]>
Commit | Line | Data |
---|---|---|
064af421 | 1 | /* |
e0edde6f | 2 | * Copyright (c) 2008, 2009, 2010, 2012 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> | |
22 | #include "util.h" | |
23 | ||
0b64afd6 BP |
24 | #ifdef __cplusplus |
25 | extern "C" { | |
26 | #endif | |
27 | ||
064af421 BP |
28 | /* A hash map node, to be embedded inside the data structure being mapped. */ |
29 | struct hmap_node { | |
30 | size_t hash; /* Hash value. */ | |
31 | struct hmap_node *next; /* Next in linked list. */ | |
32 | }; | |
33 | ||
34 | /* Returns the hash value embedded in 'node'. */ | |
35 | static inline size_t hmap_node_hash(const struct hmap_node *node) | |
36 | { | |
37 | return node->hash; | |
38 | } | |
39 | ||
1e68c073 | 40 | #define HMAP_NODE_NULL ((struct hmap_node *) 1) |
6c2e425e | 41 | #define HMAP_NODE_NULL_INITIALIZER { 0, HMAP_NODE_NULL } |
1e68c073 BP |
42 | |
43 | /* Returns true if 'node' has been set to null by hmap_node_nullify() and has | |
44 | * not been un-nullified by being inserted into an hmap. */ | |
45 | static inline bool | |
46 | hmap_node_is_null(const struct hmap_node *node) | |
47 | { | |
48 | return node->next == HMAP_NODE_NULL; | |
49 | } | |
50 | ||
51 | /* Marks 'node' with a distinctive value that can be tested with | |
52 | * hmap_node_is_null(). */ | |
53 | static inline void | |
54 | hmap_node_nullify(struct hmap_node *node) | |
55 | { | |
56 | node->next = HMAP_NODE_NULL; | |
57 | } | |
58 | ||
064af421 BP |
59 | /* A hash map. */ |
60 | struct hmap { | |
baa8f41b | 61 | struct hmap_node **buckets; /* Must point to 'one' iff 'mask' == 0. */ |
064af421 BP |
62 | struct hmap_node *one; |
63 | size_t mask; | |
64 | size_t n; | |
65 | }; | |
66 | ||
67 | /* Initializer for an empty hash map. */ | |
e37726e4 BP |
68 | #define HMAP_INITIALIZER(HMAP) \ |
69 | { (struct hmap_node **const) &(HMAP)->one, NULL, 0, 0 } | |
064af421 BP |
70 | |
71 | /* Initialization. */ | |
72 | void hmap_init(struct hmap *); | |
73 | void hmap_destroy(struct hmap *); | |
f3099647 | 74 | void hmap_clear(struct hmap *); |
064af421 | 75 | void hmap_swap(struct hmap *a, struct hmap *b); |
a4af0040 | 76 | void hmap_moved(struct hmap *hmap); |
064af421 BP |
77 | static inline size_t hmap_count(const struct hmap *); |
78 | static inline bool hmap_is_empty(const struct hmap *); | |
79 | ||
80 | /* Adjusting capacity. */ | |
81 | void hmap_expand(struct hmap *); | |
82 | void hmap_shrink(struct hmap *); | |
83 | void hmap_reserve(struct hmap *, size_t capacity); | |
84 | ||
85 | /* Insertion and deletion. */ | |
86 | static inline void hmap_insert_fast(struct hmap *, | |
87 | struct hmap_node *, size_t hash); | |
88 | static inline void hmap_insert(struct hmap *, struct hmap_node *, size_t hash); | |
89 | static inline void hmap_remove(struct hmap *, struct hmap_node *); | |
064af421 | 90 | |
63e60b86 | 91 | void hmap_node_moved(struct hmap *, struct hmap_node *, struct hmap_node *); |
064af421 | 92 | static inline void hmap_replace(struct hmap *, const struct hmap_node *old, |
43d1478b | 93 | struct hmap_node *new_node); |
064af421 | 94 | |
f2f7be86 BP |
95 | struct hmap_node *hmap_random_node(const struct hmap *); |
96 | ||
3adb8bf0 BP |
97 | /* Search. |
98 | * | |
99 | * HMAP_FOR_EACH_WITH_HASH iterates NODE over all of the nodes in HMAP that | |
100 | * have hash value equal to HASH. HMAP_FOR_EACH_IN_BUCKET iterates NODE over | |
4e8e4213 BP |
101 | * all of the nodes in HMAP that would fall in the same bucket as HASH. MEMBER |
102 | * must be the name of the 'struct hmap_node' member within NODE. | |
3adb8bf0 BP |
103 | * |
104 | * These macros may be used interchangeably to search for a particular value in | |
105 | * an hmap, see, e.g. shash_find() for an example. Usually, using | |
106 | * HMAP_FOR_EACH_WITH_HASH provides an optimization, because comparing a hash | |
107 | * value is usually cheaper than comparing an entire hash map key. But for | |
108 | * simple hash map keys, it makes sense to use HMAP_FOR_EACH_IN_BUCKET because | |
109 | * it avoids doing two comparisons when a single simple comparison suffices. | |
110 | * | |
111 | * The loop should not change NODE to point to a different node or insert or | |
112 | * delete nodes in HMAP (unless it "break"s out of the loop to terminate | |
113 | * iteration). | |
114 | * | |
115 | * HASH is only evaluated once. | |
116 | */ | |
4e8e4213 | 117 | #define HMAP_FOR_EACH_WITH_HASH(NODE, MEMBER, HASH, HMAP) \ |
772ec52b | 118 | for (ASSIGN_CONTAINER(NODE, hmap_first_with_hash(HMAP, HASH), MEMBER); \ |
55d26906 | 119 | NODE != OBJECT_CONTAINING(NULL, NODE, MEMBER); \ |
772ec52b BP |
120 | ASSIGN_CONTAINER(NODE, hmap_next_with_hash(&(NODE)->MEMBER), \ |
121 | MEMBER)) | |
4e8e4213 | 122 | #define HMAP_FOR_EACH_IN_BUCKET(NODE, MEMBER, HASH, HMAP) \ |
772ec52b | 123 | for (ASSIGN_CONTAINER(NODE, hmap_first_in_bucket(HMAP, HASH), MEMBER); \ |
55d26906 | 124 | NODE != OBJECT_CONTAINING(NULL, NODE, MEMBER); \ |
772ec52b | 125 | ASSIGN_CONTAINER(NODE, hmap_next_in_bucket(&(NODE)->MEMBER), MEMBER)) |
064af421 BP |
126 | |
127 | static inline struct hmap_node *hmap_first_with_hash(const struct hmap *, | |
128 | size_t hash); | |
129 | static inline struct hmap_node *hmap_next_with_hash(const struct hmap_node *); | |
3adb8bf0 BP |
130 | static inline struct hmap_node *hmap_first_in_bucket(const struct hmap *, |
131 | size_t hash); | |
132 | static inline struct hmap_node *hmap_next_in_bucket(const struct hmap_node *); | |
064af421 | 133 | |
e39e5b9d BP |
134 | bool hmap_contains(const struct hmap *, const struct hmap_node *); |
135 | ||
633d7b90 BP |
136 | /* Iteration. */ |
137 | ||
138 | /* Iterates through every node in HMAP. */ | |
4e8e4213 | 139 | #define HMAP_FOR_EACH(NODE, MEMBER, HMAP) \ |
772ec52b | 140 | for (ASSIGN_CONTAINER(NODE, hmap_first(HMAP), MEMBER); \ |
55d26906 | 141 | NODE != OBJECT_CONTAINING(NULL, NODE, MEMBER); \ |
772ec52b | 142 | ASSIGN_CONTAINER(NODE, hmap_next(HMAP, &(NODE)->MEMBER), MEMBER)) |
4e8e4213 | 143 | |
633d7b90 BP |
144 | /* Safe when NODE may be freed (not needed when NODE may be removed from the |
145 | * hash map but its members remain accessible and intact). */ | |
4e8e4213 | 146 | #define HMAP_FOR_EACH_SAFE(NODE, NEXT, MEMBER, HMAP) \ |
772ec52b | 147 | for (ASSIGN_CONTAINER(NODE, hmap_first(HMAP), MEMBER); \ |
55d26906 | 148 | (NODE != OBJECT_CONTAINING(NULL, NODE, MEMBER) \ |
772ec52b | 149 | ? ASSIGN_CONTAINER(NEXT, hmap_next(HMAP, &(NODE)->MEMBER), MEMBER) \ |
4e8e4213 | 150 | : 0); \ |
064af421 BP |
151 | (NODE) = (NEXT)) |
152 | ||
633d7b90 BP |
153 | /* Continues an iteration from just after NODE. */ |
154 | #define HMAP_FOR_EACH_CONTINUE(NODE, MEMBER, HMAP) \ | |
772ec52b | 155 | for (ASSIGN_CONTAINER(NODE, hmap_next(HMAP, &(NODE)->MEMBER), MEMBER); \ |
55d26906 | 156 | NODE != OBJECT_CONTAINING(NULL, NODE, MEMBER); \ |
772ec52b | 157 | ASSIGN_CONTAINER(NODE, hmap_next(HMAP, &(NODE)->MEMBER), MEMBER)) |
633d7b90 | 158 | |
064af421 BP |
159 | static inline struct hmap_node *hmap_first(const struct hmap *); |
160 | static inline struct hmap_node *hmap_next(const struct hmap *, | |
161 | const struct hmap_node *); | |
162 | ||
ee114c23 BP |
163 | struct hmap_node *hmap_at_position(const struct hmap *, |
164 | uint32_t *bucket, uint32_t *offset); | |
165 | ||
064af421 BP |
166 | /* Returns the number of nodes currently in 'hmap'. */ |
167 | static inline size_t | |
168 | hmap_count(const struct hmap *hmap) | |
169 | { | |
170 | return hmap->n; | |
171 | } | |
172 | ||
72865317 BP |
173 | /* Returns the maximum number of nodes that 'hmap' may hold before it should be |
174 | * rehashed. */ | |
175 | static inline size_t | |
176 | hmap_capacity(const struct hmap *hmap) | |
177 | { | |
178 | return hmap->mask * 2 + 1; | |
179 | } | |
180 | ||
064af421 BP |
181 | /* Returns true if 'hmap' currently contains no nodes, |
182 | * false otherwise. */ | |
183 | static inline bool | |
184 | hmap_is_empty(const struct hmap *hmap) | |
185 | { | |
186 | return hmap->n == 0; | |
187 | } | |
188 | ||
189 | /* Inserts 'node', with the given 'hash', into 'hmap'. 'hmap' is never | |
190 | * expanded automatically. */ | |
191 | static inline void | |
192 | hmap_insert_fast(struct hmap *hmap, struct hmap_node *node, size_t hash) | |
193 | { | |
194 | struct hmap_node **bucket = &hmap->buckets[hash & hmap->mask]; | |
195 | node->hash = hash; | |
196 | node->next = *bucket; | |
197 | *bucket = node; | |
198 | hmap->n++; | |
199 | } | |
200 | ||
201 | /* Inserts 'node', with the given 'hash', into 'hmap', and expands 'hmap' if | |
202 | * necessary to optimize search performance. */ | |
203 | static inline void | |
204 | hmap_insert(struct hmap *hmap, struct hmap_node *node, size_t hash) | |
205 | { | |
206 | hmap_insert_fast(hmap, node, hash); | |
207 | if (hmap->n / 2 > hmap->mask) { | |
208 | hmap_expand(hmap); | |
209 | } | |
210 | } | |
211 | ||
212 | /* Removes 'node' from 'hmap'. Does not shrink the hash table; call | |
213 | * hmap_shrink() directly if desired. */ | |
214 | static inline void | |
215 | hmap_remove(struct hmap *hmap, struct hmap_node *node) | |
216 | { | |
217 | struct hmap_node **bucket = &hmap->buckets[node->hash & hmap->mask]; | |
218 | while (*bucket != node) { | |
219 | bucket = &(*bucket)->next; | |
220 | } | |
221 | *bucket = node->next; | |
222 | hmap->n--; | |
223 | } | |
224 | ||
0b64afd6 BP |
225 | /* Puts 'new_node' in the position in 'hmap' currently occupied by 'old_node'. |
226 | * The 'new_node' must hash to the same value as 'old_node'. The client is | |
227 | * responsible for ensuring that the replacement does not violate any | |
228 | * client-imposed invariants (e.g. uniqueness of keys within a map). | |
064af421 | 229 | * |
0b64afd6 BP |
230 | * Afterward, 'old_node' is not part of 'hmap', and the client is responsible |
231 | * for freeing it (if this is desirable). */ | |
064af421 BP |
232 | static inline void |
233 | hmap_replace(struct hmap *hmap, | |
0b64afd6 | 234 | const struct hmap_node *old_node, struct hmap_node *new_node) |
064af421 | 235 | { |
0b64afd6 BP |
236 | struct hmap_node **bucket = &hmap->buckets[old_node->hash & hmap->mask]; |
237 | while (*bucket != old_node) { | |
064af421 BP |
238 | bucket = &(*bucket)->next; |
239 | } | |
0b64afd6 BP |
240 | *bucket = new_node; |
241 | new_node->hash = old_node->hash; | |
a4af0040 | 242 | new_node->next = old_node->next; |
064af421 BP |
243 | } |
244 | ||
245 | static inline struct hmap_node * | |
246 | hmap_next_with_hash__(const struct hmap_node *node, size_t hash) | |
247 | { | |
248 | while (node != NULL && node->hash != hash) { | |
249 | node = node->next; | |
250 | } | |
ebc56baa | 251 | return CONST_CAST(struct hmap_node *, node); |
064af421 BP |
252 | } |
253 | ||
254 | /* Returns the first node in 'hmap' with the given 'hash', or a null pointer if | |
255 | * no nodes have that hash value. */ | |
256 | static inline struct hmap_node * | |
257 | hmap_first_with_hash(const struct hmap *hmap, size_t hash) | |
258 | { | |
259 | return hmap_next_with_hash__(hmap->buckets[hash & hmap->mask], hash); | |
260 | } | |
261 | ||
3adb8bf0 BP |
262 | /* Returns the first node in 'hmap' in the bucket in which the given 'hash' |
263 | * would land, or a null pointer if that bucket is empty. */ | |
264 | static inline struct hmap_node * | |
265 | hmap_first_in_bucket(const struct hmap *hmap, size_t hash) | |
266 | { | |
267 | return hmap->buckets[hash & hmap->mask]; | |
268 | } | |
269 | ||
270 | /* Returns the next node in the same bucket as 'node', or a null pointer if | |
271 | * there are no more nodes in that bucket. | |
272 | * | |
273 | * If the hash map has been reallocated since 'node' was visited, some nodes | |
274 | * may be skipped; if new nodes with the same hash value have been added, they | |
275 | * will be skipped. (Removing 'node' from the hash map does not prevent | |
276 | * calling this function, since node->next is preserved, although freeing | |
277 | * 'node' of course does.) */ | |
278 | static inline struct hmap_node * | |
279 | hmap_next_in_bucket(const struct hmap_node *node) | |
280 | { | |
281 | return node->next; | |
282 | } | |
283 | ||
064af421 BP |
284 | /* Returns the next node in the same hash map as 'node' with the same hash |
285 | * value, or a null pointer if no more nodes have that hash value. | |
286 | * | |
287 | * If the hash map has been reallocated since 'node' was visited, some nodes | |
288 | * may be skipped; if new nodes with the same hash value have been added, they | |
289 | * will be skipped. (Removing 'node' from the hash map does not prevent | |
290 | * calling this function, since node->next is preserved, although freeing | |
291 | * 'node' of course does.) */ | |
292 | static inline struct hmap_node * | |
293 | hmap_next_with_hash(const struct hmap_node *node) | |
294 | { | |
295 | return hmap_next_with_hash__(node->next, node->hash); | |
296 | } | |
297 | ||
298 | static inline struct hmap_node * | |
299 | hmap_next__(const struct hmap *hmap, size_t start) | |
300 | { | |
301 | size_t i; | |
302 | for (i = start; i <= hmap->mask; i++) { | |
303 | struct hmap_node *node = hmap->buckets[i]; | |
304 | if (node) { | |
305 | return node; | |
306 | } | |
307 | } | |
308 | return NULL; | |
309 | } | |
310 | ||
311 | /* Returns the first node in 'hmap', in arbitrary order, or a null pointer if | |
312 | * 'hmap' is empty. */ | |
313 | static inline struct hmap_node * | |
314 | hmap_first(const struct hmap *hmap) | |
315 | { | |
316 | return hmap_next__(hmap, 0); | |
317 | } | |
318 | ||
319 | /* Returns the next node in 'hmap' following 'node', in arbitrary order, or a | |
320 | * null pointer if 'node' is the last node in 'hmap'. | |
321 | * | |
322 | * If the hash map has been reallocated since 'node' was visited, some nodes | |
323 | * may be skipped or visited twice. (Removing 'node' from the hash map does | |
324 | * not prevent calling this function, since node->next is preserved, although | |
325 | * freeing 'node' of course does.) */ | |
326 | static inline struct hmap_node * | |
327 | hmap_next(const struct hmap *hmap, const struct hmap_node *node) | |
328 | { | |
329 | return (node->next | |
330 | ? node->next | |
331 | : hmap_next__(hmap, (node->hash & hmap->mask) + 1)); | |
332 | } | |
333 | ||
0b64afd6 BP |
334 | #ifdef __cplusplus |
335 | } | |
336 | #endif | |
337 | ||
064af421 | 338 | #endif /* hmap.h */ |