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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> | |
8ca8d4a8 | 13 | #include <limits.h> |
e3b92422 AN |
14 | |
15 | static inline size_t hash_bits(size_t h, int bits) | |
16 | { | |
17 | /* shuffle bits and return requested number of upper bits */ | |
b2f9f153 JB |
18 | #if (__SIZEOF_SIZE_T__ == __SIZEOF_LONG_LONG__) |
19 | /* LP64 case */ | |
20 | return (h * 11400714819323198485llu) >> (__SIZEOF_LONG_LONG__ * 8 - bits); | |
21 | #elif (__SIZEOF_SIZE_T__ <= __SIZEOF_LONG__) | |
22 | return (h * 2654435769lu) >> (__SIZEOF_LONG__ * 8 - bits); | |
23 | #else | |
24 | # error "Unsupported size_t size" | |
25 | #endif | |
e3b92422 AN |
26 | } |
27 | ||
7d9c71e1 AN |
28 | /* generic C-string hashing function */ |
29 | static inline size_t str_hash(const char *s) | |
30 | { | |
31 | size_t h = 0; | |
32 | ||
33 | while (*s) { | |
34 | h = h * 31 + *s; | |
35 | s++; | |
36 | } | |
37 | return h; | |
38 | } | |
39 | ||
e3b92422 AN |
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); | |
42 | ||
43 | struct hashmap_entry { | |
44 | const void *key; | |
45 | void *value; | |
46 | struct hashmap_entry *next; | |
47 | }; | |
48 | ||
49 | struct hashmap { | |
50 | hashmap_hash_fn hash_fn; | |
51 | hashmap_equal_fn equal_fn; | |
52 | void *ctx; | |
53 | ||
54 | struct hashmap_entry **buckets; | |
55 | size_t cap; | |
56 | size_t cap_bits; | |
57 | size_t sz; | |
58 | }; | |
59 | ||
60 | #define HASHMAP_INIT(hash_fn, equal_fn, ctx) { \ | |
61 | .hash_fn = (hash_fn), \ | |
62 | .equal_fn = (equal_fn), \ | |
63 | .ctx = (ctx), \ | |
64 | .buckets = NULL, \ | |
65 | .cap = 0, \ | |
66 | .cap_bits = 0, \ | |
67 | .sz = 0, \ | |
68 | } | |
69 | ||
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, | |
74 | void *ctx); | |
75 | void hashmap__clear(struct hashmap *map); | |
76 | void hashmap__free(struct hashmap *map); | |
77 | ||
78 | size_t hashmap__size(const struct hashmap *map); | |
79 | size_t hashmap__capacity(const struct hashmap *map); | |
80 | ||
81 | /* | |
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, | |
85 | * update value; | |
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 | |
93 | * chain). | |
94 | */ | |
95 | enum hashmap_insert_strategy { | |
96 | HASHMAP_ADD, | |
97 | HASHMAP_SET, | |
98 | HASHMAP_UPDATE, | |
99 | HASHMAP_APPEND, | |
100 | }; | |
101 | ||
102 | /* | |
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 | |
107 | * management. | |
108 | */ | |
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); | |
112 | ||
113 | static inline int hashmap__add(struct hashmap *map, | |
114 | const void *key, void *value) | |
115 | { | |
116 | return hashmap__insert(map, key, value, HASHMAP_ADD, NULL, NULL); | |
117 | } | |
118 | ||
119 | static inline int hashmap__set(struct hashmap *map, | |
120 | const void *key, void *value, | |
121 | const void **old_key, void **old_value) | |
122 | { | |
123 | return hashmap__insert(map, key, value, HASHMAP_SET, | |
124 | old_key, old_value); | |
125 | } | |
126 | ||
127 | static inline int hashmap__update(struct hashmap *map, | |
128 | const void *key, void *value, | |
129 | const void **old_key, void **old_value) | |
130 | { | |
131 | return hashmap__insert(map, key, value, HASHMAP_UPDATE, | |
132 | old_key, old_value); | |
133 | } | |
134 | ||
135 | static inline int hashmap__append(struct hashmap *map, | |
136 | const void *key, void *value) | |
137 | { | |
138 | return hashmap__insert(map, key, value, HASHMAP_APPEND, NULL, NULL); | |
139 | } | |
140 | ||
141 | bool hashmap__delete(struct hashmap *map, const void *key, | |
142 | const void **old_key, void **old_value); | |
143 | ||
144 | bool hashmap__find(const struct hashmap *map, const void *key, void **value); | |
145 | ||
146 | /* | |
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 | |
151 | */ | |
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) | |
155 | ||
156 | /* | |
157 | * hashmap__for_each_entry_safe - iterate over all entries in hashmap, safe | |
158 | * against removals | |
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 | |
163 | */ | |
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; }); \ | |
168 | cur = tmp) | |
169 | ||
170 | /* | |
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 | |
175 | */ | |
176 | #define hashmap__for_each_key_entry(map, cur, _key) \ | |
177 | for (cur = ({ size_t bkt = hash_bits(map->hash_fn((_key), map->ctx),\ | |
178 | map->cap_bits); \ | |
179 | map->buckets ? map->buckets[bkt] : NULL; }); \ | |
180 | cur; \ | |
181 | cur = cur->next) \ | |
182 | if (map->equal_fn(cur->key, (_key), map->ctx)) | |
183 | ||
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),\ | |
186 | map->cap_bits); \ | |
187 | cur = map->buckets ? map->buckets[bkt] : NULL; }); \ | |
188 | cur && ({ tmp = cur->next; true; }); \ | |
189 | cur = tmp) \ | |
190 | if (map->equal_fn(cur->key, (_key), map->ctx)) | |
191 | ||
192 | #endif /* __LIBBPF_HASHMAP_H */ |