/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */ /* * Generic non-thread safe hash map implementation. * * Copyright (c) 2019 Facebook */ #ifndef __LIBBPF_HASHMAP_H #define __LIBBPF_HASHMAP_H #include <stdbool.h> #include <stddef.h> #include <limits.h> static inline size_t hash_bits(size_t h, int bits) { /* shuffle bits and return requested number of upper bits */ if (bits == 0) return 0; #if (__SIZEOF_SIZE_T__ == __SIZEOF_LONG_LONG__) /* LP64 case */ return (h * 11400714819323198485llu) >> (__SIZEOF_LONG_LONG__ * 8 - bits); #elif (__SIZEOF_SIZE_T__ <= __SIZEOF_LONG__) return (h * 2654435769lu) >> (__SIZEOF_LONG__ * 8 - bits); #else # error "Unsupported size_t size" #endif } /* generic C-string hashing function */ static inline size_t str_hash(const char *s) { size_t h = 0; while (*s) { h = h * 31 + *s; s++; } return h; } typedef size_t (*hashmap_hash_fn)(const void *key, void *ctx); typedef bool (*hashmap_equal_fn)(const void *key1, const void *key2, void *ctx); struct hashmap_entry { const void *key; void *value; struct hashmap_entry *next; }; struct hashmap { hashmap_hash_fn hash_fn; hashmap_equal_fn equal_fn; void *ctx; struct hashmap_entry **buckets; size_t cap; size_t cap_bits; size_t sz; }; #define HASHMAP_INIT(hash_fn, equal_fn, ctx) { \ .hash_fn = (hash_fn), \ .equal_fn = (equal_fn), \ .ctx = (ctx), \ .buckets = NULL, \ .cap = 0, \ .cap_bits = 0, \ .sz = 0, \ } void hashmap__init(struct hashmap *map, hashmap_hash_fn hash_fn, hashmap_equal_fn equal_fn, void *ctx); struct hashmap *hashmap__new(hashmap_hash_fn hash_fn, hashmap_equal_fn equal_fn, void *ctx); void hashmap__clear(struct hashmap *map); void hashmap__free(struct hashmap *map); size_t hashmap__size(const struct hashmap *map); size_t hashmap__capacity(const struct hashmap *map); /* * Hashmap insertion strategy: * - HASHMAP_ADD - only add key/value if key doesn't exist yet; * - HASHMAP_SET - add key/value pair if key doesn't exist yet; otherwise, * update value; * - HASHMAP_UPDATE - update value, if key already exists; otherwise, do * nothing and return -ENOENT; * - HASHMAP_APPEND - always add key/value pair, even if key already exists. * This turns hashmap into a multimap by allowing multiple values to be * associated with the same key. Most useful read API for such hashmap is * hashmap__for_each_key_entry() iteration. If hashmap__find() is still * used, it will return last inserted key/value entry (first in a bucket * chain). */ enum hashmap_insert_strategy { HASHMAP_ADD, HASHMAP_SET, HASHMAP_UPDATE, HASHMAP_APPEND, }; /* * hashmap__insert() adds key/value entry w/ various semantics, depending on * provided strategy value. If a given key/value pair replaced already * existing key/value pair, both old key and old value will be returned * through old_key and old_value to allow calling code do proper memory * management. */ int hashmap__insert(struct hashmap *map, const void *key, void *value, enum hashmap_insert_strategy strategy, const void **old_key, void **old_value); static inline int hashmap__add(struct hashmap *map, const void *key, void *value) { return hashmap__insert(map, key, value, HASHMAP_ADD, NULL, NULL); } static inline int hashmap__set(struct hashmap *map, const void *key, void *value, const void **old_key, void **old_value) { return hashmap__insert(map, key, value, HASHMAP_SET, old_key, old_value); } static inline int hashmap__update(struct hashmap *map, const void *key, void *value, const void **old_key, void **old_value) { return hashmap__insert(map, key, value, HASHMAP_UPDATE, old_key, old_value); } static inline int hashmap__append(struct hashmap *map, const void *key, void *value) { return hashmap__insert(map, key, value, HASHMAP_APPEND, NULL, NULL); } bool hashmap__delete(struct hashmap *map, const void *key, const void **old_key, void **old_value); bool hashmap__find(const struct hashmap *map, const void *key, void **value); /* * hashmap__for_each_entry - iterate over all entries in hashmap * @map: hashmap to iterate * @cur: struct hashmap_entry * used as a loop cursor * @bkt: integer used as a bucket loop cursor */ #define hashmap__for_each_entry(map, cur, bkt) \ for (bkt = 0; bkt < map->cap; bkt++) \ for (cur = map->buckets[bkt]; cur; cur = cur->next) /* * hashmap__for_each_entry_safe - iterate over all entries in hashmap, safe * against removals * @map: hashmap to iterate * @cur: struct hashmap_entry * used as a loop cursor * @tmp: struct hashmap_entry * used as a temporary next cursor storage * @bkt: integer used as a bucket loop cursor */ #define hashmap__for_each_entry_safe(map, cur, tmp, bkt) \ for (bkt = 0; bkt < map->cap; bkt++) \ for (cur = map->buckets[bkt]; \ cur && ({tmp = cur->next; true; }); \ cur = tmp) /* * hashmap__for_each_key_entry - iterate over entries associated with given key * @map: hashmap to iterate * @cur: struct hashmap_entry * used as a loop cursor * @key: key to iterate entries for */ #define hashmap__for_each_key_entry(map, cur, _key) \ for (cur = map->buckets \ ? map->buckets[hash_bits(map->hash_fn((_key), map->ctx), map->cap_bits)] \ : NULL; \ cur; \ cur = cur->next) \ if (map->equal_fn(cur->key, (_key), map->ctx)) #define hashmap__for_each_key_entry_safe(map, cur, tmp, _key) \ for (cur = map->buckets \ ? map->buckets[hash_bits(map->hash_fn((_key), map->ctx), map->cap_bits)] \ : NULL; \ cur && ({ tmp = cur->next; true; }); \ cur = tmp) \ if (map->equal_fn(cur->key, (_key), map->ctx)) #endif /* __LIBBPF_HASHMAP_H */