| 1 | /* |
| 2 | * rbtree.c -- generic red black tree |
| 3 | * |
| 4 | * Taken from Unbound, modified for ldns |
| 5 | * |
| 6 | * Copyright (c) 2001-2008, NLnet Labs. All rights reserved. |
| 7 | * |
| 8 | * This software is open source. |
| 9 | * |
| 10 | * Redistribution and use in source and binary forms, with or without |
| 11 | * modification, are permitted provided that the following conditions |
| 12 | * are met: |
| 13 | * |
| 14 | * Redistributions of source code must retain the above copyright notice, |
| 15 | * this list of conditions and the following disclaimer. |
| 16 | * |
| 17 | * Redistributions in binary form must reproduce the above copyright notice, |
| 18 | * this list of conditions and the following disclaimer in the documentation |
| 19 | * and/or other materials provided with the distribution. |
| 20 | * |
| 21 | * Neither the name of the NLNET LABS nor the names of its contributors may |
| 22 | * be used to endorse or promote products derived from this software without |
| 23 | * specific prior written permission. |
| 24 | * |
| 25 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| 26 | * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED |
| 27 | * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
| 28 | * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE |
| 29 | * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
| 30 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
| 31 | * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
| 32 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
| 33 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
| 34 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
| 35 | * POSSIBILITY OF SUCH DAMAGE. |
| 36 | * |
| 37 | */ |
| 38 | |
| 39 | /** |
| 40 | * \file |
| 41 | * Implementation of a redblack tree. |
| 42 | */ |
| 43 | |
| 44 | #include <ldns/config.h> |
| 45 | #include <ldns/rbtree.h> |
| 46 | #include <stdlib.h> |
| 47 | |
| 48 | /** Node colour black */ |
| 49 | #define BLACK 0 |
| 50 | /** Node colour red */ |
| 51 | #define RED 1 |
| 52 | |
| 53 | /** the NULL node, global alloc */ |
| 54 | ldns_rbnode_t ldns_rbtree_null_node = { |
| 55 | LDNS_RBTREE_NULL, /* Parent. */ |
| 56 | LDNS_RBTREE_NULL, /* Left. */ |
| 57 | LDNS_RBTREE_NULL, /* Right. */ |
| 58 | NULL, /* Key. */ |
| 59 | NULL, /* Data. */ |
| 60 | BLACK /* Color. */ |
| 61 | }; |
| 62 | |
| 63 | /** rotate subtree left (to preserve redblack property) */ |
| 64 | static void ldns_rbtree_rotate_left(ldns_rbtree_t *rbtree, ldns_rbnode_t *node); |
| 65 | /** rotate subtree right (to preserve redblack property) */ |
| 66 | static void ldns_rbtree_rotate_right(ldns_rbtree_t *rbtree, ldns_rbnode_t *node); |
| 67 | /** Fixup node colours when insert happened */ |
| 68 | static void ldns_rbtree_insert_fixup(ldns_rbtree_t *rbtree, ldns_rbnode_t *node); |
| 69 | /** Fixup node colours when delete happened */ |
| 70 | static void ldns_rbtree_delete_fixup(ldns_rbtree_t* rbtree, ldns_rbnode_t* child, ldns_rbnode_t* child_parent); |
| 71 | |
| 72 | /* |
| 73 | * Creates a new red black tree, intializes and returns a pointer to it. |
| 74 | * |
| 75 | * Return NULL on failure. |
| 76 | * |
| 77 | */ |
| 78 | ldns_rbtree_t * |
| 79 | ldns_rbtree_create (int (*cmpf)(const void *, const void *)) |
| 80 | { |
| 81 | ldns_rbtree_t *rbtree; |
| 82 | |
| 83 | /* Allocate memory for it */ |
| 84 | rbtree = (ldns_rbtree_t *) malloc(sizeof(ldns_rbtree_t)); |
| 85 | if (!rbtree) { |
| 86 | return NULL; |
| 87 | } |
| 88 | |
| 89 | /* Initialize it */ |
| 90 | ldns_rbtree_init(rbtree, cmpf); |
| 91 | |
| 92 | return rbtree; |
| 93 | } |
| 94 | |
| 95 | void |
| 96 | ldns_rbtree_init(ldns_rbtree_t *rbtree, int (*cmpf)(const void *, const void *)) |
| 97 | { |
| 98 | /* Initialize it */ |
| 99 | rbtree->root = LDNS_RBTREE_NULL; |
| 100 | rbtree->count = 0; |
| 101 | rbtree->cmp = cmpf; |
| 102 | } |
| 103 | |
| 104 | void |
| 105 | ldns_rbtree_free(ldns_rbtree_t *rbtree) |
| 106 | { |
| 107 | free(rbtree); |
| 108 | } |
| 109 | |
| 110 | /* |
| 111 | * Rotates the node to the left. |
| 112 | * |
| 113 | */ |
| 114 | static void |
| 115 | ldns_rbtree_rotate_left(ldns_rbtree_t *rbtree, ldns_rbnode_t *node) |
| 116 | { |
| 117 | ldns_rbnode_t *right = node->right; |
| 118 | node->right = right->left; |
| 119 | if (right->left != LDNS_RBTREE_NULL) |
| 120 | right->left->parent = node; |
| 121 | |
| 122 | right->parent = node->parent; |
| 123 | |
| 124 | if (node->parent != LDNS_RBTREE_NULL) { |
| 125 | if (node == node->parent->left) { |
| 126 | node->parent->left = right; |
| 127 | } else { |
| 128 | node->parent->right = right; |
| 129 | } |
| 130 | } else { |
| 131 | rbtree->root = right; |
| 132 | } |
| 133 | right->left = node; |
| 134 | node->parent = right; |
| 135 | } |
| 136 | |
| 137 | /* |
| 138 | * Rotates the node to the right. |
| 139 | * |
| 140 | */ |
| 141 | static void |
| 142 | ldns_rbtree_rotate_right(ldns_rbtree_t *rbtree, ldns_rbnode_t *node) |
| 143 | { |
| 144 | ldns_rbnode_t *left = node->left; |
| 145 | node->left = left->right; |
| 146 | if (left->right != LDNS_RBTREE_NULL) |
| 147 | left->right->parent = node; |
| 148 | |
| 149 | left->parent = node->parent; |
| 150 | |
| 151 | if (node->parent != LDNS_RBTREE_NULL) { |
| 152 | if (node == node->parent->right) { |
| 153 | node->parent->right = left; |
| 154 | } else { |
| 155 | node->parent->left = left; |
| 156 | } |
| 157 | } else { |
| 158 | rbtree->root = left; |
| 159 | } |
| 160 | left->right = node; |
| 161 | node->parent = left; |
| 162 | } |
| 163 | |
| 164 | static void |
| 165 | ldns_rbtree_insert_fixup(ldns_rbtree_t *rbtree, ldns_rbnode_t *node) |
| 166 | { |
| 167 | ldns_rbnode_t *uncle; |
| 168 | |
| 169 | /* While not at the root and need fixing... */ |
| 170 | while (node != rbtree->root && node->parent->color == RED) { |
| 171 | /* If our parent is left child of our grandparent... */ |
| 172 | if (node->parent == node->parent->parent->left) { |
| 173 | uncle = node->parent->parent->right; |
| 174 | |
| 175 | /* If our uncle is red... */ |
| 176 | if (uncle->color == RED) { |
| 177 | /* Paint the parent and the uncle black... */ |
| 178 | node->parent->color = BLACK; |
| 179 | uncle->color = BLACK; |
| 180 | |
| 181 | /* And the grandparent red... */ |
| 182 | node->parent->parent->color = RED; |
| 183 | |
| 184 | /* And continue fixing the grandparent */ |
| 185 | node = node->parent->parent; |
| 186 | } else { /* Our uncle is black... */ |
| 187 | /* Are we the right child? */ |
| 188 | if (node == node->parent->right) { |
| 189 | node = node->parent; |
| 190 | ldns_rbtree_rotate_left(rbtree, node); |
| 191 | } |
| 192 | /* Now we're the left child, repaint and rotate... */ |
| 193 | node->parent->color = BLACK; |
| 194 | node->parent->parent->color = RED; |
| 195 | ldns_rbtree_rotate_right(rbtree, node->parent->parent); |
| 196 | } |
| 197 | } else { |
| 198 | uncle = node->parent->parent->left; |
| 199 | |
| 200 | /* If our uncle is red... */ |
| 201 | if (uncle->color == RED) { |
| 202 | /* Paint the parent and the uncle black... */ |
| 203 | node->parent->color = BLACK; |
| 204 | uncle->color = BLACK; |
| 205 | |
| 206 | /* And the grandparent red... */ |
| 207 | node->parent->parent->color = RED; |
| 208 | |
| 209 | /* And continue fixing the grandparent */ |
| 210 | node = node->parent->parent; |
| 211 | } else { /* Our uncle is black... */ |
| 212 | /* Are we the right child? */ |
| 213 | if (node == node->parent->left) { |
| 214 | node = node->parent; |
| 215 | ldns_rbtree_rotate_right(rbtree, node); |
| 216 | } |
| 217 | /* Now we're the right child, repaint and rotate... */ |
| 218 | node->parent->color = BLACK; |
| 219 | node->parent->parent->color = RED; |
| 220 | ldns_rbtree_rotate_left(rbtree, node->parent->parent); |
| 221 | } |
| 222 | } |
| 223 | } |
| 224 | rbtree->root->color = BLACK; |
| 225 | } |
| 226 | |
| 227 | void |
| 228 | ldns_rbtree_insert_vref(ldns_rbnode_t *data, void *rbtree) |
| 229 | { |
| 230 | (void) ldns_rbtree_insert((ldns_rbtree_t *) rbtree, |
| 231 | data); |
| 232 | } |
| 233 | |
| 234 | /* |
| 235 | * Inserts a node into a red black tree. |
| 236 | * |
| 237 | * Returns NULL on failure or the pointer to the newly added node |
| 238 | * otherwise. |
| 239 | */ |
| 240 | ldns_rbnode_t * |
| 241 | ldns_rbtree_insert (ldns_rbtree_t *rbtree, ldns_rbnode_t *data) |
| 242 | { |
| 243 | /* XXX Not necessary, but keeps compiler quiet... */ |
| 244 | int r = 0; |
| 245 | |
| 246 | /* We start at the root of the tree */ |
| 247 | ldns_rbnode_t *node = rbtree->root; |
| 248 | ldns_rbnode_t *parent = LDNS_RBTREE_NULL; |
| 249 | |
| 250 | /* Lets find the new parent... */ |
| 251 | while (node != LDNS_RBTREE_NULL) { |
| 252 | /* Compare two keys, do we have a duplicate? */ |
| 253 | if ((r = rbtree->cmp(data->key, node->key)) == 0) { |
| 254 | return NULL; |
| 255 | } |
| 256 | parent = node; |
| 257 | |
| 258 | if (r < 0) { |
| 259 | node = node->left; |
| 260 | } else { |
| 261 | node = node->right; |
| 262 | } |
| 263 | } |
| 264 | |
| 265 | /* Initialize the new node */ |
| 266 | data->parent = parent; |
| 267 | data->left = data->right = LDNS_RBTREE_NULL; |
| 268 | data->color = RED; |
| 269 | rbtree->count++; |
| 270 | |
| 271 | /* Insert it into the tree... */ |
| 272 | if (parent != LDNS_RBTREE_NULL) { |
| 273 | if (r < 0) { |
| 274 | parent->left = data; |
| 275 | } else { |
| 276 | parent->right = data; |
| 277 | } |
| 278 | } else { |
| 279 | rbtree->root = data; |
| 280 | } |
| 281 | |
| 282 | /* Fix up the red-black properties... */ |
| 283 | ldns_rbtree_insert_fixup(rbtree, data); |
| 284 | |
| 285 | return data; |
| 286 | } |
| 287 | |
| 288 | /* |
| 289 | * Searches the red black tree, returns the data if key is found or NULL otherwise. |
| 290 | * |
| 291 | */ |
| 292 | ldns_rbnode_t * |
| 293 | ldns_rbtree_search (ldns_rbtree_t *rbtree, const void *key) |
| 294 | { |
| 295 | ldns_rbnode_t *node; |
| 296 | |
| 297 | if (ldns_rbtree_find_less_equal(rbtree, key, &node)) { |
| 298 | return node; |
| 299 | } else { |
| 300 | return NULL; |
| 301 | } |
| 302 | } |
| 303 | |
| 304 | /** helpers for delete: swap node colours */ |
| 305 | static void swap_int8(uint8_t* x, uint8_t* y) |
| 306 | { |
| 307 | uint8_t t = *x; *x = *y; *y = t; |
| 308 | } |
| 309 | |
| 310 | /** helpers for delete: swap node pointers */ |
| 311 | static void swap_np(ldns_rbnode_t** x, ldns_rbnode_t** y) |
| 312 | { |
| 313 | ldns_rbnode_t* t = *x; *x = *y; *y = t; |
| 314 | } |
| 315 | |
| 316 | /** Update parent pointers of child trees of 'parent' */ |
| 317 | static void change_parent_ptr(ldns_rbtree_t* rbtree, ldns_rbnode_t* parent, ldns_rbnode_t* old, ldns_rbnode_t* new) |
| 318 | { |
| 319 | if(parent == LDNS_RBTREE_NULL) |
| 320 | { |
| 321 | if(rbtree->root == old) rbtree->root = new; |
| 322 | return; |
| 323 | } |
| 324 | if(parent->left == old) parent->left = new; |
| 325 | if(parent->right == old) parent->right = new; |
| 326 | } |
| 327 | /** Update parent pointer of a node 'child' */ |
| 328 | static void change_child_ptr(ldns_rbnode_t* child, ldns_rbnode_t* old, ldns_rbnode_t* new) |
| 329 | { |
| 330 | if(child == LDNS_RBTREE_NULL) return; |
| 331 | if(child->parent == old) child->parent = new; |
| 332 | } |
| 333 | |
| 334 | ldns_rbnode_t* |
| 335 | ldns_rbtree_delete(ldns_rbtree_t *rbtree, const void *key) |
| 336 | { |
| 337 | ldns_rbnode_t *to_delete; |
| 338 | ldns_rbnode_t *child; |
| 339 | if((to_delete = ldns_rbtree_search(rbtree, key)) == 0) return 0; |
| 340 | rbtree->count--; |
| 341 | |
| 342 | /* make sure we have at most one non-leaf child */ |
| 343 | if(to_delete->left != LDNS_RBTREE_NULL && |
| 344 | to_delete->right != LDNS_RBTREE_NULL) |
| 345 | { |
| 346 | /* swap with smallest from right subtree (or largest from left) */ |
| 347 | ldns_rbnode_t *smright = to_delete->right; |
| 348 | while(smright->left != LDNS_RBTREE_NULL) |
| 349 | smright = smright->left; |
| 350 | /* swap the smright and to_delete elements in the tree, |
| 351 | * but the ldns_rbnode_t is first part of user data struct |
| 352 | * so cannot just swap the keys and data pointers. Instead |
| 353 | * readjust the pointers left,right,parent */ |
| 354 | |
| 355 | /* swap colors - colors are tied to the position in the tree */ |
| 356 | swap_int8(&to_delete->color, &smright->color); |
| 357 | |
| 358 | /* swap child pointers in parents of smright/to_delete */ |
| 359 | change_parent_ptr(rbtree, to_delete->parent, to_delete, smright); |
| 360 | if(to_delete->right != smright) |
| 361 | change_parent_ptr(rbtree, smright->parent, smright, to_delete); |
| 362 | |
| 363 | /* swap parent pointers in children of smright/to_delete */ |
| 364 | change_child_ptr(smright->left, smright, to_delete); |
| 365 | change_child_ptr(smright->left, smright, to_delete); |
| 366 | change_child_ptr(smright->right, smright, to_delete); |
| 367 | change_child_ptr(smright->right, smright, to_delete); |
| 368 | change_child_ptr(to_delete->left, to_delete, smright); |
| 369 | if(to_delete->right != smright) |
| 370 | change_child_ptr(to_delete->right, to_delete, smright); |
| 371 | if(to_delete->right == smright) |
| 372 | { |
| 373 | /* set up so after swap they work */ |
| 374 | to_delete->right = to_delete; |
| 375 | smright->parent = smright; |
| 376 | } |
| 377 | |
| 378 | /* swap pointers in to_delete/smright nodes */ |
| 379 | swap_np(&to_delete->parent, &smright->parent); |
| 380 | swap_np(&to_delete->left, &smright->left); |
| 381 | swap_np(&to_delete->right, &smright->right); |
| 382 | |
| 383 | /* now delete to_delete (which is at the location where the smright previously was) */ |
| 384 | } |
| 385 | |
| 386 | if(to_delete->left != LDNS_RBTREE_NULL) child = to_delete->left; |
| 387 | else child = to_delete->right; |
| 388 | |
| 389 | /* unlink to_delete from the tree, replace to_delete with child */ |
| 390 | change_parent_ptr(rbtree, to_delete->parent, to_delete, child); |
| 391 | change_child_ptr(child, to_delete, to_delete->parent); |
| 392 | |
| 393 | if(to_delete->color == RED) |
| 394 | { |
| 395 | /* if node is red then the child (black) can be swapped in */ |
| 396 | } |
| 397 | else if(child->color == RED) |
| 398 | { |
| 399 | /* change child to BLACK, removing a RED node is no problem */ |
| 400 | if(child!=LDNS_RBTREE_NULL) child->color = BLACK; |
| 401 | } |
| 402 | else ldns_rbtree_delete_fixup(rbtree, child, to_delete->parent); |
| 403 | |
| 404 | /* unlink completely */ |
| 405 | to_delete->parent = LDNS_RBTREE_NULL; |
| 406 | to_delete->left = LDNS_RBTREE_NULL; |
| 407 | to_delete->right = LDNS_RBTREE_NULL; |
| 408 | to_delete->color = BLACK; |
| 409 | return to_delete; |
| 410 | } |
| 411 | |
| 412 | static void ldns_rbtree_delete_fixup(ldns_rbtree_t* rbtree, ldns_rbnode_t* child, ldns_rbnode_t* child_parent) |
| 413 | { |
| 414 | ldns_rbnode_t* sibling; |
| 415 | int go_up = 1; |
| 416 | |
| 417 | /* determine sibling to the node that is one-black short */ |
| 418 | if(child_parent->right == child) sibling = child_parent->left; |
| 419 | else sibling = child_parent->right; |
| 420 | |
| 421 | while(go_up) |
| 422 | { |
| 423 | if(child_parent == LDNS_RBTREE_NULL) |
| 424 | { |
| 425 | /* removed parent==black from root, every path, so ok */ |
| 426 | return; |
| 427 | } |
| 428 | |
| 429 | if(sibling->color == RED) |
| 430 | { /* rotate to get a black sibling */ |
| 431 | child_parent->color = RED; |
| 432 | sibling->color = BLACK; |
| 433 | if(child_parent->right == child) |
| 434 | ldns_rbtree_rotate_right(rbtree, child_parent); |
| 435 | else ldns_rbtree_rotate_left(rbtree, child_parent); |
| 436 | /* new sibling after rotation */ |
| 437 | if(child_parent->right == child) sibling = child_parent->left; |
| 438 | else sibling = child_parent->right; |
| 439 | } |
| 440 | |
| 441 | if(child_parent->color == BLACK |
| 442 | && sibling->color == BLACK |
| 443 | && sibling->left->color == BLACK |
| 444 | && sibling->right->color == BLACK) |
| 445 | { /* fixup local with recolor of sibling */ |
| 446 | if(sibling != LDNS_RBTREE_NULL) |
| 447 | sibling->color = RED; |
| 448 | |
| 449 | child = child_parent; |
| 450 | child_parent = child_parent->parent; |
| 451 | /* prepare to go up, new sibling */ |
| 452 | if(child_parent->right == child) sibling = child_parent->left; |
| 453 | else sibling = child_parent->right; |
| 454 | } |
| 455 | else go_up = 0; |
| 456 | } |
| 457 | |
| 458 | if(child_parent->color == RED |
| 459 | && sibling->color == BLACK |
| 460 | && sibling->left->color == BLACK |
| 461 | && sibling->right->color == BLACK) |
| 462 | { |
| 463 | /* move red to sibling to rebalance */ |
| 464 | if(sibling != LDNS_RBTREE_NULL) |
| 465 | sibling->color = RED; |
| 466 | child_parent->color = BLACK; |
| 467 | return; |
| 468 | } |
| 469 | |
| 470 | /* get a new sibling, by rotating at sibling. See which child |
| 471 | of sibling is red */ |
| 472 | if(child_parent->right == child |
| 473 | && sibling->color == BLACK |
| 474 | && sibling->right->color == RED |
| 475 | && sibling->left->color == BLACK) |
| 476 | { |
| 477 | sibling->color = RED; |
| 478 | sibling->right->color = BLACK; |
| 479 | ldns_rbtree_rotate_left(rbtree, sibling); |
| 480 | /* new sibling after rotation */ |
| 481 | if(child_parent->right == child) sibling = child_parent->left; |
| 482 | else sibling = child_parent->right; |
| 483 | } |
| 484 | else if(child_parent->left == child |
| 485 | && sibling->color == BLACK |
| 486 | && sibling->left->color == RED |
| 487 | && sibling->right->color == BLACK) |
| 488 | { |
| 489 | sibling->color = RED; |
| 490 | sibling->left->color = BLACK; |
| 491 | ldns_rbtree_rotate_right(rbtree, sibling); |
| 492 | /* new sibling after rotation */ |
| 493 | if(child_parent->right == child) sibling = child_parent->left; |
| 494 | else sibling = child_parent->right; |
| 495 | } |
| 496 | |
| 497 | /* now we have a black sibling with a red child. rotate and exchange colors. */ |
| 498 | sibling->color = child_parent->color; |
| 499 | child_parent->color = BLACK; |
| 500 | if(child_parent->right == child) |
| 501 | { |
| 502 | sibling->left->color = BLACK; |
| 503 | ldns_rbtree_rotate_right(rbtree, child_parent); |
| 504 | } |
| 505 | else |
| 506 | { |
| 507 | sibling->right->color = BLACK; |
| 508 | ldns_rbtree_rotate_left(rbtree, child_parent); |
| 509 | } |
| 510 | } |
| 511 | |
| 512 | int |
| 513 | ldns_rbtree_find_less_equal(ldns_rbtree_t *rbtree, const void *key, ldns_rbnode_t **result) |
| 514 | { |
| 515 | int r; |
| 516 | ldns_rbnode_t *node; |
| 517 | |
| 518 | /* We start at root... */ |
| 519 | node = rbtree->root; |
| 520 | |
| 521 | *result = NULL; |
| 522 | |
| 523 | /* While there are children... */ |
| 524 | while (node != LDNS_RBTREE_NULL) { |
| 525 | r = rbtree->cmp(key, node->key); |
| 526 | if (r == 0) { |
| 527 | /* Exact match */ |
| 528 | *result = node; |
| 529 | return 1; |
| 530 | } |
| 531 | if (r < 0) { |
| 532 | node = node->left; |
| 533 | } else { |
| 534 | /* Temporary match */ |
| 535 | *result = node; |
| 536 | node = node->right; |
| 537 | } |
| 538 | } |
| 539 | return 0; |
| 540 | } |
| 541 | |
| 542 | /* |
| 543 | * Finds the first element in the red black tree |
| 544 | * |
| 545 | */ |
| 546 | ldns_rbnode_t * |
| 547 | ldns_rbtree_first (ldns_rbtree_t *rbtree) |
| 548 | { |
| 549 | ldns_rbnode_t *node = rbtree->root; |
| 550 | |
| 551 | if (rbtree->root != LDNS_RBTREE_NULL) { |
| 552 | for (node = rbtree->root; node->left != LDNS_RBTREE_NULL; node = node->left); |
| 553 | } |
| 554 | return node; |
| 555 | } |
| 556 | |
| 557 | ldns_rbnode_t * |
| 558 | ldns_rbtree_last (ldns_rbtree_t *rbtree) |
| 559 | { |
| 560 | ldns_rbnode_t *node = rbtree->root; |
| 561 | |
| 562 | if (rbtree->root != LDNS_RBTREE_NULL) { |
| 563 | for (node = rbtree->root; node->right != LDNS_RBTREE_NULL; node = node->right); |
| 564 | } |
| 565 | return node; |
| 566 | } |
| 567 | |
| 568 | /* |
| 569 | * Returns the next node... |
| 570 | * |
| 571 | */ |
| 572 | ldns_rbnode_t * |
| 573 | ldns_rbtree_next (ldns_rbnode_t *node) |
| 574 | { |
| 575 | ldns_rbnode_t *parent; |
| 576 | |
| 577 | if (node->right != LDNS_RBTREE_NULL) { |
| 578 | /* One right, then keep on going left... */ |
| 579 | for (node = node->right; |
| 580 | node->left != LDNS_RBTREE_NULL; |
| 581 | node = node->left); |
| 582 | } else { |
| 583 | parent = node->parent; |
| 584 | while (parent != LDNS_RBTREE_NULL && node == parent->right) { |
| 585 | node = parent; |
| 586 | parent = parent->parent; |
| 587 | } |
| 588 | node = parent; |
| 589 | } |
| 590 | return node; |
| 591 | } |
| 592 | |
| 593 | ldns_rbnode_t * |
| 594 | ldns_rbtree_previous(ldns_rbnode_t *node) |
| 595 | { |
| 596 | ldns_rbnode_t *parent; |
| 597 | |
| 598 | if (node->left != LDNS_RBTREE_NULL) { |
| 599 | /* One left, then keep on going right... */ |
| 600 | for (node = node->left; |
| 601 | node->right != LDNS_RBTREE_NULL; |
| 602 | node = node->right); |
| 603 | } else { |
| 604 | parent = node->parent; |
| 605 | while (parent != LDNS_RBTREE_NULL && node == parent->left) { |
| 606 | node = parent; |
| 607 | parent = parent->parent; |
| 608 | } |
| 609 | node = parent; |
| 610 | } |
| 611 | return node; |
| 612 | } |
| 613 | |
| 614 | /** |
| 615 | * split off elements number of elements from the start |
| 616 | * of the name tree and return a new tree |
| 617 | */ |
| 618 | ldns_rbtree_t * |
| 619 | ldns_rbtree_split(ldns_rbtree_t *tree, |
| 620 | size_t elements) |
| 621 | { |
| 622 | ldns_rbtree_t *new_tree; |
| 623 | ldns_rbnode_t *cur_node; |
| 624 | ldns_rbnode_t *move_node; |
| 625 | size_t count = 0; |
| 626 | |
| 627 | new_tree = ldns_rbtree_create(tree->cmp); |
| 628 | |
| 629 | cur_node = ldns_rbtree_first(tree); |
| 630 | while (count < elements && cur_node != LDNS_RBTREE_NULL) { |
| 631 | move_node = ldns_rbtree_delete(tree, cur_node->key); |
| 632 | (void)ldns_rbtree_insert(new_tree, move_node); |
| 633 | cur_node = ldns_rbtree_first(tree); |
| 634 | count++; |
| 635 | } |
| 636 | |
| 637 | return new_tree; |
| 638 | } |
| 639 | |
| 640 | /* |
| 641 | * add all node from the second tree to the first (removing them from the |
| 642 | * second), and fix up nsec(3)s if present |
| 643 | */ |
| 644 | void |
| 645 | ldns_rbtree_join(ldns_rbtree_t *tree1, ldns_rbtree_t *tree2) |
| 646 | { |
| 647 | ldns_traverse_postorder(tree2, ldns_rbtree_insert_vref, tree1); |
| 648 | } |
| 649 | |
| 650 | /** recursive descent traverse */ |
| 651 | static void |
| 652 | traverse_post(void (*func)(ldns_rbnode_t*, void*), void* arg, |
| 653 | ldns_rbnode_t* node) |
| 654 | { |
| 655 | if(!node || node == LDNS_RBTREE_NULL) |
| 656 | return; |
| 657 | /* recurse */ |
| 658 | traverse_post(func, arg, node->left); |
| 659 | traverse_post(func, arg, node->right); |
| 660 | /* call user func */ |
| 661 | (*func)(node, arg); |
| 662 | } |
| 663 | |
| 664 | void |
| 665 | ldns_traverse_postorder(ldns_rbtree_t* tree, |
| 666 | void (*func)(ldns_rbnode_t*, void*), void* arg) |
| 667 | { |
| 668 | traverse_post(func, arg, tree->root); |
| 669 | } |