/*
* Copyright (c) 2008, 2009 Nicira Networks.
*
- * Permission to use, copy, modify, and/or distribute this software for any
- * purpose with or without fee is hereby granted, provided that the above
- * copyright notice and this permission notice appear in all copies.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
*
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
*/
#ifndef HMAP_H
return node->hash;
}
+#define HMAP_NODE_NULL ((struct hmap_node *) 1)
+
+/* Returns true if 'node' has been set to null by hmap_node_nullify() and has
+ * not been un-nullified by being inserted into an hmap. */
+static inline bool
+hmap_node_is_null(const struct hmap_node *node)
+{
+ return node->next == HMAP_NODE_NULL;
+}
+
+/* Marks 'node' with a distinctive value that can be tested with
+ * hmap_node_is_null(). */
+static inline void
+hmap_node_nullify(struct hmap_node *node)
+{
+ node->next = HMAP_NODE_NULL;
+}
+
/* A hash map. */
struct hmap {
struct hmap_node **buckets;
static inline void hmap_replace(struct hmap *, const struct hmap_node *old,
struct hmap_node *new);
-/* Search. */
+/* Search.
+ *
+ * HMAP_FOR_EACH_WITH_HASH iterates NODE over all of the nodes in HMAP that
+ * have hash value equal to HASH. HMAP_FOR_EACH_IN_BUCKET iterates NODE over
+ * all of the nodes in HMAP that would fall in the same bucket as HASH. STRUCT
+ * and MEMBER must be the name of the struct that contains the 'struct
+ * hmap_node' and the name of the 'struct hmap_node' member, respectively.
+ *
+ * These macros may be used interchangeably to search for a particular value in
+ * an hmap, see, e.g. shash_find() for an example. Usually, using
+ * HMAP_FOR_EACH_WITH_HASH provides an optimization, because comparing a hash
+ * value is usually cheaper than comparing an entire hash map key. But for
+ * simple hash map keys, it makes sense to use HMAP_FOR_EACH_IN_BUCKET because
+ * it avoids doing two comparisons when a single simple comparison suffices.
+ *
+ * The loop should not change NODE to point to a different node or insert or
+ * delete nodes in HMAP (unless it "break"s out of the loop to terminate
+ * iteration).
+ *
+ * HASH is only evaluated once.
+ */
#define HMAP_FOR_EACH_WITH_HASH(NODE, STRUCT, MEMBER, HASH, HMAP) \
for ((NODE) = CONTAINER_OF(hmap_first_with_hash(HMAP, HASH), \
STRUCT, MEMBER); \
&(NODE)->MEMBER != NULL; \
(NODE) = CONTAINER_OF(hmap_next_with_hash(&(NODE)->MEMBER), \
STRUCT, MEMBER))
+#define HMAP_FOR_EACH_IN_BUCKET(NODE, STRUCT, MEMBER, HASH, HMAP) \
+ for ((NODE) = CONTAINER_OF(hmap_first_in_bucket(HMAP, HASH), \
+ STRUCT, MEMBER); \
+ &(NODE)->MEMBER != NULL; \
+ (NODE) = CONTAINER_OF(hmap_next_in_bucket(&(NODE)->MEMBER), \
+ STRUCT, MEMBER))
static inline struct hmap_node *hmap_first_with_hash(const struct hmap *,
size_t hash);
static inline struct hmap_node *hmap_next_with_hash(const struct hmap_node *);
+static inline struct hmap_node *hmap_first_in_bucket(const struct hmap *,
+ size_t hash);
+static inline struct hmap_node *hmap_next_in_bucket(const struct hmap_node *);
/* Iteration.
*
return hmap->n;
}
+/* Returns the maximum number of nodes that 'hmap' may hold before it should be
+ * rehashed. */
+static inline size_t
+hmap_capacity(const struct hmap *hmap)
+{
+ return hmap->mask * 2 + 1;
+}
+
/* Returns true if 'hmap' currently contains no nodes,
* false otherwise. */
static inline bool
}
*bucket = new;
new->hash = old->hash;
+ new->next = old->next;
}
static inline struct hmap_node *
return hmap_next_with_hash__(hmap->buckets[hash & hmap->mask], hash);
}
+/* Returns the first node in 'hmap' in the bucket in which the given 'hash'
+ * would land, or a null pointer if that bucket is empty. */
+static inline struct hmap_node *
+hmap_first_in_bucket(const struct hmap *hmap, size_t hash)
+{
+ return hmap->buckets[hash & hmap->mask];
+}
+
+/* Returns the next node in the same bucket as 'node', or a null pointer if
+ * there are no more nodes in that bucket.
+ *
+ * If the hash map has been reallocated since 'node' was visited, some nodes
+ * may be skipped; if new nodes with the same hash value have been added, they
+ * will be skipped. (Removing 'node' from the hash map does not prevent
+ * calling this function, since node->next is preserved, although freeing
+ * 'node' of course does.) */
+static inline struct hmap_node *
+hmap_next_in_bucket(const struct hmap_node *node)
+{
+ return node->next;
+}
+
/* Returns the next node in the same hash map as 'node' with the same hash
* value, or a null pointer if no more nodes have that hash value.
*
projects / openvswitch / blobdiff