numa: slab: use numa_mem_id() for slab local memory node
[linux-2.6.git] / lib / rbtree.c
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 <linux/rbtree.h>
24 #include <linux/module.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         if (root->augment_cb) {
49                 root->augment_cb(node);
50                 root->augment_cb(right);
51         }
52 }
53
54 static void __rb_rotate_right(struct rb_node *node, struct rb_root *root)
55 {
56         struct rb_node *left = node->rb_left;
57         struct rb_node *parent = rb_parent(node);
58
59         if ((node->rb_left = left->rb_right))
60                 rb_set_parent(left->rb_right, node);
61         left->rb_right = node;
62
63         rb_set_parent(left, parent);
64
65         if (parent)
66         {
67                 if (node == parent->rb_right)
68                         parent->rb_right = left;
69                 else
70                         parent->rb_left = left;
71         }
72         else
73                 root->rb_node = left;
74         rb_set_parent(node, left);
75
76         if (root->augment_cb) {
77                 root->augment_cb(node);
78                 root->augment_cb(left);
79         }
80 }
81
82 void rb_insert_color(struct rb_node *node, struct rb_root *root)
83 {
84         struct rb_node *parent, *gparent;
85
86         if (root->augment_cb)
87                 root->augment_cb(node);
88
89         while ((parent = rb_parent(node)) && rb_is_red(parent))
90         {
91                 gparent = rb_parent(parent);
92
93                 if (parent == gparent->rb_left)
94                 {
95                         {
96                                 register struct rb_node *uncle = gparent->rb_right;
97                                 if (uncle && rb_is_red(uncle))
98                                 {
99                                         rb_set_black(uncle);
100                                         rb_set_black(parent);
101                                         rb_set_red(gparent);
102                                         node = gparent;
103                                         continue;
104                                 }
105                         }
106
107                         if (parent->rb_right == node)
108                         {
109                                 register struct rb_node *tmp;
110                                 __rb_rotate_left(parent, root);
111                                 tmp = parent;
112                                 parent = node;
113                                 node = tmp;
114                         }
115
116                         rb_set_black(parent);
117                         rb_set_red(gparent);
118                         __rb_rotate_right(gparent, root);
119                 } else {
120                         {
121                                 register struct rb_node *uncle = gparent->rb_left;
122                                 if (uncle && rb_is_red(uncle))
123                                 {
124                                         rb_set_black(uncle);
125                                         rb_set_black(parent);
126                                         rb_set_red(gparent);
127                                         node = gparent;
128                                         continue;
129                                 }
130                         }
131
132                         if (parent->rb_left == node)
133                         {
134                                 register struct rb_node *tmp;
135                                 __rb_rotate_right(parent, root);
136                                 tmp = parent;
137                                 parent = node;
138                                 node = tmp;
139                         }
140
141                         rb_set_black(parent);
142                         rb_set_red(gparent);
143                         __rb_rotate_left(gparent, root);
144                 }
145         }
146
147         rb_set_black(root->rb_node);
148 }
149 EXPORT_SYMBOL(rb_insert_color);
150
151 static void __rb_erase_color(struct rb_node *node, struct rb_node *parent,
152                              struct rb_root *root)
153 {
154         struct rb_node *other;
155
156         while ((!node || rb_is_black(node)) && node != root->rb_node)
157         {
158                 if (parent->rb_left == node)
159                 {
160                         other = parent->rb_right;
161                         if (rb_is_red(other))
162                         {
163                                 rb_set_black(other);
164                                 rb_set_red(parent);
165                                 __rb_rotate_left(parent, root);
166                                 other = parent->rb_right;
167                         }
168                         if ((!other->rb_left || rb_is_black(other->rb_left)) &&
169                             (!other->rb_right || rb_is_black(other->rb_right)))
170                         {
171                                 rb_set_red(other);
172                                 node = parent;
173                                 parent = rb_parent(node);
174                         }
175                         else
176                         {
177                                 if (!other->rb_right || rb_is_black(other->rb_right))
178                                 {
179                                         rb_set_black(other->rb_left);
180                                         rb_set_red(other);
181                                         __rb_rotate_right(other, root);
182                                         other = parent->rb_right;
183                                 }
184                                 rb_set_color(other, rb_color(parent));
185                                 rb_set_black(parent);
186                                 rb_set_black(other->rb_right);
187                                 __rb_rotate_left(parent, root);
188                                 node = root->rb_node;
189                                 break;
190                         }
191                 }
192                 else
193                 {
194                         other = parent->rb_left;
195                         if (rb_is_red(other))
196                         {
197                                 rb_set_black(other);
198                                 rb_set_red(parent);
199                                 __rb_rotate_right(parent, root);
200                                 other = parent->rb_left;
201                         }
202                         if ((!other->rb_left || rb_is_black(other->rb_left)) &&
203                             (!other->rb_right || rb_is_black(other->rb_right)))
204                         {
205                                 rb_set_red(other);
206                                 node = parent;
207                                 parent = rb_parent(node);
208                         }
209                         else
210                         {
211                                 if (!other->rb_left || rb_is_black(other->rb_left))
212                                 {
213                                         rb_set_black(other->rb_right);
214                                         rb_set_red(other);
215                                         __rb_rotate_left(other, root);
216                                         other = parent->rb_left;
217                                 }
218                                 rb_set_color(other, rb_color(parent));
219                                 rb_set_black(parent);
220                                 rb_set_black(other->rb_left);
221                                 __rb_rotate_right(parent, root);
222                                 node = root->rb_node;
223                                 break;
224                         }
225                 }
226         }
227         if (node)
228                 rb_set_black(node);
229 }
230
231 void rb_erase(struct rb_node *node, struct rb_root *root)
232 {
233         struct rb_node *child, *parent;
234         int color;
235
236         if (!node->rb_left)
237                 child = node->rb_right;
238         else if (!node->rb_right)
239                 child = node->rb_left;
240         else
241         {
242                 struct rb_node *old = node, *left;
243                 int old_parent_cb = 0;
244                 int successor_parent_cb = 0;
245
246                 node = node->rb_right;
247                 while ((left = node->rb_left) != NULL)
248                         node = left;
249
250                 if (rb_parent(old)) {
251                         old_parent_cb = 1;
252                         if (rb_parent(old)->rb_left == old)
253                                 rb_parent(old)->rb_left = node;
254                         else
255                                 rb_parent(old)->rb_right = node;
256                 } else
257                         root->rb_node = node;
258
259                 child = node->rb_right;
260                 parent = rb_parent(node);
261                 color = rb_color(node);
262
263                 if (parent == old) {
264                         parent = node;
265                 } else {
266                         successor_parent_cb = 1;
267                         if (child)
268                                 rb_set_parent(child, parent);
269
270                         parent->rb_left = child;
271
272                         node->rb_right = old->rb_right;
273                         rb_set_parent(old->rb_right, node);
274                 }
275
276                 node->rb_parent_color = old->rb_parent_color;
277                 node->rb_left = old->rb_left;
278                 rb_set_parent(old->rb_left, node);
279
280                 if (root->augment_cb) {
281                         /*
282                          * Here, three different nodes can have new children.
283                          * The parent of the successor node that was selected
284                          * to replace the node to be erased.
285                          * The node that is getting erased and is now replaced
286                          * by its successor.
287                          * The parent of the node getting erased-replaced.
288                          */
289                         if (successor_parent_cb)
290                                 root->augment_cb(parent);
291
292                         root->augment_cb(node);
293
294                         if (old_parent_cb)
295                                 root->augment_cb(rb_parent(old));
296                 }
297
298                 goto color;
299         }
300
301         parent = rb_parent(node);
302         color = rb_color(node);
303
304         if (child)
305                 rb_set_parent(child, parent);
306
307         if (parent) {
308                 if (parent->rb_left == node)
309                         parent->rb_left = child;
310                 else
311                         parent->rb_right = child;
312
313                 if (root->augment_cb)
314                         root->augment_cb(parent);
315
316         } else {
317                 root->rb_node = child;
318         }
319
320  color:
321         if (color == RB_BLACK)
322                 __rb_erase_color(child, parent, root);
323 }
324 EXPORT_SYMBOL(rb_erase);
325
326 /*
327  * This function returns the first node (in sort order) of the tree.
328  */
329 struct rb_node *rb_first(const struct rb_root *root)
330 {
331         struct rb_node  *n;
332
333         n = root->rb_node;
334         if (!n)
335                 return NULL;
336         while (n->rb_left)
337                 n = n->rb_left;
338         return n;
339 }
340 EXPORT_SYMBOL(rb_first);
341
342 struct rb_node *rb_last(const struct rb_root *root)
343 {
344         struct rb_node  *n;
345
346         n = root->rb_node;
347         if (!n)
348                 return NULL;
349         while (n->rb_right)
350                 n = n->rb_right;
351         return n;
352 }
353 EXPORT_SYMBOL(rb_last);
354
355 struct rb_node *rb_next(const struct rb_node *node)
356 {
357         struct rb_node *parent;
358
359         if (rb_parent(node) == node)
360                 return NULL;
361
362         /* If we have a right-hand child, go down and then left as far
363            as we can. */
364         if (node->rb_right) {
365                 node = node->rb_right; 
366                 while (node->rb_left)
367                         node=node->rb_left;
368                 return (struct rb_node *)node;
369         }
370
371         /* No right-hand children.  Everything down and left is
372            smaller than us, so any 'next' node must be in the general
373            direction of our parent. Go up the tree; any time the
374            ancestor is a right-hand child of its parent, keep going
375            up. First time it's a left-hand child of its parent, said
376            parent is our 'next' node. */
377         while ((parent = rb_parent(node)) && node == parent->rb_right)
378                 node = parent;
379
380         return parent;
381 }
382 EXPORT_SYMBOL(rb_next);
383
384 struct rb_node *rb_prev(const struct rb_node *node)
385 {
386         struct rb_node *parent;
387
388         if (rb_parent(node) == node)
389                 return NULL;
390
391         /* If we have a left-hand child, go down and then right as far
392            as we can. */
393         if (node->rb_left) {
394                 node = node->rb_left; 
395                 while (node->rb_right)
396                         node=node->rb_right;
397                 return (struct rb_node *)node;
398         }
399
400         /* No left-hand children. Go up till we find an ancestor which
401            is a right-hand child of its parent */
402         while ((parent = rb_parent(node)) && node == parent->rb_left)
403                 node = parent;
404
405         return parent;
406 }
407 EXPORT_SYMBOL(rb_prev);
408
409 void rb_replace_node(struct rb_node *victim, struct rb_node *new,
410                      struct rb_root *root)
411 {
412         struct rb_node *parent = rb_parent(victim);
413
414         /* Set the surrounding nodes to point to the replacement */
415         if (parent) {
416                 if (victim == parent->rb_left)
417                         parent->rb_left = new;
418                 else
419                         parent->rb_right = new;
420         } else {
421                 root->rb_node = new;
422         }
423         if (victim->rb_left)
424                 rb_set_parent(victim->rb_left, new);
425         if (victim->rb_right)
426                 rb_set_parent(victim->rb_right, new);
427
428         /* Copy the pointers/colour from the victim to the replacement */
429         *new = *victim;
430 }
431 EXPORT_SYMBOL(rb_replace_node);