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 15 static inline size_t hash_bits(size_t h, int bits) 16 { 17 /* shuffle bits and return requested number of upper bits */ 18 #if (__SIZEOF_SIZE_T__ == __SIZEOF_LONG_LONG__) 19 /* LP64 case */ 20 return (h * 11400714819323198485llu) >> (__SIZEOF_LONG_LONG__ * 8 - bits); 21 #elif (__SIZEOF_SIZE_T__ <= __SIZEOF_LONG__) 22 return (h * 2654435769lu) >> (__SIZEOF_LONG__ * 8 - bits); 23 #else 24 # error "Unsupported size_t size" 25 #endif 26 } 27 28 typedef size_t (*hashmap_hash_fn)(const void *key, void *ctx); 29 typedef bool (*hashmap_equal_fn)(const void *key1, const void *key2, void *ctx); 30 31 struct hashmap_entry { 32 const void *key; 33 void *value; 34 struct hashmap_entry *next; 35 }; 36 37 struct hashmap { 38 hashmap_hash_fn hash_fn; 39 hashmap_equal_fn equal_fn; 40 void *ctx; 41 42 struct hashmap_entry **buckets; 43 size_t cap; 44 size_t cap_bits; 45 size_t sz; 46 }; 47 48 #define HASHMAP_INIT(hash_fn, equal_fn, ctx) { \ 49 .hash_fn = (hash_fn), \ 50 .equal_fn = (equal_fn), \ 51 .ctx = (ctx), \ 52 .buckets = NULL, \ 53 .cap = 0, \ 54 .cap_bits = 0, \ 55 .sz = 0, \ 56 } 57 58 void hashmap__init(struct hashmap *map, hashmap_hash_fn hash_fn, 59 hashmap_equal_fn equal_fn, void *ctx); 60 struct hashmap *hashmap__new(hashmap_hash_fn hash_fn, 61 hashmap_equal_fn equal_fn, 62 void *ctx); 63 void hashmap__clear(struct hashmap *map); 64 void hashmap__free(struct hashmap *map); 65 66 size_t hashmap__size(const struct hashmap *map); 67 size_t hashmap__capacity(const struct hashmap *map); 68 69 /* 70 * Hashmap insertion strategy: 71 * - HASHMAP_ADD - only add key/value if key doesn't exist yet; 72 * - HASHMAP_SET - add key/value pair if key doesn't exist yet; otherwise, 73 * update value; 74 * - HASHMAP_UPDATE - update value, if key already exists; otherwise, do 75 * nothing and return -ENOENT; 76 * - HASHMAP_APPEND - always add key/value pair, even if key already exists. 77 * This turns hashmap into a multimap by allowing multiple values to be 78 * associated with the same key. Most useful read API for such hashmap is 79 * hashmap__for_each_key_entry() iteration. If hashmap__find() is still 80 * used, it will return last inserted key/value entry (first in a bucket 81 * chain). 82 */ 83 enum hashmap_insert_strategy { 84 HASHMAP_ADD, 85 HASHMAP_SET, 86 HASHMAP_UPDATE, 87 HASHMAP_APPEND, 88 }; 89 90 /* 91 * hashmap__insert() adds key/value entry w/ various semantics, depending on 92 * provided strategy value. If a given key/value pair replaced already 93 * existing key/value pair, both old key and old value will be returned 94 * through old_key and old_value to allow calling code do proper memory 95 * management. 96 */ 97 int hashmap__insert(struct hashmap *map, const void *key, void *value, 98 enum hashmap_insert_strategy strategy, 99 const void **old_key, void **old_value); 100 101 static inline int hashmap__add(struct hashmap *map, 102 const void *key, void *value) 103 { 104 return hashmap__insert(map, key, value, HASHMAP_ADD, NULL, NULL); 105 } 106 107 static inline int hashmap__set(struct hashmap *map, 108 const void *key, void *value, 109 const void **old_key, void **old_value) 110 { 111 return hashmap__insert(map, key, value, HASHMAP_SET, 112 old_key, old_value); 113 } 114 115 static inline int hashmap__update(struct hashmap *map, 116 const void *key, void *value, 117 const void **old_key, void **old_value) 118 { 119 return hashmap__insert(map, key, value, HASHMAP_UPDATE, 120 old_key, old_value); 121 } 122 123 static inline int hashmap__append(struct hashmap *map, 124 const void *key, void *value) 125 { 126 return hashmap__insert(map, key, value, HASHMAP_APPEND, NULL, NULL); 127 } 128 129 bool hashmap__delete(struct hashmap *map, const void *key, 130 const void **old_key, void **old_value); 131 132 bool hashmap__find(const struct hashmap *map, const void *key, void **value); 133 134 /* 135 * hashmap__for_each_entry - iterate over all entries in hashmap 136 * @map: hashmap to iterate 137 * @cur: struct hashmap_entry * used as a loop cursor 138 * @bkt: integer used as a bucket loop cursor 139 */ 140 #define hashmap__for_each_entry(map, cur, bkt) \ 141 for (bkt = 0; bkt < map->cap; bkt++) \ 142 for (cur = map->buckets[bkt]; cur; cur = cur->next) 143 144 /* 145 * hashmap__for_each_entry_safe - iterate over all entries in hashmap, safe 146 * against removals 147 * @map: hashmap to iterate 148 * @cur: struct hashmap_entry * used as a loop cursor 149 * @tmp: struct hashmap_entry * used as a temporary next cursor storage 150 * @bkt: integer used as a bucket loop cursor 151 */ 152 #define hashmap__for_each_entry_safe(map, cur, tmp, bkt) \ 153 for (bkt = 0; bkt < map->cap; bkt++) \ 154 for (cur = map->buckets[bkt]; \ 155 cur && ({tmp = cur->next; true; }); \ 156 cur = tmp) 157 158 /* 159 * hashmap__for_each_key_entry - iterate over entries associated with given key 160 * @map: hashmap to iterate 161 * @cur: struct hashmap_entry * used as a loop cursor 162 * @key: key to iterate entries for 163 */ 164 #define hashmap__for_each_key_entry(map, cur, _key) \ 165 for (cur = ({ size_t bkt = hash_bits(map->hash_fn((_key), map->ctx),\ 166 map->cap_bits); \ 167 map->buckets ? map->buckets[bkt] : NULL; }); \ 168 cur; \ 169 cur = cur->next) \ 170 if (map->equal_fn(cur->key, (_key), map->ctx)) 171 172 #define hashmap__for_each_key_entry_safe(map, cur, tmp, _key) \ 173 for (cur = ({ size_t bkt = hash_bits(map->hash_fn((_key), map->ctx),\ 174 map->cap_bits); \ 175 cur = map->buckets ? map->buckets[bkt] : NULL; }); \ 176 cur && ({ tmp = cur->next; true; }); \ 177 cur = tmp) \ 178 if (map->equal_fn(cur->key, (_key), map->ctx)) 179 180 #endif /* __LIBBPF_HASHMAP_H */ 181