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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 Facebook7 */8#ifndef __LIBBPF_HASHMAP_H9#define __LIBBPF_HASHMAP_H10 11#include <stdbool.h>12#include <stddef.h>13#include <limits.h>14 15static inline size_t hash_bits(size_t h, int bits)16{17 /* shuffle bits and return requested number of upper bits */18 if (bits == 0)19 return 0;20 21#if (__SIZEOF_SIZE_T__ == __SIZEOF_LONG_LONG__)22 /* LP64 case */23 return (h * 11400714819323198485llu) >> (__SIZEOF_LONG_LONG__ * 8 - bits);24#elif (__SIZEOF_SIZE_T__ <= __SIZEOF_LONG__)25 return (h * 2654435769lu) >> (__SIZEOF_LONG__ * 8 - bits);26#else27# error "Unsupported size_t size"28#endif29}30 31/* generic C-string hashing function */32static inline size_t str_hash(const char *s)33{34 size_t h = 0;35 36 while (*s) {37 h = h * 31 + *s;38 s++;39 }40 return h;41}42 43typedef size_t (*hashmap_hash_fn)(long key, void *ctx);44typedef bool (*hashmap_equal_fn)(long key1, long key2, void *ctx);45 46/*47 * Hashmap interface is polymorphic, keys and values could be either48 * long-sized integers or pointers, this is achieved as follows:49 * - interface functions that operate on keys and values are hidden50 * behind auxiliary macros, e.g. hashmap_insert <-> hashmap__insert;51 * - these auxiliary macros cast the key and value parameters as52 * long or long *, so the user does not have to specify the casts explicitly;53 * - for pointer parameters (e.g. old_key) the size of the pointed54 * type is verified by hashmap_cast_ptr using _Static_assert;55 * - when iterating using hashmap__for_each_* forms56 * hasmap_entry->key should be used for integer keys and57 * hasmap_entry->pkey should be used for pointer keys,58 * same goes for values.59 */60struct hashmap_entry {61 union {62 long key;63 const void *pkey;64 };65 union {66 long value;67 void *pvalue;68 };69 struct hashmap_entry *next;70};71 72struct hashmap {73 hashmap_hash_fn hash_fn;74 hashmap_equal_fn equal_fn;75 void *ctx;76 77 struct hashmap_entry **buckets;78 size_t cap;79 size_t cap_bits;80 size_t sz;81};82 83void hashmap__init(struct hashmap *map, hashmap_hash_fn hash_fn,84 hashmap_equal_fn equal_fn, void *ctx);85struct hashmap *hashmap__new(hashmap_hash_fn hash_fn,86 hashmap_equal_fn equal_fn,87 void *ctx);88void hashmap__clear(struct hashmap *map);89void hashmap__free(struct hashmap *map);90 91size_t hashmap__size(const struct hashmap *map);92size_t hashmap__capacity(const struct hashmap *map);93 94/*95 * Hashmap insertion strategy:96 * - HASHMAP_ADD - only add key/value if key doesn't exist yet;97 * - HASHMAP_SET - add key/value pair if key doesn't exist yet; otherwise,98 * update value;99 * - HASHMAP_UPDATE - update value, if key already exists; otherwise, do100 * nothing and return -ENOENT;101 * - HASHMAP_APPEND - always add key/value pair, even if key already exists.102 * This turns hashmap into a multimap by allowing multiple values to be103 * associated with the same key. Most useful read API for such hashmap is104 * hashmap__for_each_key_entry() iteration. If hashmap__find() is still105 * used, it will return last inserted key/value entry (first in a bucket106 * chain).107 */108enum hashmap_insert_strategy {109 HASHMAP_ADD,110 HASHMAP_SET,111 HASHMAP_UPDATE,112 HASHMAP_APPEND,113};114 115#define hashmap_cast_ptr(p) ({ \116 _Static_assert((__builtin_constant_p((p)) ? (p) == NULL : 0) || \117 sizeof(*(p)) == sizeof(long), \118 #p " pointee should be a long-sized integer or a pointer"); \119 (long *)(p); \120})121 122/*123 * hashmap__insert() adds key/value entry w/ various semantics, depending on124 * provided strategy value. If a given key/value pair replaced already125 * existing key/value pair, both old key and old value will be returned126 * through old_key and old_value to allow calling code do proper memory127 * management.128 */129int hashmap_insert(struct hashmap *map, long key, long value,130 enum hashmap_insert_strategy strategy,131 long *old_key, long *old_value);132 133#define hashmap__insert(map, key, value, strategy, old_key, old_value) \134 hashmap_insert((map), (long)(key), (long)(value), (strategy), \135 hashmap_cast_ptr(old_key), \136 hashmap_cast_ptr(old_value))137 138#define hashmap__add(map, key, value) \139 hashmap__insert((map), (key), (value), HASHMAP_ADD, NULL, NULL)140 141#define hashmap__set(map, key, value, old_key, old_value) \142 hashmap__insert((map), (key), (value), HASHMAP_SET, (old_key), (old_value))143 144#define hashmap__update(map, key, value, old_key, old_value) \145 hashmap__insert((map), (key), (value), HASHMAP_UPDATE, (old_key), (old_value))146 147#define hashmap__append(map, key, value) \148 hashmap__insert((map), (key), (value), HASHMAP_APPEND, NULL, NULL)149 150bool hashmap_delete(struct hashmap *map, long key, long *old_key, long *old_value);151 152#define hashmap__delete(map, key, old_key, old_value) \153 hashmap_delete((map), (long)(key), \154 hashmap_cast_ptr(old_key), \155 hashmap_cast_ptr(old_value))156 157bool hashmap_find(const struct hashmap *map, long key, long *value);158 159#define hashmap__find(map, key, value) \160 hashmap_find((map), (long)(key), hashmap_cast_ptr(value))161 162/*163 * hashmap__for_each_entry - iterate over all entries in hashmap164 * @map: hashmap to iterate165 * @cur: struct hashmap_entry * used as a loop cursor166 * @bkt: integer used as a bucket loop cursor167 */168#define hashmap__for_each_entry(map, cur, bkt) \169 for (bkt = 0; bkt < map->cap; bkt++) \170 for (cur = map->buckets[bkt]; cur; cur = cur->next)171 172/*173 * hashmap__for_each_entry_safe - iterate over all entries in hashmap, safe174 * against removals175 * @map: hashmap to iterate176 * @cur: struct hashmap_entry * used as a loop cursor177 * @tmp: struct hashmap_entry * used as a temporary next cursor storage178 * @bkt: integer used as a bucket loop cursor179 */180#define hashmap__for_each_entry_safe(map, cur, tmp, bkt) \181 for (bkt = 0; bkt < map->cap; bkt++) \182 for (cur = map->buckets[bkt]; \183 cur && ({tmp = cur->next; true; }); \184 cur = tmp)185 186/*187 * hashmap__for_each_key_entry - iterate over entries associated with given key188 * @map: hashmap to iterate189 * @cur: struct hashmap_entry * used as a loop cursor190 * @key: key to iterate entries for191 */192#define hashmap__for_each_key_entry(map, cur, _key) \193 for (cur = map->buckets \194 ? map->buckets[hash_bits(map->hash_fn((_key), map->ctx), map->cap_bits)] \195 : NULL; \196 cur; \197 cur = cur->next) \198 if (map->equal_fn(cur->key, (_key), map->ctx))199 200#define hashmap__for_each_key_entry_safe(map, cur, tmp, _key) \201 for (cur = map->buckets \202 ? map->buckets[hash_bits(map->hash_fn((_key), map->ctx), map->cap_bits)] \203 : NULL; \204 cur && ({ tmp = cur->next; true; }); \205 cur = tmp) \206 if (map->equal_fn(cur->key, (_key), map->ctx))207 208#endif /* __LIBBPF_HASHMAP_H */209