|
0
|
1
|
|
|
2 /*
|
|
|
3 * Copyright (C) Igor Sysoev
|
|
|
4 */
|
|
|
5
|
|
|
6
|
|
|
7 #include <ngx_config.h>
|
|
|
8 #include <ngx_core.h>
|
|
|
9
|
|
|
10
|
|
|
11 /*
|
|
108
|
12 * The red-black tree code is based on the algorithm described in
|
|
|
13 * the "Introduction to Algorithms" by Cormen, Leiserson and Rivest.
|
|
0
|
14 */
|
|
|
15
|
|
|
16
|
|
108
|
17 static ngx_inline void ngx_rbtree_left_rotate(ngx_rbtree_node_t **root,
|
|
|
18 ngx_rbtree_node_t *sentinel, ngx_rbtree_node_t *node);
|
|
|
19 static ngx_inline void ngx_rbtree_right_rotate(ngx_rbtree_node_t **root,
|
|
|
20 ngx_rbtree_node_t *sentinel, ngx_rbtree_node_t *node);
|
|
0
|
21
|
|
|
22
|
|
42
|
23 void
|
|
108
|
24 ngx_rbtree_insert(ngx_thread_volatile ngx_rbtree_t *tree,
|
|
|
25 ngx_rbtree_node_t *node)
|
|
0
|
26 {
|
|
108
|
27 ngx_rbtree_node_t **root, *temp, *sentinel;
|
|
0
|
28
|
|
|
29 /* a binary tree insert */
|
|
|
30
|
|
108
|
31 root = (ngx_rbtree_node_t **) &tree->root;
|
|
|
32 sentinel = tree->sentinel;
|
|
|
33
|
|
0
|
34 if (*root == sentinel) {
|
|
|
35 node->parent = NULL;
|
|
|
36 node->left = sentinel;
|
|
|
37 node->right = sentinel;
|
|
|
38 ngx_rbt_black(node);
|
|
|
39 *root = node;
|
|
|
40
|
|
|
41 return;
|
|
|
42 }
|
|
|
43
|
|
258
|
44 tree->insert(*root, node, sentinel);
|
|
0
|
45
|
|
|
46 /* re-balance tree */
|
|
|
47
|
|
|
48 while (node != *root && ngx_rbt_is_red(node->parent)) {
|
|
|
49
|
|
|
50 if (node->parent == node->parent->parent->left) {
|
|
|
51 temp = node->parent->parent->right;
|
|
|
52
|
|
|
53 if (ngx_rbt_is_red(temp)) {
|
|
|
54 ngx_rbt_black(node->parent);
|
|
|
55 ngx_rbt_black(temp);
|
|
|
56 ngx_rbt_red(node->parent->parent);
|
|
|
57 node = node->parent->parent;
|
|
|
58
|
|
|
59 } else {
|
|
|
60 if (node == node->parent->right) {
|
|
|
61 node = node->parent;
|
|
|
62 ngx_rbtree_left_rotate(root, sentinel, node);
|
|
|
63 }
|
|
|
64
|
|
|
65 ngx_rbt_black(node->parent);
|
|
|
66 ngx_rbt_red(node->parent->parent);
|
|
|
67 ngx_rbtree_right_rotate(root, sentinel, node->parent->parent);
|
|
|
68 }
|
|
|
69
|
|
|
70 } else {
|
|
|
71 temp = node->parent->parent->left;
|
|
|
72
|
|
|
73 if (ngx_rbt_is_red(temp)) {
|
|
|
74 ngx_rbt_black(node->parent);
|
|
|
75 ngx_rbt_black(temp);
|
|
|
76 ngx_rbt_red(node->parent->parent);
|
|
|
77 node = node->parent->parent;
|
|
|
78
|
|
|
79 } else {
|
|
|
80 if (node == node->parent->left) {
|
|
|
81 node = node->parent;
|
|
|
82 ngx_rbtree_right_rotate(root, sentinel, node);
|
|
|
83 }
|
|
|
84
|
|
|
85 ngx_rbt_black(node->parent);
|
|
|
86 ngx_rbt_red(node->parent->parent);
|
|
|
87 ngx_rbtree_left_rotate(root, sentinel, node->parent->parent);
|
|
|
88 }
|
|
|
89 }
|
|
|
90 }
|
|
|
91
|
|
|
92 ngx_rbt_black(*root);
|
|
|
93 }
|
|
|
94
|
|
|
95
|
|
42
|
96 void
|
|
258
|
97 ngx_rbtree_insert_value(ngx_rbtree_node_t *temp, ngx_rbtree_node_t *node,
|
|
|
98 ngx_rbtree_node_t *sentinel)
|
|
|
99 {
|
|
|
100 for ( ;; ) {
|
|
|
101
|
|
|
102 if (node->key < temp->key) {
|
|
|
103
|
|
|
104 if (temp->left == sentinel) {
|
|
|
105 temp->left = node;
|
|
|
106 break;
|
|
|
107 }
|
|
|
108
|
|
|
109 temp = temp->left;
|
|
|
110
|
|
|
111 } else {
|
|
|
112
|
|
|
113 if (temp->right == sentinel) {
|
|
|
114 temp->right = node;
|
|
|
115 break;
|
|
|
116 }
|
|
|
117
|
|
|
118 temp = temp->right;
|
|
|
119 }
|
|
|
120 }
|
|
|
121
|
|
|
122 node->parent = temp;
|
|
|
123 node->left = sentinel;
|
|
|
124 node->right = sentinel;
|
|
|
125 ngx_rbt_red(node);
|
|
|
126 }
|
|
|
127
|
|
|
128
|
|
|
129 void
|
|
|
130 ngx_rbtree_insert_timer_value(ngx_rbtree_node_t *temp, ngx_rbtree_node_t *node,
|
|
|
131 ngx_rbtree_node_t *sentinel)
|
|
|
132 {
|
|
|
133 for ( ;; ) {
|
|
|
134
|
|
|
135 /*
|
|
|
136 * Timer values
|
|
|
137 * 1) are spread in small range, usually several minutes,
|
|
|
138 * 2) and overflow each 49 days, if milliseconds are stored in 32 bits.
|
|
|
139 * The comparison takes into account that overflow.
|
|
|
140 */
|
|
|
141
|
|
|
142 if ((ngx_rbtree_key_int_t) node->key - (ngx_rbtree_key_int_t) temp->key
|
|
|
143 < 0)
|
|
|
144 {
|
|
|
145 /* node->key < temp->key */
|
|
|
146
|
|
|
147 if (temp->left == sentinel) {
|
|
|
148 temp->left = node;
|
|
|
149 break;
|
|
|
150 }
|
|
|
151
|
|
|
152 temp = temp->left;
|
|
|
153
|
|
|
154 } else {
|
|
|
155
|
|
|
156 if (temp->right == sentinel) {
|
|
|
157 temp->right = node;
|
|
|
158 break;
|
|
|
159 }
|
|
|
160
|
|
|
161 temp = temp->right;
|
|
|
162 }
|
|
|
163 }
|
|
|
164
|
|
|
165 node->parent = temp;
|
|
|
166 node->left = sentinel;
|
|
|
167 node->right = sentinel;
|
|
|
168 ngx_rbt_red(node);
|
|
|
169 }
|
|
|
170
|
|
|
171
|
|
|
172 void
|
|
108
|
173 ngx_rbtree_delete(ngx_thread_volatile ngx_rbtree_t *tree,
|
|
|
174 ngx_rbtree_node_t *node)
|
|
0
|
175 {
|
|
258
|
176 ngx_uint_t red;
|
|
108
|
177 ngx_rbtree_node_t **root, *sentinel, *subst, *temp, *w;
|
|
0
|
178
|
|
|
179 /* a binary tree delete */
|
|
|
180
|
|
108
|
181 root = (ngx_rbtree_node_t **) &tree->root;
|
|
|
182 sentinel = tree->sentinel;
|
|
|
183
|
|
0
|
184 if (node->left == sentinel) {
|
|
|
185 temp = node->right;
|
|
|
186 subst = node;
|
|
|
187
|
|
|
188 } else if (node->right == sentinel) {
|
|
|
189 temp = node->left;
|
|
|
190 subst = node;
|
|
|
191
|
|
|
192 } else {
|
|
|
193 subst = ngx_rbtree_min(node->right, sentinel);
|
|
|
194
|
|
|
195 if (subst->left != sentinel) {
|
|
|
196 temp = subst->left;
|
|
|
197 } else {
|
|
|
198 temp = subst->right;
|
|
|
199 }
|
|
|
200 }
|
|
|
201
|
|
|
202 if (subst == *root) {
|
|
|
203 *root = temp;
|
|
|
204 ngx_rbt_black(temp);
|
|
|
205
|
|
|
206 /* DEBUG stuff */
|
|
|
207 node->left = NULL;
|
|
|
208 node->right = NULL;
|
|
|
209 node->parent = NULL;
|
|
|
210 node->key = 0;
|
|
|
211
|
|
|
212 return;
|
|
|
213 }
|
|
|
214
|
|
258
|
215 red = ngx_rbt_is_red(subst);
|
|
0
|
216
|
|
|
217 if (subst == subst->parent->left) {
|
|
|
218 subst->parent->left = temp;
|
|
|
219
|
|
|
220 } else {
|
|
|
221 subst->parent->right = temp;
|
|
|
222 }
|
|
|
223
|
|
|
224 if (subst == node) {
|
|
|
225
|
|
|
226 temp->parent = subst->parent;
|
|
|
227
|
|
|
228 } else {
|
|
|
229
|
|
|
230 if (subst->parent == node) {
|
|
|
231 temp->parent = subst;
|
|
|
232
|
|
|
233 } else {
|
|
|
234 temp->parent = subst->parent;
|
|
|
235 }
|
|
|
236
|
|
|
237 subst->left = node->left;
|
|
|
238 subst->right = node->right;
|
|
|
239 subst->parent = node->parent;
|
|
|
240 ngx_rbt_copy_color(subst, node);
|
|
|
241
|
|
|
242 if (node == *root) {
|
|
|
243 *root = subst;
|
|
|
244
|
|
|
245 } else {
|
|
|
246 if (node == node->parent->left) {
|
|
|
247 node->parent->left = subst;
|
|
|
248 } else {
|
|
|
249 node->parent->right = subst;
|
|
|
250 }
|
|
|
251 }
|
|
|
252
|
|
|
253 if (subst->left != sentinel) {
|
|
|
254 subst->left->parent = subst;
|
|
|
255 }
|
|
|
256
|
|
|
257 if (subst->right != sentinel) {
|
|
|
258 subst->right->parent = subst;
|
|
|
259 }
|
|
|
260
|
|
|
261 /* DEBUG stuff */
|
|
|
262 node->left = NULL;
|
|
|
263 node->right = NULL;
|
|
|
264 node->parent = NULL;
|
|
|
265 node->key = 0;
|
|
|
266 }
|
|
|
267
|
|
258
|
268 if (red) {
|
|
0
|
269 return;
|
|
|
270 }
|
|
|
271
|
|
|
272 /* a delete fixup */
|
|
|
273
|
|
|
274 while (temp != *root && ngx_rbt_is_black(temp)) {
|
|
|
275
|
|
|
276 if (temp == temp->parent->left) {
|
|
|
277 w = temp->parent->right;
|
|
|
278
|
|
|
279 if (ngx_rbt_is_red(w)) {
|
|
|
280 ngx_rbt_black(w);
|
|
|
281 ngx_rbt_red(temp->parent);
|
|
|
282 ngx_rbtree_left_rotate(root, sentinel, temp->parent);
|
|
|
283 w = temp->parent->right;
|
|
|
284 }
|
|
|
285
|
|
|
286 if (ngx_rbt_is_black(w->left) && ngx_rbt_is_black(w->right)) {
|
|
|
287 ngx_rbt_red(w);
|
|
|
288 temp = temp->parent;
|
|
|
289
|
|
|
290 } else {
|
|
|
291 if (ngx_rbt_is_black(w->right)) {
|
|
|
292 ngx_rbt_black(w->left);
|
|
|
293 ngx_rbt_red(w);
|
|
|
294 ngx_rbtree_right_rotate(root, sentinel, w);
|
|
|
295 w = temp->parent->right;
|
|
|
296 }
|
|
|
297
|
|
|
298 ngx_rbt_copy_color(w, temp->parent);
|
|
|
299 ngx_rbt_black(temp->parent);
|
|
|
300 ngx_rbt_black(w->right);
|
|
|
301 ngx_rbtree_left_rotate(root, sentinel, temp->parent);
|
|
|
302 temp = *root;
|
|
|
303 }
|
|
|
304
|
|
|
305 } else {
|
|
|
306 w = temp->parent->left;
|
|
|
307
|
|
|
308 if (ngx_rbt_is_red(w)) {
|
|
|
309 ngx_rbt_black(w);
|
|
|
310 ngx_rbt_red(temp->parent);
|
|
|
311 ngx_rbtree_right_rotate(root, sentinel, temp->parent);
|
|
|
312 w = temp->parent->left;
|
|
|
313 }
|
|
|
314
|
|
|
315 if (ngx_rbt_is_black(w->left) && ngx_rbt_is_black(w->right)) {
|
|
|
316 ngx_rbt_red(w);
|
|
|
317 temp = temp->parent;
|
|
|
318
|
|
|
319 } else {
|
|
|
320 if (ngx_rbt_is_black(w->left)) {
|
|
|
321 ngx_rbt_black(w->right);
|
|
|
322 ngx_rbt_red(w);
|
|
|
323 ngx_rbtree_left_rotate(root, sentinel, w);
|
|
|
324 w = temp->parent->left;
|
|
|
325 }
|
|
|
326
|
|
|
327 ngx_rbt_copy_color(w, temp->parent);
|
|
|
328 ngx_rbt_black(temp->parent);
|
|
|
329 ngx_rbt_black(w->left);
|
|
|
330 ngx_rbtree_right_rotate(root, sentinel, temp->parent);
|
|
|
331 temp = *root;
|
|
|
332 }
|
|
|
333 }
|
|
|
334 }
|
|
|
335
|
|
|
336 ngx_rbt_black(temp);
|
|
|
337 }
|
|
|
338
|
|
|
339
|
|
42
|
340 static ngx_inline void
|
|
108
|
341 ngx_rbtree_left_rotate(ngx_rbtree_node_t **root, ngx_rbtree_node_t *sentinel,
|
|
|
342 ngx_rbtree_node_t *node)
|
|
0
|
343 {
|
|
108
|
344 ngx_rbtree_node_t *temp;
|
|
0
|
345
|
|
|
346 temp = node->right;
|
|
|
347 node->right = temp->left;
|
|
|
348
|
|
|
349 if (temp->left != sentinel) {
|
|
|
350 temp->left->parent = node;
|
|
|
351 }
|
|
|
352
|
|
|
353 temp->parent = node->parent;
|
|
|
354
|
|
|
355 if (node == *root) {
|
|
|
356 *root = temp;
|
|
|
357
|
|
|
358 } else if (node == node->parent->left) {
|
|
|
359 node->parent->left = temp;
|
|
|
360
|
|
|
361 } else {
|
|
|
362 node->parent->right = temp;
|
|
|
363 }
|
|
|
364
|
|
|
365 temp->left = node;
|
|
|
366 node->parent = temp;
|
|
|
367 }
|
|
|
368
|
|
|
369
|
|
42
|
370 static ngx_inline void
|
|
108
|
371 ngx_rbtree_right_rotate(ngx_rbtree_node_t **root, ngx_rbtree_node_t *sentinel,
|
|
|
372 ngx_rbtree_node_t *node)
|
|
0
|
373 {
|
|
108
|
374 ngx_rbtree_node_t *temp;
|
|
0
|
375
|
|
|
376 temp = node->left;
|
|
|
377 node->left = temp->right;
|
|
|
378
|
|
|
379 if (temp->right != sentinel) {
|
|
|
380 temp->right->parent = node;
|
|
|
381 }
|
|
|
382
|
|
|
383 temp->parent = node->parent;
|
|
|
384
|
|
|
385 if (node == *root) {
|
|
|
386 *root = temp;
|
|
|
387
|
|
|
388 } else if (node == node->parent->right) {
|
|
|
389 node->parent->right = temp;
|
|
|
390
|
|
|
391 } else {
|
|
|
392 node->parent->left = temp;
|
|
|
393 }
|
|
|
394
|
|
|
395 temp->right = node;
|
|
|
396 node->parent = temp;
|
|
|
397 }
|
