Mikio Hara
236 lines
8.3 KiB
C
236 lines
8.3 KiB
C
/* Copyright (c) 2008, 2009 The Board of Trustees of The Leland Stanford
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* Junior University
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*
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* We are making the OpenFlow specification and associated documentation
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* (Software) available for public use and benefit with the expectation
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* that others will use, modify and enhance the Software and contribute
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* those enhancements back to the community. However, since we would
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* like to make the Software available for broadest use, with as few
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* restrictions as possible permission is hereby granted, free of
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* charge, to any person obtaining a copy of this Software to deal in
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* the Software under the copyrights without restriction, including
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* without limitation the rights to use, copy, modify, merge, publish,
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* distribute, sublicense, and/or sell copies of the Software, and to
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* permit persons to whom the Software is furnished to do so, subject to
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* the following conditions:
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*
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* The above copyright notice and this permission notice shall be
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* included in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
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* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
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* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*
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* The name and trademarks of copyright holder(s) may NOT be used in
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* advertising or publicity pertaining to the Software or any
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* derivatives without specific, written prior permission.
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*/
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#ifndef HMAP_H
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#define HMAP_H 1
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#include <stdbool.h>
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#include <stdlib.h>
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#include "util.h"
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/* A hash map node, to be embedded inside the data structure being mapped. */
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struct hmap_node {
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size_t hash; /* Hash value. */
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struct hmap_node *next; /* Next in linked list. */
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};
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/* Returns the hash value embedded in 'node'. */
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static inline size_t hmap_node_hash(const struct hmap_node *node)
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{
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return node->hash;
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}
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/* A hash map. */
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struct hmap {
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struct hmap_node **buckets;
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struct hmap_node *one;
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size_t mask;
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size_t n;
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};
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/* Initializer for an empty hash map. */
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#define HMAP_INITIALIZER(HMAP) { &(HMAP)->one, NULL, 0, 0 }
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/* Initialization. */
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void hmap_init(struct hmap *);
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void hmap_destroy(struct hmap *);
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void hmap_swap(struct hmap *a, struct hmap *b);
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static inline size_t hmap_count(const struct hmap *);
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static inline bool hmap_is_empty(const struct hmap *);
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/* Adjusting capacity. */
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void hmap_expand(struct hmap *);
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void hmap_shrink(struct hmap *);
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void hmap_reserve(struct hmap *, size_t capacity);
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/* Insertion and deletion. */
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static inline void hmap_insert_fast(struct hmap *,
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struct hmap_node *, size_t hash);
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static inline void hmap_insert(struct hmap *, struct hmap_node *, size_t hash);
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static inline void hmap_remove(struct hmap *, struct hmap_node *);
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/* Search. */
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#define HMAP_FOR_EACH_WITH_HASH(NODE, STRUCT, MEMBER, HASH, HMAP) \
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for ((NODE) = CONTAINER_OF(hmap_first_with_hash(HMAP, HASH), \
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STRUCT, MEMBER); \
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&(NODE)->MEMBER != NULL; \
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(NODE) = CONTAINER_OF(hmap_next_with_hash(&(NODE)->MEMBER), \
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STRUCT, MEMBER))
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static inline struct hmap_node *hmap_first_with_hash(const struct hmap *,
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size_t hash);
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static inline struct hmap_node *hmap_next_with_hash(const struct hmap_node *);
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/* Iteration.
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*
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* The _SAFE version is needed when NODE may be freed. It is not needed when
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* NODE may be removed from the hash map but its members remain accessible and
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* intact. */
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#define HMAP_FOR_EACH(NODE, STRUCT, MEMBER, HMAP) \
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for ((NODE) = CONTAINER_OF(hmap_first(HMAP), STRUCT, MEMBER); \
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&(NODE)->MEMBER != NULL; \
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(NODE) = CONTAINER_OF(hmap_next(HMAP, &(NODE)->MEMBER), \
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STRUCT, MEMBER))
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#define HMAP_FOR_EACH_SAFE(NODE, NEXT, STRUCT, MEMBER, HMAP) \
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for ((NODE) = CONTAINER_OF(hmap_first(HMAP), STRUCT, MEMBER); \
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(&(NODE)->MEMBER != NULL \
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? (NEXT) = CONTAINER_OF(hmap_next(HMAP, &(NODE)->MEMBER), \
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STRUCT, MEMBER), 1 \
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: 0); \
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(NODE) = (NEXT))
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static inline struct hmap_node *hmap_first(const struct hmap *);
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static inline struct hmap_node *hmap_next(const struct hmap *,
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const struct hmap_node *);
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/* Returns the number of nodes currently in 'hmap'. */
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static inline size_t
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hmap_count(const struct hmap *hmap)
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{
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return hmap->n;
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}
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/* Returns true if 'hmap' currently contains no nodes,
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* false otherwise. */
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static inline bool
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hmap_is_empty(const struct hmap *hmap)
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{
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return hmap->n == 0;
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}
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/* Inserts 'node', with the given 'hash', into 'hmap'. 'hmap' is never
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* expanded automatically. */
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static inline void
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hmap_insert_fast(struct hmap *hmap, struct hmap_node *node, size_t hash)
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{
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struct hmap_node **bucket = &hmap->buckets[hash & hmap->mask];
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node->hash = hash;
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node->next = *bucket;
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*bucket = node;
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hmap->n++;
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}
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/* Inserts 'node', with the given 'hash', into 'hmap', and expands 'hmap' if
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* necessary to optimize search performance. */
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static inline void
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hmap_insert(struct hmap *hmap, struct hmap_node *node, size_t hash)
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{
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hmap_insert_fast(hmap, node, hash);
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if (hmap->n / 2 > hmap->mask) {
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hmap_expand(hmap);
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}
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}
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/* Removes 'node' from 'hmap'. Does not shrink the hash table; call
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* hmap_shrink() directly if desired. */
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static inline void
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hmap_remove(struct hmap *hmap, struct hmap_node *node)
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{
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struct hmap_node **bucket = &hmap->buckets[node->hash & hmap->mask];
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while (*bucket != node) {
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bucket = &(*bucket)->next;
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}
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*bucket = node->next;
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hmap->n--;
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}
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static inline struct hmap_node *
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hmap_next_with_hash__(const struct hmap_node *node, size_t hash)
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{
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while (node != NULL && node->hash != hash) {
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node = node->next;
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}
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return (struct hmap_node *) node;
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}
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/* Returns the first node in 'hmap' with the given 'hash', or a null pointer if
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* no nodes have that hash value. */
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static inline struct hmap_node *
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hmap_first_with_hash(const struct hmap *hmap, size_t hash)
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{
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return hmap_next_with_hash__(hmap->buckets[hash & hmap->mask], hash);
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}
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/* Returns the next node in the same hash map as 'node' with the same hash
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* value, or a null pointer if no more nodes have that hash value.
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*
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* If the hash map has been reallocated since 'node' was visited, some nodes
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* may be skipped; if new nodes with the same hash value have been added, they
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* will be skipped. (Removing 'node' from the hash map does not prevent
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* calling this function, since node->next is preserved, although freeing
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* 'node' of course does.) */
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static inline struct hmap_node *
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hmap_next_with_hash(const struct hmap_node *node)
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{
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return hmap_next_with_hash__(node->next, node->hash);
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}
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static inline struct hmap_node *
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hmap_next__(const struct hmap *hmap, size_t start)
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{
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size_t i;
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for (i = start; i <= hmap->mask; i++) {
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struct hmap_node *node = hmap->buckets[i];
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if (node) {
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return node;
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}
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}
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return NULL;
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}
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/* Returns the first node in 'hmap', in arbitrary order, or a null pointer if
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* 'hmap' is empty. */
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static inline struct hmap_node *
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hmap_first(const struct hmap *hmap)
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{
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return hmap_next__(hmap, 0);
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}
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/* Returns the next node in 'hmap' following 'node', in arbitrary order, or a
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* null pointer if 'node' is the last node in 'hmap'.
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*
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* If the hash map has been reallocated since 'node' was visited, some nodes
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* may be skipped or visited twice. (Removing 'node' from the hash map does
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* not prevent calling this function, since node->next is preserved, although
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* freeing 'node' of course does.) */
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static inline struct hmap_node *
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hmap_next(const struct hmap *hmap, const struct hmap_node *node)
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{
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return (node->next
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? node->next
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: hmap_next__(hmap, (node->hash & hmap->mask) + 1));
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}
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#endif /* hmap.h */
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