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annotate src/vr/rbtree.c @ 12:778ed91cb7fd

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author John Tsiombikas <nuclear@member.fsf.org>
date Sat, 23 Aug 2014 12:03:29 +0300
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nuclear@7 1 /*
nuclear@7 2 rbtree - simple balanced binary search tree (red-black tree) library.
nuclear@7 3 Copyright (C) 2011-2014 John Tsiombikas <nuclear@member.fsf.org>
nuclear@7 4
nuclear@7 5 rbtree is free software, feel free to use, modify, and redistribute it, under
nuclear@7 6 the terms of the 3-clause BSD license. See COPYING for details.
nuclear@7 7 */
nuclear@7 8 #include <stdio.h>
nuclear@7 9 #include <stdlib.h>
nuclear@7 10 #include <stdint.h>
nuclear@7 11 #include <string.h>
nuclear@7 12 #include "rbtree.h"
nuclear@7 13
nuclear@7 14 #define INT2PTR(x) ((void*)(intptr_t)(x))
nuclear@7 15 #define PTR2INT(x) ((int)(intptr_t)(x))
nuclear@7 16
nuclear@7 17 struct rbtree {
nuclear@7 18 struct rbnode *root;
nuclear@7 19
nuclear@7 20 rb_alloc_func_t alloc;
nuclear@7 21 rb_free_func_t free;
nuclear@7 22
nuclear@7 23 rb_cmp_func_t cmp;
nuclear@7 24 rb_del_func_t del;
nuclear@7 25 void *del_cls;
nuclear@7 26
nuclear@7 27 struct rbnode *rstack, *iter;
nuclear@7 28 };
nuclear@7 29
nuclear@7 30 static int cmpaddr(const void *ap, const void *bp);
nuclear@7 31 static int cmpint(const void *ap, const void *bp);
nuclear@7 32
nuclear@7 33 static int count_nodes(struct rbnode *node);
nuclear@7 34 static void del_tree(struct rbnode *node, void (*delfunc)(struct rbnode*, void*), void *cls);
nuclear@7 35 static struct rbnode *insert(struct rbtree *rb, struct rbnode *tree, void *key, void *data);
nuclear@7 36 static struct rbnode *delete(struct rbtree *rb, struct rbnode *tree, void *key);
nuclear@7 37 /*static struct rbnode *find(struct rbtree *rb, struct rbnode *node, void *key);*/
nuclear@7 38 static void traverse(struct rbnode *node, void (*func)(struct rbnode*, void*), void *cls);
nuclear@7 39
nuclear@7 40 struct rbtree *rb_create(rb_cmp_func_t cmp_func)
nuclear@7 41 {
nuclear@7 42 struct rbtree *rb;
nuclear@7 43
nuclear@7 44 if(!(rb = malloc(sizeof *rb))) {
nuclear@7 45 return 0;
nuclear@7 46 }
nuclear@7 47 if(rb_init(rb, cmp_func) == -1) {
nuclear@7 48 free(rb);
nuclear@7 49 return 0;
nuclear@7 50 }
nuclear@7 51 return rb;
nuclear@7 52 }
nuclear@7 53
nuclear@7 54 void rb_free(struct rbtree *rb)
nuclear@7 55 {
nuclear@7 56 rb_destroy(rb);
nuclear@7 57 free(rb);
nuclear@7 58 }
nuclear@7 59
nuclear@7 60
nuclear@7 61 int rb_init(struct rbtree *rb, rb_cmp_func_t cmp_func)
nuclear@7 62 {
nuclear@7 63 memset(rb, 0, sizeof *rb);
nuclear@7 64
nuclear@7 65 if(cmp_func == RB_KEY_INT) {
nuclear@7 66 rb->cmp = cmpint;
nuclear@7 67 } else if(cmp_func == RB_KEY_STRING) {
nuclear@7 68 rb->cmp = (rb_cmp_func_t)strcmp;
nuclear@7 69 } else {
nuclear@7 70 rb->cmp = cmpaddr;
nuclear@7 71 }
nuclear@7 72
nuclear@7 73 rb->alloc = malloc;
nuclear@7 74 rb->free = free;
nuclear@7 75 return 0;
nuclear@7 76 }
nuclear@7 77
nuclear@7 78 void rb_destroy(struct rbtree *rb)
nuclear@7 79 {
nuclear@7 80 del_tree(rb->root, rb->del, rb->del_cls);
nuclear@7 81 }
nuclear@7 82
nuclear@7 83 void rb_set_allocator(struct rbtree *rb, rb_alloc_func_t alloc, rb_free_func_t free)
nuclear@7 84 {
nuclear@7 85 rb->alloc = alloc;
nuclear@7 86 rb->free = free;
nuclear@7 87 }
nuclear@7 88
nuclear@7 89
nuclear@7 90 void rb_set_compare_func(struct rbtree *rb, rb_cmp_func_t func)
nuclear@7 91 {
nuclear@7 92 rb->cmp = func;
nuclear@7 93 }
nuclear@7 94
nuclear@7 95 void rb_set_delete_func(struct rbtree *rb, rb_del_func_t func, void *cls)
nuclear@7 96 {
nuclear@7 97 rb->del = func;
nuclear@7 98 rb->del_cls = cls;
nuclear@7 99 }
nuclear@7 100
nuclear@7 101
nuclear@7 102 void rb_clear(struct rbtree *rb)
nuclear@7 103 {
nuclear@7 104 del_tree(rb->root, rb->del, rb->del_cls);
nuclear@7 105 rb->root = 0;
nuclear@7 106 }
nuclear@7 107
nuclear@7 108 int rb_copy(struct rbtree *dest, struct rbtree *src)
nuclear@7 109 {
nuclear@7 110 struct rbnode *node;
nuclear@7 111
nuclear@7 112 rb_clear(dest);
nuclear@7 113 rb_begin(src);
nuclear@7 114 while((node = rb_next(src))) {
nuclear@7 115 if(rb_insert(dest, node->key, node->data) == -1) {
nuclear@7 116 return -1;
nuclear@7 117 }
nuclear@7 118 }
nuclear@7 119 return 0;
nuclear@7 120 }
nuclear@7 121
nuclear@7 122 int rb_size(struct rbtree *rb)
nuclear@7 123 {
nuclear@7 124 return count_nodes(rb->root);
nuclear@7 125 }
nuclear@7 126
nuclear@7 127 int rb_insert(struct rbtree *rb, void *key, void *data)
nuclear@7 128 {
nuclear@7 129 rb->root = insert(rb, rb->root, key, data);
nuclear@7 130 rb->root->red = 0;
nuclear@7 131 return 0;
nuclear@7 132 }
nuclear@7 133
nuclear@7 134 int rb_inserti(struct rbtree *rb, int key, void *data)
nuclear@7 135 {
nuclear@7 136 rb->root = insert(rb, rb->root, INT2PTR(key), data);
nuclear@7 137 rb->root->red = 0;
nuclear@7 138 return 0;
nuclear@7 139 }
nuclear@7 140
nuclear@7 141
nuclear@7 142 int rb_delete(struct rbtree *rb, void *key)
nuclear@7 143 {
nuclear@7 144 rb->root = delete(rb, rb->root, key);
nuclear@7 145 rb->root->red = 0;
nuclear@7 146 return 0;
nuclear@7 147 }
nuclear@7 148
nuclear@7 149 int rb_deletei(struct rbtree *rb, int key)
nuclear@7 150 {
nuclear@7 151 rb->root = delete(rb, rb->root, INT2PTR(key));
nuclear@7 152 rb->root->red = 0;
nuclear@7 153 return 0;
nuclear@7 154 }
nuclear@7 155
nuclear@7 156
nuclear@7 157 void *rb_find(struct rbtree *rb, void *key)
nuclear@7 158 {
nuclear@7 159 struct rbnode *node = rb->root;
nuclear@7 160
nuclear@7 161 while(node) {
nuclear@7 162 int cmp = rb->cmp(key, node->key);
nuclear@7 163 if(cmp == 0) {
nuclear@7 164 return node->data;
nuclear@7 165 }
nuclear@7 166 node = cmp < 0 ? node->left : node->right;
nuclear@7 167 }
nuclear@7 168 return 0;
nuclear@7 169 }
nuclear@7 170
nuclear@7 171 void *rb_findi(struct rbtree *rb, int key)
nuclear@7 172 {
nuclear@7 173 return rb_find(rb, INT2PTR(key));
nuclear@7 174 }
nuclear@7 175
nuclear@7 176
nuclear@7 177 void rb_foreach(struct rbtree *rb, void (*func)(struct rbnode*, void*), void *cls)
nuclear@7 178 {
nuclear@7 179 traverse(rb->root, func, cls);
nuclear@7 180 }
nuclear@7 181
nuclear@7 182
nuclear@7 183 struct rbnode *rb_root(struct rbtree *rb)
nuclear@7 184 {
nuclear@7 185 return rb->root;
nuclear@7 186 }
nuclear@7 187
nuclear@7 188 void rb_begin(struct rbtree *rb)
nuclear@7 189 {
nuclear@7 190 rb->rstack = 0;
nuclear@7 191 rb->iter = rb->root;
nuclear@7 192 }
nuclear@7 193
nuclear@7 194 #define push(sp, x) ((x)->next = (sp), (sp) = (x))
nuclear@7 195 #define pop(sp) ((sp) = (sp)->next)
nuclear@7 196 #define top(sp) (sp)
nuclear@7 197
nuclear@7 198 struct rbnode *rb_next(struct rbtree *rb)
nuclear@7 199 {
nuclear@7 200 struct rbnode *res = 0;
nuclear@7 201
nuclear@7 202 while(rb->rstack || rb->iter) {
nuclear@7 203 if(rb->iter) {
nuclear@7 204 push(rb->rstack, rb->iter);
nuclear@7 205 rb->iter = rb->iter->left;
nuclear@7 206 } else {
nuclear@7 207 rb->iter = top(rb->rstack);
nuclear@7 208 pop(rb->rstack);
nuclear@7 209 res = rb->iter;
nuclear@7 210 rb->iter = rb->iter->right;
nuclear@7 211 break;
nuclear@7 212 }
nuclear@7 213 }
nuclear@7 214 return res;
nuclear@7 215 }
nuclear@7 216
nuclear@7 217 void *rb_node_key(struct rbnode *node)
nuclear@7 218 {
nuclear@7 219 return node ? node->key : 0;
nuclear@7 220 }
nuclear@7 221
nuclear@7 222 int rb_node_keyi(struct rbnode *node)
nuclear@7 223 {
nuclear@7 224 return node ? PTR2INT(node->key) : 0;
nuclear@7 225 }
nuclear@7 226
nuclear@7 227 void *rb_node_data(struct rbnode *node)
nuclear@7 228 {
nuclear@7 229 return node ? node->data : 0;
nuclear@7 230 }
nuclear@7 231
nuclear@7 232 static int cmpaddr(const void *ap, const void *bp)
nuclear@7 233 {
nuclear@7 234 return ap < bp ? -1 : (ap > bp ? 1 : 0);
nuclear@7 235 }
nuclear@7 236
nuclear@7 237 static int cmpint(const void *ap, const void *bp)
nuclear@7 238 {
nuclear@7 239 return PTR2INT(ap) - PTR2INT(bp);
nuclear@7 240 }
nuclear@7 241
nuclear@7 242
nuclear@7 243 /* ---- left-leaning 2-3 red-black implementation ---- */
nuclear@7 244
nuclear@7 245 /* helper prototypes */
nuclear@7 246 static int is_red(struct rbnode *tree);
nuclear@7 247 static void color_flip(struct rbnode *tree);
nuclear@7 248 static struct rbnode *rot_left(struct rbnode *a);
nuclear@7 249 static struct rbnode *rot_right(struct rbnode *a);
nuclear@7 250 static struct rbnode *find_min(struct rbnode *tree);
nuclear@7 251 static struct rbnode *del_min(struct rbtree *rb, struct rbnode *tree);
nuclear@7 252 /*static struct rbnode *move_red_right(struct rbnode *tree);*/
nuclear@7 253 static struct rbnode *move_red_left(struct rbnode *tree);
nuclear@7 254 static struct rbnode *fix_up(struct rbnode *tree);
nuclear@7 255
nuclear@7 256 static int count_nodes(struct rbnode *node)
nuclear@7 257 {
nuclear@7 258 if(!node)
nuclear@7 259 return 0;
nuclear@7 260
nuclear@7 261 return 1 + count_nodes(node->left) + count_nodes(node->right);
nuclear@7 262 }
nuclear@7 263
nuclear@7 264 static void del_tree(struct rbnode *node, rb_del_func_t delfunc, void *cls)
nuclear@7 265 {
nuclear@7 266 if(!node)
nuclear@7 267 return;
nuclear@7 268
nuclear@7 269 del_tree(node->left, delfunc, cls);
nuclear@7 270 del_tree(node->right, delfunc, cls);
nuclear@7 271
nuclear@7 272 if(delfunc) {
nuclear@7 273 delfunc(node, cls);
nuclear@7 274 }
nuclear@7 275 free(node);
nuclear@7 276 }
nuclear@7 277
nuclear@7 278 static struct rbnode *insert(struct rbtree *rb, struct rbnode *tree, void *key, void *data)
nuclear@7 279 {
nuclear@7 280 int cmp;
nuclear@7 281
nuclear@7 282 if(!tree) {
nuclear@7 283 struct rbnode *node = rb->alloc(sizeof *node);
nuclear@7 284 node->red = 1;
nuclear@7 285 node->key = key;
nuclear@7 286 node->data = data;
nuclear@7 287 node->left = node->right = 0;
nuclear@7 288 return node;
nuclear@7 289 }
nuclear@7 290
nuclear@7 291 cmp = rb->cmp(key, tree->key);
nuclear@7 292
nuclear@7 293 if(cmp < 0) {
nuclear@7 294 tree->left = insert(rb, tree->left, key, data);
nuclear@7 295 } else if(cmp > 0) {
nuclear@7 296 tree->right = insert(rb, tree->right, key, data);
nuclear@7 297 } else {
nuclear@7 298 tree->data = data;
nuclear@7 299 }
nuclear@7 300
nuclear@7 301 /* fix right-leaning reds */
nuclear@7 302 if(is_red(tree->right)) {
nuclear@7 303 tree = rot_left(tree);
nuclear@7 304 }
nuclear@7 305 /* fix two reds in a row */
nuclear@7 306 if(is_red(tree->left) && is_red(tree->left->left)) {
nuclear@7 307 tree = rot_right(tree);
nuclear@7 308 }
nuclear@7 309
nuclear@7 310 /* if 4-node, split it by color inversion */
nuclear@7 311 if(is_red(tree->left) && is_red(tree->right)) {
nuclear@7 312 color_flip(tree);
nuclear@7 313 }
nuclear@7 314
nuclear@7 315 return tree;
nuclear@7 316 }
nuclear@7 317
nuclear@7 318 static struct rbnode *delete(struct rbtree *rb, struct rbnode *tree, void *key)
nuclear@7 319 {
nuclear@7 320 int cmp;
nuclear@7 321
nuclear@7 322 if(!tree) {
nuclear@7 323 return 0;
nuclear@7 324 }
nuclear@7 325
nuclear@7 326 cmp = rb->cmp(key, tree->key);
nuclear@7 327
nuclear@7 328 if(cmp < 0) {
nuclear@7 329 if(!is_red(tree->left) && !is_red(tree->left->left)) {
nuclear@7 330 tree = move_red_left(tree);
nuclear@7 331 }
nuclear@7 332 tree->left = delete(rb, tree->left, key);
nuclear@7 333 } else {
nuclear@7 334 /* need reds on the right */
nuclear@7 335 if(is_red(tree->left)) {
nuclear@7 336 tree = rot_right(tree);
nuclear@7 337 }
nuclear@7 338
nuclear@7 339 /* found it at the bottom (XXX what certifies left is null?) */
nuclear@7 340 if(cmp == 0 && !tree->right) {
nuclear@7 341 if(rb->del) {
nuclear@7 342 rb->del(tree, rb->del_cls);
nuclear@7 343 }
nuclear@7 344 rb->free(tree);
nuclear@7 345 return 0;
nuclear@7 346 }
nuclear@7 347
nuclear@7 348 if(!is_red(tree->right) && !is_red(tree->right->left)) {
nuclear@7 349 tree = move_red_left(tree);
nuclear@7 350 }
nuclear@7 351
nuclear@7 352 if(key == tree->key) {
nuclear@7 353 struct rbnode *rmin = find_min(tree->right);
nuclear@7 354 tree->key = rmin->key;
nuclear@7 355 tree->data = rmin->data;
nuclear@7 356 tree->right = del_min(rb, tree->right);
nuclear@7 357 } else {
nuclear@7 358 tree->right = delete(rb, tree->right, key);
nuclear@7 359 }
nuclear@7 360 }
nuclear@7 361
nuclear@7 362 return fix_up(tree);
nuclear@7 363 }
nuclear@7 364
nuclear@7 365 /*static struct rbnode *find(struct rbtree *rb, struct rbnode *node, void *key)
nuclear@7 366 {
nuclear@7 367 int cmp;
nuclear@7 368
nuclear@7 369 if(!node)
nuclear@7 370 return 0;
nuclear@7 371
nuclear@7 372 if((cmp = rb->cmp(key, node->key)) == 0) {
nuclear@7 373 return node;
nuclear@7 374 }
nuclear@7 375 return find(rb, cmp < 0 ? node->left : node->right, key);
nuclear@7 376 }*/
nuclear@7 377
nuclear@7 378 static void traverse(struct rbnode *node, void (*func)(struct rbnode*, void*), void *cls)
nuclear@7 379 {
nuclear@7 380 if(!node)
nuclear@7 381 return;
nuclear@7 382
nuclear@7 383 traverse(node->left, func, cls);
nuclear@7 384 func(node, cls);
nuclear@7 385 traverse(node->right, func, cls);
nuclear@7 386 }
nuclear@7 387
nuclear@7 388 /* helpers */
nuclear@7 389
nuclear@7 390 static int is_red(struct rbnode *tree)
nuclear@7 391 {
nuclear@7 392 return tree && tree->red;
nuclear@7 393 }
nuclear@7 394
nuclear@7 395 static void color_flip(struct rbnode *tree)
nuclear@7 396 {
nuclear@7 397 tree->red = !tree->red;
nuclear@7 398 tree->left->red = !tree->left->red;
nuclear@7 399 tree->right->red = !tree->right->red;
nuclear@7 400 }
nuclear@7 401
nuclear@7 402 static struct rbnode *rot_left(struct rbnode *a)
nuclear@7 403 {
nuclear@7 404 struct rbnode *b = a->right;
nuclear@7 405 a->right = b->left;
nuclear@7 406 b->left = a;
nuclear@7 407 b->red = a->red;
nuclear@7 408 a->red = 1;
nuclear@7 409 return b;
nuclear@7 410 }
nuclear@7 411
nuclear@7 412 static struct rbnode *rot_right(struct rbnode *a)
nuclear@7 413 {
nuclear@7 414 struct rbnode *b = a->left;
nuclear@7 415 a->left = b->right;
nuclear@7 416 b->right = a;
nuclear@7 417 b->red = a->red;
nuclear@7 418 a->red = 1;
nuclear@7 419 return b;
nuclear@7 420 }
nuclear@7 421
nuclear@7 422 static struct rbnode *find_min(struct rbnode *tree)
nuclear@7 423 {
nuclear@7 424 struct rbnode *node = tree;
nuclear@7 425
nuclear@7 426 if(!tree)
nuclear@7 427 return 0;
nuclear@7 428
nuclear@7 429 while(node->left) {
nuclear@7 430 node = node->left;
nuclear@7 431 }
nuclear@7 432 return node;
nuclear@7 433 }
nuclear@7 434
nuclear@7 435 static struct rbnode *del_min(struct rbtree *rb, struct rbnode *tree)
nuclear@7 436 {
nuclear@7 437 if(!tree->left) {
nuclear@7 438 if(rb->del) {
nuclear@7 439 rb->del(tree->left, rb->del_cls);
nuclear@7 440 }
nuclear@7 441 rb->free(tree->left);
nuclear@7 442 return 0;
nuclear@7 443 }
nuclear@7 444
nuclear@7 445 /* make sure we've got red (3/4-nodes) at the left side so we can delete at the bottom */
nuclear@7 446 if(!is_red(tree->left) && !is_red(tree->left->left)) {
nuclear@7 447 tree = move_red_left(tree);
nuclear@7 448 }
nuclear@7 449 tree->left = del_min(rb, tree->left);
nuclear@7 450
nuclear@7 451 /* fix right-reds, red-reds, and split 4-nodes on the way up */
nuclear@7 452 return fix_up(tree);
nuclear@7 453 }
nuclear@7 454
nuclear@7 455 #if 0
nuclear@7 456 /* push a red link on this node to the right */
nuclear@7 457 static struct rbnode *move_red_right(struct rbnode *tree)
nuclear@7 458 {
nuclear@7 459 /* flipping it makes both children go red, so we have a red to the right */
nuclear@7 460 color_flip(tree);
nuclear@7 461
nuclear@7 462 /* if after the flip we've got a red-red situation to the left, fix it */
nuclear@7 463 if(is_red(tree->left->left)) {
nuclear@7 464 tree = rot_right(tree);
nuclear@7 465 color_flip(tree);
nuclear@7 466 }
nuclear@7 467 return tree;
nuclear@7 468 }
nuclear@7 469 #endif
nuclear@7 470
nuclear@7 471 /* push a red link on this node to the left */
nuclear@7 472 static struct rbnode *move_red_left(struct rbnode *tree)
nuclear@7 473 {
nuclear@7 474 /* flipping it makes both children go red, so we have a red to the left */
nuclear@7 475 color_flip(tree);
nuclear@7 476
nuclear@7 477 /* if after the flip we've got a red-red on the right-left, fix it */
nuclear@7 478 if(is_red(tree->right->left)) {
nuclear@7 479 tree->right = rot_right(tree->right);
nuclear@7 480 tree = rot_left(tree);
nuclear@7 481 color_flip(tree);
nuclear@7 482 }
nuclear@7 483 return tree;
nuclear@7 484 }
nuclear@7 485
nuclear@7 486 static struct rbnode *fix_up(struct rbnode *tree)
nuclear@7 487 {
nuclear@7 488 /* fix right-leaning */
nuclear@7 489 if(is_red(tree->right)) {
nuclear@7 490 tree = rot_left(tree);
nuclear@7 491 }
nuclear@7 492 /* change invalid red-red pairs into a proper 4-node */
nuclear@7 493 if(is_red(tree->left) && is_red(tree->left->left)) {
nuclear@7 494 tree = rot_right(tree);
nuclear@7 495 }
nuclear@7 496 /* split 4-nodes */
nuclear@7 497 if(is_red(tree->left) && is_red(tree->right)) {
nuclear@7 498 color_flip(tree);
nuclear@7 499 }
nuclear@7 500 return tree;
nuclear@7 501 }