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
14 #include <bits/wordsize.h>
19 static inline size_t hash_bits(size_t h, int bits)
21 /* shuffle bits and return requested number of upper bits */
22 return (h * 11400714819323198485llu) >> (__WORDSIZE - bits);
25 typedef size_t (*hashmap_hash_fn)(const void *key, void *ctx);
26 typedef bool (*hashmap_equal_fn)(const void *key1, const void *key2, void *ctx);
28 struct hashmap_entry {
31 struct hashmap_entry *next;
35 hashmap_hash_fn hash_fn;
36 hashmap_equal_fn equal_fn;
39 struct hashmap_entry **buckets;
45 #define HASHMAP_INIT(hash_fn, equal_fn, ctx) { \
46 .hash_fn = (hash_fn), \
47 .equal_fn = (equal_fn), \
55 void hashmap__init(struct hashmap *map, hashmap_hash_fn hash_fn,
56 hashmap_equal_fn equal_fn, void *ctx);
57 struct hashmap *hashmap__new(hashmap_hash_fn hash_fn,
58 hashmap_equal_fn equal_fn,
60 void hashmap__clear(struct hashmap *map);
61 void hashmap__free(struct hashmap *map);
63 size_t hashmap__size(const struct hashmap *map);
64 size_t hashmap__capacity(const struct hashmap *map);
67 * Hashmap insertion strategy:
68 * - HASHMAP_ADD - only add key/value if key doesn't exist yet;
69 * - HASHMAP_SET - add key/value pair if key doesn't exist yet; otherwise,
71 * - HASHMAP_UPDATE - update value, if key already exists; otherwise, do
72 * nothing and return -ENOENT;
73 * - HASHMAP_APPEND - always add key/value pair, even if key already exists.
74 * This turns hashmap into a multimap by allowing multiple values to be
75 * associated with the same key. Most useful read API for such hashmap is
76 * hashmap__for_each_key_entry() iteration. If hashmap__find() is still
77 * used, it will return last inserted key/value entry (first in a bucket
80 enum hashmap_insert_strategy {
88 * hashmap__insert() adds key/value entry w/ various semantics, depending on
89 * provided strategy value. If a given key/value pair replaced already
90 * existing key/value pair, both old key and old value will be returned
91 * through old_key and old_value to allow calling code do proper memory
94 int hashmap__insert(struct hashmap *map, const void *key, void *value,
95 enum hashmap_insert_strategy strategy,
96 const void **old_key, void **old_value);
98 static inline int hashmap__add(struct hashmap *map,
99 const void *key, void *value)
101 return hashmap__insert(map, key, value, HASHMAP_ADD, NULL, NULL);
104 static inline int hashmap__set(struct hashmap *map,
105 const void *key, void *value,
106 const void **old_key, void **old_value)
108 return hashmap__insert(map, key, value, HASHMAP_SET,
112 static inline int hashmap__update(struct hashmap *map,
113 const void *key, void *value,
114 const void **old_key, void **old_value)
116 return hashmap__insert(map, key, value, HASHMAP_UPDATE,
120 static inline int hashmap__append(struct hashmap *map,
121 const void *key, void *value)
123 return hashmap__insert(map, key, value, HASHMAP_APPEND, NULL, NULL);
126 bool hashmap__delete(struct hashmap *map, const void *key,
127 const void **old_key, void **old_value);
129 bool hashmap__find(const struct hashmap *map, const void *key, void **value);
132 * hashmap__for_each_entry - iterate over all entries in hashmap
133 * @map: hashmap to iterate
134 * @cur: struct hashmap_entry * used as a loop cursor
135 * @bkt: integer used as a bucket loop cursor
137 #define hashmap__for_each_entry(map, cur, bkt) \
138 for (bkt = 0; bkt < map->cap; bkt++) \
139 for (cur = map->buckets[bkt]; cur; cur = cur->next)
142 * hashmap__for_each_entry_safe - iterate over all entries in hashmap, safe
144 * @map: hashmap to iterate
145 * @cur: struct hashmap_entry * used as a loop cursor
146 * @tmp: struct hashmap_entry * used as a temporary next cursor storage
147 * @bkt: integer used as a bucket loop cursor
149 #define hashmap__for_each_entry_safe(map, cur, tmp, bkt) \
150 for (bkt = 0; bkt < map->cap; bkt++) \
151 for (cur = map->buckets[bkt]; \
152 cur && ({tmp = cur->next; true; }); \
156 * hashmap__for_each_key_entry - iterate over entries associated with given key
157 * @map: hashmap to iterate
158 * @cur: struct hashmap_entry * used as a loop cursor
159 * @key: key to iterate entries for
161 #define hashmap__for_each_key_entry(map, cur, _key) \
162 for (cur = ({ size_t bkt = hash_bits(map->hash_fn((_key), map->ctx),\
164 map->buckets ? map->buckets[bkt] : NULL; }); \
167 if (map->equal_fn(cur->key, (_key), map->ctx))
169 #define hashmap__for_each_key_entry_safe(map, cur, tmp, _key) \
170 for (cur = ({ size_t bkt = hash_bits(map->hash_fn((_key), map->ctx),\
172 cur = map->buckets ? map->buckets[bkt] : NULL; }); \
173 cur && ({ tmp = cur->next; true; }); \
175 if (map->equal_fn(cur->key, (_key), map->ctx))
177 #endif /* __LIBBPF_HASHMAP_H */