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![Arnaldo Carvalho de Melo](/assets/img/avatar_default.png)
Some systems, such as Android, don't have a define for __WORDSIZE, do it in terms of __SIZEOF_LONG__, as done in perf since 2012: http://git.kernel.org/torvalds/c/3f34f6c0233ae055b5 For reference: https://gcc.gnu.org/onlinedocs/cpp/Common-Predefined-Macros.html I build tested it here and Andrii did some Travis CI build tests too. Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/20200608161150.GA3073@kernel.org
176 lines
5.4 KiB
C
176 lines
5.4 KiB
C
/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
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/*
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* Generic non-thread safe hash map implementation.
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*
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* Copyright (c) 2019 Facebook
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*/
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#ifndef __LIBBPF_HASHMAP_H
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#define __LIBBPF_HASHMAP_H
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#include <stdbool.h>
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#include <stddef.h>
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#include <limits.h>
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#ifndef __WORDSIZE
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#define __WORDSIZE (__SIZEOF_LONG__ * 8)
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#endif
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static inline size_t hash_bits(size_t h, int bits)
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{
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/* shuffle bits and return requested number of upper bits */
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return (h * 11400714819323198485llu) >> (__WORDSIZE - bits);
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}
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typedef size_t (*hashmap_hash_fn)(const void *key, void *ctx);
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typedef bool (*hashmap_equal_fn)(const void *key1, const void *key2, void *ctx);
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struct hashmap_entry {
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const void *key;
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void *value;
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struct hashmap_entry *next;
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};
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struct hashmap {
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hashmap_hash_fn hash_fn;
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hashmap_equal_fn equal_fn;
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void *ctx;
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struct hashmap_entry **buckets;
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size_t cap;
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size_t cap_bits;
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size_t sz;
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};
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#define HASHMAP_INIT(hash_fn, equal_fn, ctx) { \
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.hash_fn = (hash_fn), \
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.equal_fn = (equal_fn), \
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.ctx = (ctx), \
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.buckets = NULL, \
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.cap = 0, \
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.cap_bits = 0, \
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.sz = 0, \
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}
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void hashmap__init(struct hashmap *map, hashmap_hash_fn hash_fn,
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hashmap_equal_fn equal_fn, void *ctx);
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struct hashmap *hashmap__new(hashmap_hash_fn hash_fn,
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hashmap_equal_fn equal_fn,
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void *ctx);
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void hashmap__clear(struct hashmap *map);
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void hashmap__free(struct hashmap *map);
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size_t hashmap__size(const struct hashmap *map);
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size_t hashmap__capacity(const struct hashmap *map);
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/*
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* Hashmap insertion strategy:
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* - HASHMAP_ADD - only add key/value if key doesn't exist yet;
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* - HASHMAP_SET - add key/value pair if key doesn't exist yet; otherwise,
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* update value;
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* - HASHMAP_UPDATE - update value, if key already exists; otherwise, do
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* nothing and return -ENOENT;
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* - HASHMAP_APPEND - always add key/value pair, even if key already exists.
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* This turns hashmap into a multimap by allowing multiple values to be
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* associated with the same key. Most useful read API for such hashmap is
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* hashmap__for_each_key_entry() iteration. If hashmap__find() is still
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* used, it will return last inserted key/value entry (first in a bucket
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* chain).
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*/
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enum hashmap_insert_strategy {
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HASHMAP_ADD,
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HASHMAP_SET,
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HASHMAP_UPDATE,
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HASHMAP_APPEND,
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};
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/*
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* hashmap__insert() adds key/value entry w/ various semantics, depending on
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* provided strategy value. If a given key/value pair replaced already
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* existing key/value pair, both old key and old value will be returned
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* through old_key and old_value to allow calling code do proper memory
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* management.
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*/
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int hashmap__insert(struct hashmap *map, const void *key, void *value,
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enum hashmap_insert_strategy strategy,
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const void **old_key, void **old_value);
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static inline int hashmap__add(struct hashmap *map,
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const void *key, void *value)
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{
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return hashmap__insert(map, key, value, HASHMAP_ADD, NULL, NULL);
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}
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static inline int hashmap__set(struct hashmap *map,
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const void *key, void *value,
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const void **old_key, void **old_value)
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{
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return hashmap__insert(map, key, value, HASHMAP_SET,
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old_key, old_value);
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}
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static inline int hashmap__update(struct hashmap *map,
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const void *key, void *value,
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const void **old_key, void **old_value)
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{
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return hashmap__insert(map, key, value, HASHMAP_UPDATE,
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old_key, old_value);
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}
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static inline int hashmap__append(struct hashmap *map,
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const void *key, void *value)
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{
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return hashmap__insert(map, key, value, HASHMAP_APPEND, NULL, NULL);
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}
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bool hashmap__delete(struct hashmap *map, const void *key,
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const void **old_key, void **old_value);
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bool hashmap__find(const struct hashmap *map, const void *key, void **value);
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/*
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* hashmap__for_each_entry - iterate over all entries in hashmap
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* @map: hashmap to iterate
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* @cur: struct hashmap_entry * used as a loop cursor
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* @bkt: integer used as a bucket loop cursor
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*/
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#define hashmap__for_each_entry(map, cur, bkt) \
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for (bkt = 0; bkt < map->cap; bkt++) \
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for (cur = map->buckets[bkt]; cur; cur = cur->next)
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/*
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* hashmap__for_each_entry_safe - iterate over all entries in hashmap, safe
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* against removals
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* @map: hashmap to iterate
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* @cur: struct hashmap_entry * used as a loop cursor
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* @tmp: struct hashmap_entry * used as a temporary next cursor storage
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* @bkt: integer used as a bucket loop cursor
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*/
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#define hashmap__for_each_entry_safe(map, cur, tmp, bkt) \
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for (bkt = 0; bkt < map->cap; bkt++) \
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for (cur = map->buckets[bkt]; \
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cur && ({tmp = cur->next; true; }); \
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cur = tmp)
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/*
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* hashmap__for_each_key_entry - iterate over entries associated with given key
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* @map: hashmap to iterate
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* @cur: struct hashmap_entry * used as a loop cursor
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* @key: key to iterate entries for
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*/
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#define hashmap__for_each_key_entry(map, cur, _key) \
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for (cur = ({ size_t bkt = hash_bits(map->hash_fn((_key), map->ctx),\
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map->cap_bits); \
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map->buckets ? map->buckets[bkt] : NULL; }); \
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cur; \
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cur = cur->next) \
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if (map->equal_fn(cur->key, (_key), map->ctx))
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#define hashmap__for_each_key_entry_safe(map, cur, tmp, _key) \
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for (cur = ({ size_t bkt = hash_bits(map->hash_fn((_key), map->ctx),\
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map->cap_bits); \
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cur = map->buckets ? map->buckets[bkt] : NULL; }); \
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cur && ({ tmp = cur->next; true; }); \
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cur = tmp) \
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if (map->equal_fn(cur->key, (_key), map->ctx))
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#endif /* __LIBBPF_HASHMAP_H */
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