1e3b92422SAndrii Nakryiko /* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
2e3b92422SAndrii Nakryiko
3e3b92422SAndrii Nakryiko /*
4e3b92422SAndrii Nakryiko * Generic non-thread safe hash map implementation.
5e3b92422SAndrii Nakryiko *
6e3b92422SAndrii Nakryiko * Copyright (c) 2019 Facebook
7e3b92422SAndrii Nakryiko */
8e3b92422SAndrii Nakryiko #ifndef __LIBBPF_HASHMAP_H
9e3b92422SAndrii Nakryiko #define __LIBBPF_HASHMAP_H
10e3b92422SAndrii Nakryiko
11e3b92422SAndrii Nakryiko #include <stdbool.h>
12e3b92422SAndrii Nakryiko #include <stddef.h>
138ca8d4a8SArnaldo Carvalho de Melo #include <limits.h>
14e3b92422SAndrii Nakryiko
hash_bits(size_t h,int bits)15e3b92422SAndrii Nakryiko static inline size_t hash_bits(size_t h, int bits)
16e3b92422SAndrii Nakryiko {
17e3b92422SAndrii Nakryiko /* shuffle bits and return requested number of upper bits */
187a078d2dSIan Rogers if (bits == 0)
197a078d2dSIan Rogers return 0;
207a078d2dSIan Rogers
21b2f9f153SJakub Bogusz #if (__SIZEOF_SIZE_T__ == __SIZEOF_LONG_LONG__)
22b2f9f153SJakub Bogusz /* LP64 case */
23b2f9f153SJakub Bogusz return (h * 11400714819323198485llu) >> (__SIZEOF_LONG_LONG__ * 8 - bits);
24b2f9f153SJakub Bogusz #elif (__SIZEOF_SIZE_T__ <= __SIZEOF_LONG__)
25b2f9f153SJakub Bogusz return (h * 2654435769lu) >> (__SIZEOF_LONG__ * 8 - bits);
26b2f9f153SJakub Bogusz #else
27b2f9f153SJakub Bogusz # error "Unsupported size_t size"
28b2f9f153SJakub Bogusz #endif
29e3b92422SAndrii Nakryiko }
30e3b92422SAndrii Nakryiko
317d9c71e1SAndrii Nakryiko /* generic C-string hashing function */
str_hash(const char * s)327d9c71e1SAndrii Nakryiko static inline size_t str_hash(const char *s)
337d9c71e1SAndrii Nakryiko {
347d9c71e1SAndrii Nakryiko size_t h = 0;
357d9c71e1SAndrii Nakryiko
367d9c71e1SAndrii Nakryiko while (*s) {
377d9c71e1SAndrii Nakryiko h = h * 31 + *s;
387d9c71e1SAndrii Nakryiko s++;
397d9c71e1SAndrii Nakryiko }
407d9c71e1SAndrii Nakryiko return h;
417d9c71e1SAndrii Nakryiko }
427d9c71e1SAndrii Nakryiko
43c302378bSEduard Zingerman typedef size_t (*hashmap_hash_fn)(long key, void *ctx);
44c302378bSEduard Zingerman typedef bool (*hashmap_equal_fn)(long key1, long key2, void *ctx);
45e3b92422SAndrii Nakryiko
46c302378bSEduard Zingerman /*
47c302378bSEduard Zingerman * Hashmap interface is polymorphic, keys and values could be either
48c302378bSEduard Zingerman * long-sized integers or pointers, this is achieved as follows:
49c302378bSEduard Zingerman * - interface functions that operate on keys and values are hidden
50c302378bSEduard Zingerman * behind auxiliary macros, e.g. hashmap_insert <-> hashmap__insert;
51c302378bSEduard Zingerman * - these auxiliary macros cast the key and value parameters as
52c302378bSEduard Zingerman * long or long *, so the user does not have to specify the casts explicitly;
53c302378bSEduard Zingerman * - for pointer parameters (e.g. old_key) the size of the pointed
54c302378bSEduard Zingerman * type is verified by hashmap_cast_ptr using _Static_assert;
55c302378bSEduard Zingerman * - when iterating using hashmap__for_each_* forms
56c302378bSEduard Zingerman * hasmap_entry->key should be used for integer keys and
57c302378bSEduard Zingerman * hasmap_entry->pkey should be used for pointer keys,
58c302378bSEduard Zingerman * same goes for values.
59c302378bSEduard Zingerman */
60e3b92422SAndrii Nakryiko struct hashmap_entry {
61c302378bSEduard Zingerman union {
62c302378bSEduard Zingerman long key;
63c302378bSEduard Zingerman const void *pkey;
64c302378bSEduard Zingerman };
65c302378bSEduard Zingerman union {
66c302378bSEduard Zingerman long value;
67c302378bSEduard Zingerman void *pvalue;
68c302378bSEduard Zingerman };
69e3b92422SAndrii Nakryiko struct hashmap_entry *next;
70e3b92422SAndrii Nakryiko };
71e3b92422SAndrii Nakryiko
72e3b92422SAndrii Nakryiko struct hashmap {
73e3b92422SAndrii Nakryiko hashmap_hash_fn hash_fn;
74e3b92422SAndrii Nakryiko hashmap_equal_fn equal_fn;
75e3b92422SAndrii Nakryiko void *ctx;
76e3b92422SAndrii Nakryiko
77e3b92422SAndrii Nakryiko struct hashmap_entry **buckets;
78e3b92422SAndrii Nakryiko size_t cap;
79e3b92422SAndrii Nakryiko size_t cap_bits;
80e3b92422SAndrii Nakryiko size_t sz;
81e3b92422SAndrii Nakryiko };
82e3b92422SAndrii Nakryiko
83e3b92422SAndrii Nakryiko void hashmap__init(struct hashmap *map, hashmap_hash_fn hash_fn,
84e3b92422SAndrii Nakryiko hashmap_equal_fn equal_fn, void *ctx);
85e3b92422SAndrii Nakryiko struct hashmap *hashmap__new(hashmap_hash_fn hash_fn,
86e3b92422SAndrii Nakryiko hashmap_equal_fn equal_fn,
87e3b92422SAndrii Nakryiko void *ctx);
88e3b92422SAndrii Nakryiko void hashmap__clear(struct hashmap *map);
89e3b92422SAndrii Nakryiko void hashmap__free(struct hashmap *map);
90e3b92422SAndrii Nakryiko
91e3b92422SAndrii Nakryiko size_t hashmap__size(const struct hashmap *map);
92e3b92422SAndrii Nakryiko size_t hashmap__capacity(const struct hashmap *map);
93e3b92422SAndrii Nakryiko
94e3b92422SAndrii Nakryiko /*
95e3b92422SAndrii Nakryiko * Hashmap insertion strategy:
96e3b92422SAndrii Nakryiko * - HASHMAP_ADD - only add key/value if key doesn't exist yet;
97e3b92422SAndrii Nakryiko * - HASHMAP_SET - add key/value pair if key doesn't exist yet; otherwise,
98e3b92422SAndrii Nakryiko * update value;
99e3b92422SAndrii Nakryiko * - HASHMAP_UPDATE - update value, if key already exists; otherwise, do
100e3b92422SAndrii Nakryiko * nothing and return -ENOENT;
101e3b92422SAndrii Nakryiko * - HASHMAP_APPEND - always add key/value pair, even if key already exists.
102e3b92422SAndrii Nakryiko * This turns hashmap into a multimap by allowing multiple values to be
103e3b92422SAndrii Nakryiko * associated with the same key. Most useful read API for such hashmap is
104e3b92422SAndrii Nakryiko * hashmap__for_each_key_entry() iteration. If hashmap__find() is still
105e3b92422SAndrii Nakryiko * used, it will return last inserted key/value entry (first in a bucket
106e3b92422SAndrii Nakryiko * chain).
107e3b92422SAndrii Nakryiko */
108e3b92422SAndrii Nakryiko enum hashmap_insert_strategy {
109e3b92422SAndrii Nakryiko HASHMAP_ADD,
110e3b92422SAndrii Nakryiko HASHMAP_SET,
111e3b92422SAndrii Nakryiko HASHMAP_UPDATE,
112e3b92422SAndrii Nakryiko HASHMAP_APPEND,
113e3b92422SAndrii Nakryiko };
114e3b92422SAndrii Nakryiko
115c302378bSEduard Zingerman #define hashmap_cast_ptr(p) ({ \
116*42597aa3SEduard Zingerman _Static_assert((__builtin_constant_p((p)) ? (p) == NULL : 0) || \
117*42597aa3SEduard Zingerman sizeof(*(p)) == sizeof(long), \
118c302378bSEduard Zingerman #p " pointee should be a long-sized integer or a pointer"); \
119c302378bSEduard Zingerman (long *)(p); \
120c302378bSEduard Zingerman })
121c302378bSEduard Zingerman
122e3b92422SAndrii Nakryiko /*
123e3b92422SAndrii Nakryiko * hashmap__insert() adds key/value entry w/ various semantics, depending on
124e3b92422SAndrii Nakryiko * provided strategy value. If a given key/value pair replaced already
125e3b92422SAndrii Nakryiko * existing key/value pair, both old key and old value will be returned
126e3b92422SAndrii Nakryiko * through old_key and old_value to allow calling code do proper memory
127e3b92422SAndrii Nakryiko * management.
128e3b92422SAndrii Nakryiko */
129c302378bSEduard Zingerman int hashmap_insert(struct hashmap *map, long key, long value,
130e3b92422SAndrii Nakryiko enum hashmap_insert_strategy strategy,
131c302378bSEduard Zingerman long *old_key, long *old_value);
132e3b92422SAndrii Nakryiko
133c302378bSEduard Zingerman #define hashmap__insert(map, key, value, strategy, old_key, old_value) \
134c302378bSEduard Zingerman hashmap_insert((map), (long)(key), (long)(value), (strategy), \
135c302378bSEduard Zingerman hashmap_cast_ptr(old_key), \
136c302378bSEduard Zingerman hashmap_cast_ptr(old_value))
137e3b92422SAndrii Nakryiko
138c302378bSEduard Zingerman #define hashmap__add(map, key, value) \
139c302378bSEduard Zingerman hashmap__insert((map), (key), (value), HASHMAP_ADD, NULL, NULL)
140e3b92422SAndrii Nakryiko
141c302378bSEduard Zingerman #define hashmap__set(map, key, value, old_key, old_value) \
142c302378bSEduard Zingerman hashmap__insert((map), (key), (value), HASHMAP_SET, (old_key), (old_value))
143e3b92422SAndrii Nakryiko
144c302378bSEduard Zingerman #define hashmap__update(map, key, value, old_key, old_value) \
145c302378bSEduard Zingerman hashmap__insert((map), (key), (value), HASHMAP_UPDATE, (old_key), (old_value))
146e3b92422SAndrii Nakryiko
147c302378bSEduard Zingerman #define hashmap__append(map, key, value) \
148c302378bSEduard Zingerman hashmap__insert((map), (key), (value), HASHMAP_APPEND, NULL, NULL)
149e3b92422SAndrii Nakryiko
150c302378bSEduard Zingerman bool hashmap_delete(struct hashmap *map, long key, long *old_key, long *old_value);
151c302378bSEduard Zingerman
152c302378bSEduard Zingerman #define hashmap__delete(map, key, old_key, old_value) \
153c302378bSEduard Zingerman hashmap_delete((map), (long)(key), \
154c302378bSEduard Zingerman hashmap_cast_ptr(old_key), \
155c302378bSEduard Zingerman hashmap_cast_ptr(old_value))
156c302378bSEduard Zingerman
157c302378bSEduard Zingerman bool hashmap_find(const struct hashmap *map, long key, long *value);
158c302378bSEduard Zingerman
159c302378bSEduard Zingerman #define hashmap__find(map, key, value) \
160c302378bSEduard Zingerman hashmap_find((map), (long)(key), hashmap_cast_ptr(value))
161e3b92422SAndrii Nakryiko
162e3b92422SAndrii Nakryiko /*
163e3b92422SAndrii Nakryiko * hashmap__for_each_entry - iterate over all entries in hashmap
164e3b92422SAndrii Nakryiko * @map: hashmap to iterate
165e3b92422SAndrii Nakryiko * @cur: struct hashmap_entry * used as a loop cursor
166e3b92422SAndrii Nakryiko * @bkt: integer used as a bucket loop cursor
167e3b92422SAndrii Nakryiko */
168e3b92422SAndrii Nakryiko #define hashmap__for_each_entry(map, cur, bkt) \
169e3b92422SAndrii Nakryiko for (bkt = 0; bkt < map->cap; bkt++) \
170e3b92422SAndrii Nakryiko for (cur = map->buckets[bkt]; cur; cur = cur->next)
171e3b92422SAndrii Nakryiko
172e3b92422SAndrii Nakryiko /*
173e3b92422SAndrii Nakryiko * hashmap__for_each_entry_safe - iterate over all entries in hashmap, safe
174e3b92422SAndrii Nakryiko * against removals
175e3b92422SAndrii Nakryiko * @map: hashmap to iterate
176e3b92422SAndrii Nakryiko * @cur: struct hashmap_entry * used as a loop cursor
177e3b92422SAndrii Nakryiko * @tmp: struct hashmap_entry * used as a temporary next cursor storage
178e3b92422SAndrii Nakryiko * @bkt: integer used as a bucket loop cursor
179e3b92422SAndrii Nakryiko */
180e3b92422SAndrii Nakryiko #define hashmap__for_each_entry_safe(map, cur, tmp, bkt) \
181e3b92422SAndrii Nakryiko for (bkt = 0; bkt < map->cap; bkt++) \
182e3b92422SAndrii Nakryiko for (cur = map->buckets[bkt]; \
183e3b92422SAndrii Nakryiko cur && ({tmp = cur->next; true; }); \
184e3b92422SAndrii Nakryiko cur = tmp)
185e3b92422SAndrii Nakryiko
186e3b92422SAndrii Nakryiko /*
187e3b92422SAndrii Nakryiko * hashmap__for_each_key_entry - iterate over entries associated with given key
188e3b92422SAndrii Nakryiko * @map: hashmap to iterate
189e3b92422SAndrii Nakryiko * @cur: struct hashmap_entry * used as a loop cursor
190e3b92422SAndrii Nakryiko * @key: key to iterate entries for
191e3b92422SAndrii Nakryiko */
192e3b92422SAndrii Nakryiko #define hashmap__for_each_key_entry(map, cur, _key) \
1937a078d2dSIan Rogers for (cur = map->buckets \
1947a078d2dSIan Rogers ? map->buckets[hash_bits(map->hash_fn((_key), map->ctx), map->cap_bits)] \
1957a078d2dSIan Rogers : NULL; \
196e3b92422SAndrii Nakryiko cur; \
197e3b92422SAndrii Nakryiko cur = cur->next) \
198e3b92422SAndrii Nakryiko if (map->equal_fn(cur->key, (_key), map->ctx))
199e3b92422SAndrii Nakryiko
200e3b92422SAndrii Nakryiko #define hashmap__for_each_key_entry_safe(map, cur, tmp, _key) \
2017a078d2dSIan Rogers for (cur = map->buckets \
2027a078d2dSIan Rogers ? map->buckets[hash_bits(map->hash_fn((_key), map->ctx), map->cap_bits)] \
2037a078d2dSIan Rogers : NULL; \
204e3b92422SAndrii Nakryiko cur && ({ tmp = cur->next; true; }); \
205e3b92422SAndrii Nakryiko cur = tmp) \
206e3b92422SAndrii Nakryiko if (map->equal_fn(cur->key, (_key), map->ctx))
207e3b92422SAndrii Nakryiko
208e3b92422SAndrii Nakryiko #endif /* __LIBBPF_HASHMAP_H */
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