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