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e3b92422 AN |
1 | /* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */ |
2 | ||
3 | /* | |
4 | * Generic non-thread safe hash map implementation. | |
5 | * | |
6 | * Copyright (c) 2019 Facebook | |
7 | */ | |
8 | #ifndef __LIBBPF_HASHMAP_H | |
9 | #define __LIBBPF_HASHMAP_H | |
10 | ||
11 | #include <stdbool.h> | |
12 | #include <stddef.h> | |
8aa259b1 AN |
13 | #ifdef __GLIBC__ |
14 | #include <bits/wordsize.h> | |
15 | #else | |
16 | #include <bits/reg.h> | |
17 | #endif | |
e3b92422 AN |
18 | #include "libbpf_internal.h" |
19 | ||
20 | static inline size_t hash_bits(size_t h, int bits) | |
21 | { | |
22 | /* shuffle bits and return requested number of upper bits */ | |
23 | return (h * 11400714819323198485llu) >> (__WORDSIZE - bits); | |
24 | } | |
25 | ||
26 | typedef size_t (*hashmap_hash_fn)(const void *key, void *ctx); | |
27 | typedef bool (*hashmap_equal_fn)(const void *key1, const void *key2, void *ctx); | |
28 | ||
29 | struct hashmap_entry { | |
30 | const void *key; | |
31 | void *value; | |
32 | struct hashmap_entry *next; | |
33 | }; | |
34 | ||
35 | struct hashmap { | |
36 | hashmap_hash_fn hash_fn; | |
37 | hashmap_equal_fn equal_fn; | |
38 | void *ctx; | |
39 | ||
40 | struct hashmap_entry **buckets; | |
41 | size_t cap; | |
42 | size_t cap_bits; | |
43 | size_t sz; | |
44 | }; | |
45 | ||
46 | #define HASHMAP_INIT(hash_fn, equal_fn, ctx) { \ | |
47 | .hash_fn = (hash_fn), \ | |
48 | .equal_fn = (equal_fn), \ | |
49 | .ctx = (ctx), \ | |
50 | .buckets = NULL, \ | |
51 | .cap = 0, \ | |
52 | .cap_bits = 0, \ | |
53 | .sz = 0, \ | |
54 | } | |
55 | ||
56 | void hashmap__init(struct hashmap *map, hashmap_hash_fn hash_fn, | |
57 | hashmap_equal_fn equal_fn, void *ctx); | |
58 | struct hashmap *hashmap__new(hashmap_hash_fn hash_fn, | |
59 | hashmap_equal_fn equal_fn, | |
60 | void *ctx); | |
61 | void hashmap__clear(struct hashmap *map); | |
62 | void hashmap__free(struct hashmap *map); | |
63 | ||
64 | size_t hashmap__size(const struct hashmap *map); | |
65 | size_t hashmap__capacity(const struct hashmap *map); | |
66 | ||
67 | /* | |
68 | * Hashmap insertion strategy: | |
69 | * - HASHMAP_ADD - only add key/value if key doesn't exist yet; | |
70 | * - HASHMAP_SET - add key/value pair if key doesn't exist yet; otherwise, | |
71 | * update value; | |
72 | * - HASHMAP_UPDATE - update value, if key already exists; otherwise, do | |
73 | * nothing and return -ENOENT; | |
74 | * - HASHMAP_APPEND - always add key/value pair, even if key already exists. | |
75 | * This turns hashmap into a multimap by allowing multiple values to be | |
76 | * associated with the same key. Most useful read API for such hashmap is | |
77 | * hashmap__for_each_key_entry() iteration. If hashmap__find() is still | |
78 | * used, it will return last inserted key/value entry (first in a bucket | |
79 | * chain). | |
80 | */ | |
81 | enum hashmap_insert_strategy { | |
82 | HASHMAP_ADD, | |
83 | HASHMAP_SET, | |
84 | HASHMAP_UPDATE, | |
85 | HASHMAP_APPEND, | |
86 | }; | |
87 | ||
88 | /* | |
89 | * hashmap__insert() adds key/value entry w/ various semantics, depending on | |
90 | * provided strategy value. If a given key/value pair replaced already | |
91 | * existing key/value pair, both old key and old value will be returned | |
92 | * through old_key and old_value to allow calling code do proper memory | |
93 | * management. | |
94 | */ | |
95 | int hashmap__insert(struct hashmap *map, const void *key, void *value, | |
96 | enum hashmap_insert_strategy strategy, | |
97 | const void **old_key, void **old_value); | |
98 | ||
99 | static inline int hashmap__add(struct hashmap *map, | |
100 | const void *key, void *value) | |
101 | { | |
102 | return hashmap__insert(map, key, value, HASHMAP_ADD, NULL, NULL); | |
103 | } | |
104 | ||
105 | static inline int hashmap__set(struct hashmap *map, | |
106 | const void *key, void *value, | |
107 | const void **old_key, void **old_value) | |
108 | { | |
109 | return hashmap__insert(map, key, value, HASHMAP_SET, | |
110 | old_key, old_value); | |
111 | } | |
112 | ||
113 | static inline int hashmap__update(struct hashmap *map, | |
114 | const void *key, void *value, | |
115 | const void **old_key, void **old_value) | |
116 | { | |
117 | return hashmap__insert(map, key, value, HASHMAP_UPDATE, | |
118 | old_key, old_value); | |
119 | } | |
120 | ||
121 | static inline int hashmap__append(struct hashmap *map, | |
122 | const void *key, void *value) | |
123 | { | |
124 | return hashmap__insert(map, key, value, HASHMAP_APPEND, NULL, NULL); | |
125 | } | |
126 | ||
127 | bool hashmap__delete(struct hashmap *map, const void *key, | |
128 | const void **old_key, void **old_value); | |
129 | ||
130 | bool hashmap__find(const struct hashmap *map, const void *key, void **value); | |
131 | ||
132 | /* | |
133 | * hashmap__for_each_entry - iterate over all entries in hashmap | |
134 | * @map: hashmap to iterate | |
135 | * @cur: struct hashmap_entry * used as a loop cursor | |
136 | * @bkt: integer used as a bucket loop cursor | |
137 | */ | |
138 | #define hashmap__for_each_entry(map, cur, bkt) \ | |
139 | for (bkt = 0; bkt < map->cap; bkt++) \ | |
140 | for (cur = map->buckets[bkt]; cur; cur = cur->next) | |
141 | ||
142 | /* | |
143 | * hashmap__for_each_entry_safe - iterate over all entries in hashmap, safe | |
144 | * against removals | |
145 | * @map: hashmap to iterate | |
146 | * @cur: struct hashmap_entry * used as a loop cursor | |
147 | * @tmp: struct hashmap_entry * used as a temporary next cursor storage | |
148 | * @bkt: integer used as a bucket loop cursor | |
149 | */ | |
150 | #define hashmap__for_each_entry_safe(map, cur, tmp, bkt) \ | |
151 | for (bkt = 0; bkt < map->cap; bkt++) \ | |
152 | for (cur = map->buckets[bkt]; \ | |
153 | cur && ({tmp = cur->next; true; }); \ | |
154 | cur = tmp) | |
155 | ||
156 | /* | |
157 | * hashmap__for_each_key_entry - iterate over entries associated with given key | |
158 | * @map: hashmap to iterate | |
159 | * @cur: struct hashmap_entry * used as a loop cursor | |
160 | * @key: key to iterate entries for | |
161 | */ | |
162 | #define hashmap__for_each_key_entry(map, cur, _key) \ | |
163 | for (cur = ({ size_t bkt = hash_bits(map->hash_fn((_key), map->ctx),\ | |
164 | map->cap_bits); \ | |
165 | map->buckets ? map->buckets[bkt] : NULL; }); \ | |
166 | cur; \ | |
167 | cur = cur->next) \ | |
168 | if (map->equal_fn(cur->key, (_key), map->ctx)) | |
169 | ||
170 | #define hashmap__for_each_key_entry_safe(map, cur, tmp, _key) \ | |
171 | for (cur = ({ size_t bkt = hash_bits(map->hash_fn((_key), map->ctx),\ | |
172 | map->cap_bits); \ | |
173 | cur = map->buckets ? map->buckets[bkt] : NULL; }); \ | |
174 | cur && ({ tmp = cur->next; true; }); \ | |
175 | cur = tmp) \ | |
176 | if (map->equal_fn(cur->key, (_key), map->ctx)) | |
177 | ||
178 | #endif /* __LIBBPF_HASHMAP_H */ |