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 20 static 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 26 typedef size_t (*hashmap_hash_fn)(const void *key, void *ctx); 27 typedef bool (*hashmap_equal_fn)(const void *key1, const void *key2, void *ctx); 28 29 struct hashmap_entry { 30 const void *key; 31 void *value; 32 struct hashmap_entry *next; 33 }; 34 35 struct 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 56 void hashmap__init(struct hashmap *map, hashmap_hash_fn hash_fn, 57 hashmap_equal_fn equal_fn, void *ctx); 58 struct hashmap *hashmap__new(hashmap_hash_fn hash_fn, 59 hashmap_equal_fn equal_fn, 60 void *ctx); 61 void hashmap__clear(struct hashmap *map); 62 void hashmap__free(struct hashmap *map); 63 64 size_t hashmap__size(const struct hashmap *map); 65 size_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 */ 81 enum 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 */ 95 int 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 99 static 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 } 104 105 static 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 } 112 113 static 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 } 120 121 static 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 } 126 127 bool hashmap__delete(struct hashmap *map, const void *key, 128 const void **old_key, void **old_value); 129 130 bool 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 */ 179