www.tinc-vpn.org Git - tinc/blob - lib/splay_tree.c

   1 /*
   2     splay_tree.c -- splay tree and linked list convenience
   3     Copyright (C) 2004 Guus Sliepen <guus@tinc-vpn.org>
   4
   5     This program is free software; you can redistribute it and/or modify
   6     it under the terms of the GNU General Public License as published by
   7     the Free Software Foundation; either version 2 of the License, or
   8     (at your option) any later version.
   9
  10     This program is distributed in the hope that it will be useful,
  11     but WITHOUT ANY WARRANTY; without even the implied warranty of
  12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13     GNU General Public License for more details.
  14
  15     You should have received a copy of the GNU General Public License
  16     along with this program; if not, write to the Free Software
  17     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  18
  19     $Id: splay_tree.c 1374 2004-03-21 14:21:22Z guus $
  20 */
  21
  22 #include "system.h"
  23
  24 #include "splay_tree.h"
  25 #include "xalloc.h"
  26
  27 /* Splay operation */
  28
  29 static splay_node_t *splay_top_down(splay_tree_t *tree, const void *data, int *result) {
  30         splay_node_t left = {0}, right = {0};
  31         splay_node_t *leftbottom = &left, *rightbottom = &right, *child, *grandchild;
  32         splay_node_t *root = tree->root;
  33         int c;
  34
  35         if(!root) {
  36                 if(result)
  37                         *result = 0;
  38                 return NULL;
  39         }
  40
  41         while((c = tree->compare(data, root->data))) {
  42                 if(c < 0 && (child = root->left)) {
  43                         c = tree->compare(data, child->data);
  44
  45                         if(c < 0 && (grandchild = child->left)) {
  46                                 rightbottom->left = child;
  47                                 child->parent = rightbottom;
  48                                 rightbottom = child;
  49
  50                                 if((root->left = child->right))
  51                                         child->right->parent = root;
  52
  53                                 child->right = root;
  54                                 root->parent = child;
  55
  56                                 child->left = NULL;
  57                                 grandchild->parent = NULL;
  58
  59                                 root = grandchild;
  60                         } else if (c > 0 && (grandchild = child->right)) {
  61                                 leftbottom->right = child;
  62                                 child->parent = leftbottom;
  63                                 leftbottom = child;
  64
  65                                 child->right = NULL;
  66                                 grandchild->parent = NULL;
  67
  68                                 rightbottom->left = root;
  69                                 root->parent = rightbottom;
  70                                 rightbottom = root;
  71
  72                                 root->left = NULL;
  73
  74                                 root = grandchild;
  75                         } else {
  76                                 rightbottom->left = root;
  77                                 root->parent = rightbottom;
  78                                 rightbottom = root;
  79
  80                                 root->left = NULL;
  81                                 child->parent = NULL;
  82
  83                                 root = child;
  84                                 break;
  85                         }
  86                 } else if(c > 0 && (child = root->right)) {
  87                         c = tree->compare(data, child->data);
  88
  89                         if(c > 0 && (grandchild = child->right)) {
  90                                 leftbottom->right = child;
  91                                 child->parent = leftbottom;
  92                                 leftbottom = child;
  93
  94                                 if((root->right = child->left))
  95                                         child->left->parent = root;
  96
  97                                 child->left = root;
  98                                 root->parent = child;
  99
 100                                 child->right = NULL;
 101                                 grandchild->parent = NULL;
 102
 103                                 root = grandchild;
 104                         } else if (c < 0 && (grandchild = child->left)) {
 105                                 rightbottom->left = child;
 106                                 child->parent = rightbottom;
 107                                 rightbottom = child;
 108
 109                                 child->left = NULL;
 110                                 grandchild->parent = NULL;
 111
 112                                 leftbottom->right = root;
 113                                 root->parent = leftbottom;
 114                                 leftbottom = root;
 115
 116                                 root->right = NULL;
 117
 118                                 root = grandchild;
 119                         } else {
 120                                 leftbottom->right = root;
 121                                 root->parent = leftbottom;
 122                                 leftbottom = root;
 123
 124                                 root->right = NULL;
 125                                 child->parent = NULL;
 126
 127                                 root = child;
 128                                 break;
 129                         }
 130                 } else {
 131                         break;
 132                 }
 133         }
 134
 135         /* Merge trees */
 136
 137         if(left.right) {
 138                 if(root->left) {
 139                         leftbottom->right = root->left;
 140                         root->left->parent = leftbottom;
 141                 }
 142                 root->left = left.right;
 143                 left.right->parent = root;
 144         }
 145
 146         if(right.left) {
 147                 if(root->right) {
 148                         rightbottom->left = root->right;
 149                         root->right->parent = rightbottom;
 150                 }
 151                 root->right = right.left;
 152                 right.left->parent = root;
 153         }
 154
 155         /* Return result */
 156
 157         tree->root = root;
 158         if(result)
 159                 *result = c;
 160
 161         return tree->root;
 162 }
 163
 164 static void splay_bottom_up(splay_tree_t *tree, splay_node_t *node) {
 165         splay_node_t *parent, *grandparent, *greatgrandparent;
 166
 167         while((parent = node->parent)) {
 168                 if(!(grandparent = parent->parent)) { /* zig */
 169                         if(node == parent->left) {
 170                                 if((parent->left = node->right))
 171                                         parent->left->parent = parent;
 172                                 node->right = parent;
 173                         } else {
 174                                 if((parent->right = node->left))
 175                                         parent->right->parent = parent;
 176                                 node->left = parent;
 177                         }
 178
 179                         parent->parent = node;
 180                         node->parent = NULL;
 181                 } else {
 182                         greatgrandparent = grandparent->parent;
 183
 184                         if(node == parent->left && parent == grandparent->left) { /* left zig-zig */
 185                                 if((grandparent->left = parent->right))
 186                                         grandparent->left->parent = grandparent;
 187                                 parent->right = grandparent;
 188                                 grandparent->parent = parent;
 189
 190                                 if((parent->left = node->right))
 191                                         parent->left->parent = parent;
 192                                 node->right = parent;
 193                                 parent->parent = node;
 194                         } else if(node == parent->right && parent == grandparent->right) { /* right zig-zig */
 195                                 if((grandparent->right = parent->left))
 196                                         grandparent->right->parent = grandparent;
 197                                 parent->left = grandparent;
 198                                 grandparent->parent = parent;
 199
 200                                 if((parent->right = node->left))
 201                                         parent->right->parent = parent;
 202                                 node->left = parent;
 203                                 parent->parent = node;
 204                         } else if(node == parent->right && parent == grandparent->left) { /* left-right zig-zag */
 205                                 if((parent->right = node->left))
 206                                         parent->right->parent = parent;
 207                                 node->left = parent;
 208                                 parent->parent = node;
 209
 210                                 if((grandparent->left = node->right))
 211                                         grandparent->left->parent = grandparent;
 212                                 node->right = grandparent;
 213                                 grandparent->parent = node;
 214                         } else { /* right-left zig-zag */
 215                                 if((parent->left = node->right))
 216                                         parent->left->parent = parent;
 217                                 node->right = parent;
 218                                 parent->parent = node;
 219
 220                                 if((grandparent->right = node->left))
 221                                         grandparent->right->parent = grandparent;
 222                                 node->left = grandparent;
 223                                 grandparent->parent = node;
 224                         }
 225
 226                         if((node->parent = greatgrandparent)) {
 227                                 if(grandparent == greatgrandparent->left)
 228                                         greatgrandparent->left = node;
 229                                 else
 230                                         greatgrandparent->right = node;
 231                         }
 232                 }
 233         }
 234
 235         tree->root = node;
 236 }
 237
 238 /* (De)constructors */
 239
 240 splay_tree_t *splay_alloc_tree(splay_compare_t compare, splay_action_t delete) {
 241         splay_tree_t *tree;
 242
 243         tree = xmalloc_and_zero(sizeof(splay_tree_t));
 244         tree->compare = compare;
 245         tree->delete = delete;
 246
 247         return tree;
 248 }
 249
 250 void splay_free_tree(splay_tree_t *tree) {
 251         free(tree);
 252 }
 253
 254 splay_node_t *splay_alloc_node(void) {
 255         return xmalloc_and_zero(sizeof(splay_node_t));
 256 }
 257
 258 void splay_free_node(splay_tree_t *tree, splay_node_t *node) {
 259         if(node->data && tree->delete)
 260                 tree->delete(node->data);
 261
 262         free(node);
 263 }
 264
 265 /* Searching */
 266
 267 void *splay_search(splay_tree_t *tree, const void *data) {
 268         splay_node_t *node;
 269
 270         node = splay_search_node(tree, data);
 271
 272         return node ? node->data : NULL;
 273 }
 274
 275 void *splay_search_closest(splay_tree_t *tree, const void *data, int *result) {
 276         splay_node_t *node;
 277
 278         node = splay_search_closest_node(tree, data, result);
 279
 280         return node ? node->data : NULL;
 281 }
 282
 283 void *splay_search_closest_smaller(splay_tree_t *tree, const void *data) {
 284         splay_node_t *node;
 285
 286         node = splay_search_closest_smaller_node(tree, data);
 287
 288         return node ? node->data : NULL;
 289 }
 290
 291 void *splay_search_closest_greater(splay_tree_t *tree, const void *data) {
 292         splay_node_t *node;
 293
 294         node = splay_search_closest_greater_node(tree, data);
 295
 296         return node ? node->data : NULL;
 297 }
 298
 299 splay_node_t *splay_search_node(splay_tree_t *tree, const void *data) {
 300         splay_node_t *node;
 301         int result;
 302
 303         node = splay_search_closest_node(tree, data, &result);
 304
 305         return result ? NULL : node;
 306 }
 307
 308 splay_node_t *splay_search_closest_node_nosplay(const splay_tree_t *tree, const void *data, int *result) {
 309         splay_node_t *node;
 310         int c;
 311
 312         node = tree->root;
 313
 314         if(!node) {
 315                 if(result)
 316                         *result = 0;
 317                 return NULL;
 318         }
 319
 320         for(;;) {
 321                 c = tree->compare(data, node->data);
 322
 323                 if(c < 0) {
 324                         if(node->left)
 325                                 node = node->left;
 326                         else
 327                                 break;
 328                 } else if(c > 0) {
 329                         if(node->right)
 330                                 node = node->right;
 331                         else
 332                                 break;
 333                 } else {
 334                         break;
 335                 }
 336         }
 337
 338         if(result)
 339                 *result = c;
 340         return node;
 341 }
 342
 343 splay_node_t *splay_search_closest_node(splay_tree_t *tree, const void *data, int *result) {
 344         return splay_top_down(tree, data, result);
 345 }
 346
 347 splay_node_t *splay_search_closest_smaller_node(splay_tree_t *tree, const void *data) {
 348         splay_node_t *node;
 349         int result;
 350
 351         node = splay_search_closest_node(tree, data, &result);
 352
 353         if(result < 0)
 354                 node = node->prev;
 355
 356         return node;
 357 }
 358
 359 splay_node_t *splay_search_closest_greater_node(splay_tree_t *tree, const void *data) {
 360         splay_node_t *node;
 361         int result;
 362
 363         node = splay_search_closest_node(tree, data, &result);
 364
 365         if(result > 0)
 366                 node = node->next;
 367
 368         return node;
 369 }
 370
 371 /* Insertion and deletion */
 372
 373 splay_node_t *splay_insert(splay_tree_t *tree, void *data) {
 374         splay_node_t *closest, *new;
 375         int result;
 376
 377         if(!tree->root) {
 378                 new = splay_alloc_node();
 379                 new->data = data;
 380                 splay_insert_top(tree, new);
 381         } else {
 382                 closest = splay_search_closest_node(tree, data, &result);
 383
 384                 if(!result)
 385                         return NULL;
 386
 387                 new = splay_alloc_node();
 388                 new->data = data;
 389
 390                 if(result < 0)
 391                         splay_insert_before(tree, closest, new);
 392                 else
 393                         splay_insert_after(tree, closest, new);
 394         }
 395
 396         return new;
 397 }
 398
 399 splay_node_t *splay_insert_node(splay_tree_t *tree, splay_node_t *node) {
 400         splay_node_t *closest;
 401         int result;
 402
 403         if(!tree->root)
 404                 splay_insert_top(tree, node);
 405         else {
 406                 closest = splay_search_closest_node(tree, node->data, &result);
 407
 408                 if(!result)
 409                         return NULL;
 410
 411                 if(result < 0)
 412                         splay_insert_before(tree, closest, node);
 413                 else
 414                         splay_insert_after(tree, closest, node);
 415         }
 416
 417         return node;
 418 }
 419
 420 void splay_insert_top(splay_tree_t *tree, splay_node_t *node) {
 421         node->prev = node->next = node->left = node->right = node->parent = NULL;
 422         tree->head = tree->tail = tree->root = node;
 423 }
 424
 425 void splay_insert_before(splay_tree_t *tree, splay_node_t *before, splay_node_t *node) {
 426         if(!before) {
 427                 if(tree->tail)
 428                         splay_insert_after(tree, tree->tail, node);
 429                 else
 430                         splay_insert_top(tree, node);
 431                 return;
 432         }
 433
 434         node->next = before;
 435         if((node->prev = before->prev))
 436                 before->prev->next = node;
 437         else
 438                 tree->head = node;
 439         before->prev = node;
 440
 441         splay_bottom_up(tree, before);
 442
 443         node->right = before;
 444         before->parent = node;
 445         if((node->left = before->left))
 446                 before->left->parent = node;
 447         before->left = NULL;
 448
 449         node->parent = NULL;
 450         tree->root = node;
 451 }
 452
 453 void splay_insert_after(splay_tree_t *tree, splay_node_t *after, splay_node_t *node) {
 454         if(!after) {
 455                 if(tree->head)
 456                         splay_insert_before(tree, tree->head, node);
 457                 else
 458                         splay_insert_top(tree, node);
 459                 return;
 460         }
 461
 462         node->prev = after;
 463         if((node->next = after->next))
 464                 after->next->prev = node;
 465         else
 466                 tree->tail = node;
 467         after->next = node;
 468
 469         splay_bottom_up(tree, after);
 470
 471         node->left = after;
 472         after->parent = node;
 473         if((node->right = after->right))
 474                 after->right->parent = node;
 475         after->right = NULL;
 476
 477         node->parent = NULL;
 478         tree->root = node;
 479 }
 480
 481 splay_node_t *splay_unlink(splay_tree_t *tree, void *data) {
 482         splay_node_t *node;
 483
 484         node = splay_search_node(tree, data);
 485
 486         if(node)
 487                 splay_unlink_node(tree, node);
 488
 489         return node;
 490 }
 491
 492 void splay_unlink_node(splay_tree_t *tree, splay_node_t *node) {
 493         if(node->prev)
 494                 node->prev->next = node->next;
 495         else
 496                 tree->head = node->next;
 497
 498         if(node->next)
 499                 node->next->prev = node->prev;
 500         else
 501                 tree->tail = node->prev;
 502
 503         splay_bottom_up(tree, node);
 504
 505         if(node->prev) {
 506                 node->left->parent = NULL;
 507                 tree->root = node->left;
 508                 if((node->prev->right = node->right))
 509                         node->right->parent = node->prev;
 510         } else if(node->next) {
 511                 tree->root = node->right;
 512                 node->right->parent = NULL;
 513         } else {
 514                 tree->root = NULL;
 515         }
 516 }
 517
 518 void splay_delete_node(splay_tree_t *tree, splay_node_t *node) {
 519         splay_unlink_node(tree, node);
 520         splay_free_node(tree, node);
 521 }
 522
 523 void splay_delete(splay_tree_t *tree, void *data) {
 524         splay_node_t *node;
 525
 526         node = splay_search_node(tree, data);
 527
 528         if(node)
 529                 splay_delete_node(tree, node);
 530 }
 531
 532 /* Fast tree cleanup */
 533
 534 void splay_delete_tree(splay_tree_t *tree) {
 535         splay_node_t *node, *next;
 536
 537         for(node = tree->root; node; node = next) {
 538                 next = node->next;
 539                 splay_free_node(tree, node);
 540         }
 541
 542         splay_free_tree(tree);
 543 }
 544
 545 /* Tree walking */
 546
 547 void splay_foreach(const splay_tree_t *tree, splay_action_t action) {
 548         splay_node_t *node, *next;
 549
 550         for(node = tree->head; node; node = next) {
 551                 next = node->next;
 552                 action(node->data);
 553         }
 554 }
 555
 556 void splay_foreach_node(const splay_tree_t *tree, splay_action_t action) {
 557         splay_node_t *node, *next;
 558
 559         for(node = tree->head; node; node = next) {
 560                 next = node->next;
 561                 action(node);
 562         }
 563 }