source: branches/samba-3.3.x/source/lib/rbtree.c@ 206

Last change on this file since 206 was 206, checked in by Herwig Bauernfeind, 16 years ago

Import Samba 3.3 branch at 3.0.0 level (psmedley's port)
File size: 9.4 KB
Line 
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
18 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
19
20 linux/lib/rbtree.c
21*/
22
23#include "includes.h"
24#include "rbtree.h"
25
26#define RB_RED 0
27#define RB_BLACK 1
28
29#define rb_parent(r) ((struct rb_node *)((r)->rb_parent_color & ~3))
30#define rb_color(r) ((r)->rb_parent_color & 1)
31#define rb_is_red(r) (!rb_color(r))
32#define rb_is_black(r) rb_color(r)
33#define rb_set_red(r) do { (r)->rb_parent_color &= ~1; } while (0)
34#define rb_set_black(r) do { (r)->rb_parent_color |= 1; } while (0)
35
36static void rb_set_parent(struct rb_node *rb, struct rb_node *p)
37{
38 rb->rb_parent_color = (rb->rb_parent_color & 3) | (unsigned long)p;
39}
40static void rb_set_color(struct rb_node *rb, int color)
41{
42 rb->rb_parent_color = (rb->rb_parent_color & ~1) | color;
43}
44
45#define RB_EMPTY_ROOT(root) ((root)->rb_node == NULL)
46#define RB_EMPTY_NODE(node) (rb_parent(node) == node)
47#define RB_CLEAR_NODE(node) (rb_set_parent(node, node))
48
49static void __rb_rotate_left(struct rb_node *node, struct rb_root *root)
50{
51 struct rb_node *right = node->rb_right;
52 struct rb_node *parent = rb_parent(node);
53
54 if ((node->rb_right = right->rb_left))
55 rb_set_parent(right->rb_left, node);
56 right->rb_left = node;
57
58 rb_set_parent(right, parent);
59
60 if (parent)
61 {
62 if (node == parent->rb_left)
63 parent->rb_left = right;
64 else
65 parent->rb_right = right;
66 }
67 else
68 root->rb_node = right;
69 rb_set_parent(node, right);
70}
71
72static void __rb_rotate_right(struct rb_node *node, struct rb_root *root)
73{
74 struct rb_node *left = node->rb_left;
75 struct rb_node *parent = rb_parent(node);
76
77 if ((node->rb_left = left->rb_right))
78 rb_set_parent(left->rb_right, node);
79 left->rb_right = node;
80
81 rb_set_parent(left, parent);
82
83 if (parent)
84 {
85 if (node == parent->rb_right)
86 parent->rb_right = left;
87 else
88 parent->rb_left = left;
89 }
90 else
91 root->rb_node = left;
92 rb_set_parent(node, left);
93}
94
95void rb_insert_color(struct rb_node *node, struct rb_root *root)
96{
97 struct rb_node *parent, *gparent;
98
99 while ((parent = rb_parent(node)) && rb_is_red(parent))
100 {
101 gparent = rb_parent(parent);
102
103 if (parent == gparent->rb_left)
104 {
105 {
106 register struct rb_node *uncle = gparent->rb_right;
107 if (uncle && rb_is_red(uncle))
108 {
109 rb_set_black(uncle);
110 rb_set_black(parent);
111 rb_set_red(gparent);
112 node = gparent;
113 continue;
114 }
115 }
116
117 if (parent->rb_right == node)
118 {
119 register struct rb_node *tmp;
120 __rb_rotate_left(parent, root);
121 tmp = parent;
122 parent = node;
123 node = tmp;
124 }
125
126 rb_set_black(parent);
127 rb_set_red(gparent);
128 __rb_rotate_right(gparent, root);
129 } else {
130 {
131 register struct rb_node *uncle = gparent->rb_left;
132 if (uncle && rb_is_red(uncle))
133 {
134 rb_set_black(uncle);
135 rb_set_black(parent);
136 rb_set_red(gparent);
137 node = gparent;
138 continue;
139 }
140 }
141
142 if (parent->rb_left == node)
143 {
144 register struct rb_node *tmp;
145 __rb_rotate_right(parent, root);
146 tmp = parent;
147 parent = node;
148 node = tmp;
149 }
150
151 rb_set_black(parent);
152 rb_set_red(gparent);
153 __rb_rotate_left(gparent, root);
154 }
155 }
156
157 rb_set_black(root->rb_node);
158}
159
160static void __rb_erase_color(struct rb_node *node, struct rb_node *parent,
161 struct rb_root *root)
162{
163 struct rb_node *other;
164
165 while ((!node || rb_is_black(node)) && node != root->rb_node)
166 {
167 if (parent->rb_left == node)
168 {
169 other = parent->rb_right;
170 if (rb_is_red(other))
171 {
172 rb_set_black(other);
173 rb_set_red(parent);
174 __rb_rotate_left(parent, root);
175 other = parent->rb_right;
176 }
177 if ((!other->rb_left || rb_is_black(other->rb_left)) &&
178 (!other->rb_right || rb_is_black(other->rb_right)))
179 {
180 rb_set_red(other);
181 node = parent;
182 parent = rb_parent(node);
183 }
184 else
185 {
186 if (!other->rb_right || rb_is_black(other->rb_right))
187 {
188 struct rb_node *o_left;
189 if ((o_left = other->rb_left))
190 rb_set_black(o_left);
191 rb_set_red(other);
192 __rb_rotate_right(other, root);
193 other = parent->rb_right;
194 }
195 rb_set_color(other, rb_color(parent));
196 rb_set_black(parent);
197 if (other->rb_right)
198 rb_set_black(other->rb_right);
199 __rb_rotate_left(parent, root);
200 node = root->rb_node;
201 break;
202 }
203 }
204 else
205 {
206 other = parent->rb_left;
207 if (rb_is_red(other))
208 {
209 rb_set_black(other);
210 rb_set_red(parent);
211 __rb_rotate_right(parent, root);
212 other = parent->rb_left;
213 }
214 if ((!other->rb_left || rb_is_black(other->rb_left)) &&
215 (!other->rb_right || rb_is_black(other->rb_right)))
216 {
217 rb_set_red(other);
218 node = parent;
219 parent = rb_parent(node);
220 }
221 else
222 {
223 if (!other->rb_left || rb_is_black(other->rb_left))
224 {
225 register struct rb_node *o_right;
226 if ((o_right = other->rb_right))
227 rb_set_black(o_right);
228 rb_set_red(other);
229 __rb_rotate_left(other, root);
230 other = parent->rb_left;
231 }
232 rb_set_color(other, rb_color(parent));
233 rb_set_black(parent);
234 if (other->rb_left)
235 rb_set_black(other->rb_left);
236 __rb_rotate_right(parent, root);
237 node = root->rb_node;
238 break;
239 }
240 }
241 }
242 if (node)
243 rb_set_black(node);
244}
245
246void rb_erase(struct rb_node *node, struct rb_root *root)
247{
248 struct rb_node *child, *parent;
249 int color;
250
251 if (!node->rb_left)
252 child = node->rb_right;
253 else if (!node->rb_right)
254 child = node->rb_left;
255 else
256 {
257 struct rb_node *old = node, *left;
258
259 node = node->rb_right;
260 while ((left = node->rb_left) != NULL)
261 node = left;
262 child = node->rb_right;
263 parent = rb_parent(node);
264 color = rb_color(node);
265
266 if (child)
267 rb_set_parent(child, parent);
268 if (parent == old) {
269 parent->rb_right = child;
270 parent = node;
271 } else
272 parent->rb_left = child;
273
274 node->rb_parent_color = old->rb_parent_color;
275 node->rb_right = old->rb_right;
276 node->rb_left = old->rb_left;
277
278 if (rb_parent(old))
279 {
280 if (rb_parent(old)->rb_left == old)
281 rb_parent(old)->rb_left = node;
282 else
283 rb_parent(old)->rb_right = node;
284 } else
285 root->rb_node = node;
286
287 rb_set_parent(old->rb_left, node);
288 if (old->rb_right)
289 rb_set_parent(old->rb_right, node);
290 goto color;
291 }
292
293 parent = rb_parent(node);
294 color = rb_color(node);
295
296 if (child)
297 rb_set_parent(child, parent);
298 if (parent)
299 {
300 if (parent->rb_left == node)
301 parent->rb_left = child;
302 else
303 parent->rb_right = child;
304 }
305 else
306 root->rb_node = child;
307
308 color:
309 if (color == RB_BLACK)
310 __rb_erase_color(child, parent, root);
311}
312
313/*
314 * This function returns the first node (in sort order) of the tree.
315 */
316struct rb_node *rb_first(struct rb_root *root)
317{
318 struct rb_node *n;
319
320 n = root->rb_node;
321 if (!n)
322 return NULL;
323 while (n->rb_left)
324 n = n->rb_left;
325 return n;
326}
327
328struct rb_node *rb_last(struct rb_root *root)
329{
330 struct rb_node *n;
331
332 n = root->rb_node;
333 if (!n)
334 return NULL;
335 while (n->rb_right)
336 n = n->rb_right;
337 return n;
338}
339
340struct rb_node *rb_next(struct rb_node *node)
341{
342 struct rb_node *parent;
343
344 if (rb_parent(node) == node)
345 return NULL;
346
347 /* If we have a right-hand child, go down and then left as far
348 as we can. */
349 if (node->rb_right) {
350 node = node->rb_right;
351 while (node->rb_left)
352 node=node->rb_left;
353 return node;
354 }
355
356 /* No right-hand children. Everything down and left is
357 smaller than us, so any 'next' node must be in the general
358 direction of our parent. Go up the tree; any time the
359 ancestor is a right-hand child of its parent, keep going
360 up. First time it's a left-hand child of its parent, said
361 parent is our 'next' node. */
362 while ((parent = rb_parent(node)) && node == parent->rb_right)
363 node = parent;
364
365 return parent;
366}
367
368struct rb_node *rb_prev(struct rb_node *node)
369{
370 struct rb_node *parent;
371
372 if (rb_parent(node) == node)
373 return NULL;
374
375 /* If we have a left-hand child, go down and then right as far
376 as we can. */
377 if (node->rb_left) {
378 node = node->rb_left;
379 while (node->rb_right)
380 node=node->rb_right;
381 return node;
382 }
383
384 /* No left-hand children. Go up till we find an ancestor which
385 is a right-hand child of its parent */
386 while ((parent = rb_parent(node)) && node == parent->rb_left)
387 node = parent;
388
389 return parent;
390}
391
392void rb_replace_node(struct rb_node *victim, struct rb_node *new_node,
393 struct rb_root *root)
394{
395 struct rb_node *parent = rb_parent(victim);
396
397 /* Set the surrounding nodes to point to the replacement */
398 if (parent) {
399 if (victim == parent->rb_left)
400 parent->rb_left = new_node;
401 else
402 parent->rb_right = new_node;
403 } else {
404 root->rb_node = new_node;
405 }
406 if (victim->rb_left)
407 rb_set_parent(victim->rb_left, new_node);
408 if (victim->rb_right)
409 rb_set_parent(victim->rb_right, new_node);
410
411 /* Copy the pointers/colour from the victim to the replacement */
412 *new_node = *victim;
413}
414
415void rb_link_node(struct rb_node * node, struct rb_node * parent,
416 struct rb_node ** rb_link)
417{
418 node->rb_parent_color = (unsigned long )parent;
419 node->rb_left = node->rb_right = NULL;
420
421 *rb_link = node;
422}
Note: See TracBrowser for help on using the repository browser.