2 * Copyright (c) 2008, 2009, 2010, 2012, 2013, 2015 Nicira, Inc.
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:
8 * http://www.apache.org/licenses/LICENSE-2.0
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.
28 /* A hash map node, to be embedded inside the data structure being mapped. */
30 size_t hash; /* Hash value. */
31 struct hmap_node *next; /* Next in linked list. */
34 /* Returns the hash value embedded in 'node'. */
35 static inline size_t hmap_node_hash(const struct hmap_node *node)
40 #define HMAP_NODE_NULL ((struct hmap_node *) 1)
41 #define HMAP_NODE_NULL_INITIALIZER { 0, HMAP_NODE_NULL }
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. */
46 hmap_node_is_null(const struct hmap_node *node)
48 return node->next == HMAP_NODE_NULL;
51 /* Marks 'node' with a distinctive value that can be tested with
52 * hmap_node_is_null(). */
54 hmap_node_nullify(struct hmap_node *node)
56 node->next = HMAP_NODE_NULL;
61 struct hmap_node **buckets; /* Must point to 'one' iff 'mask' == 0. */
62 struct hmap_node *one;
67 /* Initializer for an empty hash map. */
68 #define HMAP_INITIALIZER(HMAP) \
69 { (struct hmap_node **const) &(HMAP)->one, NULL, 0, 0 }
71 /* Initializer for an immutable struct hmap 'HMAP' that contains a single
73 #define HMAP_CONST1(HMAP, NODE) { \
74 CONST_CAST(struct hmap_node **, &(HMAP)->one), NODE, 0, 1 }
75 #define HMAP_NODE_INIT(HASH) { HASH, NULL }
78 void hmap_init(struct hmap *);
79 void hmap_destroy(struct hmap *);
80 void hmap_clear(struct hmap *);
81 void hmap_swap(struct hmap *a, struct hmap *b);
82 void hmap_moved(struct hmap *hmap);
83 static inline size_t hmap_count(const struct hmap *);
84 static inline bool hmap_is_empty(const struct hmap *);
86 /* Adjusting capacity. */
87 void hmap_expand_at(struct hmap *, const char *where);
88 #define hmap_expand(HMAP) hmap_expand_at(HMAP, OVS_SOURCE_LOCATOR)
90 void hmap_shrink_at(struct hmap *, const char *where);
91 #define hmap_shrink(HMAP) hmap_shrink_at(HMAP, OVS_SOURCE_LOCATOR)
93 void hmap_reserve_at(struct hmap *, size_t capacity, const char *where);
94 #define hmap_reserve(HMAP, CAPACITY) \
95 hmap_reserve_at(HMAP, CAPACITY, OVS_SOURCE_LOCATOR)
97 /* Insertion and deletion. */
98 static inline void hmap_insert_at(struct hmap *, struct hmap_node *,
99 size_t hash, const char *where);
100 #define hmap_insert(HMAP, NODE, HASH) \
101 hmap_insert_at(HMAP, NODE, HASH, OVS_SOURCE_LOCATOR)
103 static inline void hmap_insert_fast(struct hmap *,
104 struct hmap_node *, size_t hash);
105 static inline void hmap_remove(struct hmap *, struct hmap_node *);
107 void hmap_node_moved(struct hmap *, struct hmap_node *, struct hmap_node *);
108 static inline void hmap_replace(struct hmap *, const struct hmap_node *old,
109 struct hmap_node *new_node);
111 struct hmap_node *hmap_random_node(const struct hmap *);
115 * HMAP_FOR_EACH_WITH_HASH iterates NODE over all of the nodes in HMAP that
116 * have hash value equal to HASH. HMAP_FOR_EACH_IN_BUCKET iterates NODE over
117 * all of the nodes in HMAP that would fall in the same bucket as HASH. MEMBER
118 * must be the name of the 'struct hmap_node' member within NODE.
120 * These macros may be used interchangeably to search for a particular value in
121 * an hmap, see, e.g. shash_find() for an example. Usually, using
122 * HMAP_FOR_EACH_WITH_HASH provides an optimization, because comparing a hash
123 * value is usually cheaper than comparing an entire hash map key. But for
124 * simple hash map keys, it makes sense to use HMAP_FOR_EACH_IN_BUCKET because
125 * it avoids doing two comparisons when a single simple comparison suffices.
127 * The loop should not change NODE to point to a different node or insert or
128 * delete nodes in HMAP (unless it "break"s out of the loop to terminate
131 * HASH is only evaluated once.
133 * When the loop terminates normally, meaning the iteration has completed
134 * without using 'break', NODE will be NULL. This is true for all of the
135 * HMAP_FOR_EACH_*() macros.
137 #define HMAP_FOR_EACH_WITH_HASH(NODE, MEMBER, HASH, HMAP) \
138 for (INIT_CONTAINER(NODE, hmap_first_with_hash(HMAP, HASH), MEMBER); \
139 (NODE != OBJECT_CONTAINING(NULL, NODE, MEMBER)) || (NODE = NULL); \
140 ASSIGN_CONTAINER(NODE, hmap_next_with_hash(&(NODE)->MEMBER), \
142 #define HMAP_FOR_EACH_IN_BUCKET(NODE, MEMBER, HASH, HMAP) \
143 for (INIT_CONTAINER(NODE, hmap_first_in_bucket(HMAP, HASH), MEMBER); \
144 (NODE != OBJECT_CONTAINING(NULL, NODE, MEMBER)) || (NODE = NULL); \
145 ASSIGN_CONTAINER(NODE, hmap_next_in_bucket(&(NODE)->MEMBER), MEMBER))
147 static inline struct hmap_node *hmap_first_with_hash(const struct hmap *,
149 static inline struct hmap_node *hmap_next_with_hash(const struct hmap_node *);
150 static inline struct hmap_node *hmap_first_in_bucket(const struct hmap *,
152 static inline struct hmap_node *hmap_next_in_bucket(const struct hmap_node *);
154 bool hmap_contains(const struct hmap *, const struct hmap_node *);
158 /* Iterates through every node in HMAP. */
159 #define HMAP_FOR_EACH(NODE, MEMBER, HMAP) \
160 for (INIT_CONTAINER(NODE, hmap_first(HMAP), MEMBER); \
161 (NODE != OBJECT_CONTAINING(NULL, NODE, MEMBER)) || (NODE = NULL); \
162 ASSIGN_CONTAINER(NODE, hmap_next(HMAP, &(NODE)->MEMBER), MEMBER))
164 /* Safe when NODE may be freed (not needed when NODE may be removed from the
165 * hash map but its members remain accessible and intact). */
166 #define HMAP_FOR_EACH_SAFE(NODE, NEXT, MEMBER, HMAP) \
167 for (INIT_CONTAINER(NODE, hmap_first(HMAP), MEMBER); \
168 ((NODE != OBJECT_CONTAINING(NULL, NODE, MEMBER)) || (NODE = NULL) \
169 ? INIT_CONTAINER(NEXT, hmap_next(HMAP, &(NODE)->MEMBER), MEMBER), 1 \
173 /* Continues an iteration from just after NODE. */
174 #define HMAP_FOR_EACH_CONTINUE(NODE, MEMBER, HMAP) \
175 for (ASSIGN_CONTAINER(NODE, hmap_next(HMAP, &(NODE)->MEMBER), MEMBER); \
176 (NODE != OBJECT_CONTAINING(NULL, NODE, MEMBER)) || (NODE = NULL); \
177 ASSIGN_CONTAINER(NODE, hmap_next(HMAP, &(NODE)->MEMBER), MEMBER))
179 static inline struct hmap_node *hmap_first(const struct hmap *);
180 static inline struct hmap_node *hmap_next(const struct hmap *,
181 const struct hmap_node *);
183 struct hmap_node *hmap_at_position(const struct hmap *,
184 uint32_t *bucket, uint32_t *offset);
186 /* Returns the number of nodes currently in 'hmap'. */
188 hmap_count(const struct hmap *hmap)
193 /* Returns the maximum number of nodes that 'hmap' may hold before it should be
196 hmap_capacity(const struct hmap *hmap)
198 return hmap->mask * 2 + 1;
201 /* Returns true if 'hmap' currently contains no nodes,
203 * Note: While hmap in general is not thread-safe without additional locking,
204 * hmap_is_empty() is. */
206 hmap_is_empty(const struct hmap *hmap)
211 /* Inserts 'node', with the given 'hash', into 'hmap'. 'hmap' is never
212 * expanded automatically. */
214 hmap_insert_fast(struct hmap *hmap, struct hmap_node *node, size_t hash)
216 struct hmap_node **bucket = &hmap->buckets[hash & hmap->mask];
218 node->next = *bucket;
223 /* Inserts 'node', with the given 'hash', into 'hmap', and expands 'hmap' if
224 * necessary to optimize search performance.
226 * ('where' is used in debug logging. Commonly one would use hmap_insert() to
227 * automatically provide the caller's source file and line number for
230 hmap_insert_at(struct hmap *hmap, struct hmap_node *node, size_t hash,
233 hmap_insert_fast(hmap, node, hash);
234 if (hmap->n / 2 > hmap->mask) {
235 hmap_expand_at(hmap, where);
239 /* Removes 'node' from 'hmap'. Does not shrink the hash table; call
240 * hmap_shrink() directly if desired. */
242 hmap_remove(struct hmap *hmap, struct hmap_node *node)
244 struct hmap_node **bucket = &hmap->buckets[node->hash & hmap->mask];
245 while (*bucket != node) {
246 bucket = &(*bucket)->next;
248 *bucket = node->next;
252 /* Puts 'new_node' in the position in 'hmap' currently occupied by 'old_node'.
253 * The 'new_node' must hash to the same value as 'old_node'. The client is
254 * responsible for ensuring that the replacement does not violate any
255 * client-imposed invariants (e.g. uniqueness of keys within a map).
257 * Afterward, 'old_node' is not part of 'hmap', and the client is responsible
258 * for freeing it (if this is desirable). */
260 hmap_replace(struct hmap *hmap,
261 const struct hmap_node *old_node, struct hmap_node *new_node)
263 struct hmap_node **bucket = &hmap->buckets[old_node->hash & hmap->mask];
264 while (*bucket != old_node) {
265 bucket = &(*bucket)->next;
268 new_node->hash = old_node->hash;
269 new_node->next = old_node->next;
272 static inline struct hmap_node *
273 hmap_next_with_hash__(const struct hmap_node *node, size_t hash)
275 while (node != NULL && node->hash != hash) {
278 return CONST_CAST(struct hmap_node *, node);
281 /* Returns the first node in 'hmap' with the given 'hash', or a null pointer if
282 * no nodes have that hash value. */
283 static inline struct hmap_node *
284 hmap_first_with_hash(const struct hmap *hmap, size_t hash)
286 return hmap_next_with_hash__(hmap->buckets[hash & hmap->mask], hash);
289 /* Returns the first node in 'hmap' in the bucket in which the given 'hash'
290 * would land, or a null pointer if that bucket is empty. */
291 static inline struct hmap_node *
292 hmap_first_in_bucket(const struct hmap *hmap, size_t hash)
294 return hmap->buckets[hash & hmap->mask];
297 /* Returns the next node in the same bucket as 'node', or a null pointer if
298 * there are no more nodes in that bucket.
300 * If the hash map has been reallocated since 'node' was visited, some nodes
301 * may be skipped; if new nodes with the same hash value have been added, they
302 * will be skipped. (Removing 'node' from the hash map does not prevent
303 * calling this function, since node->next is preserved, although freeing
304 * 'node' of course does.) */
305 static inline struct hmap_node *
306 hmap_next_in_bucket(const struct hmap_node *node)
311 /* Returns the next node in the same hash map as 'node' with the same hash
312 * value, or a null pointer if no more nodes have that hash value.
314 * If the hash map has been reallocated since 'node' was visited, some nodes
315 * may be skipped; if new nodes with the same hash value have been added, they
316 * will be skipped. (Removing 'node' from the hash map does not prevent
317 * calling this function, since node->next is preserved, although freeing
318 * 'node' of course does.) */
319 static inline struct hmap_node *
320 hmap_next_with_hash(const struct hmap_node *node)
322 return hmap_next_with_hash__(node->next, node->hash);
325 static inline struct hmap_node *
326 hmap_next__(const struct hmap *hmap, size_t start)
329 for (i = start; i <= hmap->mask; i++) {
330 struct hmap_node *node = hmap->buckets[i];
338 /* Returns the first node in 'hmap', in arbitrary order, or a null pointer if
339 * 'hmap' is empty. */
340 static inline struct hmap_node *
341 hmap_first(const struct hmap *hmap)
343 return hmap_next__(hmap, 0);
346 /* Returns the next node in 'hmap' following 'node', in arbitrary order, or a
347 * null pointer if 'node' is the last node in 'hmap'.
349 * If the hash map has been reallocated since 'node' was visited, some nodes
350 * may be skipped or visited twice. (Removing 'node' from the hash map does
351 * not prevent calling this function, since node->next is preserved, although
352 * freeing 'node' of course does.) */
353 static inline struct hmap_node *
354 hmap_next(const struct hmap *hmap, const struct hmap_node *node)
358 : hmap_next__(hmap, (node->hash & hmap->mask) + 1));