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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) { &(HMAP)->one, NULL, 0, 0 }
71 void hmap_init(struct hmap
*);
72 void hmap_destroy(struct hmap
*);
73 void hmap_clear(struct hmap
*);
74 void hmap_swap(struct hmap
*a
, struct hmap
*b
);
75 void hmap_moved(struct hmap
*hmap
);
76 static inline size_t hmap_count(const struct hmap
*);
77 static inline bool hmap_is_empty(const struct hmap
*);
79 /* Adjusting capacity. */
80 void hmap_expand(struct hmap
*);
81 void hmap_shrink(struct hmap
*);
82 void hmap_reserve(struct hmap
*, size_t capacity
);
84 /* Insertion and deletion. */
85 static inline void hmap_insert_fast(struct hmap
*,
86 struct hmap_node
*, size_t hash
);
87 static inline void hmap_insert(struct hmap
*, struct hmap_node
*, size_t hash
);
88 static inline void hmap_remove(struct hmap
*, struct hmap_node
*);
90 void hmap_node_moved(struct hmap
*, struct hmap_node
*, struct hmap_node
*);
91 static inline void hmap_replace(struct hmap
*, const struct hmap_node
*old
,
92 struct hmap_node
*new_node
);
94 struct hmap_node
*hmap_random_node(const struct hmap
*);
98 * HMAP_FOR_EACH_WITH_HASH iterates NODE over all of the nodes in HMAP that
99 * have hash value equal to HASH. HMAP_FOR_EACH_IN_BUCKET iterates NODE over
100 * all of the nodes in HMAP that would fall in the same bucket as HASH. MEMBER
101 * must be the name of the 'struct hmap_node' member within NODE.
103 * These macros may be used interchangeably to search for a particular value in
104 * an hmap, see, e.g. shash_find() for an example. Usually, using
105 * HMAP_FOR_EACH_WITH_HASH provides an optimization, because comparing a hash
106 * value is usually cheaper than comparing an entire hash map key. But for
107 * simple hash map keys, it makes sense to use HMAP_FOR_EACH_IN_BUCKET because
108 * it avoids doing two comparisons when a single simple comparison suffices.
110 * The loop should not change NODE to point to a different node or insert or
111 * delete nodes in HMAP (unless it "break"s out of the loop to terminate
114 * HASH is only evaluated once.
116 #define HMAP_FOR_EACH_WITH_HASH(NODE, MEMBER, HASH, HMAP) \
117 for (ASSIGN_CONTAINER(NODE, hmap_first_with_hash(HMAP, HASH), MEMBER); \
118 &(NODE)->MEMBER != NULL; \
119 ASSIGN_CONTAINER(NODE, hmap_next_with_hash(&(NODE)->MEMBER), \
121 #define HMAP_FOR_EACH_IN_BUCKET(NODE, MEMBER, HASH, HMAP) \
122 for (ASSIGN_CONTAINER(NODE, hmap_first_in_bucket(HMAP, HASH), MEMBER); \
123 &(NODE)->MEMBER != NULL; \
124 ASSIGN_CONTAINER(NODE, hmap_next_in_bucket(&(NODE)->MEMBER), MEMBER))
126 static inline struct hmap_node
*hmap_first_with_hash(const struct hmap
*,
128 static inline struct hmap_node
*hmap_next_with_hash(const struct hmap_node
*);
129 static inline struct hmap_node
*hmap_first_in_bucket(const struct hmap
*,
131 static inline struct hmap_node
*hmap_next_in_bucket(const struct hmap_node
*);
133 bool hmap_contains(const struct hmap
*, const struct hmap_node
*);
137 /* Iterates through every node in HMAP. */
138 #define HMAP_FOR_EACH(NODE, MEMBER, HMAP) \
139 for (ASSIGN_CONTAINER(NODE, hmap_first(HMAP), MEMBER); \
140 &(NODE)->MEMBER != NULL; \
141 ASSIGN_CONTAINER(NODE, hmap_next(HMAP, &(NODE)->MEMBER), MEMBER))
143 /* Safe when NODE may be freed (not needed when NODE may be removed from the
144 * hash map but its members remain accessible and intact). */
145 #define HMAP_FOR_EACH_SAFE(NODE, NEXT, MEMBER, HMAP) \
146 for (ASSIGN_CONTAINER(NODE, hmap_first(HMAP), MEMBER); \
147 (&(NODE)->MEMBER != NULL \
148 ? ASSIGN_CONTAINER(NEXT, hmap_next(HMAP, &(NODE)->MEMBER), MEMBER) \
152 /* Continues an iteration from just after NODE. */
153 #define HMAP_FOR_EACH_CONTINUE(NODE, MEMBER, HMAP) \
154 for (ASSIGN_CONTAINER(NODE, hmap_next(HMAP, &(NODE)->MEMBER), MEMBER); \
155 &(NODE)->MEMBER != NULL; \
156 ASSIGN_CONTAINER(NODE, hmap_next(HMAP, &(NODE)->MEMBER), MEMBER))
158 static inline struct hmap_node
*hmap_first(const struct hmap
*);
159 static inline struct hmap_node
*hmap_next(const struct hmap
*,
160 const struct hmap_node
*);
162 struct hmap_node
*hmap_at_position(const struct hmap
*,
163 uint32_t *bucket
, uint32_t *offset
);
165 /* Returns the number of nodes currently in 'hmap'. */
167 hmap_count(const struct hmap
*hmap
)
172 /* Returns the maximum number of nodes that 'hmap' may hold before it should be
175 hmap_capacity(const struct hmap
*hmap
)
177 return hmap
->mask
* 2 + 1;
180 /* Returns true if 'hmap' currently contains no nodes,
181 * false otherwise. */
183 hmap_is_empty(const struct hmap
*hmap
)
188 /* Inserts 'node', with the given 'hash', into 'hmap'. 'hmap' is never
189 * expanded automatically. */
191 hmap_insert_fast(struct hmap
*hmap
, struct hmap_node
*node
, size_t hash
)
193 struct hmap_node
**bucket
= &hmap
->buckets
[hash
& hmap
->mask
];
195 node
->next
= *bucket
;
200 /* Inserts 'node', with the given 'hash', into 'hmap', and expands 'hmap' if
201 * necessary to optimize search performance. */
203 hmap_insert(struct hmap
*hmap
, struct hmap_node
*node
, size_t hash
)
205 hmap_insert_fast(hmap
, node
, hash
);
206 if (hmap
->n
/ 2 > hmap
->mask
) {
211 /* Removes 'node' from 'hmap'. Does not shrink the hash table; call
212 * hmap_shrink() directly if desired. */
214 hmap_remove(struct hmap
*hmap
, struct hmap_node
*node
)
216 struct hmap_node
**bucket
= &hmap
->buckets
[node
->hash
& hmap
->mask
];
217 while (*bucket
!= node
) {
218 bucket
= &(*bucket
)->next
;
220 *bucket
= node
->next
;
224 /* Puts 'new_node' in the position in 'hmap' currently occupied by 'old_node'.
225 * The 'new_node' must hash to the same value as 'old_node'. The client is
226 * responsible for ensuring that the replacement does not violate any
227 * client-imposed invariants (e.g. uniqueness of keys within a map).
229 * Afterward, 'old_node' is not part of 'hmap', and the client is responsible
230 * for freeing it (if this is desirable). */
232 hmap_replace(struct hmap
*hmap
,
233 const struct hmap_node
*old_node
, struct hmap_node
*new_node
)
235 struct hmap_node
**bucket
= &hmap
->buckets
[old_node
->hash
& hmap
->mask
];
236 while (*bucket
!= old_node
) {
237 bucket
= &(*bucket
)->next
;
240 new_node
->hash
= old_node
->hash
;
241 new_node
->next
= old_node
->next
;
244 static inline struct hmap_node
*
245 hmap_next_with_hash__(const struct hmap_node
*node
, size_t hash
)
247 while (node
!= NULL
&& node
->hash
!= hash
) {
250 return (struct hmap_node
*) node
;
253 /* Returns the first node in 'hmap' with the given 'hash', or a null pointer if
254 * no nodes have that hash value. */
255 static inline struct hmap_node
*
256 hmap_first_with_hash(const struct hmap
*hmap
, size_t hash
)
258 return hmap_next_with_hash__(hmap
->buckets
[hash
& hmap
->mask
], hash
);
261 /* Returns the first node in 'hmap' in the bucket in which the given 'hash'
262 * would land, or a null pointer if that bucket is empty. */
263 static inline struct hmap_node
*
264 hmap_first_in_bucket(const struct hmap
*hmap
, size_t hash
)
266 return hmap
->buckets
[hash
& hmap
->mask
];
269 /* Returns the next node in the same bucket as 'node', or a null pointer if
270 * there are no more nodes in that bucket.
272 * If the hash map has been reallocated since 'node' was visited, some nodes
273 * may be skipped; if new nodes with the same hash value have been added, they
274 * will be skipped. (Removing 'node' from the hash map does not prevent
275 * calling this function, since node->next is preserved, although freeing
276 * 'node' of course does.) */
277 static inline struct hmap_node
*
278 hmap_next_in_bucket(const struct hmap_node
*node
)
283 /* Returns the next node in the same hash map as 'node' with the same hash
284 * value, or a null pointer if no more nodes have that hash value.
286 * If the hash map has been reallocated since 'node' was visited, some nodes
287 * may be skipped; if new nodes with the same hash value have been added, they
288 * will be skipped. (Removing 'node' from the hash map does not prevent
289 * calling this function, since node->next is preserved, although freeing
290 * 'node' of course does.) */
291 static inline struct hmap_node
*
292 hmap_next_with_hash(const struct hmap_node
*node
)
294 return hmap_next_with_hash__(node
->next
, node
->hash
);
297 static inline struct hmap_node
*
298 hmap_next__(const struct hmap
*hmap
, size_t start
)
301 for (i
= start
; i
<= hmap
->mask
; i
++) {
302 struct hmap_node
*node
= hmap
->buckets
[i
];
310 /* Returns the first node in 'hmap', in arbitrary order, or a null pointer if
311 * 'hmap' is empty. */
312 static inline struct hmap_node
*
313 hmap_first(const struct hmap
*hmap
)
315 return hmap_next__(hmap
, 0);
318 /* Returns the next node in 'hmap' following 'node', in arbitrary order, or a
319 * null pointer if 'node' is the last node in 'hmap'.
321 * If the hash map has been reallocated since 'node' was visited, some nodes
322 * may be skipped or visited twice. (Removing 'node' from the hash map does
323 * not prevent calling this function, since node->next is preserved, although
324 * freeing 'node' of course does.) */
325 static inline struct hmap_node
*
326 hmap_next(const struct hmap
*hmap
, const struct hmap_node
*node
)
330 : hmap_next__(hmap
, (node
->hash
& hmap
->mask
) + 1));