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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>
13#include <limits.h>
14
15static inline size_t hash_bits(size_t h, int bits)
16{
17 /* shuffle bits and return requested number of upper bits */
18 if (bits == 0)
19 return 0;
20
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
29}
30
31/* generic C-string hashing function */
32static 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
43typedef size_t (*hashmap_hash_fn)(long key, void *ctx);
44typedef bool (*hashmap_equal_fn)(long key1, long key2, void *ctx);
45
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 */
60struct hashmap_entry {
61 union {
62 long key;
63 const void *pkey;
64 };
65 union {
66 long value;
67 void *pvalue;
68 };
69 struct hashmap_entry *next;
70};
71
72struct 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
83void hashmap__init(struct hashmap *map, hashmap_hash_fn hash_fn,
84 hashmap_equal_fn equal_fn, void *ctx);
85struct hashmap *hashmap__new(hashmap_hash_fn hash_fn,
86 hashmap_equal_fn equal_fn,
87 void *ctx);
88void hashmap__clear(struct hashmap *map);
89void hashmap__free(struct hashmap *map);
90
91size_t hashmap__size(const struct hashmap *map);
92size_t hashmap__capacity(const struct hashmap *map);
93
94/*
95 * Hashmap insertion strategy:
96 * - HASHMAP_ADD - only add key/value if key doesn't exist yet;
97 * - HASHMAP_SET - add key/value pair if key doesn't exist yet; otherwise,
98 * update value;
99 * - HASHMAP_UPDATE - update value, if key already exists; otherwise, do
100 * nothing and return -ENOENT;
101 * - HASHMAP_APPEND - always add key/value pair, even if key already exists.
102 * This turns hashmap into a multimap by allowing multiple values to be
103 * associated with the same key. Most useful read API for such hashmap is
104 * hashmap__for_each_key_entry() iteration. If hashmap__find() is still
105 * used, it will return last inserted key/value entry (first in a bucket
106 * chain).
107 */
108enum hashmap_insert_strategy {
109 HASHMAP_ADD,
110 HASHMAP_SET,
111 HASHMAP_UPDATE,
112 HASHMAP_APPEND,
113};
114
115#define hashmap_cast_ptr(p) ({ \
116 _Static_assert((__builtin_constant_p((p)) ? (p) == NULL : 0) || \
117 sizeof(*(p)) == sizeof(long), \
118 #p " pointee should be a long-sized integer or a pointer"); \
119 (long *)(p); \
120})
121
122/*
123 * hashmap__insert() adds key/value entry w/ various semantics, depending on
124 * provided strategy value. If a given key/value pair replaced already
125 * existing key/value pair, both old key and old value will be returned
126 * through old_key and old_value to allow calling code do proper memory
127 * management.
128 */
129int hashmap_insert(struct hashmap *map, long key, long value,
130 enum hashmap_insert_strategy strategy,
131 long *old_key, long *old_value);
132
133#define hashmap__insert(map, key, value, strategy, old_key, old_value) \
134 hashmap_insert((map), (long)(key), (long)(value), (strategy), \
135 hashmap_cast_ptr(old_key), \
136 hashmap_cast_ptr(old_value))
137
138#define hashmap__add(map, key, value) \
139 hashmap__insert((map), (key), (value), HASHMAP_ADD, NULL, NULL)
140
141#define hashmap__set(map, key, value, old_key, old_value) \
142 hashmap__insert((map), (key), (value), HASHMAP_SET, (old_key), (old_value))
143
144#define hashmap__update(map, key, value, old_key, old_value) \
145 hashmap__insert((map), (key), (value), HASHMAP_UPDATE, (old_key), (old_value))
146
147#define hashmap__append(map, key, value) \
148 hashmap__insert((map), (key), (value), HASHMAP_APPEND, NULL, NULL)
149
150bool hashmap_delete(struct hashmap *map, long key, long *old_key, long *old_value);
151
152#define hashmap__delete(map, key, old_key, old_value) \
153 hashmap_delete((map), (long)(key), \
154 hashmap_cast_ptr(old_key), \
155 hashmap_cast_ptr(old_value))
156
157bool hashmap_find(const struct hashmap *map, long key, long *value);
158
159#define hashmap__find(map, key, value) \
160 hashmap_find((map), (long)(key), hashmap_cast_ptr(value))
161
162/*
163 * hashmap__for_each_entry - iterate over all entries in hashmap
164 * @map: hashmap to iterate
165 * @cur: struct hashmap_entry * used as a loop cursor
166 * @bkt: integer used as a bucket loop cursor
167 */
168#define hashmap__for_each_entry(map, cur, bkt) \
169 for (bkt = 0; bkt < map->cap; bkt++) \
170 for (cur = map->buckets[bkt]; cur; cur = cur->next)
171
172/*
173 * hashmap__for_each_entry_safe - iterate over all entries in hashmap, safe
174 * against removals
175 * @map: hashmap to iterate
176 * @cur: struct hashmap_entry * used as a loop cursor
177 * @tmp: struct hashmap_entry * used as a temporary next cursor storage
178 * @bkt: integer used as a bucket loop cursor
179 */
180#define hashmap__for_each_entry_safe(map, cur, tmp, bkt) \
181 for (bkt = 0; bkt < map->cap; bkt++) \
182 for (cur = map->buckets[bkt]; \
183 cur && ({tmp = cur->next; true; }); \
184 cur = tmp)
185
186/*
187 * hashmap__for_each_key_entry - iterate over entries associated with given key
188 * @map: hashmap to iterate
189 * @cur: struct hashmap_entry * used as a loop cursor
190 * @key: key to iterate entries for
191 */
192#define hashmap__for_each_key_entry(map, cur, _key) \
193 for (cur = map->buckets \
194 ? map->buckets[hash_bits(map->hash_fn((_key), map->ctx), map->cap_bits)] \
195 : NULL; \
196 cur; \
197 cur = cur->next) \
198 if (map->equal_fn(cur->key, (_key), map->ctx))
199
200#define hashmap__for_each_key_entry_safe(map, cur, tmp, _key) \
201 for (cur = map->buckets \
202 ? map->buckets[hash_bits(map->hash_fn((_key), map->ctx), map->cap_bits)] \
203 : NULL; \
204 cur && ({ tmp = cur->next; true; }); \
205 cur = tmp) \
206 if (map->equal_fn(cur->key, (_key), map->ctx))
207
208#endif /* __LIBBPF_HASHMAP_H */
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>
13#include <limits.h>
14
15static inline size_t hash_bits(size_t h, int bits)
16{
17 /* shuffle bits and return requested number of upper bits */
18 if (bits == 0)
19 return 0;
20
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
29}
30
31/* generic C-string hashing function */
32static 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
43typedef size_t (*hashmap_hash_fn)(const void *key, void *ctx);
44typedef bool (*hashmap_equal_fn)(const void *key1, const void *key2, void *ctx);
45
46struct hashmap_entry {
47 const void *key;
48 void *value;
49 struct hashmap_entry *next;
50};
51
52struct hashmap {
53 hashmap_hash_fn hash_fn;
54 hashmap_equal_fn equal_fn;
55 void *ctx;
56
57 struct hashmap_entry **buckets;
58 size_t cap;
59 size_t cap_bits;
60 size_t sz;
61};
62
63#define HASHMAP_INIT(hash_fn, equal_fn, ctx) { \
64 .hash_fn = (hash_fn), \
65 .equal_fn = (equal_fn), \
66 .ctx = (ctx), \
67 .buckets = NULL, \
68 .cap = 0, \
69 .cap_bits = 0, \
70 .sz = 0, \
71}
72
73void hashmap__init(struct hashmap *map, hashmap_hash_fn hash_fn,
74 hashmap_equal_fn equal_fn, void *ctx);
75struct hashmap *hashmap__new(hashmap_hash_fn hash_fn,
76 hashmap_equal_fn equal_fn,
77 void *ctx);
78void hashmap__clear(struct hashmap *map);
79void hashmap__free(struct hashmap *map);
80
81size_t hashmap__size(const struct hashmap *map);
82size_t hashmap__capacity(const struct hashmap *map);
83
84/*
85 * Hashmap insertion strategy:
86 * - HASHMAP_ADD - only add key/value if key doesn't exist yet;
87 * - HASHMAP_SET - add key/value pair if key doesn't exist yet; otherwise,
88 * update value;
89 * - HASHMAP_UPDATE - update value, if key already exists; otherwise, do
90 * nothing and return -ENOENT;
91 * - HASHMAP_APPEND - always add key/value pair, even if key already exists.
92 * This turns hashmap into a multimap by allowing multiple values to be
93 * associated with the same key. Most useful read API for such hashmap is
94 * hashmap__for_each_key_entry() iteration. If hashmap__find() is still
95 * used, it will return last inserted key/value entry (first in a bucket
96 * chain).
97 */
98enum hashmap_insert_strategy {
99 HASHMAP_ADD,
100 HASHMAP_SET,
101 HASHMAP_UPDATE,
102 HASHMAP_APPEND,
103};
104
105/*
106 * hashmap__insert() adds key/value entry w/ various semantics, depending on
107 * provided strategy value. If a given key/value pair replaced already
108 * existing key/value pair, both old key and old value will be returned
109 * through old_key and old_value to allow calling code do proper memory
110 * management.
111 */
112int hashmap__insert(struct hashmap *map, const void *key, void *value,
113 enum hashmap_insert_strategy strategy,
114 const void **old_key, void **old_value);
115
116static inline int hashmap__add(struct hashmap *map,
117 const void *key, void *value)
118{
119 return hashmap__insert(map, key, value, HASHMAP_ADD, NULL, NULL);
120}
121
122static inline int hashmap__set(struct hashmap *map,
123 const void *key, void *value,
124 const void **old_key, void **old_value)
125{
126 return hashmap__insert(map, key, value, HASHMAP_SET,
127 old_key, old_value);
128}
129
130static inline int hashmap__update(struct hashmap *map,
131 const void *key, void *value,
132 const void **old_key, void **old_value)
133{
134 return hashmap__insert(map, key, value, HASHMAP_UPDATE,
135 old_key, old_value);
136}
137
138static inline int hashmap__append(struct hashmap *map,
139 const void *key, void *value)
140{
141 return hashmap__insert(map, key, value, HASHMAP_APPEND, NULL, NULL);
142}
143
144bool hashmap__delete(struct hashmap *map, const void *key,
145 const void **old_key, void **old_value);
146
147bool hashmap__find(const struct hashmap *map, const void *key, void **value);
148
149/*
150 * hashmap__for_each_entry - iterate over all entries in hashmap
151 * @map: hashmap to iterate
152 * @cur: struct hashmap_entry * used as a loop cursor
153 * @bkt: integer used as a bucket loop cursor
154 */
155#define hashmap__for_each_entry(map, cur, bkt) \
156 for (bkt = 0; bkt < map->cap; bkt++) \
157 for (cur = map->buckets[bkt]; cur; cur = cur->next)
158
159/*
160 * hashmap__for_each_entry_safe - iterate over all entries in hashmap, safe
161 * against removals
162 * @map: hashmap to iterate
163 * @cur: struct hashmap_entry * used as a loop cursor
164 * @tmp: struct hashmap_entry * used as a temporary next cursor storage
165 * @bkt: integer used as a bucket loop cursor
166 */
167#define hashmap__for_each_entry_safe(map, cur, tmp, bkt) \
168 for (bkt = 0; bkt < map->cap; bkt++) \
169 for (cur = map->buckets[bkt]; \
170 cur && ({tmp = cur->next; true; }); \
171 cur = tmp)
172
173/*
174 * hashmap__for_each_key_entry - iterate over entries associated with given key
175 * @map: hashmap to iterate
176 * @cur: struct hashmap_entry * used as a loop cursor
177 * @key: key to iterate entries for
178 */
179#define hashmap__for_each_key_entry(map, cur, _key) \
180 for (cur = map->buckets \
181 ? map->buckets[hash_bits(map->hash_fn((_key), map->ctx), map->cap_bits)] \
182 : NULL; \
183 cur; \
184 cur = cur->next) \
185 if (map->equal_fn(cur->key, (_key), map->ctx))
186
187#define hashmap__for_each_key_entry_safe(map, cur, tmp, _key) \
188 for (cur = map->buckets \
189 ? map->buckets[hash_bits(map->hash_fn((_key), map->ctx), map->cap_bits)] \
190 : NULL; \
191 cur && ({ tmp = cur->next; true; }); \
192 cur = tmp) \
193 if (map->equal_fn(cur->key, (_key), map->ctx))
194
195#endif /* __LIBBPF_HASHMAP_H */