/* * Copyright (c) 2008, 2009, 2010, 2012, 2013 Nicira, Inc. * * 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: * * 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 #define HMAP_H 1 #include #include #include "ovs-atomic.h" #include "util.h" #ifdef __cplusplus extern "C" { #endif /* A hash map node, to be embedded inside the data structure being mapped. */ struct hmap_node { size_t hash; /* Hash value. */ struct hmap_node *next; /* Next in linked list. */ }; /* Returns the hash value embedded in 'node'. */ static inline size_t hmap_node_hash(const struct hmap_node *node) { return node->hash; } #define HMAP_NODE_NULL ((struct hmap_node *) 1) #define HMAP_NODE_NULL_INITIALIZER { 0, HMAP_NODE_NULL } /* 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; /* Must point to 'one' iff 'mask' == 0. */ struct hmap_node *one; size_t mask; size_t n; }; /* Initializer for an empty hash map. */ #define HMAP_INITIALIZER(HMAP) \ { (struct hmap_node **const) &(HMAP)->one, NULL, 0, 0 } /* Initialization. */ void hmap_init(struct hmap *); void hmap_destroy(struct hmap *); void hmap_clear(struct hmap *); void hmap_swap(struct hmap *a, struct hmap *b); void hmap_moved(struct hmap *hmap); static inline size_t hmap_count(const struct hmap *); static inline bool hmap_is_empty(const struct hmap *); /* Adjusting capacity. */ void hmap_expand_at(struct hmap *, const char *where); #define hmap_expand(HMAP) hmap_expand_at(HMAP, SOURCE_LOCATOR) void hmap_shrink_at(struct hmap *, const char *where); #define hmap_shrink(HMAP) hmap_shrink_at(HMAP, SOURCE_LOCATOR) void hmap_reserve_at(struct hmap *, size_t capacity, const char *where); #define hmap_reserve(HMAP, CAPACITY) \ hmap_reserve_at(HMAP, CAPACITY, SOURCE_LOCATOR) /* Insertion and deletion. */ static inline void hmap_insert_at(struct hmap *, struct hmap_node *, size_t hash, const char *where); #define hmap_insert(HMAP, NODE, HASH) \ hmap_insert_at(HMAP, NODE, HASH, SOURCE_LOCATOR) static inline void hmap_insert_fast(struct hmap *, struct hmap_node *, size_t hash); static inline void hmap_remove(struct hmap *, struct hmap_node *); void hmap_node_moved(struct hmap *, struct hmap_node *, struct hmap_node *); static inline void hmap_replace(struct hmap *, const struct hmap_node *old, struct hmap_node *new_node); struct hmap_node *hmap_random_node(const struct hmap *); /* 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. MEMBER * must be the name of the 'struct hmap_node' member within NODE. * * 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, MEMBER, HASH, HMAP) \ for (ASSIGN_CONTAINER(NODE, hmap_first_with_hash(HMAP, HASH), MEMBER); \ NODE != OBJECT_CONTAINING(NULL, NODE, MEMBER); \ ASSIGN_CONTAINER(NODE, hmap_next_with_hash(&(NODE)->MEMBER), \ MEMBER)) #define HMAP_FOR_EACH_IN_BUCKET(NODE, MEMBER, HASH, HMAP) \ for (ASSIGN_CONTAINER(NODE, hmap_first_in_bucket(HMAP, HASH), MEMBER); \ NODE != OBJECT_CONTAINING(NULL, NODE, MEMBER); \ ASSIGN_CONTAINER(NODE, hmap_next_in_bucket(&(NODE)->MEMBER), 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 *); bool hmap_contains(const struct hmap *, const struct hmap_node *); /* Iteration. */ /* Iterates through every node in HMAP. */ #define HMAP_FOR_EACH(NODE, MEMBER, HMAP) \ for (ASSIGN_CONTAINER(NODE, hmap_first(HMAP), MEMBER); \ NODE != OBJECT_CONTAINING(NULL, NODE, MEMBER); \ ASSIGN_CONTAINER(NODE, hmap_next(HMAP, &(NODE)->MEMBER), MEMBER)) /* Safe when NODE may be freed (not needed when NODE may be removed from the * hash map but its members remain accessible and intact). */ #define HMAP_FOR_EACH_SAFE(NODE, NEXT, MEMBER, HMAP) \ for (ASSIGN_CONTAINER(NODE, hmap_first(HMAP), MEMBER); \ (NODE != OBJECT_CONTAINING(NULL, NODE, MEMBER) \ ? ASSIGN_CONTAINER(NEXT, hmap_next(HMAP, &(NODE)->MEMBER), MEMBER), 1 \ : 0); \ (NODE) = (NEXT)) /* Continues an iteration from just after NODE. */ #define HMAP_FOR_EACH_CONTINUE(NODE, MEMBER, HMAP) \ for (ASSIGN_CONTAINER(NODE, hmap_next(HMAP, &(NODE)->MEMBER), MEMBER); \ NODE != OBJECT_CONTAINING(NULL, NODE, MEMBER); \ ASSIGN_CONTAINER(NODE, hmap_next(HMAP, &(NODE)->MEMBER), MEMBER)) static inline struct hmap_node *hmap_first(const struct hmap *); static inline struct hmap_node *hmap_next(const struct hmap *, const struct hmap_node *); struct hmap_node *hmap_at_position(const struct hmap *, uint32_t *bucket, uint32_t *offset); /* Returns the number of nodes currently in 'hmap'. */ static inline size_t hmap_count(const struct hmap *hmap) { 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. * Note: While hmap in general is not thread-safe without additional locking, * hmap_is_empty() is. */ static inline bool hmap_is_empty(const struct hmap *hmap) { return hmap->n == 0; } /* Inserts 'node', with the given 'hash', into 'hmap'. 'hmap' is never * expanded automatically. */ static inline void hmap_insert_fast(struct hmap *hmap, struct hmap_node *node, size_t hash) { struct hmap_node **bucket = &hmap->buckets[hash & hmap->mask]; node->hash = hash; node->next = *bucket; *bucket = node; hmap->n++; } /* Inserts 'node', with the given 'hash', into 'hmap', and expands 'hmap' if * necessary to optimize search performance. * * ('where' is used in debug logging. Commonly one would use hmap_insert() to * automatically provide the caller's source file and line number for * 'where'.) */ static inline void hmap_insert_at(struct hmap *hmap, struct hmap_node *node, size_t hash, const char *where) { hmap_insert_fast(hmap, node, hash); if (hmap->n / 2 > hmap->mask) { hmap_expand_at(hmap, where); } } /* Removes 'node' from 'hmap'. Does not shrink the hash table; call * hmap_shrink() directly if desired. */ static inline void hmap_remove(struct hmap *hmap, struct hmap_node *node) { struct hmap_node **bucket = &hmap->buckets[node->hash & hmap->mask]; while (*bucket != node) { bucket = &(*bucket)->next; } *bucket = node->next; hmap->n--; } /* Puts 'new_node' in the position in 'hmap' currently occupied by 'old_node'. * The 'new_node' must hash to the same value as 'old_node'. The client is * responsible for ensuring that the replacement does not violate any * client-imposed invariants (e.g. uniqueness of keys within a map). * * Afterward, 'old_node' is not part of 'hmap', and the client is responsible * for freeing it (if this is desirable). */ static inline void hmap_replace(struct hmap *hmap, const struct hmap_node *old_node, struct hmap_node *new_node) { struct hmap_node **bucket = &hmap->buckets[old_node->hash & hmap->mask]; while (*bucket != old_node) { bucket = &(*bucket)->next; } *bucket = new_node; new_node->hash = old_node->hash; new_node->next = old_node->next; } static inline struct hmap_node * hmap_next_with_hash__(const struct hmap_node *node, size_t hash) { while (node != NULL && node->hash != hash) { node = node->next; } return CONST_CAST(struct hmap_node *, node); } /* Returns the first node in 'hmap' with the given 'hash', or a null pointer if * no nodes have that hash value. */ static inline struct hmap_node * hmap_first_with_hash(const struct hmap *hmap, size_t hash) { 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. * * 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_with_hash(const struct hmap_node *node) { return hmap_next_with_hash__(node->next, node->hash); } static inline struct hmap_node * hmap_next__(const struct hmap *hmap, size_t start) { size_t i; for (i = start; i <= hmap->mask; i++) { struct hmap_node *node = hmap->buckets[i]; if (node) { return node; } } return NULL; } /* Returns the first node in 'hmap', in arbitrary order, or a null pointer if * 'hmap' is empty. */ static inline struct hmap_node * hmap_first(const struct hmap *hmap) { return hmap_next__(hmap, 0); } /* Returns the next node in 'hmap' following 'node', in arbitrary order, or a * null pointer if 'node' is the last node in 'hmap'. * * If the hash map has been reallocated since 'node' was visited, some nodes * may be skipped or visited twice. (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(const struct hmap *hmap, const struct hmap_node *node) { return (node->next ? node->next : hmap_next__(hmap, (node->hash & hmap->mask) + 1)); } #ifdef __cplusplus } #endif #endif /* hmap.h */