|
0
|
1
|
|
|
2 /*
|
|
|
3 * Copyright (C) Igor Sysoev
|
|
660
|
4 * Copyright (C) Nginx, Inc.
|
|
0
|
5 */
|
|
|
6
|
|
|
7
|
|
|
8 #include <ngx_config.h>
|
|
|
9 #include <ngx_core.h>
|
|
|
10
|
|
|
11
|
|
|
12 /*
|
|
108
|
13 * The red-black tree code is based on the algorithm described in
|
|
|
14 * the "Introduction to Algorithms" by Cormen, Leiserson and Rivest.
|
|
0
|
15 */
|
|
|
16
|
|
|
17
|
|
108
|
18 static ngx_inline void ngx_rbtree_left_rotate(ngx_rbtree_node_t **root,
|
|
|
19 ngx_rbtree_node_t *sentinel, ngx_rbtree_node_t *node);
|
|
|
20 static ngx_inline void ngx_rbtree_right_rotate(ngx_rbtree_node_t **root,
|
|
|
21 ngx_rbtree_node_t *sentinel, ngx_rbtree_node_t *node);
|
|
0
|
22
|
|
|
23
|
|
42
|
24 void
|
|
108
|
25 ngx_rbtree_insert(ngx_thread_volatile ngx_rbtree_t *tree,
|
|
|
26 ngx_rbtree_node_t *node)
|
|
0
|
27 {
|
|
108
|
28 ngx_rbtree_node_t **root, *temp, *sentinel;
|
|
0
|
29
|
|
|
30 /* a binary tree insert */
|
|
|
31
|
|
108
|
32 root = (ngx_rbtree_node_t **) &tree->root;
|
|
|
33 sentinel = tree->sentinel;
|
|
|
34
|
|
0
|
35 if (*root == sentinel) {
|
|
|
36 node->parent = NULL;
|
|
|
37 node->left = sentinel;
|
|
|
38 node->right = sentinel;
|
|
|
39 ngx_rbt_black(node);
|
|
|
40 *root = node;
|
|
|
41
|
|
|
42 return;
|
|
|
43 }
|
|
|
44
|
|
258
|
45 tree->insert(*root, node, sentinel);
|
|
0
|
46
|
|
|
47 /* re-balance tree */
|
|
|
48
|
|
|
49 while (node != *root && ngx_rbt_is_red(node->parent)) {
|
|
|
50
|
|
|
51 if (node->parent == node->parent->parent->left) {
|
|
|
52 temp = node->parent->parent->right;
|
|
|
53
|
|
|
54 if (ngx_rbt_is_red(temp)) {
|
|
|
55 ngx_rbt_black(node->parent);
|
|
|
56 ngx_rbt_black(temp);
|
|
|
57 ngx_rbt_red(node->parent->parent);
|
|
|
58 node = node->parent->parent;
|
|
|
59
|
|
|
60 } else {
|
|
|
61 if (node == node->parent->right) {
|
|
|
62 node = node->parent;
|
|
|
63 ngx_rbtree_left_rotate(root, sentinel, node);
|
|
|
64 }
|
|
|
65
|
|
|
66 ngx_rbt_black(node->parent);
|
|
|
67 ngx_rbt_red(node->parent->parent);
|
|
|
68 ngx_rbtree_right_rotate(root, sentinel, node->parent->parent);
|
|
|
69 }
|
|
|
70
|
|
|
71 } else {
|
|
|
72 temp = node->parent->parent->left;
|
|
|
73
|
|
|
74 if (ngx_rbt_is_red(temp)) {
|
|
|
75 ngx_rbt_black(node->parent);
|
|
|
76 ngx_rbt_black(temp);
|
|
|
77 ngx_rbt_red(node->parent->parent);
|
|
|
78 node = node->parent->parent;
|
|
|
79
|
|
|
80 } else {
|
|
|
81 if (node == node->parent->left) {
|
|
|
82 node = node->parent;
|
|
|
83 ngx_rbtree_right_rotate(root, sentinel, node);
|
|
|
84 }
|
|
|
85
|
|
|
86 ngx_rbt_black(node->parent);
|
|
|
87 ngx_rbt_red(node->parent->parent);
|
|
|
88 ngx_rbtree_left_rotate(root, sentinel, node->parent->parent);
|
|
|
89 }
|
|
|
90 }
|
|
|
91 }
|
|
|
92
|
|
|
93 ngx_rbt_black(*root);
|
|
|
94 }
|
|
|
95
|
|
|
96
|
|
42
|
97 void
|
|
258
|
98 ngx_rbtree_insert_value(ngx_rbtree_node_t *temp, ngx_rbtree_node_t *node,
|
|
|
99 ngx_rbtree_node_t *sentinel)
|
|
|
100 {
|
|
356
|
101 ngx_rbtree_node_t **p;
|
|
|
102
|
|
258
|
103 for ( ;; ) {
|
|
|
104
|
|
356
|
105 p = (node->key < temp->key) ? &temp->left : &temp->right;
|
|
258
|
106
|
|
356
|
107 if (*p == sentinel) {
|
|
|
108 break;
|
|
|
109 }
|
|
258
|
110
|
|
356
|
111 temp = *p;
|
|
258
|
112 }
|
|
|
113
|
|
356
|
114 *p = node;
|
|
258
|
115 node->parent = temp;
|
|
|
116 node->left = sentinel;
|
|
|
117 node->right = sentinel;
|
|
|
118 ngx_rbt_red(node);
|
|
|
119 }
|
|
|
120
|
|
|
121
|
|
|
122 void
|
|
|
123 ngx_rbtree_insert_timer_value(ngx_rbtree_node_t *temp, ngx_rbtree_node_t *node,
|
|
|
124 ngx_rbtree_node_t *sentinel)
|
|
|
125 {
|
|
356
|
126 ngx_rbtree_node_t **p;
|
|
|
127
|
|
258
|
128 for ( ;; ) {
|
|
|
129
|
|
|
130 /*
|
|
|
131 * Timer values
|
|
|
132 * 1) are spread in small range, usually several minutes,
|
|
|
133 * 2) and overflow each 49 days, if milliseconds are stored in 32 bits.
|
|
|
134 * The comparison takes into account that overflow.
|
|
|
135 */
|
|
|
136
|
|
356
|
137 /* node->key < temp->key */
|
|
258
|
138
|
|
670
|
139 p = ((ngx_rbtree_key_int_t) (node->key - temp->key) < 0)
|
|
356
|
140 ? &temp->left : &temp->right;
|
|
258
|
141
|
|
356
|
142 if (*p == sentinel) {
|
|
|
143 break;
|
|
|
144 }
|
|
258
|
145
|
|
356
|
146 temp = *p;
|
|
258
|
147 }
|
|
|
148
|
|
356
|
149 *p = node;
|
|
258
|
150 node->parent = temp;
|
|
|
151 node->left = sentinel;
|
|
|
152 node->right = sentinel;
|
|
|
153 ngx_rbt_red(node);
|
|
|
154 }
|
|
|
155
|
|
|
156
|
|
|
157 void
|
|
108
|
158 ngx_rbtree_delete(ngx_thread_volatile ngx_rbtree_t *tree,
|
|
|
159 ngx_rbtree_node_t *node)
|
|
0
|
160 {
|
|
258
|
161 ngx_uint_t red;
|
|
108
|
162 ngx_rbtree_node_t **root, *sentinel, *subst, *temp, *w;
|
|
0
|
163
|
|
|
164 /* a binary tree delete */
|
|
|
165
|
|
108
|
166 root = (ngx_rbtree_node_t **) &tree->root;
|
|
|
167 sentinel = tree->sentinel;
|
|
|
168
|
|
0
|
169 if (node->left == sentinel) {
|
|
|
170 temp = node->right;
|
|
|
171 subst = node;
|
|
|
172
|
|
|
173 } else if (node->right == sentinel) {
|
|
|
174 temp = node->left;
|
|
|
175 subst = node;
|
|
|
176
|
|
|
177 } else {
|
|
|
178 subst = ngx_rbtree_min(node->right, sentinel);
|
|
|
179
|
|
|
180 if (subst->left != sentinel) {
|
|
|
181 temp = subst->left;
|
|
|
182 } else {
|
|
|
183 temp = subst->right;
|
|
|
184 }
|
|
|
185 }
|
|
|
186
|
|
|
187 if (subst == *root) {
|
|
|
188 *root = temp;
|
|
|
189 ngx_rbt_black(temp);
|
|
|
190
|
|
|
191 /* DEBUG stuff */
|
|
|
192 node->left = NULL;
|
|
|
193 node->right = NULL;
|
|
|
194 node->parent = NULL;
|
|
|
195 node->key = 0;
|
|
|
196
|
|
|
197 return;
|
|
|
198 }
|
|
|
199
|
|
258
|
200 red = ngx_rbt_is_red(subst);
|
|
0
|
201
|
|
|
202 if (subst == subst->parent->left) {
|
|
|
203 subst->parent->left = temp;
|
|
|
204
|
|
|
205 } else {
|
|
|
206 subst->parent->right = temp;
|
|
|
207 }
|
|
|
208
|
|
|
209 if (subst == node) {
|
|
|
210
|
|
|
211 temp->parent = subst->parent;
|
|
|
212
|
|
|
213 } else {
|
|
|
214
|
|
|
215 if (subst->parent == node) {
|
|
|
216 temp->parent = subst;
|
|
|
217
|
|
|
218 } else {
|
|
|
219 temp->parent = subst->parent;
|
|
|
220 }
|
|
|
221
|
|
|
222 subst->left = node->left;
|
|
|
223 subst->right = node->right;
|
|
|
224 subst->parent = node->parent;
|
|
|
225 ngx_rbt_copy_color(subst, node);
|
|
|
226
|
|
|
227 if (node == *root) {
|
|
|
228 *root = subst;
|
|
|
229
|
|
|
230 } else {
|
|
|
231 if (node == node->parent->left) {
|
|
|
232 node->parent->left = subst;
|
|
|
233 } else {
|
|
|
234 node->parent->right = subst;
|
|
|
235 }
|
|
|
236 }
|
|
|
237
|
|
|
238 if (subst->left != sentinel) {
|
|
|
239 subst->left->parent = subst;
|
|
|
240 }
|
|
|
241
|
|
|
242 if (subst->right != sentinel) {
|
|
|
243 subst->right->parent = subst;
|
|
|
244 }
|
|
358
|
245 }
|
|
0
|
246
|
|
358
|
247 /* DEBUG stuff */
|
|
|
248 node->left = NULL;
|
|
|
249 node->right = NULL;
|
|
|
250 node->parent = NULL;
|
|
|
251 node->key = 0;
|
|
0
|
252
|
|
258
|
253 if (red) {
|
|
0
|
254 return;
|
|
|
255 }
|
|
|
256
|
|
|
257 /* a delete fixup */
|
|
|
258
|
|
|
259 while (temp != *root && ngx_rbt_is_black(temp)) {
|
|
|
260
|
|
|
261 if (temp == temp->parent->left) {
|
|
|
262 w = temp->parent->right;
|
|
|
263
|
|
|
264 if (ngx_rbt_is_red(w)) {
|
|
|
265 ngx_rbt_black(w);
|
|
|
266 ngx_rbt_red(temp->parent);
|
|
|
267 ngx_rbtree_left_rotate(root, sentinel, temp->parent);
|
|
|
268 w = temp->parent->right;
|
|
|
269 }
|
|
|
270
|
|
|
271 if (ngx_rbt_is_black(w->left) && ngx_rbt_is_black(w->right)) {
|
|
|
272 ngx_rbt_red(w);
|
|
|
273 temp = temp->parent;
|
|
|
274
|
|
|
275 } else {
|
|
|
276 if (ngx_rbt_is_black(w->right)) {
|
|
|
277 ngx_rbt_black(w->left);
|
|
|
278 ngx_rbt_red(w);
|
|
|
279 ngx_rbtree_right_rotate(root, sentinel, w);
|
|
|
280 w = temp->parent->right;
|
|
|
281 }
|
|
|
282
|
|
|
283 ngx_rbt_copy_color(w, temp->parent);
|
|
|
284 ngx_rbt_black(temp->parent);
|
|
|
285 ngx_rbt_black(w->right);
|
|
|
286 ngx_rbtree_left_rotate(root, sentinel, temp->parent);
|
|
|
287 temp = *root;
|
|
|
288 }
|
|
|
289
|
|
|
290 } else {
|
|
|
291 w = temp->parent->left;
|
|
|
292
|
|
|
293 if (ngx_rbt_is_red(w)) {
|
|
|
294 ngx_rbt_black(w);
|
|
|
295 ngx_rbt_red(temp->parent);
|
|
|
296 ngx_rbtree_right_rotate(root, sentinel, temp->parent);
|
|
|
297 w = temp->parent->left;
|
|
|
298 }
|
|
|
299
|
|
|
300 if (ngx_rbt_is_black(w->left) && ngx_rbt_is_black(w->right)) {
|
|
|
301 ngx_rbt_red(w);
|
|
|
302 temp = temp->parent;
|
|
|
303
|
|
|
304 } else {
|
|
|
305 if (ngx_rbt_is_black(w->left)) {
|
|
|
306 ngx_rbt_black(w->right);
|
|
|
307 ngx_rbt_red(w);
|
|
|
308 ngx_rbtree_left_rotate(root, sentinel, w);
|
|
|
309 w = temp->parent->left;
|
|
|
310 }
|
|
|
311
|
|
|
312 ngx_rbt_copy_color(w, temp->parent);
|
|
|
313 ngx_rbt_black(temp->parent);
|
|
|
314 ngx_rbt_black(w->left);
|
|
|
315 ngx_rbtree_right_rotate(root, sentinel, temp->parent);
|
|
|
316 temp = *root;
|
|
|
317 }
|
|
|
318 }
|
|
|
319 }
|
|
|
320
|
|
|
321 ngx_rbt_black(temp);
|
|
|
322 }
|
|
|
323
|
|
|
324
|
|
42
|
325 static ngx_inline void
|
|
108
|
326 ngx_rbtree_left_rotate(ngx_rbtree_node_t **root, ngx_rbtree_node_t *sentinel,
|
|
|
327 ngx_rbtree_node_t *node)
|
|
0
|
328 {
|
|
108
|
329 ngx_rbtree_node_t *temp;
|
|
0
|
330
|
|
|
331 temp = node->right;
|
|
|
332 node->right = temp->left;
|
|
|
333
|
|
|
334 if (temp->left != sentinel) {
|
|
|
335 temp->left->parent = node;
|
|
|
336 }
|
|
|
337
|
|
|
338 temp->parent = node->parent;
|
|
|
339
|
|
|
340 if (node == *root) {
|
|
|
341 *root = temp;
|
|
|
342
|
|
|
343 } else if (node == node->parent->left) {
|
|
|
344 node->parent->left = temp;
|
|
|
345
|
|
|
346 } else {
|
|
|
347 node->parent->right = temp;
|
|
|
348 }
|
|
|
349
|
|
|
350 temp->left = node;
|
|
|
351 node->parent = temp;
|
|
|
352 }
|
|
|
353
|
|
|
354
|
|
42
|
355 static ngx_inline void
|
|
108
|
356 ngx_rbtree_right_rotate(ngx_rbtree_node_t **root, ngx_rbtree_node_t *sentinel,
|
|
|
357 ngx_rbtree_node_t *node)
|
|
0
|
358 {
|
|
108
|
359 ngx_rbtree_node_t *temp;
|
|
0
|
360
|
|
|
361 temp = node->left;
|
|
|
362 node->left = temp->right;
|
|
|
363
|
|
|
364 if (temp->right != sentinel) {
|
|
|
365 temp->right->parent = node;
|
|
|
366 }
|
|
|
367
|
|
|
368 temp->parent = node->parent;
|
|
|
369
|
|
|
370 if (node == *root) {
|
|
|
371 *root = temp;
|
|
|
372
|
|
|
373 } else if (node == node->parent->right) {
|
|
|
374 node->parent->right = temp;
|
|
|
375
|
|
|
376 } else {
|
|
|
377 node->parent->left = temp;
|
|
|
378 }
|
|
|
379
|
|
|
380 temp->right = node;
|
|
|
381 node->parent = temp;
|
|
|
382 }
|
