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 19 static inline size_t hash_bits(size_t h, int bits) 20 { 21 /* shuffle bits and return requested number of upper bits */ 22 return (h * 11400714819323198485llu) >> (__WORDSIZE - bits); 23 } 24 25 typedef size_t (*hashmap_hash_fn)(const void *key, void *ctx); 26 typedef bool (*hashmap_equal_fn)(const void *key1, const void *key2, void *ctx); 27 28 struct hashmap_entry { 29 const void *key; 30 void *value; 31 struct hashmap_entry *next; 32 }; 33 34 struct hashmap { 35 hashmap_hash_fn hash_fn; 36 hashmap_equal_fn equal_fn; 37 void *ctx; 38 39 struct hashmap_entry **buckets; 40 size_t cap; 41 size_t cap_bits; 42 size_t sz; 43 }; 44 45 #define HASHMAP_INIT(hash_fn, equal_fn, ctx) { \ 46 .hash_fn = (hash_fn), \ 47 .equal_fn = (equal_fn), \ 48 .ctx = (ctx), \ 49 .buckets = NULL, \ 50 .cap = 0, \ 51 .cap_bits = 0, \ 52 .sz = 0, \ 53 } 54 55 void hashmap__init(struct hashmap *map, hashmap_hash_fn hash_fn, 56 hashmap_equal_fn equal_fn, void *ctx); 57 struct hashmap *hashmap__new(hashmap_hash_fn hash_fn, 58 hashmap_equal_fn equal_fn, 59 void *ctx); 60 void hashmap__clear(struct hashmap *map); 61 void hashmap__free(struct hashmap *map); 62 63 size_t hashmap__size(const struct hashmap *map); 64 size_t hashmap__capacity(const struct hashmap *map); 65 66 /* 67 * Hashmap insertion strategy: 68 * - HASHMAP_ADD - only add key/value if key doesn't exist yet; 69 * - HASHMAP_SET - add key/value pair if key doesn't exist yet; otherwise, 70 * update value; 71 * - HASHMAP_UPDATE - update value, if key already exists; otherwise, do 72 * nothing and return -ENOENT; 73 * - HASHMAP_APPEND - always add key/value pair, even if key already exists. 74 * This turns hashmap into a multimap by allowing multiple values to be 75 * associated with the same key. Most useful read API for such hashmap is 76 * hashmap__for_each_key_entry() iteration. If hashmap__find() is still 77 * used, it will return last inserted key/value entry (first in a bucket 78 * chain). 79 */ 80 enum hashmap_insert_strategy { 81 HASHMAP_ADD, 82 HASHMAP_SET, 83 HASHMAP_UPDATE, 84 HASHMAP_APPEND, 85 }; 86 87 /* 88 * hashmap__insert() adds key/value entry w/ various semantics, depending on 89 * provided strategy value. If a given key/value pair replaced already 90 * existing key/value pair, both old key and old value will be returned 91 * through old_key and old_value to allow calling code do proper memory 92 * management. 93 */ 94 int hashmap__insert(struct hashmap *map, const void *key, void *value, 95 enum hashmap_insert_strategy strategy, 96 const void **old_key, void **old_value); 97 98 static inline int hashmap__add(struct hashmap *map, 99 const void *key, void *value) 100 { 101 return hashmap__insert(map, key, value, HASHMAP_ADD, NULL, NULL); 102 } 103 104 static inline int hashmap__set(struct hashmap *map, 105 const void *key, void *value, 106 const void **old_key, void **old_value) 107 { 108 return hashmap__insert(map, key, value, HASHMAP_SET, 109 old_key, old_value); 110 } 111 112 static inline int hashmap__update(struct hashmap *map, 113 const void *key, void *value, 114 const void **old_key, void **old_value) 115 { 116 return hashmap__insert(map, key, value, HASHMAP_UPDATE, 117 old_key, old_value); 118 } 119 120 static inline int hashmap__append(struct hashmap *map, 121 const void *key, void *value) 122 { 123 return hashmap__insert(map, key, value, HASHMAP_APPEND, NULL, NULL); 124 } 125 126 bool hashmap__delete(struct hashmap *map, const void *key, 127 const void **old_key, void **old_value); 128 129 bool hashmap__find(const struct hashmap *map, const void *key, void **value); 130 131 /* 132 * hashmap__for_each_entry - iterate over all entries in hashmap 133 * @map: hashmap to iterate 134 * @cur: struct hashmap_entry * used as a loop cursor 135 * @bkt: integer used as a bucket loop cursor 136 */ 137 #define hashmap__for_each_entry(map, cur, bkt) \ 138 for (bkt = 0; bkt < map->cap; bkt++) \ 139 for (cur = map->buckets[bkt]; cur; cur = cur->next) 140 141 /* 142 * hashmap__for_each_entry_safe - iterate over all entries in hashmap, safe 143 * against removals 144 * @map: hashmap to iterate 145 * @cur: struct hashmap_entry * used as a loop cursor 146 * @tmp: struct hashmap_entry * used as a temporary next cursor storage 147 * @bkt: integer used as a bucket loop cursor 148 */ 149 #define hashmap__for_each_entry_safe(map, cur, tmp, bkt) \ 150 for (bkt = 0; bkt < map->cap; bkt++) \ 151 for (cur = map->buckets[bkt]; \ 152 cur && ({tmp = cur->next; true; }); \ 153 cur = tmp) 154 155 /* 156 * hashmap__for_each_key_entry - iterate over entries associated with given key 157 * @map: hashmap to iterate 158 * @cur: struct hashmap_entry * used as a loop cursor 159 * @key: key to iterate entries for 160 */ 161 #define hashmap__for_each_key_entry(map, cur, _key) \ 162 for (cur = ({ size_t bkt = hash_bits(map->hash_fn((_key), map->ctx),\ 163 map->cap_bits); \ 164 map->buckets ? map->buckets[bkt] : NULL; }); \ 165 cur; \ 166 cur = cur->next) \ 167 if (map->equal_fn(cur->key, (_key), map->ctx)) 168 169 #define hashmap__for_each_key_entry_safe(map, cur, tmp, _key) \ 170 for (cur = ({ size_t bkt = hash_bits(map->hash_fn((_key), map->ctx),\ 171 map->cap_bits); \ 172 cur = map->buckets ? map->buckets[bkt] : NULL; }); \ 173 cur && ({ tmp = cur->next; true; }); \ 174 cur = tmp) \ 175 if (map->equal_fn(cur->key, (_key), map->ctx)) 176 177 #endif /* __LIBBPF_HASHMAP_H */ 178