1 /* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
4 * Generic non-thread safe hash map implementation.
6 * Copyright (c) 2019 Facebook
8 #ifndef __LIBBPF_HASHMAP_H
9 #define __LIBBPF_HASHMAP_H
15 static inline size_t hash_bits(size_t h, int bits)
17 /* shuffle bits and return requested number of upper bits */
18 #if (__SIZEOF_SIZE_T__ == __SIZEOF_LONG_LONG__)
20 return (h * 11400714819323198485llu) >> (__SIZEOF_LONG_LONG__ * 8 - bits);
21 #elif (__SIZEOF_SIZE_T__ <= __SIZEOF_LONG__)
22 return (h * 2654435769lu) >> (__SIZEOF_LONG__ * 8 - bits);
24 # error "Unsupported size_t size"
28 /* generic C-string hashing function */
29 static inline size_t str_hash(const char *s)
40 typedef size_t (*hashmap_hash_fn)(const void *key, void *ctx);
41 typedef bool (*hashmap_equal_fn)(const void *key1, const void *key2, void *ctx);
43 struct hashmap_entry {
46 struct hashmap_entry *next;
50 hashmap_hash_fn hash_fn;
51 hashmap_equal_fn equal_fn;
54 struct hashmap_entry **buckets;
60 #define HASHMAP_INIT(hash_fn, equal_fn, ctx) { \
61 .hash_fn = (hash_fn), \
62 .equal_fn = (equal_fn), \
70 void hashmap__init(struct hashmap *map, hashmap_hash_fn hash_fn,
71 hashmap_equal_fn equal_fn, void *ctx);
72 struct hashmap *hashmap__new(hashmap_hash_fn hash_fn,
73 hashmap_equal_fn equal_fn,
75 void hashmap__clear(struct hashmap *map);
76 void hashmap__free(struct hashmap *map);
78 size_t hashmap__size(const struct hashmap *map);
79 size_t hashmap__capacity(const struct hashmap *map);
82 * Hashmap insertion strategy:
83 * - HASHMAP_ADD - only add key/value if key doesn't exist yet;
84 * - HASHMAP_SET - add key/value pair if key doesn't exist yet; otherwise,
86 * - HASHMAP_UPDATE - update value, if key already exists; otherwise, do
87 * nothing and return -ENOENT;
88 * - HASHMAP_APPEND - always add key/value pair, even if key already exists.
89 * This turns hashmap into a multimap by allowing multiple values to be
90 * associated with the same key. Most useful read API for such hashmap is
91 * hashmap__for_each_key_entry() iteration. If hashmap__find() is still
92 * used, it will return last inserted key/value entry (first in a bucket
95 enum hashmap_insert_strategy {
103 * hashmap__insert() adds key/value entry w/ various semantics, depending on
104 * provided strategy value. If a given key/value pair replaced already
105 * existing key/value pair, both old key and old value will be returned
106 * through old_key and old_value to allow calling code do proper memory
109 int hashmap__insert(struct hashmap *map, const void *key, void *value,
110 enum hashmap_insert_strategy strategy,
111 const void **old_key, void **old_value);
113 static inline int hashmap__add(struct hashmap *map,
114 const void *key, void *value)
116 return hashmap__insert(map, key, value, HASHMAP_ADD, NULL, NULL);
119 static inline int hashmap__set(struct hashmap *map,
120 const void *key, void *value,
121 const void **old_key, void **old_value)
123 return hashmap__insert(map, key, value, HASHMAP_SET,
127 static inline int hashmap__update(struct hashmap *map,
128 const void *key, void *value,
129 const void **old_key, void **old_value)
131 return hashmap__insert(map, key, value, HASHMAP_UPDATE,
135 static inline int hashmap__append(struct hashmap *map,
136 const void *key, void *value)
138 return hashmap__insert(map, key, value, HASHMAP_APPEND, NULL, NULL);
141 bool hashmap__delete(struct hashmap *map, const void *key,
142 const void **old_key, void **old_value);
144 bool hashmap__find(const struct hashmap *map, const void *key, void **value);
147 * hashmap__for_each_entry - iterate over all entries in hashmap
148 * @map: hashmap to iterate
149 * @cur: struct hashmap_entry * used as a loop cursor
150 * @bkt: integer used as a bucket loop cursor
152 #define hashmap__for_each_entry(map, cur, bkt) \
153 for (bkt = 0; bkt < map->cap; bkt++) \
154 for (cur = map->buckets[bkt]; cur; cur = cur->next)
157 * hashmap__for_each_entry_safe - iterate over all entries in hashmap, safe
159 * @map: hashmap to iterate
160 * @cur: struct hashmap_entry * used as a loop cursor
161 * @tmp: struct hashmap_entry * used as a temporary next cursor storage
162 * @bkt: integer used as a bucket loop cursor
164 #define hashmap__for_each_entry_safe(map, cur, tmp, bkt) \
165 for (bkt = 0; bkt < map->cap; bkt++) \
166 for (cur = map->buckets[bkt]; \
167 cur && ({tmp = cur->next; true; }); \
171 * hashmap__for_each_key_entry - iterate over entries associated with given key
172 * @map: hashmap to iterate
173 * @cur: struct hashmap_entry * used as a loop cursor
174 * @key: key to iterate entries for
176 #define hashmap__for_each_key_entry(map, cur, _key) \
177 for (cur = ({ size_t bkt = hash_bits(map->hash_fn((_key), map->ctx),\
179 map->buckets ? map->buckets[bkt] : NULL; }); \
182 if (map->equal_fn(cur->key, (_key), map->ctx))
184 #define hashmap__for_each_key_entry_safe(map, cur, tmp, _key) \
185 for (cur = ({ size_t bkt = hash_bits(map->hash_fn((_key), map->ctx),\
187 cur = map->buckets ? map->buckets[bkt] : NULL; }); \
188 cur && ({ tmp = cur->next; true; }); \
190 if (map->equal_fn(cur->key, (_key), map->ctx))
192 #endif /* __LIBBPF_HASHMAP_H */