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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#ifdef __GLIBC__
14#include <bits/wordsize.h>
15#else
16#include <bits/reg.h>
17#endif
18#include "libbpf_internal.h"
19
20static 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
26typedef size_t (*hashmap_hash_fn)(const void *key, void *ctx);
27typedef bool (*hashmap_equal_fn)(const void *key1, const void *key2, void *ctx);
28
29struct hashmap_entry {
30 const void *key;
31 void *value;
32 struct hashmap_entry *next;
33};
34
35struct 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
56void hashmap__init(struct hashmap *map, hashmap_hash_fn hash_fn,
57 hashmap_equal_fn equal_fn, void *ctx);
58struct hashmap *hashmap__new(hashmap_hash_fn hash_fn,
59 hashmap_equal_fn equal_fn,
60 void *ctx);
61void hashmap__clear(struct hashmap *map);
62void hashmap__free(struct hashmap *map);
63
64size_t hashmap__size(const struct hashmap *map);
65size_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 */
81enum 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 */
95int 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
99static 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
105static 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
113static 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
121static 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
127bool hashmap__delete(struct hashmap *map, const void *key,
128 const void **old_key, void **old_value);
129
130bool 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 */