kern
view src/rbtree.c @ 69:b45e2d5f0ae1
ok I *think* i've fixed it now
| author | John Tsiombikas <nuclear@member.fsf.org> |
|---|---|
| date | Wed, 12 Oct 2011 14:39:40 +0300 |
| parents | 0a205396e1a0 |
| children | b4b7198986a6 |
line source
1 #include <stdio.h>
2 #include <stdlib.h>
3 #include <string.h>
4 #include "rbtree.h"
5 #include "panic.h"
7 #define INT2PTR(x) ((void*)(x))
8 #define PTR2INT(x) ((int)(x))
10 static int cmpaddr(void *ap, void *bp);
11 static int cmpint(void *ap, void *bp);
13 static int count_nodes(struct rbnode *node);
14 static void del_tree(struct rbnode *node, void (*delfunc)(struct rbnode*, void*), void *cls);
15 static struct rbnode *insert(struct rbtree *rb, struct rbnode *tree, void *key, void *data);
16 static struct rbnode *delete(struct rbtree *rb, struct rbnode *tree, void *key);
17 static void traverse(struct rbnode *node, void (*func)(struct rbnode*, void*), void *cls);
19 struct rbtree *rb_create(rb_cmp_func_t cmp_func)
20 {
21 struct rbtree *rb;
23 if(!(rb = malloc(sizeof *rb))) {
24 return 0;
25 }
26 if(rb_init(rb, cmp_func) == -1) {
27 free(rb);
28 return 0;
29 }
30 return rb;
31 }
33 void rb_free(struct rbtree *rb)
34 {
35 rb_destroy(rb);
36 free(rb);
37 }
40 int rb_init(struct rbtree *rb, rb_cmp_func_t cmp_func)
41 {
42 memset(rb, 0, sizeof *rb);
44 if(cmp_func == RB_KEY_INT) {
45 rb->cmp = cmpint;
46 } else if(cmp_func == RB_KEY_STRING) {
47 rb->cmp = (rb_cmp_func_t)strcmp;
48 } else {
49 rb->cmp = cmpaddr;
50 }
52 rb->alloc = malloc;
53 rb->free = free;
54 return 0;
55 }
57 void rb_destroy(struct rbtree *rb)
58 {
59 del_tree(rb->root, rb->del, rb->del_cls);
60 }
62 void rb_clear(struct rbtree *rb)
63 {
64 del_tree(rb->root, rb->del, rb->del_cls);
65 rb->root = 0;
66 }
68 int rb_copy(struct rbtree *dest, struct rbtree *src)
69 {
70 struct rbnode *node;
72 rb_clear(dest);
74 rb_begin(src);
75 while((node = rb_next(src))) {
76 if(rb_insert(dest, node->key, node->data) == -1) {
77 return -1;
78 }
79 }
80 return 0;
81 }
83 void rb_set_allocator(struct rbtree *rb, rb_alloc_func_t alloc, rb_free_func_t free)
84 {
85 rb->alloc = alloc;
86 rb->free = free;
87 }
90 void rb_set_compare_func(struct rbtree *rb, rb_cmp_func_t func)
91 {
92 rb->cmp = func;
93 }
95 void rb_set_delete_func(struct rbtree *rb, rb_del_func_t func, void *cls)
96 {
97 rb->del = func;
98 rb->del_cls = cls;
99 }
101 int rb_size(struct rbtree *rb)
102 {
103 return count_nodes(rb->root);
104 }
106 int rb_insert(struct rbtree *rb, void *key, void *data)
107 {
108 rb->root = insert(rb, rb->root, key, data);
109 rb->root->red = 0;
110 return 0;
111 }
113 int rb_inserti(struct rbtree *rb, int key, void *data)
114 {
115 rb->root = insert(rb, rb->root, INT2PTR(key), data);
116 rb->root->red = 0;
117 return 0;
118 }
121 int rb_delete(struct rbtree *rb, void *key)
122 {
123 rb->root = delete(rb, rb->root, key);
124 rb->root->red = 0;
125 return 0;
126 }
128 int rb_deletei(struct rbtree *rb, int key)
129 {
130 rb->root = delete(rb, rb->root, INT2PTR(key));
131 rb->root->red = 0;
132 return 0;
133 }
136 void *rb_find(struct rbtree *rb, void *key)
137 {
138 struct rbnode *node = rb->root;
140 while(node) {
141 int cmp = rb->cmp(key, node->key);
142 if(cmp == 0) {
143 return node;
144 }
145 node = cmp < 0 ? node->left : node->right;
146 }
147 return 0;
148 }
150 void *rb_findi(struct rbtree *rb, int key)
151 {
152 return rb_find(rb, INT2PTR(key));
153 }
156 void rb_foreach(struct rbtree *rb, void (*func)(struct rbnode*, void*), void *cls)
157 {
158 traverse(rb->root, func, cls);
159 }
162 struct rbnode *rb_root(struct rbtree *rb)
163 {
164 return rb->root;
165 }
167 void rb_begin(struct rbtree *rb)
168 {
169 rb->rstack = 0;
170 rb->iter = rb->root;
171 }
173 #define push(sp, x) ((x)->next = (sp), (sp) = (x))
174 #define pop(sp) ((sp) = (sp)->next)
175 #define top(sp) (sp)
177 struct rbnode *rb_next(struct rbtree *rb)
178 {
179 struct rbnode *res = 0;
181 while(rb->rstack || rb->iter) {
182 if(rb->iter) {
183 push(rb->rstack, rb->iter);
184 rb->iter = rb->iter->left;
185 } else {
186 rb->iter = top(rb->rstack);
187 pop(rb->rstack);
188 res = rb->iter;
189 rb->iter = rb->iter->right;
190 break;
191 }
192 }
193 return res;
194 }
196 void *rb_node_key(struct rbnode *node)
197 {
198 return node ? node->key : 0;
199 }
201 int rb_node_keyi(struct rbnode *node)
202 {
203 return node ? PTR2INT(node->key) : 0;
204 }
206 void *rb_node_data(struct rbnode *node)
207 {
208 return node ? node->data : 0;
209 }
211 static int cmpaddr(void *ap, void *bp)
212 {
213 return ap < bp ? -1 : (ap > bp ? 1 : 0);
214 }
216 static int cmpint(void *ap, void *bp)
217 {
218 return PTR2INT(ap) - PTR2INT(bp);
219 }
222 /* ---- left-leaning 2-3 red-black implementation ---- */
224 /* helper prototypes */
225 static int is_red(struct rbnode *tree);
226 static void color_flip(struct rbnode *tree);
227 static struct rbnode *rot_left(struct rbnode *a);
228 static struct rbnode *rot_right(struct rbnode *a);
229 static struct rbnode *find_min(struct rbnode *tree);
230 static struct rbnode *del_min(struct rbtree *rb, struct rbnode *tree);
231 /*static struct rbnode *move_red_right(struct rbnode *tree);*/
232 static struct rbnode *move_red_left(struct rbnode *tree);
233 static struct rbnode *fix_up(struct rbnode *tree);
235 static int count_nodes(struct rbnode *node)
236 {
237 if(!node)
238 return 0;
240 return 1 + count_nodes(node->left) + count_nodes(node->right);
241 }
243 static void del_tree(struct rbnode *node, rb_del_func_t delfunc, void *cls)
244 {
245 if(!node)
246 return;
248 del_tree(node->left, delfunc, cls);
249 del_tree(node->right, delfunc, cls);
251 delfunc(node, cls);
252 free(node);
253 }
255 static struct rbnode *insert(struct rbtree *rb, struct rbnode *tree, void *key, void *data)
256 {
257 int cmp;
259 if(!tree) {
260 struct rbnode *node = rb->alloc(sizeof *node);
261 if(!node) {
262 panic("failed to allocate tree node\n");
263 }
264 node->red = 1;
265 node->key = key;
266 node->data = data;
267 node->left = node->right = 0;
268 return node;
269 }
271 cmp = rb->cmp(key, tree->key);
273 if(cmp < 0) {
274 tree->left = insert(rb, tree->left, key, data);
275 } else if(cmp > 0) {
276 tree->right = insert(rb, tree->right, key, data);
277 } else {
278 tree->data = data;
279 }
281 /* fix right-leaning reds */
282 if(is_red(tree->right)) {
283 tree = rot_left(tree);
284 }
285 /* fix two reds in a row */
286 if(is_red(tree->left) && is_red(tree->left->left)) {
287 tree = rot_right(tree);
288 }
290 /* if 4-node, split it by color inversion */
291 if(is_red(tree->left) && is_red(tree->right)) {
292 color_flip(tree);
293 }
295 return tree;
296 }
298 static struct rbnode *delete(struct rbtree *rb, struct rbnode *tree, void *key)
299 {
300 int cmp;
302 if(!tree) {
303 return 0;
304 }
306 cmp = rb->cmp(key, tree->key);
308 if(cmp < 0) {
309 if(!is_red(tree->left) && !is_red(tree->left->left)) {
310 tree = move_red_left(tree);
311 }
312 tree->left = delete(rb, tree->left, key);
313 } else {
314 /* need reds on the right */
315 if(is_red(tree->left)) {
316 tree = rot_right(tree);
317 }
319 /* found it at the bottom (XXX what certifies left is null?) */
320 if(cmp == 0 && !tree->right) {
321 if(rb->del) {
322 rb->del(tree, rb->del_cls);
323 }
324 rb->free(tree);
325 return 0;
326 }
328 if(!is_red(tree->right) && !is_red(tree->right->left)) {
329 tree = move_red_left(tree);
330 }
332 if(key == tree->key) {
333 struct rbnode *rmin = find_min(tree->right);
334 tree->key = rmin->key;
335 tree->data = rmin->data;
336 tree->right = del_min(rb, tree->right);
337 } else {
338 tree->right = delete(rb, tree->right, key);
339 }
340 }
342 return fix_up(tree);
343 }
345 /*static struct rbnode *find(struct rbtree *rb, struct rbnode *node, void *key)
346 {
347 int cmp;
349 if(!node)
350 return 0;
352 if((cmp = rb->cmp(key, node->key)) == 0) {
353 return node;
354 }
355 return find(rb, cmp < 0 ? node->left : node->right, key);
356 }*/
358 static void traverse(struct rbnode *node, void (*func)(struct rbnode*, void*), void *cls)
359 {
360 if(!node)
361 return;
363 traverse(node->left, func, cls);
364 func(node, cls);
365 traverse(node->right, func, cls);
366 }
368 /* helpers */
370 static int is_red(struct rbnode *tree)
371 {
372 return tree && tree->red;
373 }
375 static void color_flip(struct rbnode *tree)
376 {
377 tree->red = !tree->red;
378 tree->left->red = !tree->left->red;
379 tree->right->red = !tree->right->red;
380 }
382 static struct rbnode *rot_left(struct rbnode *a)
383 {
384 struct rbnode *b = a->right;
385 a->right = b->left;
386 b->left = a;
387 b->red = a->red;
388 a->red = 1;
389 return b;
390 }
392 static struct rbnode *rot_right(struct rbnode *a)
393 {
394 struct rbnode *b = a->left;
395 a->left = b->right;
396 b->right = a;
397 b->red = a->red;
398 a->red = 1;
399 return b;
400 }
402 static struct rbnode *find_min(struct rbnode *tree)
403 {
404 struct rbnode *node;
406 if(!tree)
407 return 0;
409 while(node->left) {
410 node = node->left;
411 }
412 return node;
413 }
415 static struct rbnode *del_min(struct rbtree *rb, struct rbnode *tree)
416 {
417 if(!tree->left) {
418 if(rb->del) {
419 rb->del(tree->left, rb->del_cls);
420 }
421 rb->free(tree->left);
422 return 0;
423 }
425 /* make sure we've got red (3/4-nodes) at the left side so we can delete at the bottom */
426 if(!is_red(tree->left) && !is_red(tree->left->left)) {
427 tree = move_red_left(tree);
428 }
429 tree->left = del_min(rb, tree->left);
431 /* fix right-reds, red-reds, and split 4-nodes on the way up */
432 return fix_up(tree);
433 }
435 #if 0
436 /* push a red link on this node to the right */
437 static struct rbnode *move_red_right(struct rbnode *tree)
438 {
439 /* flipping it makes both children go red, so we have a red to the right */
440 color_flip(tree);
442 /* if after the flip we've got a red-red situation to the left, fix it */
443 if(is_red(tree->left->left)) {
444 tree = rot_right(tree);
445 color_flip(tree);
446 }
447 return tree;
448 }
449 #endif
451 /* push a red link on this node to the left */
452 static struct rbnode *move_red_left(struct rbnode *tree)
453 {
454 /* flipping it makes both children go red, so we have a red to the left */
455 color_flip(tree);
457 /* if after the flip we've got a red-red on the right-left, fix it */
458 if(is_red(tree->right->left)) {
459 tree->right = rot_right(tree->right);
460 tree = rot_left(tree);
461 color_flip(tree);
462 }
463 return tree;
464 }
466 static struct rbnode *fix_up(struct rbnode *tree)
467 {
468 /* fix right-leaning */
469 if(is_red(tree->right)) {
470 tree = rot_left(tree);
471 }
472 /* change invalid red-red pairs into a proper 4-node */
473 if(is_red(tree->left) && is_red(tree->left->left)) {
474 tree = rot_right(tree);
475 }
476 /* split 4-nodes */
477 if(is_red(tree->left) && is_red(tree->right)) {
478 color_flip(tree);
479 }
480 return tree;
481 }
483 void rb_dbg_print_tree(struct rbtree *tree)
484 {
485 struct rbnode *node;
487 rb_begin(tree);
488 while((node = rb_next(tree))) {
489 printf("%d ", rb_node_keyi(node));
490 }
491 printf("\n");
492 }