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Kyungmin Park7ba890b2008-10-08 11:01:17 +09001/*
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
18 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
19
20 linux/lib/rbtree.c
21*/
22
23#include <ubi_uboot.h>
24#include <linux/rbtree.h>
25
26static 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
49static 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
72void 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
137static 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 {
165 struct rb_node *o_left;
166 if ((o_left = other->rb_left))
167 rb_set_black(o_left);
168 rb_set_red(other);
169 __rb_rotate_right(other, root);
170 other = parent->rb_right;
171 }
172 rb_set_color(other, rb_color(parent));
173 rb_set_black(parent);
174 if (other->rb_right)
175 rb_set_black(other->rb_right);
176 __rb_rotate_left(parent, root);
177 node = root->rb_node;
178 break;
179 }
180 }
181 else
182 {
183 other = parent->rb_left;
184 if (rb_is_red(other))
185 {
186 rb_set_black(other);
187 rb_set_red(parent);
188 __rb_rotate_right(parent, root);
189 other = parent->rb_left;
190 }
191 if ((!other->rb_left || rb_is_black(other->rb_left)) &&
192 (!other->rb_right || rb_is_black(other->rb_right)))
193 {
194 rb_set_red(other);
195 node = parent;
196 parent = rb_parent(node);
197 }
198 else
199 {
200 if (!other->rb_left || rb_is_black(other->rb_left))
201 {
202 register struct rb_node *o_right;
203 if ((o_right = other->rb_right))
204 rb_set_black(o_right);
205 rb_set_red(other);
206 __rb_rotate_left(other, root);
207 other = parent->rb_left;
208 }
209 rb_set_color(other, rb_color(parent));
210 rb_set_black(parent);
211 if (other->rb_left)
212 rb_set_black(other->rb_left);
213 __rb_rotate_right(parent, root);
214 node = root->rb_node;
215 break;
216 }
217 }
218 }
219 if (node)
220 rb_set_black(node);
221}
222
223void rb_erase(struct rb_node *node, struct rb_root *root)
224{
225 struct rb_node *child, *parent;
226 int color;
227
228 if (!node->rb_left)
229 child = node->rb_right;
230 else if (!node->rb_right)
231 child = node->rb_left;
232 else
233 {
234 struct rb_node *old = node, *left;
235
236 node = node->rb_right;
237 while ((left = node->rb_left) != NULL)
238 node = left;
239 child = node->rb_right;
240 parent = rb_parent(node);
241 color = rb_color(node);
242
243 if (child)
244 rb_set_parent(child, parent);
245 if (parent == old) {
246 parent->rb_right = child;
247 parent = node;
248 } else
249 parent->rb_left = child;
250
251 node->rb_parent_color = old->rb_parent_color;
252 node->rb_right = old->rb_right;
253 node->rb_left = old->rb_left;
254
255 if (rb_parent(old))
256 {
257 if (rb_parent(old)->rb_left == old)
258 rb_parent(old)->rb_left = node;
259 else
260 rb_parent(old)->rb_right = node;
261 } else
262 root->rb_node = node;
263
264 rb_set_parent(old->rb_left, node);
265 if (old->rb_right)
266 rb_set_parent(old->rb_right, node);
267 goto color;
268 }
269
270 parent = rb_parent(node);
271 color = rb_color(node);
272
273 if (child)
274 rb_set_parent(child, parent);
275 if (parent)
276 {
277 if (parent->rb_left == node)
278 parent->rb_left = child;
279 else
280 parent->rb_right = child;
281 }
282 else
283 root->rb_node = child;
284
285 color:
286 if (color == RB_BLACK)
287 __rb_erase_color(child, parent, root);
288}
289
290/*
291 * This function returns the first node (in sort order) of the tree.
292 */
293struct rb_node *rb_first(struct rb_root *root)
294{
295 struct rb_node *n;
296
297 n = root->rb_node;
298 if (!n)
299 return NULL;
300 while (n->rb_left)
301 n = n->rb_left;
302 return n;
303}
304
305struct rb_node *rb_last(struct rb_root *root)
306{
307 struct rb_node *n;
308
309 n = root->rb_node;
310 if (!n)
311 return NULL;
312 while (n->rb_right)
313 n = n->rb_right;
314 return n;
315}
316
317struct rb_node *rb_next(struct rb_node *node)
318{
319 struct rb_node *parent;
320
321 if (rb_parent(node) == node)
322 return NULL;
323
324 /* If we have a right-hand child, go down and then left as far
325 as we can. */
326 if (node->rb_right) {
327 node = node->rb_right;
328 while (node->rb_left)
329 node=node->rb_left;
330 return node;
331 }
332
333 /* No right-hand children. Everything down and left is
334 smaller than us, so any 'next' node must be in the general
335 direction of our parent. Go up the tree; any time the
336 ancestor is a right-hand child of its parent, keep going
337 up. First time it's a left-hand child of its parent, said
338 parent is our 'next' node. */
339 while ((parent = rb_parent(node)) && node == parent->rb_right)
340 node = parent;
341
342 return parent;
343}
344
345struct rb_node *rb_prev(struct rb_node *node)
346{
347 struct rb_node *parent;
348
349 if (rb_parent(node) == node)
350 return NULL;
351
352 /* If we have a left-hand child, go down and then right as far
353 as we can. */
354 if (node->rb_left) {
355 node = node->rb_left;
356 while (node->rb_right)
357 node=node->rb_right;
358 return node;
359 }
360
361 /* No left-hand children. Go up till we find an ancestor which
362 is a right-hand child of its parent */
363 while ((parent = rb_parent(node)) && node == parent->rb_left)
364 node = parent;
365
366 return parent;
367}
368
369void rb_replace_node(struct rb_node *victim, struct rb_node *new,
370 struct rb_root *root)
371{
372 struct rb_node *parent = rb_parent(victim);
373
374 /* Set the surrounding nodes to point to the replacement */
375 if (parent) {
376 if (victim == parent->rb_left)
377 parent->rb_left = new;
378 else
379 parent->rb_right = new;
380 } else {
381 root->rb_node = new;
382 }
383 if (victim->rb_left)
384 rb_set_parent(victim->rb_left, new);
385 if (victim->rb_right)
386 rb_set_parent(victim->rb_right, new);
387
388 /* Copy the pointers/colour from the victim to the replacement */
389 *new = *victim;
390}