2 * Copyright (c) 2008, 2009, 2010, 2012 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(struct hmap *);
82 void hmap_shrink(struct hmap *);
83 void hmap_reserve(struct hmap *, size_t capacity);
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 *);
91 void hmap_node_moved(struct hmap *, struct hmap_node *, struct hmap_node *);
92 static inline void hmap_replace(struct hmap *, const struct hmap_node *old,
93 struct hmap_node *new_node);
95 struct hmap_node *hmap_random_node(const struct hmap *);
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
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.
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.
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
115 * HASH is only evaluated once.
117 #define HMAP_FOR_EACH_WITH_HASH(NODE, MEMBER, HASH, HMAP) \
118 for (ASSIGN_CONTAINER(NODE, hmap_first_with_hash(HMAP, HASH), MEMBER); \
119 NODE != OBJECT_CONTAINING(NULL, NODE, MEMBER); \
120 ASSIGN_CONTAINER(NODE, hmap_next_with_hash(&(NODE)->MEMBER), \
122 #define HMAP_FOR_EACH_IN_BUCKET(NODE, MEMBER, HASH, HMAP) \
123 for (ASSIGN_CONTAINER(NODE, hmap_first_in_bucket(HMAP, HASH), MEMBER); \
124 NODE != OBJECT_CONTAINING(NULL, NODE, MEMBER); \
125 ASSIGN_CONTAINER(NODE, hmap_next_in_bucket(&(NODE)->MEMBER), MEMBER))
127 static inline struct hmap_node *hmap_first_with_hash(const struct hmap *,
129 static inline struct hmap_node *hmap_next_with_hash(const struct hmap_node *);
130 static inline struct hmap_node *hmap_first_in_bucket(const struct hmap *,
132 static inline struct hmap_node *hmap_next_in_bucket(const struct hmap_node *);
134 bool hmap_contains(const struct hmap *, const struct hmap_node *);
138 /* Iterates through every node in HMAP. */
139 #define HMAP_FOR_EACH(NODE, MEMBER, HMAP) \
140 for (ASSIGN_CONTAINER(NODE, hmap_first(HMAP), MEMBER); \
141 NODE != OBJECT_CONTAINING(NULL, NODE, MEMBER); \
142 ASSIGN_CONTAINER(NODE, hmap_next(HMAP, &(NODE)->MEMBER), MEMBER))
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). */
146 #define HMAP_FOR_EACH_SAFE(NODE, NEXT, MEMBER, HMAP) \
147 for (ASSIGN_CONTAINER(NODE, hmap_first(HMAP), MEMBER); \
148 (NODE != OBJECT_CONTAINING(NULL, NODE, MEMBER) \
149 ? ASSIGN_CONTAINER(NEXT, hmap_next(HMAP, &(NODE)->MEMBER), MEMBER), 1 \
153 /* Continues an iteration from just after NODE. */
154 #define HMAP_FOR_EACH_CONTINUE(NODE, MEMBER, HMAP) \
155 for (ASSIGN_CONTAINER(NODE, hmap_next(HMAP, &(NODE)->MEMBER), MEMBER); \
156 NODE != OBJECT_CONTAINING(NULL, NODE, MEMBER); \
157 ASSIGN_CONTAINER(NODE, hmap_next(HMAP, &(NODE)->MEMBER), MEMBER))
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 *);
163 struct hmap_node *hmap_at_position(const struct hmap *,
164 uint32_t *bucket, uint32_t *offset);
166 /* Returns the number of nodes currently in 'hmap'. */
168 hmap_count(const struct hmap *hmap)
173 /* Returns the maximum number of nodes that 'hmap' may hold before it should be
176 hmap_capacity(const struct hmap *hmap)
178 return hmap->mask * 2 + 1;
181 /* Returns true if 'hmap' currently contains no nodes,
182 * false otherwise. */
184 hmap_is_empty(const struct hmap *hmap)
189 /* Inserts 'node', with the given 'hash', into 'hmap'. 'hmap' is never
190 * expanded automatically. */
192 hmap_insert_fast(struct hmap *hmap, struct hmap_node *node, size_t hash)
194 struct hmap_node **bucket = &hmap->buckets[hash & hmap->mask];
196 node->next = *bucket;
201 /* Inserts 'node', with the given 'hash', into 'hmap', and expands 'hmap' if
202 * necessary to optimize search performance. */
204 hmap_insert(struct hmap *hmap, struct hmap_node *node, size_t hash)
206 hmap_insert_fast(hmap, node, hash);
207 if (hmap->n / 2 > hmap->mask) {
212 /* Removes 'node' from 'hmap'. Does not shrink the hash table; call
213 * hmap_shrink() directly if desired. */
215 hmap_remove(struct hmap *hmap, struct hmap_node *node)
217 struct hmap_node **bucket = &hmap->buckets[node->hash & hmap->mask];
218 while (*bucket != node) {
219 bucket = &(*bucket)->next;
221 *bucket = node->next;
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).
230 * Afterward, 'old_node' is not part of 'hmap', and the client is responsible
231 * for freeing it (if this is desirable). */
233 hmap_replace(struct hmap *hmap,
234 const struct hmap_node *old_node, struct hmap_node *new_node)
236 struct hmap_node **bucket = &hmap->buckets[old_node->hash & hmap->mask];
237 while (*bucket != old_node) {
238 bucket = &(*bucket)->next;
241 new_node->hash = old_node->hash;
242 new_node->next = old_node->next;
245 static inline struct hmap_node *
246 hmap_next_with_hash__(const struct hmap_node *node, size_t hash)
248 while (node != NULL && node->hash != hash) {
251 return CONST_CAST(struct hmap_node *, node);
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)
259 return hmap_next_with_hash__(hmap->buckets[hash & hmap->mask], hash);
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)
267 return hmap->buckets[hash & hmap->mask];
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.
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)
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.
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)
295 return hmap_next_with_hash__(node->next, node->hash);
298 static inline struct hmap_node *
299 hmap_next__(const struct hmap *hmap, size_t start)
302 for (i = start; i <= hmap->mask; i++) {
303 struct hmap_node *node = hmap->buckets[i];
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)
316 return hmap_next__(hmap, 0);
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'.
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)
331 : hmap_next__(hmap, (node->hash & hmap->mask) + 1));