2 * Copyright (c) 2008, 2009, 2010, 2012, 2013, 2015, 2016 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 * The *_INIT variants of these macros additionally evaluate the expressions
159 * supplied following the HMAP argument once during the loop initialization.
160 * This makes it possible for data structures that wrap around hmaps to insert
161 * additional initialization into their iteration macros without having to
162 * completely rewrite them. In particular, it can be a good idea to insert
163 * BUILD_ASSERT_TYPE checks for map and node types that wrap hmap, since
164 * otherwise it is possible for clients to accidentally confuse two derived
165 * data structures that happen to use the same member names for struct hmap and
166 * struct hmap_node. */
168 /* Iterates through every node in HMAP. */
169 #define HMAP_FOR_EACH(NODE, MEMBER, HMAP) \
170 HMAP_FOR_EACH_INIT(NODE, MEMBER, HMAP, (void) 0)
171 #define HMAP_FOR_EACH_INIT(NODE, MEMBER, HMAP, ...) \
172 for (INIT_CONTAINER(NODE, hmap_first(HMAP), MEMBER), __VA_ARGS__; \
173 (NODE != OBJECT_CONTAINING(NULL, NODE, MEMBER)) || (NODE = NULL); \
174 ASSIGN_CONTAINER(NODE, hmap_next(HMAP, &(NODE)->MEMBER), MEMBER))
176 /* Safe when NODE may be freed (not needed when NODE may be removed from the
177 * hash map but its members remain accessible and intact). */
178 #define HMAP_FOR_EACH_SAFE(NODE, NEXT, MEMBER, HMAP) \
179 HMAP_FOR_EACH_SAFE_INIT(NODE, NEXT, MEMBER, HMAP, (void) 0)
180 #define HMAP_FOR_EACH_SAFE_INIT(NODE, NEXT, MEMBER, HMAP, ...) \
181 for (INIT_CONTAINER(NODE, hmap_first(HMAP), MEMBER), __VA_ARGS__; \
182 ((NODE != OBJECT_CONTAINING(NULL, NODE, MEMBER)) || (NODE = NULL) \
183 ? INIT_CONTAINER(NEXT, hmap_next(HMAP, &(NODE)->MEMBER), MEMBER), 1 \
187 /* Continues an iteration from just after NODE. */
188 #define HMAP_FOR_EACH_CONTINUE(NODE, MEMBER, HMAP) \
189 HMAP_FOR_EACH_CONTINUE_INIT(NODE, MEMBER, HMAP, (void) 0)
190 #define HMAP_FOR_EACH_CONTINUE_INIT(NODE, MEMBER, HMAP, ...) \
191 for (ASSIGN_CONTAINER(NODE, hmap_next(HMAP, &(NODE)->MEMBER), MEMBER), \
193 (NODE != OBJECT_CONTAINING(NULL, NODE, MEMBER)) || (NODE = NULL); \
194 ASSIGN_CONTAINER(NODE, hmap_next(HMAP, &(NODE)->MEMBER), MEMBER))
196 static inline struct hmap_node *hmap_first(const struct hmap *);
197 static inline struct hmap_node *hmap_next(const struct hmap *,
198 const struct hmap_node *);
200 struct hmap_node *hmap_at_position(const struct hmap *,
201 uint32_t *bucket, uint32_t *offset);
203 /* Returns the number of nodes currently in 'hmap'. */
205 hmap_count(const struct hmap *hmap)
210 /* Returns the maximum number of nodes that 'hmap' may hold before it should be
213 hmap_capacity(const struct hmap *hmap)
215 return hmap->mask * 2 + 1;
218 /* Returns true if 'hmap' currently contains no nodes,
220 * Note: While hmap in general is not thread-safe without additional locking,
221 * hmap_is_empty() is. */
223 hmap_is_empty(const struct hmap *hmap)
228 /* Inserts 'node', with the given 'hash', into 'hmap'. 'hmap' is never
229 * expanded automatically. */
231 hmap_insert_fast(struct hmap *hmap, struct hmap_node *node, size_t hash)
233 struct hmap_node **bucket = &hmap->buckets[hash & hmap->mask];
235 node->next = *bucket;
240 /* Inserts 'node', with the given 'hash', into 'hmap', and expands 'hmap' if
241 * necessary to optimize search performance.
243 * ('where' is used in debug logging. Commonly one would use hmap_insert() to
244 * automatically provide the caller's source file and line number for
247 hmap_insert_at(struct hmap *hmap, struct hmap_node *node, size_t hash,
250 hmap_insert_fast(hmap, node, hash);
251 if (hmap->n / 2 > hmap->mask) {
252 hmap_expand_at(hmap, where);
256 /* Removes 'node' from 'hmap'. Does not shrink the hash table; call
257 * hmap_shrink() directly if desired. */
259 hmap_remove(struct hmap *hmap, struct hmap_node *node)
261 struct hmap_node **bucket = &hmap->buckets[node->hash & hmap->mask];
262 while (*bucket != node) {
263 bucket = &(*bucket)->next;
265 *bucket = node->next;
269 /* Puts 'new_node' in the position in 'hmap' currently occupied by 'old_node'.
270 * The 'new_node' must hash to the same value as 'old_node'. The client is
271 * responsible for ensuring that the replacement does not violate any
272 * client-imposed invariants (e.g. uniqueness of keys within a map).
274 * Afterward, 'old_node' is not part of 'hmap', and the client is responsible
275 * for freeing it (if this is desirable). */
277 hmap_replace(struct hmap *hmap,
278 const struct hmap_node *old_node, struct hmap_node *new_node)
280 struct hmap_node **bucket = &hmap->buckets[old_node->hash & hmap->mask];
281 while (*bucket != old_node) {
282 bucket = &(*bucket)->next;
285 new_node->hash = old_node->hash;
286 new_node->next = old_node->next;
289 static inline struct hmap_node *
290 hmap_next_with_hash__(const struct hmap_node *node, size_t hash)
292 while (node != NULL && node->hash != hash) {
295 return CONST_CAST(struct hmap_node *, node);
298 /* Returns the first node in 'hmap' with the given 'hash', or a null pointer if
299 * no nodes have that hash value. */
300 static inline struct hmap_node *
301 hmap_first_with_hash(const struct hmap *hmap, size_t hash)
303 return hmap_next_with_hash__(hmap->buckets[hash & hmap->mask], hash);
306 /* Returns the first node in 'hmap' in the bucket in which the given 'hash'
307 * would land, or a null pointer if that bucket is empty. */
308 static inline struct hmap_node *
309 hmap_first_in_bucket(const struct hmap *hmap, size_t hash)
311 return hmap->buckets[hash & hmap->mask];
314 /* Returns the next node in the same bucket as 'node', or a null pointer if
315 * there are no more nodes in that bucket.
317 * If the hash map has been reallocated since 'node' was visited, some nodes
318 * may be skipped; if new nodes with the same hash value have been added, they
319 * will be skipped. (Removing 'node' from the hash map does not prevent
320 * calling this function, since node->next is preserved, although freeing
321 * 'node' of course does.) */
322 static inline struct hmap_node *
323 hmap_next_in_bucket(const struct hmap_node *node)
328 /* Returns the next node in the same hash map as 'node' with the same hash
329 * value, or a null pointer if no more nodes have that hash value.
331 * If the hash map has been reallocated since 'node' was visited, some nodes
332 * may be skipped; if new nodes with the same hash value have been added, they
333 * will be skipped. (Removing 'node' from the hash map does not prevent
334 * calling this function, since node->next is preserved, although freeing
335 * 'node' of course does.) */
336 static inline struct hmap_node *
337 hmap_next_with_hash(const struct hmap_node *node)
339 return hmap_next_with_hash__(node->next, node->hash);
342 static inline struct hmap_node *
343 hmap_next__(const struct hmap *hmap, size_t start)
346 for (i = start; i <= hmap->mask; i++) {
347 struct hmap_node *node = hmap->buckets[i];
355 /* Returns the first node in 'hmap', in arbitrary order, or a null pointer if
356 * 'hmap' is empty. */
357 static inline struct hmap_node *
358 hmap_first(const struct hmap *hmap)
360 return hmap_next__(hmap, 0);
363 /* Returns the next node in 'hmap' following 'node', in arbitrary order, or a
364 * null pointer if 'node' is the last node in 'hmap'.
366 * If the hash map has been reallocated since 'node' was visited, some nodes
367 * may be skipped or visited twice. (Removing 'node' from the hash map does
368 * not prevent calling this function, since node->next is preserved, although
369 * freeing 'node' of course does.) */
370 static inline struct hmap_node *
371 hmap_next(const struct hmap *hmap, const struct hmap_node *node)
375 : hmap_next__(hmap, (node->hash & hmap->mask) + 1));