rbtree

annotate src/rbtree.c @ 14:1b8a3a6088b6

find changesets by author, revision, files, or words in the commit message
simplified find_min
author John Tsiombikas <nuclear@member.fsf.org>
date Sun, 02 Nov 2014 10:56:08 +0200
parents 5b955b3a4675
children 1b77b72688fe
rev   line source
nuclear@13 1 /*
nuclear@13 2 rbtree - simple balanced binary search tree (red-black tree) library.
nuclear@13 3 Copyright (C) 2011-2014 John Tsiombikas <nuclear@member.fsf.org>
nuclear@13 4
nuclear@13 5 rbtree is free software, feel free to use, modify, and redistribute it, under
nuclear@13 6 the terms of the 3-clause BSD license. See COPYING for details.
nuclear@13 7 */
nuclear@0 8 #include <stdio.h>
nuclear@0 9 #include <stdlib.h>
nuclear@10 10 #include <stdint.h>
nuclear@0 11 #include <string.h>
nuclear@0 12 #include "rbtree.h"
nuclear@0 13
nuclear@10 14 #define INT2PTR(x) ((void*)(intptr_t)(x))
nuclear@10 15 #define PTR2INT(x) ((int)(intptr_t)(x))
nuclear@0 16
nuclear@0 17 struct rbtree {
nuclear@0 18 struct rbnode *root;
nuclear@0 19
nuclear@0 20 rb_alloc_func_t alloc;
nuclear@0 21 rb_free_func_t free;
nuclear@0 22
nuclear@0 23 rb_cmp_func_t cmp;
nuclear@0 24 rb_del_func_t del;
nuclear@0 25 void *del_cls;
nuclear@0 26
nuclear@0 27 struct rbnode *rstack, *iter;
nuclear@0 28 };
nuclear@0 29
nuclear@10 30 static int cmpaddr(const void *ap, const void *bp);
nuclear@10 31 static int cmpint(const void *ap, const void *bp);
nuclear@0 32
nuclear@0 33 static int count_nodes(struct rbnode *node);
nuclear@0 34 static void del_tree(struct rbnode *node, void (*delfunc)(struct rbnode*, void*), void *cls);
nuclear@0 35 static struct rbnode *insert(struct rbtree *rb, struct rbnode *tree, void *key, void *data);
nuclear@0 36 static struct rbnode *delete(struct rbtree *rb, struct rbnode *tree, void *key);
nuclear@3 37 /*static struct rbnode *find(struct rbtree *rb, struct rbnode *node, void *key);*/
nuclear@0 38 static void traverse(struct rbnode *node, void (*func)(struct rbnode*, void*), void *cls);
nuclear@0 39
nuclear@0 40 struct rbtree *rb_create(rb_cmp_func_t cmp_func)
nuclear@0 41 {
nuclear@0 42 struct rbtree *rb;
nuclear@0 43
nuclear@0 44 if(!(rb = malloc(sizeof *rb))) {
nuclear@0 45 return 0;
nuclear@0 46 }
nuclear@0 47 if(rb_init(rb, cmp_func) == -1) {
nuclear@0 48 free(rb);
nuclear@0 49 return 0;
nuclear@0 50 }
nuclear@0 51 return rb;
nuclear@0 52 }
nuclear@0 53
nuclear@0 54 void rb_free(struct rbtree *rb)
nuclear@0 55 {
nuclear@0 56 rb_destroy(rb);
nuclear@0 57 free(rb);
nuclear@0 58 }
nuclear@0 59
nuclear@0 60
nuclear@0 61 int rb_init(struct rbtree *rb, rb_cmp_func_t cmp_func)
nuclear@0 62 {
nuclear@0 63 memset(rb, 0, sizeof *rb);
nuclear@0 64
nuclear@0 65 if(cmp_func == RB_KEY_INT) {
nuclear@0 66 rb->cmp = cmpint;
nuclear@0 67 } else if(cmp_func == RB_KEY_STRING) {
nuclear@0 68 rb->cmp = (rb_cmp_func_t)strcmp;
nuclear@0 69 } else {
nuclear@0 70 rb->cmp = cmpaddr;
nuclear@0 71 }
nuclear@0 72
nuclear@0 73 rb->alloc = malloc;
nuclear@0 74 rb->free = free;
nuclear@0 75 return 0;
nuclear@0 76 }
nuclear@0 77
nuclear@0 78 void rb_destroy(struct rbtree *rb)
nuclear@0 79 {
nuclear@0 80 del_tree(rb->root, rb->del, rb->del_cls);
nuclear@0 81 }
nuclear@0 82
nuclear@0 83 void rb_set_allocator(struct rbtree *rb, rb_alloc_func_t alloc, rb_free_func_t free)
nuclear@0 84 {
nuclear@0 85 rb->alloc = alloc;
nuclear@0 86 rb->free = free;
nuclear@0 87 }
nuclear@0 88
nuclear@0 89
nuclear@0 90 void rb_set_compare_func(struct rbtree *rb, rb_cmp_func_t func)
nuclear@0 91 {
nuclear@0 92 rb->cmp = func;
nuclear@0 93 }
nuclear@0 94
nuclear@0 95 void rb_set_delete_func(struct rbtree *rb, rb_del_func_t func, void *cls)
nuclear@0 96 {
nuclear@0 97 rb->del = func;
nuclear@0 98 rb->del_cls = cls;
nuclear@0 99 }
nuclear@0 100
nuclear@5 101
nuclear@5 102 void rb_clear(struct rbtree *rb)
nuclear@5 103 {
nuclear@5 104 del_tree(rb->root, rb->del, rb->del_cls);
nuclear@5 105 rb->root = 0;
nuclear@5 106 }
nuclear@5 107
nuclear@5 108 int rb_copy(struct rbtree *dest, struct rbtree *src)
nuclear@5 109 {
nuclear@5 110 struct rbnode *node;
nuclear@5 111
nuclear@5 112 rb_clear(dest);
nuclear@5 113 rb_begin(src);
nuclear@5 114 while((node = rb_next(src))) {
nuclear@5 115 if(rb_insert(dest, node->key, node->data) == -1) {
nuclear@5 116 return -1;
nuclear@5 117 }
nuclear@5 118 }
nuclear@5 119 return 0;
nuclear@5 120 }
nuclear@5 121
nuclear@0 122 int rb_size(struct rbtree *rb)
nuclear@0 123 {
nuclear@0 124 return count_nodes(rb->root);
nuclear@0 125 }
nuclear@0 126
nuclear@0 127 int rb_insert(struct rbtree *rb, void *key, void *data)
nuclear@0 128 {
nuclear@0 129 rb->root = insert(rb, rb->root, key, data);
nuclear@0 130 rb->root->red = 0;
nuclear@0 131 return 0;
nuclear@0 132 }
nuclear@0 133
nuclear@0 134 int rb_inserti(struct rbtree *rb, int key, void *data)
nuclear@0 135 {
nuclear@0 136 rb->root = insert(rb, rb->root, INT2PTR(key), data);
nuclear@0 137 rb->root->red = 0;
nuclear@0 138 return 0;
nuclear@0 139 }
nuclear@0 140
nuclear@0 141
nuclear@0 142 int rb_delete(struct rbtree *rb, void *key)
nuclear@0 143 {
nuclear@0 144 rb->root = delete(rb, rb->root, key);
nuclear@0 145 rb->root->red = 0;
nuclear@0 146 return 0;
nuclear@0 147 }
nuclear@0 148
nuclear@0 149 int rb_deletei(struct rbtree *rb, int key)
nuclear@0 150 {
nuclear@0 151 rb->root = delete(rb, rb->root, INT2PTR(key));
nuclear@0 152 rb->root->red = 0;
nuclear@0 153 return 0;
nuclear@0 154 }
nuclear@0 155
nuclear@0 156
nuclear@0 157 void *rb_find(struct rbtree *rb, void *key)
nuclear@0 158 {
nuclear@3 159 struct rbnode *node = rb->root;
nuclear@3 160
nuclear@3 161 while(node) {
nuclear@3 162 int cmp = rb->cmp(key, node->key);
nuclear@3 163 if(cmp == 0) {
nuclear@3 164 return node;
nuclear@3 165 }
nuclear@3 166 node = cmp < 0 ? node->left : node->right;
nuclear@3 167 }
nuclear@3 168 return 0;
nuclear@0 169 }
nuclear@0 170
nuclear@0 171 void *rb_findi(struct rbtree *rb, int key)
nuclear@0 172 {
nuclear@3 173 return rb_find(rb, INT2PTR(key));
nuclear@0 174 }
nuclear@0 175
nuclear@0 176
nuclear@0 177 void rb_foreach(struct rbtree *rb, void (*func)(struct rbnode*, void*), void *cls)
nuclear@0 178 {
nuclear@0 179 traverse(rb->root, func, cls);
nuclear@0 180 }
nuclear@0 181
nuclear@0 182
nuclear@0 183 struct rbnode *rb_root(struct rbtree *rb)
nuclear@0 184 {
nuclear@0 185 return rb->root;
nuclear@0 186 }
nuclear@0 187
nuclear@0 188 void rb_begin(struct rbtree *rb)
nuclear@0 189 {
nuclear@0 190 rb->rstack = 0;
nuclear@0 191 rb->iter = rb->root;
nuclear@0 192 }
nuclear@0 193
nuclear@0 194 #define push(sp, x) ((x)->next = (sp), (sp) = (x))
nuclear@0 195 #define pop(sp) ((sp) = (sp)->next)
nuclear@0 196 #define top(sp) (sp)
nuclear@0 197
nuclear@0 198 struct rbnode *rb_next(struct rbtree *rb)
nuclear@0 199 {
nuclear@0 200 struct rbnode *res = 0;
nuclear@0 201
nuclear@0 202 while(rb->rstack || rb->iter) {
nuclear@0 203 if(rb->iter) {
nuclear@0 204 push(rb->rstack, rb->iter);
nuclear@0 205 rb->iter = rb->iter->left;
nuclear@0 206 } else {
nuclear@0 207 rb->iter = top(rb->rstack);
nuclear@0 208 pop(rb->rstack);
nuclear@0 209 res = rb->iter;
nuclear@0 210 rb->iter = rb->iter->right;
nuclear@0 211 break;
nuclear@0 212 }
nuclear@0 213 }
nuclear@0 214 return res;
nuclear@0 215 }
nuclear@0 216
nuclear@0 217 void *rb_node_key(struct rbnode *node)
nuclear@0 218 {
nuclear@0 219 return node ? node->key : 0;
nuclear@0 220 }
nuclear@0 221
nuclear@0 222 int rb_node_keyi(struct rbnode *node)
nuclear@0 223 {
nuclear@0 224 return node ? PTR2INT(node->key) : 0;
nuclear@0 225 }
nuclear@0 226
nuclear@0 227 void *rb_node_data(struct rbnode *node)
nuclear@0 228 {
nuclear@0 229 return node ? node->data : 0;
nuclear@0 230 }
nuclear@0 231
nuclear@10 232 static int cmpaddr(const void *ap, const void *bp)
nuclear@0 233 {
nuclear@0 234 return ap < bp ? -1 : (ap > bp ? 1 : 0);
nuclear@0 235 }
nuclear@0 236
nuclear@10 237 static int cmpint(const void *ap, const void *bp)
nuclear@0 238 {
nuclear@0 239 return PTR2INT(ap) - PTR2INT(bp);
nuclear@0 240 }
nuclear@0 241
nuclear@0 242
nuclear@0 243 /* ---- left-leaning 2-3 red-black implementation ---- */
nuclear@0 244
nuclear@0 245 /* helper prototypes */
nuclear@0 246 static int is_red(struct rbnode *tree);
nuclear@0 247 static void color_flip(struct rbnode *tree);
nuclear@0 248 static struct rbnode *rot_left(struct rbnode *a);
nuclear@0 249 static struct rbnode *rot_right(struct rbnode *a);
nuclear@0 250 static struct rbnode *find_min(struct rbnode *tree);
nuclear@0 251 static struct rbnode *del_min(struct rbtree *rb, struct rbnode *tree);
nuclear@0 252 /*static struct rbnode *move_red_right(struct rbnode *tree);*/
nuclear@0 253 static struct rbnode *move_red_left(struct rbnode *tree);
nuclear@0 254 static struct rbnode *fix_up(struct rbnode *tree);
nuclear@0 255
nuclear@0 256 static int count_nodes(struct rbnode *node)
nuclear@0 257 {
nuclear@0 258 if(!node)
nuclear@0 259 return 0;
nuclear@0 260
nuclear@0 261 return 1 + count_nodes(node->left) + count_nodes(node->right);
nuclear@0 262 }
nuclear@0 263
nuclear@0 264 static void del_tree(struct rbnode *node, rb_del_func_t delfunc, void *cls)
nuclear@0 265 {
nuclear@0 266 if(!node)
nuclear@0 267 return;
nuclear@0 268
nuclear@0 269 del_tree(node->left, delfunc, cls);
nuclear@0 270 del_tree(node->right, delfunc, cls);
nuclear@0 271
nuclear@7 272 if(delfunc) {
nuclear@7 273 delfunc(node, cls);
nuclear@7 274 }
nuclear@0 275 free(node);
nuclear@0 276 }
nuclear@0 277
nuclear@0 278 static struct rbnode *insert(struct rbtree *rb, struct rbnode *tree, void *key, void *data)
nuclear@0 279 {
nuclear@0 280 int cmp;
nuclear@0 281
nuclear@0 282 if(!tree) {
nuclear@0 283 struct rbnode *node = rb->alloc(sizeof *node);
nuclear@0 284 node->red = 1;
nuclear@0 285 node->key = key;
nuclear@0 286 node->data = data;
nuclear@0 287 node->left = node->right = 0;
nuclear@0 288 return node;
nuclear@0 289 }
nuclear@0 290
nuclear@0 291 cmp = rb->cmp(key, tree->key);
nuclear@0 292
nuclear@0 293 if(cmp < 0) {
nuclear@0 294 tree->left = insert(rb, tree->left, key, data);
nuclear@0 295 } else if(cmp > 0) {
nuclear@0 296 tree->right = insert(rb, tree->right, key, data);
nuclear@0 297 } else {
nuclear@0 298 tree->data = data;
nuclear@0 299 }
nuclear@0 300
nuclear@0 301 /* fix right-leaning reds */
nuclear@0 302 if(is_red(tree->right)) {
nuclear@0 303 tree = rot_left(tree);
nuclear@0 304 }
nuclear@0 305 /* fix two reds in a row */
nuclear@0 306 if(is_red(tree->left) && is_red(tree->left->left)) {
nuclear@0 307 tree = rot_right(tree);
nuclear@0 308 }
nuclear@0 309
nuclear@0 310 /* if 4-node, split it by color inversion */
nuclear@0 311 if(is_red(tree->left) && is_red(tree->right)) {
nuclear@0 312 color_flip(tree);
nuclear@0 313 }
nuclear@0 314
nuclear@0 315 return tree;
nuclear@0 316 }
nuclear@0 317
nuclear@0 318 static struct rbnode *delete(struct rbtree *rb, struct rbnode *tree, void *key)
nuclear@0 319 {
nuclear@0 320 int cmp;
nuclear@0 321
nuclear@0 322 if(!tree) {
nuclear@0 323 return 0;
nuclear@0 324 }
nuclear@0 325
nuclear@0 326 cmp = rb->cmp(key, tree->key);
nuclear@0 327
nuclear@0 328 if(cmp < 0) {
nuclear@0 329 if(!is_red(tree->left) && !is_red(tree->left->left)) {
nuclear@0 330 tree = move_red_left(tree);
nuclear@0 331 }
nuclear@0 332 tree->left = delete(rb, tree->left, key);
nuclear@0 333 } else {
nuclear@0 334 /* need reds on the right */
nuclear@0 335 if(is_red(tree->left)) {
nuclear@0 336 tree = rot_right(tree);
nuclear@0 337 }
nuclear@0 338
nuclear@0 339 /* found it at the bottom (XXX what certifies left is null?) */
nuclear@0 340 if(cmp == 0 && !tree->right) {
nuclear@0 341 if(rb->del) {
nuclear@0 342 rb->del(tree, rb->del_cls);
nuclear@0 343 }
nuclear@0 344 rb->free(tree);
nuclear@0 345 return 0;
nuclear@0 346 }
nuclear@0 347
nuclear@0 348 if(!is_red(tree->right) && !is_red(tree->right->left)) {
nuclear@0 349 tree = move_red_left(tree);
nuclear@0 350 }
nuclear@0 351
nuclear@0 352 if(key == tree->key) {
nuclear@0 353 struct rbnode *rmin = find_min(tree->right);
nuclear@0 354 tree->key = rmin->key;
nuclear@0 355 tree->data = rmin->data;
nuclear@0 356 tree->right = del_min(rb, tree->right);
nuclear@0 357 } else {
nuclear@0 358 tree->right = delete(rb, tree->right, key);
nuclear@0 359 }
nuclear@0 360 }
nuclear@0 361
nuclear@0 362 return fix_up(tree);
nuclear@0 363 }
nuclear@0 364
nuclear@3 365 /*static struct rbnode *find(struct rbtree *rb, struct rbnode *node, void *key)
nuclear@0 366 {
nuclear@0 367 int cmp;
nuclear@0 368
nuclear@0 369 if(!node)
nuclear@0 370 return 0;
nuclear@0 371
nuclear@0 372 if((cmp = rb->cmp(key, node->key)) == 0) {
nuclear@0 373 return node;
nuclear@0 374 }
nuclear@0 375 return find(rb, cmp < 0 ? node->left : node->right, key);
nuclear@3 376 }*/
nuclear@0 377
nuclear@0 378 static void traverse(struct rbnode *node, void (*func)(struct rbnode*, void*), void *cls)
nuclear@0 379 {
nuclear@0 380 if(!node)
nuclear@0 381 return;
nuclear@0 382
nuclear@0 383 traverse(node->left, func, cls);
nuclear@0 384 func(node, cls);
nuclear@0 385 traverse(node->right, func, cls);
nuclear@0 386 }
nuclear@0 387
nuclear@0 388 /* helpers */
nuclear@0 389
nuclear@0 390 static int is_red(struct rbnode *tree)
nuclear@0 391 {
nuclear@0 392 return tree && tree->red;
nuclear@0 393 }
nuclear@0 394
nuclear@0 395 static void color_flip(struct rbnode *tree)
nuclear@0 396 {
nuclear@0 397 tree->red = !tree->red;
nuclear@0 398 tree->left->red = !tree->left->red;
nuclear@0 399 tree->right->red = !tree->right->red;
nuclear@0 400 }
nuclear@0 401
nuclear@0 402 static struct rbnode *rot_left(struct rbnode *a)
nuclear@0 403 {
nuclear@0 404 struct rbnode *b = a->right;
nuclear@0 405 a->right = b->left;
nuclear@0 406 b->left = a;
nuclear@0 407 b->red = a->red;
nuclear@0 408 a->red = 1;
nuclear@0 409 return b;
nuclear@0 410 }
nuclear@0 411
nuclear@0 412 static struct rbnode *rot_right(struct rbnode *a)
nuclear@0 413 {
nuclear@0 414 struct rbnode *b = a->left;
nuclear@0 415 a->left = b->right;
nuclear@0 416 b->right = a;
nuclear@0 417 b->red = a->red;
nuclear@0 418 a->red = 1;
nuclear@0 419 return b;
nuclear@0 420 }
nuclear@0 421
nuclear@0 422 static struct rbnode *find_min(struct rbnode *tree)
nuclear@0 423 {
nuclear@3 424 if(!tree)
nuclear@3 425 return 0;
nuclear@3 426
nuclear@14 427 while(tree->left) {
nuclear@14 428 tree = tree->left;
nuclear@0 429 }
nuclear@14 430 return tree;
nuclear@0 431 }
nuclear@0 432
nuclear@0 433 static struct rbnode *del_min(struct rbtree *rb, struct rbnode *tree)
nuclear@0 434 {
nuclear@0 435 if(!tree->left) {
nuclear@0 436 if(rb->del) {
nuclear@0 437 rb->del(tree->left, rb->del_cls);
nuclear@0 438 }
nuclear@0 439 rb->free(tree->left);
nuclear@0 440 return 0;
nuclear@0 441 }
nuclear@0 442
nuclear@0 443 /* make sure we've got red (3/4-nodes) at the left side so we can delete at the bottom */
nuclear@0 444 if(!is_red(tree->left) && !is_red(tree->left->left)) {
nuclear@0 445 tree = move_red_left(tree);
nuclear@0 446 }
nuclear@0 447 tree->left = del_min(rb, tree->left);
nuclear@0 448
nuclear@0 449 /* fix right-reds, red-reds, and split 4-nodes on the way up */
nuclear@0 450 return fix_up(tree);
nuclear@0 451 }
nuclear@0 452
nuclear@0 453 #if 0
nuclear@0 454 /* push a red link on this node to the right */
nuclear@0 455 static struct rbnode *move_red_right(struct rbnode *tree)
nuclear@0 456 {
nuclear@0 457 /* flipping it makes both children go red, so we have a red to the right */
nuclear@0 458 color_flip(tree);
nuclear@0 459
nuclear@0 460 /* if after the flip we've got a red-red situation to the left, fix it */
nuclear@0 461 if(is_red(tree->left->left)) {
nuclear@0 462 tree = rot_right(tree);
nuclear@0 463 color_flip(tree);
nuclear@0 464 }
nuclear@0 465 return tree;
nuclear@0 466 }
nuclear@0 467 #endif
nuclear@0 468
nuclear@0 469 /* push a red link on this node to the left */
nuclear@0 470 static struct rbnode *move_red_left(struct rbnode *tree)
nuclear@0 471 {
nuclear@0 472 /* flipping it makes both children go red, so we have a red to the left */
nuclear@0 473 color_flip(tree);
nuclear@0 474
nuclear@0 475 /* if after the flip we've got a red-red on the right-left, fix it */
nuclear@0 476 if(is_red(tree->right->left)) {
nuclear@0 477 tree->right = rot_right(tree->right);
nuclear@0 478 tree = rot_left(tree);
nuclear@0 479 color_flip(tree);
nuclear@0 480 }
nuclear@0 481 return tree;
nuclear@0 482 }
nuclear@0 483
nuclear@0 484 static struct rbnode *fix_up(struct rbnode *tree)
nuclear@0 485 {
nuclear@0 486 /* fix right-leaning */
nuclear@0 487 if(is_red(tree->right)) {
nuclear@0 488 tree = rot_left(tree);
nuclear@0 489 }
nuclear@0 490 /* change invalid red-red pairs into a proper 4-node */
nuclear@0 491 if(is_red(tree->left) && is_red(tree->left->left)) {
nuclear@0 492 tree = rot_right(tree);
nuclear@0 493 }
nuclear@0 494 /* split 4-nodes */
nuclear@0 495 if(is_red(tree->left) && is_red(tree->right)) {
nuclear@0 496 color_flip(tree);
nuclear@0 497 }
nuclear@0 498 return tree;
nuclear@0 499 }