3 (C) 1999 Andrea Arcangeli <andrea@suse.de>
4 (C) 2002 David Woodhouse <dwmw2@infradead.org>
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.
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.
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
18 Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
25 static void __rb_rotate_left(struct rb_node *node, struct rb_root *root)
27 struct rb_node *right = node->rb_right;
28 struct rb_node *parent = ext2fs_rb_parent(node);
30 if ((node->rb_right = right->rb_left))
31 ext2fs_rb_set_parent(right->rb_left, node);
32 right->rb_left = node;
34 ext2fs_rb_set_parent(right, parent);
38 if (node == parent->rb_left)
39 parent->rb_left = right;
41 parent->rb_right = right;
44 root->rb_node = right;
45 ext2fs_rb_set_parent(node, right);
48 static void __rb_rotate_right(struct rb_node *node, struct rb_root *root)
50 struct rb_node *left = node->rb_left;
51 struct rb_node *parent = ext2fs_rb_parent(node);
53 if ((node->rb_left = left->rb_right))
54 ext2fs_rb_set_parent(left->rb_right, node);
55 left->rb_right = node;
57 ext2fs_rb_set_parent(left, parent);
61 if (node == parent->rb_right)
62 parent->rb_right = left;
64 parent->rb_left = left;
68 ext2fs_rb_set_parent(node, left);
71 void ext2fs_rb_insert_color(struct rb_node *node, struct rb_root *root)
73 struct rb_node *parent, *gparent;
75 while ((parent = ext2fs_rb_parent(node)) && ext2fs_rb_is_red(parent))
77 gparent = ext2fs_rb_parent(parent);
79 if (parent == gparent->rb_left)
82 register struct rb_node *uncle = gparent->rb_right;
83 if (uncle && ext2fs_rb_is_red(uncle))
85 ext2fs_rb_set_black(uncle);
86 ext2fs_rb_set_black(parent);
87 ext2fs_rb_set_red(gparent);
93 if (parent->rb_right == node)
95 register struct rb_node *tmp;
96 __rb_rotate_left(parent, root);
102 ext2fs_rb_set_black(parent);
103 ext2fs_rb_set_red(gparent);
104 __rb_rotate_right(gparent, root);
107 register struct rb_node *uncle = gparent->rb_left;
108 if (uncle && ext2fs_rb_is_red(uncle))
110 ext2fs_rb_set_black(uncle);
111 ext2fs_rb_set_black(parent);
112 ext2fs_rb_set_red(gparent);
118 if (parent->rb_left == node)
120 register struct rb_node *tmp;
121 __rb_rotate_right(parent, root);
127 ext2fs_rb_set_black(parent);
128 ext2fs_rb_set_red(gparent);
129 __rb_rotate_left(gparent, root);
133 ext2fs_rb_set_black(root->rb_node);
136 static void __rb_erase_color(struct rb_node *node, struct rb_node *parent,
137 struct rb_root *root)
139 struct rb_node *other;
141 while ((!node || ext2fs_rb_is_black(node)) && node != root->rb_node)
143 if (parent->rb_left == node)
145 other = parent->rb_right;
146 if (ext2fs_rb_is_red(other))
148 ext2fs_rb_set_black(other);
149 ext2fs_rb_set_red(parent);
150 __rb_rotate_left(parent, root);
151 other = parent->rb_right;
153 if ((!other->rb_left || ext2fs_rb_is_black(other->rb_left)) &&
154 (!other->rb_right || ext2fs_rb_is_black(other->rb_right)))
156 ext2fs_rb_set_red(other);
158 parent = ext2fs_rb_parent(node);
162 if (!other->rb_right || ext2fs_rb_is_black(other->rb_right))
164 ext2fs_rb_set_black(other->rb_left);
165 ext2fs_rb_set_red(other);
166 __rb_rotate_right(other, root);
167 other = parent->rb_right;
169 ext2fs_rb_set_color(other, ext2fs_rb_color(parent));
170 ext2fs_rb_set_black(parent);
171 ext2fs_rb_set_black(other->rb_right);
172 __rb_rotate_left(parent, root);
173 node = root->rb_node;
179 other = parent->rb_left;
180 if (ext2fs_rb_is_red(other))
182 ext2fs_rb_set_black(other);
183 ext2fs_rb_set_red(parent);
184 __rb_rotate_right(parent, root);
185 other = parent->rb_left;
187 if ((!other->rb_left || ext2fs_rb_is_black(other->rb_left)) &&
188 (!other->rb_right || ext2fs_rb_is_black(other->rb_right)))
190 ext2fs_rb_set_red(other);
192 parent = ext2fs_rb_parent(node);
196 if (!other->rb_left || ext2fs_rb_is_black(other->rb_left))
198 ext2fs_rb_set_black(other->rb_right);
199 ext2fs_rb_set_red(other);
200 __rb_rotate_left(other, root);
201 other = parent->rb_left;
203 ext2fs_rb_set_color(other, ext2fs_rb_color(parent));
204 ext2fs_rb_set_black(parent);
205 ext2fs_rb_set_black(other->rb_left);
206 __rb_rotate_right(parent, root);
207 node = root->rb_node;
213 ext2fs_rb_set_black(node);
216 void ext2fs_rb_erase(struct rb_node *node, struct rb_root *root)
218 struct rb_node *child, *parent;
222 child = node->rb_right;
223 else if (!node->rb_right)
224 child = node->rb_left;
227 struct rb_node *old = node, *left;
229 node = node->rb_right;
230 while ((left = node->rb_left) != NULL)
233 if (ext2fs_rb_parent(old)) {
234 if (ext2fs_rb_parent(old)->rb_left == old)
235 ext2fs_rb_parent(old)->rb_left = node;
237 ext2fs_rb_parent(old)->rb_right = node;
239 root->rb_node = node;
241 child = node->rb_right;
242 parent = ext2fs_rb_parent(node);
243 color = ext2fs_rb_color(node);
249 ext2fs_rb_set_parent(child, parent);
250 parent->rb_left = child;
252 node->rb_right = old->rb_right;
253 ext2fs_rb_set_parent(old->rb_right, node);
256 node->rb_parent_color = old->rb_parent_color;
257 node->rb_left = old->rb_left;
258 ext2fs_rb_set_parent(old->rb_left, node);
263 parent = ext2fs_rb_parent(node);
264 color = ext2fs_rb_color(node);
267 ext2fs_rb_set_parent(child, parent);
270 if (parent->rb_left == node)
271 parent->rb_left = child;
273 parent->rb_right = child;
276 root->rb_node = child;
279 if (color == RB_BLACK)
280 __rb_erase_color(child, parent, root);
283 static void ext2fs_rb_augment_path(struct rb_node *node, rb_augment_f func, void *data)
285 struct rb_node *parent;
289 parent = ext2fs_rb_parent(node);
293 if (node == parent->rb_left && parent->rb_right)
294 func(parent->rb_right, data);
295 else if (parent->rb_left)
296 func(parent->rb_left, data);
303 * after inserting @node into the tree, update the tree to account for
304 * both the new entry and any damage done by rebalance
306 void ext2fs_rb_augment_insert(struct rb_node *node, rb_augment_f func, void *data)
309 node = node->rb_left;
310 else if (node->rb_right)
311 node = node->rb_right;
313 ext2fs_rb_augment_path(node, func, data);
317 * before removing the node, find the deepest node on the rebalance path
318 * that will still be there after @node gets removed
320 struct rb_node *ext2fs_rb_augment_erase_begin(struct rb_node *node)
322 struct rb_node *deepest;
324 if (!node->rb_right && !node->rb_left)
325 deepest = ext2fs_rb_parent(node);
326 else if (!node->rb_right)
327 deepest = node->rb_left;
328 else if (!node->rb_left)
329 deepest = node->rb_right;
331 deepest = ext2fs_rb_next(node);
332 if (deepest->rb_right)
333 deepest = deepest->rb_right;
334 else if (ext2fs_rb_parent(deepest) != node)
335 deepest = ext2fs_rb_parent(deepest);
342 * after removal, update the tree to account for the removed entry
343 * and any rebalance damage.
345 void ext2fs_rb_augment_erase_end(struct rb_node *node, rb_augment_f func, void *data)
348 ext2fs_rb_augment_path(node, func, data);
352 * This function returns the first node (in sort order) of the tree.
354 struct rb_node *ext2fs_rb_first(const struct rb_root *root)
366 struct rb_node *ext2fs_rb_last(const struct rb_root *root)
378 struct rb_node *ext2fs_rb_next(struct rb_node *node)
380 struct rb_node *parent;
382 if (ext2fs_rb_parent(node) == node)
385 /* If we have a right-hand child, go down and then left as far
387 if (node->rb_right) {
388 node = node->rb_right;
389 while (node->rb_left)
391 return (struct rb_node *)node;
394 /* No right-hand children. Everything down and left is
395 smaller than us, so any 'next' node must be in the general
396 direction of our parent. Go up the tree; any time the
397 ancestor is a right-hand child of its parent, keep going
398 up. First time it's a left-hand child of its parent, said
399 parent is our 'next' node. */
400 while ((parent = ext2fs_rb_parent(node)) && node == parent->rb_right)
406 struct rb_node *ext2fs_rb_prev(struct rb_node *node)
408 struct rb_node *parent;
410 if (ext2fs_rb_parent(node) == node)
413 /* If we have a left-hand child, go down and then right as far
416 node = node->rb_left;
417 while (node->rb_right)
419 return (struct rb_node *)node;
422 /* No left-hand children. Go up till we find an ancestor which
423 is a right-hand child of its parent */
424 while ((parent = ext2fs_rb_parent(node)) && node == parent->rb_left)
430 void ext2fs_rb_replace_node(struct rb_node *victim, struct rb_node *new,
431 struct rb_root *root)
433 struct rb_node *parent = ext2fs_rb_parent(victim);
435 /* Set the surrounding nodes to point to the replacement */
437 if (victim == parent->rb_left)
438 parent->rb_left = new;
440 parent->rb_right = new;
445 ext2fs_rb_set_parent(victim->rb_left, new);
446 if (victim->rb_right)
447 ext2fs_rb_set_parent(victim->rb_right, new);
449 /* Copy the pointers/colour from the victim to the replacement */