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064af421 | 1 | /* |
0c5e05bf | 2 | * Copyright (c) 2008, 2009, 2010, 2012, 2013 Nicira, Inc. |
064af421 | 3 | * |
a14bc59f BP |
4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
5 | * you may not use this file except in compliance with the License. | |
6 | * You may obtain a copy of the License at: | |
064af421 | 7 | * |
a14bc59f BP |
8 | * http://www.apache.org/licenses/LICENSE-2.0 |
9 | * | |
10 | * Unless required by applicable law or agreed to in writing, software | |
11 | * distributed under the License is distributed on an "AS IS" BASIS, | |
12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |
13 | * See the License for the specific language governing permissions and | |
14 | * limitations under the License. | |
064af421 BP |
15 | */ |
16 | ||
17 | #ifndef HMAP_H | |
18 | #define HMAP_H 1 | |
19 | ||
20 | #include <stdbool.h> | |
21 | #include <stdlib.h> | |
7614e5d0 | 22 | #include "ovs-atomic.h" |
064af421 BP |
23 | #include "util.h" |
24 | ||
0b64afd6 BP |
25 | #ifdef __cplusplus |
26 | extern "C" { | |
27 | #endif | |
28 | ||
064af421 BP |
29 | /* A hash map node, to be embedded inside the data structure being mapped. */ |
30 | struct hmap_node { | |
31 | size_t hash; /* Hash value. */ | |
32 | struct hmap_node *next; /* Next in linked list. */ | |
33 | }; | |
34 | ||
35 | /* Returns the hash value embedded in 'node'. */ | |
36 | static inline size_t hmap_node_hash(const struct hmap_node *node) | |
37 | { | |
38 | return node->hash; | |
39 | } | |
40 | ||
1e68c073 | 41 | #define HMAP_NODE_NULL ((struct hmap_node *) 1) |
6c2e425e | 42 | #define HMAP_NODE_NULL_INITIALIZER { 0, HMAP_NODE_NULL } |
1e68c073 BP |
43 | |
44 | /* Returns true if 'node' has been set to null by hmap_node_nullify() and has | |
45 | * not been un-nullified by being inserted into an hmap. */ | |
46 | static inline bool | |
47 | hmap_node_is_null(const struct hmap_node *node) | |
48 | { | |
49 | return node->next == HMAP_NODE_NULL; | |
50 | } | |
51 | ||
52 | /* Marks 'node' with a distinctive value that can be tested with | |
53 | * hmap_node_is_null(). */ | |
54 | static inline void | |
55 | hmap_node_nullify(struct hmap_node *node) | |
56 | { | |
57 | node->next = HMAP_NODE_NULL; | |
58 | } | |
59 | ||
064af421 BP |
60 | /* A hash map. */ |
61 | struct hmap { | |
baa8f41b | 62 | struct hmap_node **buckets; /* Must point to 'one' iff 'mask' == 0. */ |
064af421 BP |
63 | struct hmap_node *one; |
64 | size_t mask; | |
65 | size_t n; | |
66 | }; | |
67 | ||
68 | /* Initializer for an empty hash map. */ | |
e37726e4 BP |
69 | #define HMAP_INITIALIZER(HMAP) \ |
70 | { (struct hmap_node **const) &(HMAP)->one, NULL, 0, 0 } | |
064af421 BP |
71 | |
72 | /* Initialization. */ | |
73 | void hmap_init(struct hmap *); | |
74 | void hmap_destroy(struct hmap *); | |
f3099647 | 75 | void hmap_clear(struct hmap *); |
064af421 | 76 | void hmap_swap(struct hmap *a, struct hmap *b); |
a4af0040 | 77 | void hmap_moved(struct hmap *hmap); |
064af421 BP |
78 | static inline size_t hmap_count(const struct hmap *); |
79 | static inline bool hmap_is_empty(const struct hmap *); | |
80 | ||
81 | /* Adjusting capacity. */ | |
0c5e05bf BP |
82 | void hmap_expand_at(struct hmap *, const char *where); |
83 | #define hmap_expand(HMAP) hmap_expand_at(HMAP, SOURCE_LOCATOR) | |
84 | ||
85 | void hmap_shrink_at(struct hmap *, const char *where); | |
86 | #define hmap_shrink(HMAP) hmap_shrink_at(HMAP, SOURCE_LOCATOR) | |
87 | ||
88 | void hmap_reserve_at(struct hmap *, size_t capacity, const char *where); | |
89 | #define hmap_reserve(HMAP, CAPACITY) \ | |
90 | hmap_reserve_at(HMAP, CAPACITY, SOURCE_LOCATOR) | |
064af421 BP |
91 | |
92 | /* Insertion and deletion. */ | |
0c5e05bf BP |
93 | static inline void hmap_insert_at(struct hmap *, struct hmap_node *, |
94 | size_t hash, const char *where); | |
95 | #define hmap_insert(HMAP, NODE, HASH) \ | |
96 | hmap_insert_at(HMAP, NODE, HASH, SOURCE_LOCATOR) | |
97 | ||
064af421 BP |
98 | static inline void hmap_insert_fast(struct hmap *, |
99 | struct hmap_node *, size_t hash); | |
064af421 | 100 | static inline void hmap_remove(struct hmap *, struct hmap_node *); |
064af421 | 101 | |
63e60b86 | 102 | void hmap_node_moved(struct hmap *, struct hmap_node *, struct hmap_node *); |
064af421 | 103 | static inline void hmap_replace(struct hmap *, const struct hmap_node *old, |
43d1478b | 104 | struct hmap_node *new_node); |
064af421 | 105 | |
f2f7be86 BP |
106 | struct hmap_node *hmap_random_node(const struct hmap *); |
107 | ||
3adb8bf0 BP |
108 | /* Search. |
109 | * | |
110 | * HMAP_FOR_EACH_WITH_HASH iterates NODE over all of the nodes in HMAP that | |
111 | * have hash value equal to HASH. HMAP_FOR_EACH_IN_BUCKET iterates NODE over | |
4e8e4213 BP |
112 | * all of the nodes in HMAP that would fall in the same bucket as HASH. MEMBER |
113 | * must be the name of the 'struct hmap_node' member within NODE. | |
3adb8bf0 BP |
114 | * |
115 | * These macros may be used interchangeably to search for a particular value in | |
116 | * an hmap, see, e.g. shash_find() for an example. Usually, using | |
117 | * HMAP_FOR_EACH_WITH_HASH provides an optimization, because comparing a hash | |
118 | * value is usually cheaper than comparing an entire hash map key. But for | |
119 | * simple hash map keys, it makes sense to use HMAP_FOR_EACH_IN_BUCKET because | |
120 | * it avoids doing two comparisons when a single simple comparison suffices. | |
121 | * | |
122 | * The loop should not change NODE to point to a different node or insert or | |
123 | * delete nodes in HMAP (unless it "break"s out of the loop to terminate | |
124 | * iteration). | |
125 | * | |
126 | * HASH is only evaluated once. | |
127 | */ | |
4e8e4213 | 128 | #define HMAP_FOR_EACH_WITH_HASH(NODE, MEMBER, HASH, HMAP) \ |
772ec52b | 129 | for (ASSIGN_CONTAINER(NODE, hmap_first_with_hash(HMAP, HASH), MEMBER); \ |
55d26906 | 130 | NODE != OBJECT_CONTAINING(NULL, NODE, MEMBER); \ |
772ec52b BP |
131 | ASSIGN_CONTAINER(NODE, hmap_next_with_hash(&(NODE)->MEMBER), \ |
132 | MEMBER)) | |
4e8e4213 | 133 | #define HMAP_FOR_EACH_IN_BUCKET(NODE, MEMBER, HASH, HMAP) \ |
772ec52b | 134 | for (ASSIGN_CONTAINER(NODE, hmap_first_in_bucket(HMAP, HASH), MEMBER); \ |
55d26906 | 135 | NODE != OBJECT_CONTAINING(NULL, NODE, MEMBER); \ |
772ec52b | 136 | ASSIGN_CONTAINER(NODE, hmap_next_in_bucket(&(NODE)->MEMBER), MEMBER)) |
064af421 BP |
137 | |
138 | static inline struct hmap_node *hmap_first_with_hash(const struct hmap *, | |
139 | size_t hash); | |
140 | static inline struct hmap_node *hmap_next_with_hash(const struct hmap_node *); | |
3adb8bf0 BP |
141 | static inline struct hmap_node *hmap_first_in_bucket(const struct hmap *, |
142 | size_t hash); | |
143 | static inline struct hmap_node *hmap_next_in_bucket(const struct hmap_node *); | |
064af421 | 144 | |
e39e5b9d BP |
145 | bool hmap_contains(const struct hmap *, const struct hmap_node *); |
146 | ||
633d7b90 BP |
147 | /* Iteration. */ |
148 | ||
149 | /* Iterates through every node in HMAP. */ | |
4e8e4213 | 150 | #define HMAP_FOR_EACH(NODE, MEMBER, HMAP) \ |
772ec52b | 151 | for (ASSIGN_CONTAINER(NODE, hmap_first(HMAP), MEMBER); \ |
55d26906 | 152 | NODE != OBJECT_CONTAINING(NULL, NODE, MEMBER); \ |
772ec52b | 153 | ASSIGN_CONTAINER(NODE, hmap_next(HMAP, &(NODE)->MEMBER), MEMBER)) |
4e8e4213 | 154 | |
633d7b90 BP |
155 | /* Safe when NODE may be freed (not needed when NODE may be removed from the |
156 | * hash map but its members remain accessible and intact). */ | |
4e8e4213 | 157 | #define HMAP_FOR_EACH_SAFE(NODE, NEXT, MEMBER, HMAP) \ |
772ec52b | 158 | for (ASSIGN_CONTAINER(NODE, hmap_first(HMAP), MEMBER); \ |
55d26906 | 159 | (NODE != OBJECT_CONTAINING(NULL, NODE, MEMBER) \ |
33e191a0 | 160 | ? ASSIGN_CONTAINER(NEXT, hmap_next(HMAP, &(NODE)->MEMBER), MEMBER), 1 \ |
4e8e4213 | 161 | : 0); \ |
064af421 BP |
162 | (NODE) = (NEXT)) |
163 | ||
633d7b90 BP |
164 | /* Continues an iteration from just after NODE. */ |
165 | #define HMAP_FOR_EACH_CONTINUE(NODE, MEMBER, HMAP) \ | |
772ec52b | 166 | for (ASSIGN_CONTAINER(NODE, hmap_next(HMAP, &(NODE)->MEMBER), MEMBER); \ |
55d26906 | 167 | NODE != OBJECT_CONTAINING(NULL, NODE, MEMBER); \ |
772ec52b | 168 | ASSIGN_CONTAINER(NODE, hmap_next(HMAP, &(NODE)->MEMBER), MEMBER)) |
633d7b90 | 169 | |
064af421 BP |
170 | static inline struct hmap_node *hmap_first(const struct hmap *); |
171 | static inline struct hmap_node *hmap_next(const struct hmap *, | |
172 | const struct hmap_node *); | |
173 | ||
ee114c23 BP |
174 | struct hmap_node *hmap_at_position(const struct hmap *, |
175 | uint32_t *bucket, uint32_t *offset); | |
176 | ||
064af421 BP |
177 | /* Returns the number of nodes currently in 'hmap'. */ |
178 | static inline size_t | |
179 | hmap_count(const struct hmap *hmap) | |
180 | { | |
181 | return hmap->n; | |
182 | } | |
183 | ||
72865317 BP |
184 | /* Returns the maximum number of nodes that 'hmap' may hold before it should be |
185 | * rehashed. */ | |
186 | static inline size_t | |
187 | hmap_capacity(const struct hmap *hmap) | |
188 | { | |
189 | return hmap->mask * 2 + 1; | |
190 | } | |
191 | ||
064af421 | 192 | /* Returns true if 'hmap' currently contains no nodes, |
7614e5d0 JR |
193 | * false otherwise. |
194 | * Note: While hmap in general is not thread-safe without additional locking, | |
195 | * hmap_is_empty() is. */ | |
064af421 BP |
196 | static inline bool |
197 | hmap_is_empty(const struct hmap *hmap) | |
198 | { | |
7614e5d0 | 199 | atomic_thread_fence(memory_order_acquire); |
064af421 BP |
200 | return hmap->n == 0; |
201 | } | |
202 | ||
203 | /* Inserts 'node', with the given 'hash', into 'hmap'. 'hmap' is never | |
204 | * expanded automatically. */ | |
205 | static inline void | |
206 | hmap_insert_fast(struct hmap *hmap, struct hmap_node *node, size_t hash) | |
207 | { | |
208 | struct hmap_node **bucket = &hmap->buckets[hash & hmap->mask]; | |
209 | node->hash = hash; | |
210 | node->next = *bucket; | |
211 | *bucket = node; | |
212 | hmap->n++; | |
213 | } | |
214 | ||
215 | /* Inserts 'node', with the given 'hash', into 'hmap', and expands 'hmap' if | |
0c5e05bf BP |
216 | * necessary to optimize search performance. |
217 | * | |
218 | * ('where' is used in debug logging. Commonly one would use hmap_insert() to | |
219 | * automatically provide the caller's source file and line number for | |
220 | * 'where'.) */ | |
064af421 | 221 | static inline void |
0c5e05bf BP |
222 | hmap_insert_at(struct hmap *hmap, struct hmap_node *node, size_t hash, |
223 | const char *where) | |
064af421 BP |
224 | { |
225 | hmap_insert_fast(hmap, node, hash); | |
226 | if (hmap->n / 2 > hmap->mask) { | |
0c5e05bf | 227 | hmap_expand_at(hmap, where); |
064af421 BP |
228 | } |
229 | } | |
230 | ||
231 | /* Removes 'node' from 'hmap'. Does not shrink the hash table; call | |
232 | * hmap_shrink() directly if desired. */ | |
233 | static inline void | |
234 | hmap_remove(struct hmap *hmap, struct hmap_node *node) | |
235 | { | |
236 | struct hmap_node **bucket = &hmap->buckets[node->hash & hmap->mask]; | |
237 | while (*bucket != node) { | |
238 | bucket = &(*bucket)->next; | |
239 | } | |
240 | *bucket = node->next; | |
241 | hmap->n--; | |
242 | } | |
243 | ||
0b64afd6 BP |
244 | /* Puts 'new_node' in the position in 'hmap' currently occupied by 'old_node'. |
245 | * The 'new_node' must hash to the same value as 'old_node'. The client is | |
246 | * responsible for ensuring that the replacement does not violate any | |
247 | * client-imposed invariants (e.g. uniqueness of keys within a map). | |
064af421 | 248 | * |
0b64afd6 BP |
249 | * Afterward, 'old_node' is not part of 'hmap', and the client is responsible |
250 | * for freeing it (if this is desirable). */ | |
064af421 BP |
251 | static inline void |
252 | hmap_replace(struct hmap *hmap, | |
0b64afd6 | 253 | const struct hmap_node *old_node, struct hmap_node *new_node) |
064af421 | 254 | { |
0b64afd6 BP |
255 | struct hmap_node **bucket = &hmap->buckets[old_node->hash & hmap->mask]; |
256 | while (*bucket != old_node) { | |
064af421 BP |
257 | bucket = &(*bucket)->next; |
258 | } | |
0b64afd6 BP |
259 | *bucket = new_node; |
260 | new_node->hash = old_node->hash; | |
a4af0040 | 261 | new_node->next = old_node->next; |
064af421 BP |
262 | } |
263 | ||
264 | static inline struct hmap_node * | |
265 | hmap_next_with_hash__(const struct hmap_node *node, size_t hash) | |
266 | { | |
267 | while (node != NULL && node->hash != hash) { | |
268 | node = node->next; | |
269 | } | |
ebc56baa | 270 | return CONST_CAST(struct hmap_node *, node); |
064af421 BP |
271 | } |
272 | ||
273 | /* Returns the first node in 'hmap' with the given 'hash', or a null pointer if | |
274 | * no nodes have that hash value. */ | |
275 | static inline struct hmap_node * | |
276 | hmap_first_with_hash(const struct hmap *hmap, size_t hash) | |
277 | { | |
278 | return hmap_next_with_hash__(hmap->buckets[hash & hmap->mask], hash); | |
279 | } | |
280 | ||
3adb8bf0 BP |
281 | /* Returns the first node in 'hmap' in the bucket in which the given 'hash' |
282 | * would land, or a null pointer if that bucket is empty. */ | |
283 | static inline struct hmap_node * | |
284 | hmap_first_in_bucket(const struct hmap *hmap, size_t hash) | |
285 | { | |
286 | return hmap->buckets[hash & hmap->mask]; | |
287 | } | |
288 | ||
289 | /* Returns the next node in the same bucket as 'node', or a null pointer if | |
290 | * there are no more nodes in that bucket. | |
291 | * | |
292 | * If the hash map has been reallocated since 'node' was visited, some nodes | |
293 | * may be skipped; if new nodes with the same hash value have been added, they | |
294 | * will be skipped. (Removing 'node' from the hash map does not prevent | |
295 | * calling this function, since node->next is preserved, although freeing | |
296 | * 'node' of course does.) */ | |
297 | static inline struct hmap_node * | |
298 | hmap_next_in_bucket(const struct hmap_node *node) | |
299 | { | |
300 | return node->next; | |
301 | } | |
302 | ||
064af421 BP |
303 | /* Returns the next node in the same hash map as 'node' with the same hash |
304 | * value, or a null pointer if no more nodes have that hash value. | |
305 | * | |
306 | * If the hash map has been reallocated since 'node' was visited, some nodes | |
307 | * may be skipped; if new nodes with the same hash value have been added, they | |
308 | * will be skipped. (Removing 'node' from the hash map does not prevent | |
309 | * calling this function, since node->next is preserved, although freeing | |
310 | * 'node' of course does.) */ | |
311 | static inline struct hmap_node * | |
312 | hmap_next_with_hash(const struct hmap_node *node) | |
313 | { | |
314 | return hmap_next_with_hash__(node->next, node->hash); | |
315 | } | |
316 | ||
317 | static inline struct hmap_node * | |
318 | hmap_next__(const struct hmap *hmap, size_t start) | |
319 | { | |
320 | size_t i; | |
321 | for (i = start; i <= hmap->mask; i++) { | |
322 | struct hmap_node *node = hmap->buckets[i]; | |
323 | if (node) { | |
324 | return node; | |
325 | } | |
326 | } | |
327 | return NULL; | |
328 | } | |
329 | ||
330 | /* Returns the first node in 'hmap', in arbitrary order, or a null pointer if | |
331 | * 'hmap' is empty. */ | |
332 | static inline struct hmap_node * | |
333 | hmap_first(const struct hmap *hmap) | |
334 | { | |
335 | return hmap_next__(hmap, 0); | |
336 | } | |
337 | ||
338 | /* Returns the next node in 'hmap' following 'node', in arbitrary order, or a | |
339 | * null pointer if 'node' is the last node in 'hmap'. | |
340 | * | |
341 | * If the hash map has been reallocated since 'node' was visited, some nodes | |
342 | * may be skipped or visited twice. (Removing 'node' from the hash map does | |
343 | * not prevent calling this function, since node->next is preserved, although | |
344 | * freeing 'node' of course does.) */ | |
345 | static inline struct hmap_node * | |
346 | hmap_next(const struct hmap *hmap, const struct hmap_node *node) | |
347 | { | |
348 | return (node->next | |
349 | ? node->next | |
350 | : hmap_next__(hmap, (node->hash & hmap->mask) + 1)); | |
351 | } | |
352 | ||
0b64afd6 BP |
353 | #ifdef __cplusplus |
354 | } | |
355 | #endif | |
356 | ||
064af421 | 357 | #endif /* hmap.h */ |