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/* 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 */
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