb;
nuclear@0 35
nuclear@0 36 if(!(rb = malloc(sizeof *rb))) {
nuclear@0 37 return 0;
nuclear@0 38 }
nuclear@0 39 if(rb_init(rb, cmp_func) == -1) {
nuclear@0 40 free(rb);
nuclear@0 41 return 0;
nuclear@0 42 }
nuclear@0 43 return rb;
nuclear@0 44 }
nuclear@0 45
nuclear@0 46 void rb_free(struct rbtree *rb)
nuclear@0 47 {
nuclear@0 48 rb_destroy(rb);
nuclear@0 49 free(rb);
nuclear@0 50 }
nuclear@0 51
nuclear@0 52
nuclear@0 53 int rb_init(struct rbtree *rb, rb_cmp_func_t cmp_func)
nuclear@0 54 {
nuclear@0 55 memset(rb, 0, sizeof *rb);
nuclear@0 56
nuclear@0 57 if(cmp_func == RB_KEY_INT) {
nuclear@0 58 rb->cmp = cmpint;
nuclear@0 59 } else if(cmp_func == RB_KEY_STRING) {
nuclear@0 60 rb->cmp = (rb_cmp_func_t)strcmp;
nuclear@0 61 } else {
nuclear@0 62 rb->cmp = cmpaddr;
nuclear@0 63 }
nuclear@0 64
nuclear@0 65 rb->alloc = malloc;
nuclear@0 66 rb->free = free;
nuclear@0 67 return 0;
nuclear@0 68 }
nuclear@0 69
nuclear@0 70 void rb_destroy(struct rbtree *rb)
nuclear@0 71 {
nuclear@0 72 del_tree(rb->root, rb->del, rb->del_cls);
nuclear@0 73 }
nuclear@0 74
nuclear@0 75 void rb_set_allocator(struct rbtree *rb, rb_alloc_func_t alloc, rb_free_func_t free)
nuclear@0 76 {
nuclear@0 77 rb->alloc = alloc;
nuclear@0 78 rb->free = free;
nuclear@0 79 }
nuclear@0 80
nuclear@0 81
nuclear@0 82 void rb_set_compare_func(struct rbtree *rb, rb_cmp_func_t func)
nuclear@0 83 {
nuclear@0 84 rb->cmp = func;
nuclear@0 85 }
nuclear@0 86
nuclear@0 87 void rb_set_delete_func(struct rbtree *rb, rb_del_func_t func, void *cls)
nuclear@0 88 {
nuclear@0 89 rb->del = func;
nuclear@0 90 rb->del_cls = cls;
nuclear@0 91 }
nuclear@0 92
nuclear@0 93 int rb_size(struct rbtree *rb)
nuclear@0 94 {
nuclear@0 95 return count_nodes(rb->root);
nuclear@0 96 }
nuclear@0 97
nuclear@0 98 int rb_insert(struct rbtree *rb, void *key, void *data)
nuclear@0 99 {
nuclear@0 100 rb->root = insert(rb, rb->root, key, data);
nuclear@0 101 rb->root->red = 0;
nuclear@0 102 return 0;
nuclear@0 103 }
nuclear@0 104
nuclear@0 105 int rb_inserti(struct rbtree *rb, int key, void *data)
nuclear@0 106 {
nuclear@0 107 rb->root = insert(rb, rb->root, INT2PTR(key), data);
nuclear@0 108 rb->root->red = 0;
nuclear@0 109 return 0;
nuclear@0 110 }
nuclear@0 111
nuclear@0 112
nuclear@0 113 int rb_delete(struct rbtree *rb, void *key)
nuclear@0 114 {
nuclear@0 115 rb->root = delete(rb, rb->root, key);
nuclear@0 116 rb->root->red = 0;
nuclear@0 117 return 0;
nuclear@0 118 }
nuclear@0 119
nuclear@0 120 int rb_deletei(struct rbtree *rb, int key)
nuclear@0 121 {
nuclear@0 122 rb->root = delete(rb, rb->root, INT2PTR(key));
nuclear@0 123 rb->root->red = 0;
nuclear@0 124 return 0;
nuclear@0 125 }
nuclear@0 126
nuclear@0 127
nuclear@0 128 void *rb_find(struct rbtree *rb, void *key)
nuclear@0 129 {
nuclear@0 130 return find(rb, rb->root, key);
nuclear@0 131 }
nuclear@0 132
nuclear@0 133 void *rb_findi(struct rbtree *rb, int key)
nuclear@0 134 {
nuclear@0 135 return find(rb, rb->root, INT2PTR(key));
nuclear@0 136 }
nuclear@0 137
nuclear@0 138
nuclear@0 139 void rb_foreach(struct rbtree *rb, void (*func)(struct rbnode*, void*), void *cls)
nuclear@0 140 {
nuclear@0 141 traverse(rb->root, func, cls);
nuclear@0 142 }
nuclear@0 143
nuclear@0 144
nuclear@0 145 struct rbnode *rb_root(struct rbtree *rb)
nuclear@0 146 {
nuclear@0 147 return rb->root;
nuclear@0 148 }
nuclear@0 149
nuclear@0 150 void rb_begin(struct rbtree *rb)
nuclear@0 151 {
nuclear@0 152 rb->rstack = 0;
nuclear@0 153 rb->iter = rb->root;
nuclear@0 154 }
nuclear@0 155
nuclear@0 156 #define push(sp, x) ((x)->next = (sp), (sp) = (x))
nuclear@0 157 #define pop(sp) ((sp) = (sp)->next)
nuclear@0 158 #define top(sp) (sp)
nuclear@0 159
nuclear@0 160 struct rbnode *rb_next(struct rbtree *rb)
nuclear@0 161 {
nuclear@0 162 struct rbnode *res = 0;
nuclear@0 163
nuclear@0 164 while(rb->rstack || rb->iter) {
nuclear@0 165 if(rb->iter) {
nuclear@0 166 push(rb->rstack, rb->iter);
nuclear@0 167 rb->iter = rb->iter->left;
nuclear@0 168 } else {
nuclear@0 169 rb->iter = top(rb->rstack);
nuclear@0 170 pop(rb->rstack);
nuclear@0 171 res = rb->iter;
nuclear@0 172 rb->iter = rb->iter->right;
nuclear@0 173 break;
nuclear@0 174 }
nuclear@0 175 }
nuclear@0 176 return res;
nuclear@0 177 }
nuclear@0 178
nuclear@0 179 void *rb_node_key(struct rbnode *node)
nuclear@0 180 {
nuclear@0 181 return node ? node->key : 0;
nuclear@0 182 }
nuclear@0 183
nuclear@0 184 int rb_node_keyi(struct rbnode *node)
nuclear@0 185 {
nuclear@0 186 return node ? PTR2INT(node->key) : 0;
nuclear@0 187 }
nuclear@0 188
nuclear@0 189 void *rb_node_data(struct rbnode *node)
nuclear@0 190 {
nuclear@0 191 return node ? node->data : 0;
nuclear@0 192 }
nuclear@0 193
nuclear@0 194 static int cmpaddr(void *ap, void *bp)
nuclear@0 195 {
nuclear@0 196 return ap < bp ? -1 : (ap > bp ? 1 : 0);
nuclear@0 197 }
nuclear@0 198
nuclear@0 199 static int cmpint(void *ap, void *bp)
nuclear@0 200 {
nuclear@0 201 return PTR2INT(ap) - PTR2INT(bp);
nuclear@0 202 }
nuclear@0 203
nuclear@0 204
nuclear@0 205 /* ---- left-leaning 2-3 red-black implementation ---- */
nuclear@0 206
nuclear@0 207 /* helper prototypes */
nuclear@0 208 static int is_red(struct rbnode *tree);
nuclear@0 209 static void color_flip(struct rbnode *tree);
nuclear@0 210 static struct rbnode *rot_left(struct rbnode *a);
nuclear@0 211 static struct rbnode *rot_right(struct rbnode *a);
nuclear@0 212 static struct rbnode *find_min(struct rbnode *tree);
nuclear@0 213 static struct rbnode *del_min(struct rbtree *rb, struct rbnode *tree);
nuclear@0 214 /*static struct rbnode *move_red_right(struct rbnode *tree);*/
nuclear@0 215 static struct rbnode *move_red_left(struct rbnode *tree);
nuclear@0 216 static struct rbnode *fix_up(struct rbnode *tree);
nuclear@0 217
nuclear@0 218 static int count_nodes(struct rbnode *node)
nuclear@0 219 {
nuclear@0 220 if(!node)
nuclear@0 221 return 0;
nuclear@0 222
nuclear@0 223 return 1 + count_nodes(node->left) + count_nodes(node->right);
nuclear@0 224 }
nuclear@0 225
nuclear@0 226 static void del_tree(struct rbnode *node, rb_del_func_t delfunc, void *cls)
nuclear@0 227 {
nuclear@0 228 if(!node)
nuclear@0 229 return;
nuclear@0 230
nuclear@0 231 del_tree(node->left, delfunc, cls);
nuclear@0 232 del_tree(node->right, delfunc, cls);
nuclear@0 233
nuclear@0 234 delfunc(node, cls);
nuclear@0 235 free(node);
nuclear@0 236 }
nuclear@0 237
nuclear@0 238 static struct rbnode *insert(struct rbtree *rb, struct rbnode *tree, void *key, void *data)
nuclear@0 239 {
nuclear@0 240 int cmp;
nuclear@0 241
nuclear@0 242 if(!tree) {
nuclear@0 243 struct rbnode *node = rb->alloc(sizeof *node);
nuclear@0 244 node->red = 1;
nuclear@0 245 node->key = key;
nuclear@0 246 node->data = data;
nuclear@0 247 node->left = node->right = 0;
nuclear@0 248 return node;
nuclear@0 249 }
nuclear@0 250
nuclear@0 251 cmp = rb->cmp(key, tree->key);
nuclear@0 252
nuclear@0 253 if(cmp < 0) {
nuclear@0 254 tree->left = insert(rb, tree->left, key, data);
nuclear@0 255 } else if(cmp > 0) {
nuclear@0 256 tree->right = insert(rb, tree->right, key, data);
nuclear@0 257 } else {
nuclear@0 258 tree->data = data;
nuclear@0 259 }
nuclear@0 260
nuclear@0 261 /* fix right-leaning reds */
nuclear@0 262 if(is_red(tree->right)) {
nuclear@0 263 tree = rot_left(tree);
nuclear@0 264 }
nuclear@0 265 /* fix two reds in a row */
nuclear@0 266 if(is_red(tree->left) && is_red(tree->left->left)) {
nuclear@0 267 tree = rot_right(tree);
nuclear@0 268 }
nuclear@0 269
nuclear@0 270 /* if 4-node, split it by color inversion */
nuclear@0 271 if(is_red(tree->left) && is_red(tree->right)) {
nuclear@0 272 color_flip(tree);
nuclear@0 273 }
nuclear@0 274
nuclear@0 275 return tree;
nuclear@0 276 }
nuclear@0 277
nuclear@0 278 static struct rbnode *delete(struct rbtree *rb, struct rbnode *tree, void *key)
nuclear@0 279 {
nuclear@0 280 int cmp;
nuclear@0 281
nuclear@0 282 if(!tree) {
nuclear@0 283 return 0;
nuclear@0 284 }
nuclear@0 285
nuclear@0 286 cmp = rb->cmp(key, tree->key);
nuclear@0 287
nuclear@0 288 if(cmp < 0) {
nuclear@0 289 if(!is_red(tree->left) && !is_red(tree->left->left)) {
nuclear@0 290 tree = move_red_left(tree);
nuclear@0 291 }
nuclear@0 292 tree->left = delete(rb, tree->left, key);
nuclear@0 293 } else {
nuclear@0 294 /* need reds on the right */
nuclear@0 295 if(is_red(tree->left)) {
nuclear@0 296 tree = rot_right(tree);
nuclear@0 297 }
nuclear@0 298
nuclear@0 299 /* found it at the bottom (XXX what certifies left is null?) */
nuclear@0 300 if(cmp == 0 && !tree->right) {
nuclear@0 301 if(rb->del) {
nuclear@0 302 rb->del(tree, rb->del_cls);
nuclear@0 303 }
nuclear@0 304 rb->free(tree);
nuclear@0 305 return 0;
nuclear@0 306 }
nuclear@0 307
nuclear@0 308 if(!is_red(tree->right) && !is_red(tree->right->left)) {
nuclear@0 309 tree = move_red_left(tree);
nuclear@0 310 }
nuclear@0 311
nuclear@0 312 if(key == tree->key) {
nuclear@0 313 struct rbnode *rmin = find_min(tree->right);
nuclear@0 314 tree->key = rmin->key;
nuclear@0 315 tree->data = rmin->data;
nuclear@0 316 tree->right = del_min(rb, tree->right);
nuclear@0 317 } else {
nuclear@0 318 tree->right = delete(rb, tree->right, key);
nuclear@0 319 }
nuclear@0 320 }
nuclear@0 321
nuclear@0 322 return fix_up(tree);
nuclear@0 323 }
nuclear@0 324
nuclear@0 325 static struct rbnode *find(struct rbtree *rb, struct rbnode *node, void *key)
nuclear@0 326 {
nuclear@0 327 int cmp;
nuclear@0 328
nuclear@0 329 if(!node)
nuclear@0 330 return 0;
nuclear@0 331
nuclear@0 332 if((cmp = rb->cmp(key, node->key)) == 0) {
nuclear@0 333 return node;
nuclear@0 334 }
nuclear@0 335 return find(rb, cmp < 0 ? node->left : node->right, key);
nuclear@0 336 }
nuclear@0 337
nuclear@0 338 static void traverse(struct rbnode *node, void (*func)(struct rbnode*, void*), void *cls)
nuclear@0 339 {
nuclear@0 340 if(!node)
nuclear@0 341 return;
nuclear@0 342
nuclear@0 343 traverse(node->left, func, cls);
nuclear@0 344 func(node, cls);
nuclear@0 345 traverse(node->right, func, cls);
nuclear@0 346 }
nuclear@0 347
nuclear@0 348 /* helpers */
nuclear@0 349
nuclear@0 350 static int is_red(struct rbnode *tree)
nuclear@0 351 {
nuclear@0 352 return tree && tree->red;
nuclear@0 353 }
nuclear@0 354
nuclear@0 355 static void color_flip(struct rbnode *tree)
nuclear@0 356 {
nuclear@0 357 tree->red = !tree->red;
nuclear@0 358 tree->left->red = !tree->left->red;
nuclear@0 359 tree->right->red = !tree->right->red;
nuclear@0 360 }
nuclear@0 361
nuclear@0 362 static struct rbnode *rot_left(struct rbnode *a)
nuclear@0 363 {
nuclear@0 364 struct rbnode *b = a->right;
nuclear@0 365 a->right = b->left;
nuclear@0 366 b->left = a;
nuclear@0 367 b->red = a->red;
nuclear@0 368 a->red = 1;
nuclear@0 369 return b;
nuclear@0 370 }
nuclear@0 371
nuclear@0 372 static struct rbnode *rot_right(struct rbnode *a)
nuclear@0 373 {
nuclear@0 374 struct rbnode *b = a->left;
nuclear@0 375 a->left = b->right;
nuclear@0 376 b->right = a;
nuclear@0 377 b->red = a->red;
nuclear@0 378 a->red = 1;
nuclear@0 379 return b;
nuclear@0 380 }
nuclear@0 381
nuclear@0 382 static struct rbnode *find_min(struct rbnode *tree)
nuclear@0 383 {
nuclear@0 384 if(!tree || !tree->left) {
nuclear@0 385 return tree;
nuclear@0 386 }
nuclear@0 387 return find_min(tree->left);
nuclear@0 388 }
nuclear@0 389
nuclear@0 390 static struct rbnode *del_min(struct rbtree *rb, struct rbnode *tree)
nuclear@0 391 {
nuclear@0 392 if(!tree->left) {
nuclear@0 393 if(rb->del) {
nuclear@0 394 rb->del(tree->left, rb->del_cls);
nuclear@0 395 }
nuclear@0 396 rb->free(tree->left);
nuclear@0 397 return 0;
nuclear@0 398 }
nuclear@0 399
nuclear@0 400 /* make sure we've got red (3/4-nodes) at the left side so we can delete at the bottom */
nuclear@0 401 if(!is_red(tree->left) && !is_red(tree->left->left)) {
nuclear@0 402 tree = move_red_left(tree);
nuclear@0 403 }
nuclear@0 404 tree->left = del_min(rb, tree->left);
nuclear@0 405
nuclear@0 406 /* fix right-reds, red-reds, and split 4-nodes on the way up */
nuclear@0 407 return fix_up(tree);
nuclear@0 408 }
nuclear@0 409
nuclear@0 410 #if 0
nuclear@0 411 /* push a red link on this node to the right */
nuclear@0 412 static struct rbnode *move_red_right(struct rbnode *tree)
nuclear@0 413 {
nuclear@0 414 /* flipping it makes both children go red, so we have a red to the right */
nuclear@0 415 color_flip(tree);
nuclear@0 416
nuclear@0 417 /* if after the flip we've got a red-red situation to the left, fix it */
nuclear@0 418 if(is_red(tree->left->left)) {
nuclear@0 419 tree = rot_right(tree);
nuclear@0 420 color_flip(tree);
nuclear@0 421 }
nuclear@0 422 return tree;
nuclear@0 423 }
nuclear@0 424 #endif
nuclear@0 425
nuclear@0 426 /* push a red link on this node to the left */
nuclear@0 427 static struct rbnode *move_red_left(struct rbnode *tree)
nuclear@0 428 {
nuclear@0 429 /* flipping it makes both children go red, so we have a red to the left */
nuclear@0 430 color_flip(tree);
nuclear@0 431
nuclear@0 432 /* if after the flip we've got a red-red on the right-left, fix it */
nuclear@0 433 if(is_red(tree->right->left)) {
nuclear@0 434 tree->right = rot_right(tree->right);
nuclear@0 435 tree = rot_left(tree);
nuclear@0 436 color_flip(tree);
nuclear@0 437 }
nuclear@0 438 return tree;
nuclear@0 439 }
nuclear@0 440
nuclear@0 441 static struct rbnode *fix_up(struct rbnode *tree)
nuclear@0 442 {
nuclear@0 443 /* fix right-leaning */
nuclear@0 444 if(is_red(tree->right)) {
nuclear@0 445 tree = rot_left(tree);
nuclear@0 446 }
nuclear@0 447 /* change invalid red-red pairs into a proper 4-node */
nuclear@0 448 if(is_red(tree->left) && is_red(tree->left->left)) {
nuclear@0 449 tree = rot_right(tree);
nuclear@0 450 }
nuclear@0 451 /* split 4-nodes */
nuclear@0 452 if(is_red(tree->left) && is_red(tree->right)) {
nuclear@0 453 color_flip(tree);
nuclear@0 454 }
nuclear@0 455 return tree;
nuclear@0 456 }