2 * Copyright (c) 2008, 2009, 2010, 2012, 2013 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 }
72 void hmap_init(struct hmap *);
73 void hmap_destroy(struct hmap *);
74 void hmap_clear(struct hmap *);
75 void hmap_swap(struct hmap *a, struct hmap *b);
76 void hmap_moved(struct hmap *hmap);
77 static inline size_t hmap_count(const struct hmap *);
78 static inline bool hmap_is_empty(const struct hmap *);
80 /* Adjusting capacity. */
81 void hmap_expand_at(struct hmap *, const char *where);
82 #define hmap_expand(HMAP) hmap_expand_at(HMAP, SOURCE_LOCATOR)
84 void hmap_shrink_at(struct hmap *, const char *where);
85 #define hmap_shrink(HMAP) hmap_shrink_at(HMAP, SOURCE_LOCATOR)
87 void hmap_reserve_at(struct hmap *, size_t capacity, const char *where);
88 #define hmap_reserve(HMAP, CAPACITY) \
89 hmap_reserve_at(HMAP, CAPACITY, SOURCE_LOCATOR)
91 /* Insertion and deletion. */
92 static inline void hmap_insert_at(struct hmap *, struct hmap_node *,
93 size_t hash, const char *where);
94 #define hmap_insert(HMAP, NODE, HASH) \
95 hmap_insert_at(HMAP, NODE, HASH, SOURCE_LOCATOR)
97 static inline void hmap_insert_fast(struct hmap *,
98 struct hmap_node *, size_t hash);
99 static inline void hmap_remove(struct hmap *, struct hmap_node *);
101 void hmap_node_moved(struct hmap *, struct hmap_node *, struct hmap_node *);
102 static inline void hmap_replace(struct hmap *, const struct hmap_node *old,
103 struct hmap_node *new_node);
105 struct hmap_node *hmap_random_node(const struct hmap *);
109 * HMAP_FOR_EACH_WITH_HASH iterates NODE over all of the nodes in HMAP that
110 * have hash value equal to HASH. HMAP_FOR_EACH_IN_BUCKET iterates NODE over
111 * all of the nodes in HMAP that would fall in the same bucket as HASH. MEMBER
112 * must be the name of the 'struct hmap_node' member within NODE.
114 * These macros may be used interchangeably to search for a particular value in
115 * an hmap, see, e.g. shash_find() for an example. Usually, using
116 * HMAP_FOR_EACH_WITH_HASH provides an optimization, because comparing a hash
117 * value is usually cheaper than comparing an entire hash map key. But for
118 * simple hash map keys, it makes sense to use HMAP_FOR_EACH_IN_BUCKET because
119 * it avoids doing two comparisons when a single simple comparison suffices.
121 * The loop should not change NODE to point to a different node or insert or
122 * delete nodes in HMAP (unless it "break"s out of the loop to terminate
125 * HASH is only evaluated once.
127 #define HMAP_FOR_EACH_WITH_HASH(NODE, MEMBER, HASH, HMAP) \
128 for (ASSIGN_CONTAINER(NODE, hmap_first_with_hash(HMAP, HASH), MEMBER); \
129 NODE != OBJECT_CONTAINING(NULL, NODE, MEMBER); \
130 ASSIGN_CONTAINER(NODE, hmap_next_with_hash(&(NODE)->MEMBER), \
132 #define HMAP_FOR_EACH_IN_BUCKET(NODE, MEMBER, HASH, HMAP) \
133 for (ASSIGN_CONTAINER(NODE, hmap_first_in_bucket(HMAP, HASH), MEMBER); \
134 NODE != OBJECT_CONTAINING(NULL, NODE, MEMBER); \
135 ASSIGN_CONTAINER(NODE, hmap_next_in_bucket(&(NODE)->MEMBER), MEMBER))
137 static inline struct hmap_node *hmap_first_with_hash(const struct hmap *,
139 static inline struct hmap_node *hmap_next_with_hash(const struct hmap_node *);
140 static inline struct hmap_node *hmap_first_in_bucket(const struct hmap *,
142 static inline struct hmap_node *hmap_next_in_bucket(const struct hmap_node *);
144 bool hmap_contains(const struct hmap *, const struct hmap_node *);
148 /* Iterates through every node in HMAP. */
149 #define HMAP_FOR_EACH(NODE, MEMBER, HMAP) \
150 for (ASSIGN_CONTAINER(NODE, hmap_first(HMAP), MEMBER); \
151 NODE != OBJECT_CONTAINING(NULL, NODE, MEMBER); \
152 ASSIGN_CONTAINER(NODE, hmap_next(HMAP, &(NODE)->MEMBER), MEMBER))
154 /* Safe when NODE may be freed (not needed when NODE may be removed from the
155 * hash map but its members remain accessible and intact). */
156 #define HMAP_FOR_EACH_SAFE(NODE, NEXT, MEMBER, HMAP) \
157 for (ASSIGN_CONTAINER(NODE, hmap_first(HMAP), MEMBER); \
158 (NODE != OBJECT_CONTAINING(NULL, NODE, MEMBER) \
159 ? ASSIGN_CONTAINER(NEXT, hmap_next(HMAP, &(NODE)->MEMBER), MEMBER), 1 \
163 /* Continues an iteration from just after NODE. */
164 #define HMAP_FOR_EACH_CONTINUE(NODE, MEMBER, HMAP) \
165 for (ASSIGN_CONTAINER(NODE, hmap_next(HMAP, &(NODE)->MEMBER), MEMBER); \
166 NODE != OBJECT_CONTAINING(NULL, NODE, MEMBER); \
167 ASSIGN_CONTAINER(NODE, hmap_next(HMAP, &(NODE)->MEMBER), MEMBER))
169 static inline struct hmap_node *hmap_first(const struct hmap *);
170 static inline struct hmap_node *hmap_next(const struct hmap *,
171 const struct hmap_node *);
173 struct hmap_node *hmap_at_position(const struct hmap *,
174 uint32_t *bucket, uint32_t *offset);
176 /* Returns the number of nodes currently in 'hmap'. */
178 hmap_count(const struct hmap *hmap)
183 /* Returns the maximum number of nodes that 'hmap' may hold before it should be
186 hmap_capacity(const struct hmap *hmap)
188 return hmap->mask * 2 + 1;
191 /* Returns true if 'hmap' currently contains no nodes,
192 * false otherwise. */
194 hmap_is_empty(const struct hmap *hmap)
199 /* Inserts 'node', with the given 'hash', into 'hmap'. 'hmap' is never
200 * expanded automatically. */
202 hmap_insert_fast(struct hmap *hmap, struct hmap_node *node, size_t hash)
204 struct hmap_node **bucket = &hmap->buckets[hash & hmap->mask];
206 node->next = *bucket;
211 /* Inserts 'node', with the given 'hash', into 'hmap', and expands 'hmap' if
212 * necessary to optimize search performance.
214 * ('where' is used in debug logging. Commonly one would use hmap_insert() to
215 * automatically provide the caller's source file and line number for
218 hmap_insert_at(struct hmap *hmap, struct hmap_node *node, size_t hash,
221 hmap_insert_fast(hmap, node, hash);
222 if (hmap->n / 2 > hmap->mask) {
223 hmap_expand_at(hmap, where);
227 /* Removes 'node' from 'hmap'. Does not shrink the hash table; call
228 * hmap_shrink() directly if desired. */
230 hmap_remove(struct hmap *hmap, struct hmap_node *node)
232 struct hmap_node **bucket = &hmap->buckets[node->hash & hmap->mask];
233 while (*bucket != node) {
234 bucket = &(*bucket)->next;
236 *bucket = node->next;
240 /* Puts 'new_node' in the position in 'hmap' currently occupied by 'old_node'.
241 * The 'new_node' must hash to the same value as 'old_node'. The client is
242 * responsible for ensuring that the replacement does not violate any
243 * client-imposed invariants (e.g. uniqueness of keys within a map).
245 * Afterward, 'old_node' is not part of 'hmap', and the client is responsible
246 * for freeing it (if this is desirable). */
248 hmap_replace(struct hmap *hmap,
249 const struct hmap_node *old_node, struct hmap_node *new_node)
251 struct hmap_node **bucket = &hmap->buckets[old_node->hash & hmap->mask];
252 while (*bucket != old_node) {
253 bucket = &(*bucket)->next;
256 new_node->hash = old_node->hash;
257 new_node->next = old_node->next;
260 static inline struct hmap_node *
261 hmap_next_with_hash__(const struct hmap_node *node, size_t hash)
263 while (node != NULL && node->hash != hash) {
266 return CONST_CAST(struct hmap_node *, node);
269 /* Returns the first node in 'hmap' with the given 'hash', or a null pointer if
270 * no nodes have that hash value. */
271 static inline struct hmap_node *
272 hmap_first_with_hash(const struct hmap *hmap, size_t hash)
274 return hmap_next_with_hash__(hmap->buckets[hash & hmap->mask], hash);
277 /* Returns the first node in 'hmap' in the bucket in which the given 'hash'
278 * would land, or a null pointer if that bucket is empty. */
279 static inline struct hmap_node *
280 hmap_first_in_bucket(const struct hmap *hmap, size_t hash)
282 return hmap->buckets[hash & hmap->mask];
285 /* Returns the next node in the same bucket as 'node', or a null pointer if
286 * there are no more nodes in that bucket.
288 * If the hash map has been reallocated since 'node' was visited, some nodes
289 * may be skipped; if new nodes with the same hash value have been added, they
290 * will be skipped. (Removing 'node' from the hash map does not prevent
291 * calling this function, since node->next is preserved, although freeing
292 * 'node' of course does.) */
293 static inline struct hmap_node *
294 hmap_next_in_bucket(const struct hmap_node *node)
299 /* Returns the next node in the same hash map as 'node' with the same hash
300 * value, or a null pointer if no more nodes have that hash value.
302 * If the hash map has been reallocated since 'node' was visited, some nodes
303 * may be skipped; if new nodes with the same hash value have been added, they
304 * will be skipped. (Removing 'node' from the hash map does not prevent
305 * calling this function, since node->next is preserved, although freeing
306 * 'node' of course does.) */
307 static inline struct hmap_node *
308 hmap_next_with_hash(const struct hmap_node *node)
310 return hmap_next_with_hash__(node->next, node->hash);
313 static inline struct hmap_node *
314 hmap_next__(const struct hmap *hmap, size_t start)
317 for (i = start; i <= hmap->mask; i++) {
318 struct hmap_node *node = hmap->buckets[i];
326 /* Returns the first node in 'hmap', in arbitrary order, or a null pointer if
327 * 'hmap' is empty. */
328 static inline struct hmap_node *
329 hmap_first(const struct hmap *hmap)
331 return hmap_next__(hmap, 0);
334 /* Returns the next node in 'hmap' following 'node', in arbitrary order, or a
335 * null pointer if 'node' is the last node in 'hmap'.
337 * If the hash map has been reallocated since 'node' was visited, some nodes
338 * may be skipped or visited twice. (Removing 'node' from the hash map does
339 * not prevent calling this function, since node->next is preserved, although
340 * freeing 'node' of course does.) */
341 static inline struct hmap_node *
342 hmap_next(const struct hmap *hmap, const struct hmap_node *node)
346 : hmap_next__(hmap, (node->hash & hmap->mask) + 1));