Pablo Neira Ayuso | f74db0b | 2011-09-26 11:44:57 +0200 | [diff] [blame] | 1 | /* |
| 2 | Red Black Trees |
| 3 | (C) 1999 Andrea Arcangeli <andrea@suse.de> |
| 4 | (C) 2002 David Woodhouse <dwmw2@infradead.org> |
| 5 | |
| 6 | This program is free software; you can redistribute it and/or modify |
| 7 | it under the terms of the GNU General Public License as published by |
| 8 | the Free Software Foundation; either version 2 of the License, or |
| 9 | (at your option) any later version. |
| 10 | |
| 11 | This program is distributed in the hope that it will be useful, |
| 12 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 14 | GNU General Public License for more details. |
| 15 | |
| 16 | You should have received a copy of the GNU General Public License |
| 17 | along with this program; if not, write to the Free Software |
Jaroslav Škarvada | 2b82c1c | 2015-11-11 16:02:54 +0100 | [diff] [blame] | 18 | Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, |
| 19 | MA 02110-1301, USA |
Pablo Neira Ayuso | f74db0b | 2011-09-26 11:44:57 +0200 | [diff] [blame] | 20 | |
| 21 | linux/lib/rbtree.c |
| 22 | */ |
| 23 | |
| 24 | #include <osmocom/core/linuxrbtree.h> |
| 25 | |
| 26 | static void __rb_rotate_left(struct rb_node *node, struct rb_root *root) |
| 27 | { |
| 28 | struct rb_node *right = node->rb_right; |
| 29 | struct rb_node *parent = rb_parent(node); |
| 30 | |
| 31 | if ((node->rb_right = right->rb_left)) |
| 32 | rb_set_parent(right->rb_left, node); |
| 33 | right->rb_left = node; |
| 34 | |
| 35 | rb_set_parent(right, parent); |
| 36 | |
| 37 | if (parent) |
| 38 | { |
| 39 | if (node == parent->rb_left) |
| 40 | parent->rb_left = right; |
| 41 | else |
| 42 | parent->rb_right = right; |
| 43 | } |
| 44 | else |
| 45 | root->rb_node = right; |
| 46 | rb_set_parent(node, right); |
| 47 | } |
| 48 | |
| 49 | static void __rb_rotate_right(struct rb_node *node, struct rb_root *root) |
| 50 | { |
| 51 | struct rb_node *left = node->rb_left; |
| 52 | struct rb_node *parent = rb_parent(node); |
| 53 | |
| 54 | if ((node->rb_left = left->rb_right)) |
| 55 | rb_set_parent(left->rb_right, node); |
| 56 | left->rb_right = node; |
| 57 | |
| 58 | rb_set_parent(left, parent); |
| 59 | |
| 60 | if (parent) |
| 61 | { |
| 62 | if (node == parent->rb_right) |
| 63 | parent->rb_right = left; |
| 64 | else |
| 65 | parent->rb_left = left; |
| 66 | } |
| 67 | else |
| 68 | root->rb_node = left; |
| 69 | rb_set_parent(node, left); |
| 70 | } |
| 71 | |
| 72 | void rb_insert_color(struct rb_node *node, struct rb_root *root) |
| 73 | { |
| 74 | struct rb_node *parent, *gparent; |
| 75 | |
| 76 | while ((parent = rb_parent(node)) && rb_is_red(parent)) |
| 77 | { |
| 78 | gparent = rb_parent(parent); |
| 79 | |
| 80 | if (parent == gparent->rb_left) |
| 81 | { |
| 82 | { |
| 83 | register struct rb_node *uncle = gparent->rb_right; |
| 84 | if (uncle && rb_is_red(uncle)) |
| 85 | { |
| 86 | rb_set_black(uncle); |
| 87 | rb_set_black(parent); |
| 88 | rb_set_red(gparent); |
| 89 | node = gparent; |
| 90 | continue; |
| 91 | } |
| 92 | } |
| 93 | |
| 94 | if (parent->rb_right == node) |
| 95 | { |
| 96 | register struct rb_node *tmp; |
| 97 | __rb_rotate_left(parent, root); |
| 98 | tmp = parent; |
| 99 | parent = node; |
| 100 | node = tmp; |
| 101 | } |
| 102 | |
| 103 | rb_set_black(parent); |
| 104 | rb_set_red(gparent); |
| 105 | __rb_rotate_right(gparent, root); |
| 106 | } else { |
| 107 | { |
| 108 | register struct rb_node *uncle = gparent->rb_left; |
| 109 | if (uncle && rb_is_red(uncle)) |
| 110 | { |
| 111 | rb_set_black(uncle); |
| 112 | rb_set_black(parent); |
| 113 | rb_set_red(gparent); |
| 114 | node = gparent; |
| 115 | continue; |
| 116 | } |
| 117 | } |
| 118 | |
| 119 | if (parent->rb_left == node) |
| 120 | { |
| 121 | register struct rb_node *tmp; |
| 122 | __rb_rotate_right(parent, root); |
| 123 | tmp = parent; |
| 124 | parent = node; |
| 125 | node = tmp; |
| 126 | } |
| 127 | |
| 128 | rb_set_black(parent); |
| 129 | rb_set_red(gparent); |
| 130 | __rb_rotate_left(gparent, root); |
| 131 | } |
| 132 | } |
| 133 | |
| 134 | rb_set_black(root->rb_node); |
| 135 | } |
| 136 | |
| 137 | static void __rb_erase_color(struct rb_node *node, struct rb_node *parent, |
| 138 | struct rb_root *root) |
| 139 | { |
| 140 | struct rb_node *other; |
| 141 | |
| 142 | while ((!node || rb_is_black(node)) && node != root->rb_node) |
| 143 | { |
| 144 | if (parent->rb_left == node) |
| 145 | { |
| 146 | other = parent->rb_right; |
| 147 | if (rb_is_red(other)) |
| 148 | { |
| 149 | rb_set_black(other); |
| 150 | rb_set_red(parent); |
| 151 | __rb_rotate_left(parent, root); |
| 152 | other = parent->rb_right; |
| 153 | } |
| 154 | if ((!other->rb_left || rb_is_black(other->rb_left)) && |
| 155 | (!other->rb_right || rb_is_black(other->rb_right))) |
| 156 | { |
| 157 | rb_set_red(other); |
| 158 | node = parent; |
| 159 | parent = rb_parent(node); |
| 160 | } |
| 161 | else |
| 162 | { |
| 163 | if (!other->rb_right || rb_is_black(other->rb_right)) |
| 164 | { |
Sylvain Munaut | 0395c6e | 2011-11-11 15:25:25 +0100 | [diff] [blame] | 165 | rb_set_black(other->rb_left); |
Pablo Neira Ayuso | f74db0b | 2011-09-26 11:44:57 +0200 | [diff] [blame] | 166 | rb_set_red(other); |
| 167 | __rb_rotate_right(other, root); |
| 168 | other = parent->rb_right; |
| 169 | } |
| 170 | rb_set_color(other, rb_color(parent)); |
| 171 | rb_set_black(parent); |
Sylvain Munaut | 0395c6e | 2011-11-11 15:25:25 +0100 | [diff] [blame] | 172 | rb_set_black(other->rb_right); |
Pablo Neira Ayuso | f74db0b | 2011-09-26 11:44:57 +0200 | [diff] [blame] | 173 | __rb_rotate_left(parent, root); |
| 174 | node = root->rb_node; |
| 175 | break; |
| 176 | } |
| 177 | } |
| 178 | else |
| 179 | { |
| 180 | other = parent->rb_left; |
| 181 | if (rb_is_red(other)) |
| 182 | { |
| 183 | rb_set_black(other); |
| 184 | rb_set_red(parent); |
| 185 | __rb_rotate_right(parent, root); |
| 186 | other = parent->rb_left; |
| 187 | } |
| 188 | if ((!other->rb_left || rb_is_black(other->rb_left)) && |
| 189 | (!other->rb_right || rb_is_black(other->rb_right))) |
| 190 | { |
| 191 | rb_set_red(other); |
| 192 | node = parent; |
| 193 | parent = rb_parent(node); |
| 194 | } |
| 195 | else |
| 196 | { |
| 197 | if (!other->rb_left || rb_is_black(other->rb_left)) |
| 198 | { |
Sylvain Munaut | 0395c6e | 2011-11-11 15:25:25 +0100 | [diff] [blame] | 199 | rb_set_black(other->rb_right); |
Pablo Neira Ayuso | f74db0b | 2011-09-26 11:44:57 +0200 | [diff] [blame] | 200 | rb_set_red(other); |
| 201 | __rb_rotate_left(other, root); |
| 202 | other = parent->rb_left; |
| 203 | } |
| 204 | rb_set_color(other, rb_color(parent)); |
| 205 | rb_set_black(parent); |
Sylvain Munaut | 0395c6e | 2011-11-11 15:25:25 +0100 | [diff] [blame] | 206 | rb_set_black(other->rb_left); |
Pablo Neira Ayuso | f74db0b | 2011-09-26 11:44:57 +0200 | [diff] [blame] | 207 | __rb_rotate_right(parent, root); |
| 208 | node = root->rb_node; |
| 209 | break; |
| 210 | } |
| 211 | } |
| 212 | } |
| 213 | if (node) |
| 214 | rb_set_black(node); |
| 215 | } |
| 216 | |
| 217 | void rb_erase(struct rb_node *node, struct rb_root *root) |
| 218 | { |
| 219 | struct rb_node *child, *parent; |
| 220 | int color; |
| 221 | |
| 222 | if (!node->rb_left) |
| 223 | child = node->rb_right; |
| 224 | else if (!node->rb_right) |
| 225 | child = node->rb_left; |
| 226 | else |
| 227 | { |
| 228 | struct rb_node *old = node, *left; |
| 229 | |
| 230 | node = node->rb_right; |
| 231 | while ((left = node->rb_left) != NULL) |
| 232 | node = left; |
Sylvain Munaut | b8c5bde | 2011-11-11 15:28:01 +0100 | [diff] [blame] | 233 | |
| 234 | if (rb_parent(old)) { |
| 235 | if (rb_parent(old)->rb_left == old) |
| 236 | rb_parent(old)->rb_left = node; |
| 237 | else |
| 238 | rb_parent(old)->rb_right = node; |
| 239 | } else |
| 240 | root->rb_node = node; |
| 241 | |
Pablo Neira Ayuso | f74db0b | 2011-09-26 11:44:57 +0200 | [diff] [blame] | 242 | child = node->rb_right; |
| 243 | parent = rb_parent(node); |
| 244 | color = rb_color(node); |
| 245 | |
Pablo Neira Ayuso | f74db0b | 2011-09-26 11:44:57 +0200 | [diff] [blame] | 246 | if (parent == old) { |
Pablo Neira Ayuso | f74db0b | 2011-09-26 11:44:57 +0200 | [diff] [blame] | 247 | parent = node; |
Sylvain Munaut | a83cbe1 | 2011-11-11 15:29:59 +0100 | [diff] [blame] | 248 | } else { |
| 249 | if (child) |
| 250 | rb_set_parent(child, parent); |
Pablo Neira Ayuso | f74db0b | 2011-09-26 11:44:57 +0200 | [diff] [blame] | 251 | parent->rb_left = child; |
Sylvain Munaut | 54187ba | 2011-11-11 15:31:01 +0100 | [diff] [blame] | 252 | |
| 253 | node->rb_right = old->rb_right; |
| 254 | rb_set_parent(old->rb_right, node); |
Sylvain Munaut | a83cbe1 | 2011-11-11 15:29:59 +0100 | [diff] [blame] | 255 | } |
Pablo Neira Ayuso | f74db0b | 2011-09-26 11:44:57 +0200 | [diff] [blame] | 256 | |
| 257 | node->rb_parent_color = old->rb_parent_color; |
Pablo Neira Ayuso | f74db0b | 2011-09-26 11:44:57 +0200 | [diff] [blame] | 258 | node->rb_left = old->rb_left; |
Pablo Neira Ayuso | f74db0b | 2011-09-26 11:44:57 +0200 | [diff] [blame] | 259 | rb_set_parent(old->rb_left, node); |
Sylvain Munaut | 54187ba | 2011-11-11 15:31:01 +0100 | [diff] [blame] | 260 | |
Pablo Neira Ayuso | f74db0b | 2011-09-26 11:44:57 +0200 | [diff] [blame] | 261 | goto color; |
| 262 | } |
| 263 | |
| 264 | parent = rb_parent(node); |
| 265 | color = rb_color(node); |
| 266 | |
| 267 | if (child) |
| 268 | rb_set_parent(child, parent); |
| 269 | if (parent) |
| 270 | { |
| 271 | if (parent->rb_left == node) |
| 272 | parent->rb_left = child; |
| 273 | else |
| 274 | parent->rb_right = child; |
| 275 | } |
| 276 | else |
| 277 | root->rb_node = child; |
| 278 | |
| 279 | color: |
| 280 | if (color == RB_BLACK) |
| 281 | __rb_erase_color(child, parent, root); |
| 282 | } |
| 283 | |
| 284 | /* |
| 285 | * This function returns the first node (in sort order) of the tree. |
| 286 | */ |
Sylvain Munaut | 2179f40 | 2011-11-11 15:32:57 +0100 | [diff] [blame] | 287 | struct rb_node *rb_first(const struct rb_root *root) |
Pablo Neira Ayuso | f74db0b | 2011-09-26 11:44:57 +0200 | [diff] [blame] | 288 | { |
| 289 | struct rb_node *n; |
| 290 | |
| 291 | n = root->rb_node; |
| 292 | if (!n) |
| 293 | return NULL; |
| 294 | while (n->rb_left) |
| 295 | n = n->rb_left; |
| 296 | return n; |
| 297 | } |
| 298 | |
Sylvain Munaut | 2179f40 | 2011-11-11 15:32:57 +0100 | [diff] [blame] | 299 | struct rb_node *rb_last(const struct rb_root *root) |
Pablo Neira Ayuso | f74db0b | 2011-09-26 11:44:57 +0200 | [diff] [blame] | 300 | { |
| 301 | struct rb_node *n; |
| 302 | |
| 303 | n = root->rb_node; |
| 304 | if (!n) |
| 305 | return NULL; |
| 306 | while (n->rb_right) |
| 307 | n = n->rb_right; |
| 308 | return n; |
| 309 | } |
| 310 | |
Sylvain Munaut | 2179f40 | 2011-11-11 15:32:57 +0100 | [diff] [blame] | 311 | struct rb_node *rb_next(const struct rb_node *node) |
Pablo Neira Ayuso | f74db0b | 2011-09-26 11:44:57 +0200 | [diff] [blame] | 312 | { |
| 313 | struct rb_node *parent; |
| 314 | |
| 315 | if (rb_parent(node) == node) |
| 316 | return NULL; |
| 317 | |
| 318 | /* If we have a right-hand child, go down and then left as far |
| 319 | as we can. */ |
| 320 | if (node->rb_right) { |
| 321 | node = node->rb_right; |
| 322 | while (node->rb_left) |
| 323 | node=node->rb_left; |
Sylvain Munaut | 2179f40 | 2011-11-11 15:32:57 +0100 | [diff] [blame] | 324 | return (struct rb_node *)node; |
Pablo Neira Ayuso | f74db0b | 2011-09-26 11:44:57 +0200 | [diff] [blame] | 325 | } |
| 326 | |
| 327 | /* No right-hand children. Everything down and left is |
| 328 | smaller than us, so any 'next' node must be in the general |
| 329 | direction of our parent. Go up the tree; any time the |
| 330 | ancestor is a right-hand child of its parent, keep going |
| 331 | up. First time it's a left-hand child of its parent, said |
| 332 | parent is our 'next' node. */ |
| 333 | while ((parent = rb_parent(node)) && node == parent->rb_right) |
| 334 | node = parent; |
| 335 | |
| 336 | return parent; |
| 337 | } |
| 338 | |
Sylvain Munaut | 2179f40 | 2011-11-11 15:32:57 +0100 | [diff] [blame] | 339 | struct rb_node *rb_prev(const struct rb_node *node) |
Pablo Neira Ayuso | f74db0b | 2011-09-26 11:44:57 +0200 | [diff] [blame] | 340 | { |
| 341 | struct rb_node *parent; |
| 342 | |
| 343 | if (rb_parent(node) == node) |
| 344 | return NULL; |
| 345 | |
| 346 | /* If we have a left-hand child, go down and then right as far |
| 347 | as we can. */ |
| 348 | if (node->rb_left) { |
| 349 | node = node->rb_left; |
| 350 | while (node->rb_right) |
| 351 | node=node->rb_right; |
Sylvain Munaut | 2179f40 | 2011-11-11 15:32:57 +0100 | [diff] [blame] | 352 | return (struct rb_node *)node; |
Pablo Neira Ayuso | f74db0b | 2011-09-26 11:44:57 +0200 | [diff] [blame] | 353 | } |
| 354 | |
| 355 | /* No left-hand children. Go up till we find an ancestor which |
| 356 | is a right-hand child of its parent */ |
| 357 | while ((parent = rb_parent(node)) && node == parent->rb_left) |
| 358 | node = parent; |
| 359 | |
| 360 | return parent; |
| 361 | } |
| 362 | |
| 363 | void rb_replace_node(struct rb_node *victim, struct rb_node *new, |
| 364 | struct rb_root *root) |
| 365 | { |
| 366 | struct rb_node *parent = rb_parent(victim); |
| 367 | |
| 368 | /* Set the surrounding nodes to point to the replacement */ |
| 369 | if (parent) { |
| 370 | if (victim == parent->rb_left) |
| 371 | parent->rb_left = new; |
| 372 | else |
| 373 | parent->rb_right = new; |
| 374 | } else { |
| 375 | root->rb_node = new; |
| 376 | } |
| 377 | if (victim->rb_left) |
| 378 | rb_set_parent(victim->rb_left, new); |
| 379 | if (victim->rb_right) |
| 380 | rb_set_parent(victim->rb_right, new); |
| 381 | |
| 382 | /* Copy the pointers/colour from the victim to the replacement */ |
| 383 | *new = *victim; |
| 384 | } |