rbtree

annotate src/rbtree.c @ 3:53afe96233f2

find changesets by author, revision, files, or words in the commit message
changed the tail-recursive find and find_min to loops
author John Tsiombikas <nuclear@mutantstargoat.com>
date Sun, 09 Oct 2011 08:30:54 +0300
parents 6621337b6378
children 56a08d00bb41
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@3 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@3 130 struct rbnode *node = rb->root;
nuclear@3 131
nuclear@3 132 while(node) {
nuclear@3 133 int cmp = rb->cmp(key, node->key);
nuclear@3 134 if(cmp == 0) {
nuclear@3 135 return node;
nuclear@3 136 }
nuclear@3 137 node = cmp < 0 ? node->left : node->right;
nuclear@3 138 }
nuclear@3 139 return 0;
nuclear@0 140 }
nuclear@0 141
nuclear@0 142 void *rb_findi(struct rbtree *rb, int key)
nuclear@0 143 {
nuclear@3 144 return rb_find(rb, INT2PTR(key));
nuclear@0 145 }
nuclear@0 146
nuclear@0 147
nuclear@0 148 void rb_foreach(struct rbtree *rb, void (*func)(struct rbnode*, void*), void *cls)
nuclear@0 149 {
nuclear@0 150 traverse(rb->root, func, cls);
nuclear@0 151 }
nuclear@0 152
nuclear@0 153
nuclear@0 154 struct rbnode *rb_root(struct rbtree *rb)
nuclear@0 155 {
nuclear@0 156 return rb->root;
nuclear@0 157 }
nuclear@0 158
nuclear@0 159 void rb_begin(struct rbtree *rb)
nuclear@0 160 {
nuclear@0 161 rb->rstack = 0;
nuclear@0 162 rb->iter = rb->root;
nuclear@0 163 }
nuclear@0 164
nuclear@0 165 #define push(sp, x) ((x)->next = (sp), (sp) = (x))
nuclear@0 166 #define pop(sp) ((sp) = (sp)->next)
nuclear@0 167 #define top(sp) (sp)
nuclear@0 168
nuclear@0 169 struct rbnode *rb_next(struct rbtree *rb)
nuclear@0 170 {
nuclear@0 171 struct rbnode *res = 0;
nuclear@0 172
nuclear@0 173 while(rb->rstack || rb->iter) {
nuclear@0 174 if(rb->iter) {
nuclear@0 175 push(rb->rstack, rb->iter);
nuclear@0 176 rb->iter = rb->iter->left;
nuclear@0 177 } else {
nuclear@0 178 rb->iter = top(rb->rstack);
nuclear@0 179 pop(rb->rstack);
nuclear@0 180 res = rb->iter;
nuclear@0 181 rb->iter = rb->iter->right;
nuclear@0 182 break;
nuclear@0 183 }
nuclear@0 184 }
nuclear@0 185 return res;
nuclear@0 186 }
nuclear@0 187
nuclear@0 188 void *rb_node_key(struct rbnode *node)
nuclear@0 189 {
nuclear@0 190 return node ? node->key : 0;
nuclear@0 191 }
nuclear@0 192
nuclear@0 193 int rb_node_keyi(struct rbnode *node)
nuclear@0 194 {
nuclear@0 195 return node ? PTR2INT(node->key) : 0;
nuclear@0 196 }
nuclear@0 197
nuclear@0 198 void *rb_node_data(struct rbnode *node)
nuclear@0 199 {
nuclear@0 200 return node ? node->data : 0;
nuclear@0 201 }
nuclear@0 202
nuclear@0 203 static int cmpaddr(void *ap, void *bp)
nuclear@0 204 {
nuclear@0 205 return ap < bp ? -1 : (ap > bp ? 1 : 0);
nuclear@0 206 }
nuclear@0 207
nuclear@0 208 static int cmpint(void *ap, void *bp)
nuclear@0 209 {
nuclear@0 210 return PTR2INT(ap) - PTR2INT(bp);
nuclear@0 211 }
nuclear@0 212
nuclear@0 213
nuclear@0 214 /* ---- left-leaning 2-3 red-black implementation ---- */
nuclear@0 215
nuclear@0 216 /* helper prototypes */
nuclear@0 217 static int is_red(struct rbnode *tree);
nuclear@0 218 static void color_flip(struct rbnode *tree);
nuclear@0 219 static struct rbnode *rot_left(struct rbnode *a);
nuclear@0 220 static struct rbnode *rot_right(struct rbnode *a);
nuclear@0 221 static struct rbnode *find_min(struct rbnode *tree);
nuclear@0 222 static struct rbnode *del_min(struct rbtree *rb, struct rbnode *tree);
nuclear@0 223 /*static struct rbnode *move_red_right(struct rbnode *tree);*/
nuclear@0 224 static struct rbnode *move_red_left(struct rbnode *tree);
nuclear@0 225 static struct rbnode *fix_up(struct rbnode *tree);
nuclear@0 226
nuclear@0 227 static int count_nodes(struct rbnode *node)
nuclear@0 228 {
nuclear@0 229 if(!node)
nuclear@0 230 return 0;
nuclear@0 231
nuclear@0 232 return 1 + count_nodes(node->left) + count_nodes(node->right);
nuclear@0 233 }
nuclear@0 234
nuclear@0 235 static void del_tree(struct rbnode *node, rb_del_func_t delfunc, void *cls)
nuclear@0 236 {
nuclear@0 237 if(!node)
nuclear@0 238 return;
nuclear@0 239
nuclear@0 240 del_tree(node->left, delfunc, cls);
nuclear@0 241 del_tree(node->right, delfunc, cls);
nuclear@0 242
nuclear@0 243 delfunc(node, cls);
nuclear@0 244 free(node);
nuclear@0 245 }
nuclear@0 246
nuclear@0 247 static struct rbnode *insert(struct rbtree *rb, struct rbnode *tree, void *key, void *data)
nuclear@0 248 {
nuclear@0 249 int cmp;
nuclear@0 250
nuclear@0 251 if(!tree) {
nuclear@0 252 struct rbnode *node = rb->alloc(sizeof *node);
nuclear@0 253 node->red = 1;
nuclear@0 254 node->key = key;
nuclear@0 255 node->data = data;
nuclear@0 256 node->left = node->right = 0;
nuclear@0 257 return node;
nuclear@0 258 }
nuclear@0 259
nuclear@0 260 cmp = rb->cmp(key, tree->key);
nuclear@0 261
nuclear@0 262 if(cmp < 0) {
nuclear@0 263 tree->left = insert(rb, tree->left, key, data);
nuclear@0 264 } else if(cmp > 0) {
nuclear@0 265 tree->right = insert(rb, tree->right, key, data);
nuclear@0 266 } else {
nuclear@0 267 tree->data = data;
nuclear@0 268 }
nuclear@0 269
nuclear@0 270 /* fix right-leaning reds */
nuclear@0 271 if(is_red(tree->right)) {
nuclear@0 272 tree = rot_left(tree);
nuclear@0 273 }
nuclear@0 274 /* fix two reds in a row */
nuclear@0 275 if(is_red(tree->left) && is_red(tree->left->left)) {
nuclear@0 276 tree = rot_right(tree);
nuclear@0 277 }
nuclear@0 278
nuclear@0 279 /* if 4-node, split it by color inversion */
nuclear@0 280 if(is_red(tree->left) && is_red(tree->right)) {
nuclear@0 281 color_flip(tree);
nuclear@0 282 }
nuclear@0 283
nuclear@0 284 return tree;
nuclear@0 285 }
nuclear@0 286
nuclear@0 287 static struct rbnode *delete(struct rbtree *rb, struct rbnode *tree, void *key)
nuclear@0 288 {
nuclear@0 289 int cmp;
nuclear@0 290
nuclear@0 291 if(!tree) {
nuclear@0 292 return 0;
nuclear@0 293 }
nuclear@0 294
nuclear@0 295 cmp = rb->cmp(key, tree->key);
nuclear@0 296
nuclear@0 297 if(cmp < 0) {
nuclear@0 298 if(!is_red(tree->left) && !is_red(tree->left->left)) {
nuclear@0 299 tree = move_red_left(tree);
nuclear@0 300 }
nuclear@0 301 tree->left = delete(rb, tree->left, key);
nuclear@0 302 } else {
nuclear@0 303 /* need reds on the right */
nuclear@0 304 if(is_red(tree->left)) {
nuclear@0 305 tree = rot_right(tree);
nuclear@0 306 }
nuclear@0 307
nuclear@0 308 /* found it at the bottom (XXX what certifies left is null?) */
nuclear@0 309 if(cmp == 0 && !tree->right) {
nuclear@0 310 if(rb->del) {
nuclear@0 311 rb->del(tree, rb->del_cls);
nuclear@0 312 }
nuclear@0 313 rb->free(tree);
nuclear@0 314 return 0;
nuclear@0 315 }
nuclear@0 316
nuclear@0 317 if(!is_red(tree->right) && !is_red(tree->right->left)) {
nuclear@0 318 tree = move_red_left(tree);
nuclear@0 319 }
nuclear@0 320
nuclear@0 321 if(key == tree->key) {
nuclear@0 322 struct rbnode *rmin = find_min(tree->right);
nuclear@0 323 tree->key = rmin->key;
nuclear@0 324 tree->data = rmin->data;
nuclear@0 325 tree->right = del_min(rb, tree->right);
nuclear@0 326 } else {
nuclear@0 327 tree->right = delete(rb, tree->right, key);
nuclear@0 328 }
nuclear@0 329 }
nuclear@0 330
nuclear@0 331 return fix_up(tree);
nuclear@0 332 }
nuclear@0 333
nuclear@3 334 /*static struct rbnode *find(struct rbtree *rb, struct rbnode *node, void *key)
nuclear@0 335 {
nuclear@0 336 int cmp;
nuclear@0 337
nuclear@0 338 if(!node)
nuclear@0 339 return 0;
nuclear@0 340
nuclear@0 341 if((cmp = rb->cmp(key, node->key)) == 0) {
nuclear@0 342 return node;
nuclear@0 343 }
nuclear@0 344 return find(rb, cmp < 0 ? node->left : node->right, key);
nuclear@3 345 }*/
nuclear@0 346
nuclear@0 347 static void traverse(struct rbnode *node, void (*func)(struct rbnode*, void*), void *cls)
nuclear@0 348 {
nuclear@0 349 if(!node)
nuclear@0 350 return;
nuclear@0 351
nuclear@0 352 traverse(node->left, func, cls);
nuclear@0 353 func(node, cls);
nuclear@0 354 traverse(node->right, func, cls);
nuclear@0 355 }
nuclear@0 356
nuclear@0 357 /* helpers */
nuclear@0 358
nuclear@0 359 static int is_red(struct rbnode *tree)
nuclear@0 360 {
nuclear@0 361 return tree && tree->red;
nuclear@0 362 }
nuclear@0 363
nuclear@0 364 static void color_flip(struct rbnode *tree)
nuclear@0 365 {
nuclear@0 366 tree->red = !tree->red;
nuclear@0 367 tree->left->red = !tree->left->red;
nuclear@0 368 tree->right->red = !tree->right->red;
nuclear@0 369 }
nuclear@0 370
nuclear@0 371 static struct rbnode *rot_left(struct rbnode *a)
nuclear@0 372 {
nuclear@0 373 struct rbnode *b = a->right;
nuclear@0 374 a->right = b->left;
nuclear@0 375 b->left = a;
nuclear@0 376 b->red = a->red;
nuclear@0 377 a->red = 1;
nuclear@0 378 return b;
nuclear@0 379 }
nuclear@0 380
nuclear@0 381 static struct rbnode *rot_right(struct rbnode *a)
nuclear@0 382 {
nuclear@0 383 struct rbnode *b = a->left;
nuclear@0 384 a->left = b->right;
nuclear@0 385 b->right = a;
nuclear@0 386 b->red = a->red;
nuclear@0 387 a->red = 1;
nuclear@0 388 return b;
nuclear@0 389 }
nuclear@0 390
nuclear@0 391 static struct rbnode *find_min(struct rbnode *tree)
nuclear@0 392 {
nuclear@3 393 struct rbnode *node;
nuclear@3 394
nuclear@3 395 if(!tree)
nuclear@3 396 return 0;
nuclear@3 397
nuclear@3 398 while(node->left) {
nuclear@3 399 node = node->left;
nuclear@0 400 }
nuclear@3 401 return node;
nuclear@0 402 }
nuclear@0 403
nuclear@0 404 static struct rbnode *del_min(struct rbtree *rb, struct rbnode *tree)
nuclear@0 405 {
nuclear@0 406 if(!tree->left) {
nuclear@0 407 if(rb->del) {
nuclear@0 408 rb->del(tree->left, rb->del_cls);
nuclear@0 409 }
nuclear@0 410 rb->free(tree->left);
nuclear@0 411 return 0;
nuclear@0 412 }
nuclear@0 413
nuclear@0 414 /* make sure we've got red (3/4-nodes) at the left side so we can delete at the bottom */
nuclear@0 415 if(!is_red(tree->left) && !is_red(tree->left->left)) {
nuclear@0 416 tree = move_red_left(tree);
nuclear@0 417 }
nuclear@0 418 tree->left = del_min(rb, tree->left);
nuclear@0 419
nuclear@0 420 /* fix right-reds, red-reds, and split 4-nodes on the way up */
nuclear@0 421 return fix_up(tree);
nuclear@0 422 }
nuclear@0 423
nuclear@0 424 #if 0
nuclear@0 425 /* push a red link on this node to the right */
nuclear@0 426 static struct rbnode *move_red_right(struct rbnode *tree)
nuclear@0 427 {
nuclear@0 428 /* flipping it makes both children go red, so we have a red to the right */
nuclear@0 429 color_flip(tree);
nuclear@0 430
nuclear@0 431 /* if after the flip we've got a red-red situation to the left, fix it */
nuclear@0 432 if(is_red(tree->left->left)) {
nuclear@0 433 tree = rot_right(tree);
nuclear@0 434 color_flip(tree);
nuclear@0 435 }
nuclear@0 436 return tree;
nuclear@0 437 }
nuclear@0 438 #endif
nuclear@0 439
nuclear@0 440 /* push a red link on this node to the left */
nuclear@0 441 static struct rbnode *move_red_left(struct rbnode *tree)
nuclear@0 442 {
nuclear@0 443 /* flipping it makes both children go red, so we have a red to the left */
nuclear@0 444 color_flip(tree);
nuclear@0 445
nuclear@0 446 /* if after the flip we've got a red-red on the right-left, fix it */
nuclear@0 447 if(is_red(tree->right->left)) {
nuclear@0 448 tree->right = rot_right(tree->right);
nuclear@0 449 tree = rot_left(tree);
nuclear@0 450 color_flip(tree);
nuclear@0 451 }
nuclear@0 452 return tree;
nuclear@0 453 }
nuclear@0 454
nuclear@0 455 static struct rbnode *fix_up(struct rbnode *tree)
nuclear@0 456 {
nuclear@0 457 /* fix right-leaning */
nuclear@0 458 if(is_red(tree->right)) {
nuclear@0 459 tree = rot_left(tree);
nuclear@0 460 }
nuclear@0 461 /* change invalid red-red pairs into a proper 4-node */
nuclear@0 462 if(is_red(tree->left) && is_red(tree->left->left)) {
nuclear@0 463 tree = rot_right(tree);
nuclear@0 464 }
nuclear@0 465 /* split 4-nodes */
nuclear@0 466 if(is_red(tree->left) && is_red(tree->right)) {
nuclear@0 467 color_flip(tree);
nuclear@0 468 }
nuclear@0 469 return tree;
nuclear@0 470 }