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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 */ | |
7a078d2d IR |
18 | if (bits == 0) |
19 | return 0; | |
20 | ||
b2f9f153 JB |
21 | #if (__SIZEOF_SIZE_T__ == __SIZEOF_LONG_LONG__) |
22 | /* LP64 case */ | |
23 | return (h * 11400714819323198485llu) >> (__SIZEOF_LONG_LONG__ * 8 - bits); | |
24 | #elif (__SIZEOF_SIZE_T__ <= __SIZEOF_LONG__) | |
25 | return (h * 2654435769lu) >> (__SIZEOF_LONG__ * 8 - bits); | |
26 | #else | |
27 | # error "Unsupported size_t size" | |
28 | #endif | |
e3b92422 AN |
29 | } |
30 | ||
7d9c71e1 AN |
31 | /* generic C-string hashing function */ |
32 | static inline size_t str_hash(const char *s) | |
33 | { | |
34 | size_t h = 0; | |
35 | ||
36 | while (*s) { | |
37 | h = h * 31 + *s; | |
38 | s++; | |
39 | } | |
40 | return h; | |
41 | } | |
42 | ||
c302378b EZ |
43 | typedef size_t (*hashmap_hash_fn)(long key, void *ctx); |
44 | typedef bool (*hashmap_equal_fn)(long key1, long key2, void *ctx); | |
e3b92422 | 45 | |
c302378b EZ |
46 | /* |
47 | * Hashmap interface is polymorphic, keys and values could be either | |
48 | * long-sized integers or pointers, this is achieved as follows: | |
49 | * - interface functions that operate on keys and values are hidden | |
50 | * behind auxiliary macros, e.g. hashmap_insert <-> hashmap__insert; | |
51 | * - these auxiliary macros cast the key and value parameters as | |
52 | * long or long *, so the user does not have to specify the casts explicitly; | |
53 | * - for pointer parameters (e.g. old_key) the size of the pointed | |
54 | * type is verified by hashmap_cast_ptr using _Static_assert; | |
55 | * - when iterating using hashmap__for_each_* forms | |
56 | * hasmap_entry->key should be used for integer keys and | |
57 | * hasmap_entry->pkey should be used for pointer keys, | |
58 | * same goes for values. | |
59 | */ | |
e3b92422 | 60 | struct hashmap_entry { |
c302378b EZ |
61 | union { |
62 | long key; | |
63 | const void *pkey; | |
64 | }; | |
65 | union { | |
66 | long value; | |
67 | void *pvalue; | |
68 | }; | |
e3b92422 AN |
69 | struct hashmap_entry *next; |
70 | }; | |
71 | ||
72 | struct hashmap { | |
73 | hashmap_hash_fn hash_fn; | |
74 | hashmap_equal_fn equal_fn; | |
75 | void *ctx; | |
76 | ||
77 | struct hashmap_entry **buckets; | |
78 | size_t cap; | |
79 | size_t cap_bits; | |
80 | size_t sz; | |
81 | }; | |
82 | ||
83 | #define HASHMAP_INIT(hash_fn, equal_fn, ctx) { \ | |
84 | .hash_fn = (hash_fn), \ | |
85 | .equal_fn = (equal_fn), \ | |
86 | .ctx = (ctx), \ | |
87 | .buckets = NULL, \ | |
88 | .cap = 0, \ | |
89 | .cap_bits = 0, \ | |
90 | .sz = 0, \ | |
91 | } | |
92 | ||
93 | void hashmap__init(struct hashmap *map, hashmap_hash_fn hash_fn, | |
94 | hashmap_equal_fn equal_fn, void *ctx); | |
95 | struct hashmap *hashmap__new(hashmap_hash_fn hash_fn, | |
96 | hashmap_equal_fn equal_fn, | |
97 | void *ctx); | |
98 | void hashmap__clear(struct hashmap *map); | |
99 | void hashmap__free(struct hashmap *map); | |
100 | ||
101 | size_t hashmap__size(const struct hashmap *map); | |
102 | size_t hashmap__capacity(const struct hashmap *map); | |
103 | ||
104 | /* | |
105 | * Hashmap insertion strategy: | |
106 | * - HASHMAP_ADD - only add key/value if key doesn't exist yet; | |
107 | * - HASHMAP_SET - add key/value pair if key doesn't exist yet; otherwise, | |
108 | * update value; | |
109 | * - HASHMAP_UPDATE - update value, if key already exists; otherwise, do | |
110 | * nothing and return -ENOENT; | |
111 | * - HASHMAP_APPEND - always add key/value pair, even if key already exists. | |
112 | * This turns hashmap into a multimap by allowing multiple values to be | |
113 | * associated with the same key. Most useful read API for such hashmap is | |
114 | * hashmap__for_each_key_entry() iteration. If hashmap__find() is still | |
115 | * used, it will return last inserted key/value entry (first in a bucket | |
116 | * chain). | |
117 | */ | |
118 | enum hashmap_insert_strategy { | |
119 | HASHMAP_ADD, | |
120 | HASHMAP_SET, | |
121 | HASHMAP_UPDATE, | |
122 | HASHMAP_APPEND, | |
123 | }; | |
124 | ||
c302378b EZ |
125 | #define hashmap_cast_ptr(p) ({ \ |
126 | _Static_assert((p) == NULL || sizeof(*(p)) == sizeof(long), \ | |
127 | #p " pointee should be a long-sized integer or a pointer"); \ | |
128 | (long *)(p); \ | |
129 | }) | |
130 | ||
e3b92422 AN |
131 | /* |
132 | * hashmap__insert() adds key/value entry w/ various semantics, depending on | |
133 | * provided strategy value. If a given key/value pair replaced already | |
134 | * existing key/value pair, both old key and old value will be returned | |
135 | * through old_key and old_value to allow calling code do proper memory | |
136 | * management. | |
137 | */ | |
c302378b EZ |
138 | int hashmap_insert(struct hashmap *map, long key, long value, |
139 | enum hashmap_insert_strategy strategy, | |
140 | long *old_key, long *old_value); | |
e3b92422 | 141 | |
c302378b EZ |
142 | #define hashmap__insert(map, key, value, strategy, old_key, old_value) \ |
143 | hashmap_insert((map), (long)(key), (long)(value), (strategy), \ | |
144 | hashmap_cast_ptr(old_key), \ | |
145 | hashmap_cast_ptr(old_value)) | |
e3b92422 | 146 | |
c302378b EZ |
147 | #define hashmap__add(map, key, value) \ |
148 | hashmap__insert((map), (key), (value), HASHMAP_ADD, NULL, NULL) | |
e3b92422 | 149 | |
c302378b EZ |
150 | #define hashmap__set(map, key, value, old_key, old_value) \ |
151 | hashmap__insert((map), (key), (value), HASHMAP_SET, (old_key), (old_value)) | |
e3b92422 | 152 | |
c302378b EZ |
153 | #define hashmap__update(map, key, value, old_key, old_value) \ |
154 | hashmap__insert((map), (key), (value), HASHMAP_UPDATE, (old_key), (old_value)) | |
155 | ||
156 | #define hashmap__append(map, key, value) \ | |
157 | hashmap__insert((map), (key), (value), HASHMAP_APPEND, NULL, NULL) | |
158 | ||
159 | bool hashmap_delete(struct hashmap *map, long key, long *old_key, long *old_value); | |
160 | ||
161 | #define hashmap__delete(map, key, old_key, old_value) \ | |
162 | hashmap_delete((map), (long)(key), \ | |
163 | hashmap_cast_ptr(old_key), \ | |
164 | hashmap_cast_ptr(old_value)) | |
e3b92422 | 165 | |
c302378b | 166 | bool hashmap_find(const struct hashmap *map, long key, long *value); |
e3b92422 | 167 | |
c302378b EZ |
168 | #define hashmap__find(map, key, value) \ |
169 | hashmap_find((map), (long)(key), hashmap_cast_ptr(value)) | |
e3b92422 AN |
170 | |
171 | /* | |
172 | * hashmap__for_each_entry - iterate over all entries in hashmap | |
173 | * @map: hashmap to iterate | |
174 | * @cur: struct hashmap_entry * used as a loop cursor | |
175 | * @bkt: integer used as a bucket loop cursor | |
176 | */ | |
177 | #define hashmap__for_each_entry(map, cur, bkt) \ | |
178 | for (bkt = 0; bkt < map->cap; bkt++) \ | |
179 | for (cur = map->buckets[bkt]; cur; cur = cur->next) | |
180 | ||
181 | /* | |
182 | * hashmap__for_each_entry_safe - iterate over all entries in hashmap, safe | |
183 | * against removals | |
184 | * @map: hashmap to iterate | |
185 | * @cur: struct hashmap_entry * used as a loop cursor | |
186 | * @tmp: struct hashmap_entry * used as a temporary next cursor storage | |
187 | * @bkt: integer used as a bucket loop cursor | |
188 | */ | |
189 | #define hashmap__for_each_entry_safe(map, cur, tmp, bkt) \ | |
190 | for (bkt = 0; bkt < map->cap; bkt++) \ | |
191 | for (cur = map->buckets[bkt]; \ | |
192 | cur && ({tmp = cur->next; true; }); \ | |
193 | cur = tmp) | |
194 | ||
195 | /* | |
196 | * hashmap__for_each_key_entry - iterate over entries associated with given key | |
197 | * @map: hashmap to iterate | |
198 | * @cur: struct hashmap_entry * used as a loop cursor | |
199 | * @key: key to iterate entries for | |
200 | */ | |
201 | #define hashmap__for_each_key_entry(map, cur, _key) \ | |
7a078d2d IR |
202 | for (cur = map->buckets \ |
203 | ? map->buckets[hash_bits(map->hash_fn((_key), map->ctx), map->cap_bits)] \ | |
204 | : NULL; \ | |
e3b92422 AN |
205 | cur; \ |
206 | cur = cur->next) \ | |
207 | if (map->equal_fn(cur->key, (_key), map->ctx)) | |
208 | ||
209 | #define hashmap__for_each_key_entry_safe(map, cur, tmp, _key) \ | |
7a078d2d IR |
210 | for (cur = map->buckets \ |
211 | ? map->buckets[hash_bits(map->hash_fn((_key), map->ctx), map->cap_bits)] \ | |
212 | : NULL; \ | |
e3b92422 AN |
213 | cur && ({ tmp = cur->next; true; }); \ |
214 | cur = tmp) \ | |
215 | if (map->equal_fn(cur->key, (_key), map->ctx)) | |
216 | ||
217 | #endif /* __LIBBPF_HASHMAP_H */ |