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
13 #include "libbpf_internal.h"
15 static inline size_t hash_bits(size_t h, int bits)
17 /* shuffle bits and return requested number of upper bits */
18 return (h * 11400714819323198485llu) >> (__WORDSIZE - bits);
21 typedef size_t (*hashmap_hash_fn)(const void *key, void *ctx);
22 typedef bool (*hashmap_equal_fn)(const void *key1, const void *key2, void *ctx);
24 struct hashmap_entry {
27 struct hashmap_entry *next;
31 hashmap_hash_fn hash_fn;
32 hashmap_equal_fn equal_fn;
35 struct hashmap_entry **buckets;
41 #define HASHMAP_INIT(hash_fn, equal_fn, ctx) { \
42 .hash_fn = (hash_fn), \
43 .equal_fn = (equal_fn), \
51 void hashmap__init(struct hashmap *map, hashmap_hash_fn hash_fn,
52 hashmap_equal_fn equal_fn, void *ctx);
53 struct hashmap *hashmap__new(hashmap_hash_fn hash_fn,
54 hashmap_equal_fn equal_fn,
56 void hashmap__clear(struct hashmap *map);
57 void hashmap__free(struct hashmap *map);
59 size_t hashmap__size(const struct hashmap *map);
60 size_t hashmap__capacity(const struct hashmap *map);
63 * Hashmap insertion strategy:
64 * - HASHMAP_ADD - only add key/value if key doesn't exist yet;
65 * - HASHMAP_SET - add key/value pair if key doesn't exist yet; otherwise,
67 * - HASHMAP_UPDATE - update value, if key already exists; otherwise, do
68 * nothing and return -ENOENT;
69 * - HASHMAP_APPEND - always add key/value pair, even if key already exists.
70 * This turns hashmap into a multimap by allowing multiple values to be
71 * associated with the same key. Most useful read API for such hashmap is
72 * hashmap__for_each_key_entry() iteration. If hashmap__find() is still
73 * used, it will return last inserted key/value entry (first in a bucket
76 enum hashmap_insert_strategy {
84 * hashmap__insert() adds key/value entry w/ various semantics, depending on
85 * provided strategy value. If a given key/value pair replaced already
86 * existing key/value pair, both old key and old value will be returned
87 * through old_key and old_value to allow calling code do proper memory
90 int hashmap__insert(struct hashmap *map, const void *key, void *value,
91 enum hashmap_insert_strategy strategy,
92 const void **old_key, void **old_value);
94 static inline int hashmap__add(struct hashmap *map,
95 const void *key, void *value)
97 return hashmap__insert(map, key, value, HASHMAP_ADD, NULL, NULL);
100 static inline int hashmap__set(struct hashmap *map,
101 const void *key, void *value,
102 const void **old_key, void **old_value)
104 return hashmap__insert(map, key, value, HASHMAP_SET,
108 static inline int hashmap__update(struct hashmap *map,
109 const void *key, void *value,
110 const void **old_key, void **old_value)
112 return hashmap__insert(map, key, value, HASHMAP_UPDATE,
116 static inline int hashmap__append(struct hashmap *map,
117 const void *key, void *value)
119 return hashmap__insert(map, key, value, HASHMAP_APPEND, NULL, NULL);
122 bool hashmap__delete(struct hashmap *map, const void *key,
123 const void **old_key, void **old_value);
125 bool hashmap__find(const struct hashmap *map, const void *key, void **value);
128 * hashmap__for_each_entry - iterate over all entries in hashmap
129 * @map: hashmap to iterate
130 * @cur: struct hashmap_entry * used as a loop cursor
131 * @bkt: integer used as a bucket loop cursor
133 #define hashmap__for_each_entry(map, cur, bkt) \
134 for (bkt = 0; bkt < map->cap; bkt++) \
135 for (cur = map->buckets[bkt]; cur; cur = cur->next)
138 * hashmap__for_each_entry_safe - iterate over all entries in hashmap, safe
140 * @map: hashmap to iterate
141 * @cur: struct hashmap_entry * used as a loop cursor
142 * @tmp: struct hashmap_entry * used as a temporary next cursor storage
143 * @bkt: integer used as a bucket loop cursor
145 #define hashmap__for_each_entry_safe(map, cur, tmp, bkt) \
146 for (bkt = 0; bkt < map->cap; bkt++) \
147 for (cur = map->buckets[bkt]; \
148 cur && ({tmp = cur->next; true; }); \
152 * hashmap__for_each_key_entry - iterate over entries associated with given key
153 * @map: hashmap to iterate
154 * @cur: struct hashmap_entry * used as a loop cursor
155 * @key: key to iterate entries for
157 #define hashmap__for_each_key_entry(map, cur, _key) \
158 for (cur = ({ size_t bkt = hash_bits(map->hash_fn((_key), map->ctx),\
160 map->buckets ? map->buckets[bkt] : NULL; }); \
163 if (map->equal_fn(cur->key, (_key), map->ctx))
165 #define hashmap__for_each_key_entry_safe(map, cur, tmp, _key) \
166 for (cur = ({ size_t bkt = hash_bits(map->hash_fn((_key), map->ctx),\
168 cur = map->buckets ? map->buckets[bkt] : NULL; }); \
169 cur && ({ tmp = cur->next; true; }); \
171 if (map->equal_fn(cur->key, (_key), map->ctx))
173 #endif /* __LIBBPF_HASHMAP_H */