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241 lines
5.0 KiB
241 lines
5.0 KiB
// 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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#include <stdint.h> |
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#include <stdlib.h> |
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#include <stdio.h> |
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#include <errno.h> |
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#include <linux/err.h> |
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#include "hashmap.h" |
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/* make sure libbpf doesn't use kernel-only integer typedefs */ |
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#pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64 |
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/* prevent accidental re-addition of reallocarray() */ |
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#pragma GCC poison reallocarray |
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/* start with 4 buckets */ |
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#define HASHMAP_MIN_CAP_BITS 2 |
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static void hashmap_add_entry(struct hashmap_entry **pprev, |
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struct hashmap_entry *entry) |
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{ |
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entry->next = *pprev; |
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*pprev = entry; |
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} |
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static void hashmap_del_entry(struct hashmap_entry **pprev, |
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struct hashmap_entry *entry) |
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{ |
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*pprev = entry->next; |
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entry->next = NULL; |
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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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{ |
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map->hash_fn = hash_fn; |
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map->equal_fn = equal_fn; |
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map->ctx = ctx; |
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map->buckets = NULL; |
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map->cap = 0; |
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map->cap_bits = 0; |
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map->sz = 0; |
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} |
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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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{ |
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struct hashmap *map = malloc(sizeof(struct hashmap)); |
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if (!map) |
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return ERR_PTR(-ENOMEM); |
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hashmap__init(map, hash_fn, equal_fn, ctx); |
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return map; |
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} |
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void hashmap__clear(struct hashmap *map) |
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{ |
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struct hashmap_entry *cur, *tmp; |
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size_t bkt; |
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hashmap__for_each_entry_safe(map, cur, tmp, bkt) { |
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free(cur); |
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} |
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free(map->buckets); |
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map->buckets = NULL; |
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map->cap = map->cap_bits = map->sz = 0; |
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} |
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void hashmap__free(struct hashmap *map) |
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{ |
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if (!map) |
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return; |
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hashmap__clear(map); |
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free(map); |
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} |
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size_t hashmap__size(const struct hashmap *map) |
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{ |
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return map->sz; |
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} |
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size_t hashmap__capacity(const struct hashmap *map) |
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{ |
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return map->cap; |
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} |
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static bool hashmap_needs_to_grow(struct hashmap *map) |
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{ |
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/* grow if empty or more than 75% filled */ |
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return (map->cap == 0) || ((map->sz + 1) * 4 / 3 > map->cap); |
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} |
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static int hashmap_grow(struct hashmap *map) |
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{ |
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struct hashmap_entry **new_buckets; |
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struct hashmap_entry *cur, *tmp; |
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size_t new_cap_bits, new_cap; |
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size_t h, bkt; |
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new_cap_bits = map->cap_bits + 1; |
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if (new_cap_bits < HASHMAP_MIN_CAP_BITS) |
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new_cap_bits = HASHMAP_MIN_CAP_BITS; |
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new_cap = 1UL << new_cap_bits; |
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new_buckets = calloc(new_cap, sizeof(new_buckets[0])); |
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if (!new_buckets) |
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return -ENOMEM; |
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hashmap__for_each_entry_safe(map, cur, tmp, bkt) { |
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h = hash_bits(map->hash_fn(cur->key, map->ctx), new_cap_bits); |
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hashmap_add_entry(&new_buckets[h], cur); |
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} |
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map->cap = new_cap; |
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map->cap_bits = new_cap_bits; |
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free(map->buckets); |
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map->buckets = new_buckets; |
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return 0; |
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} |
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static bool hashmap_find_entry(const struct hashmap *map, |
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const void *key, size_t hash, |
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struct hashmap_entry ***pprev, |
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struct hashmap_entry **entry) |
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{ |
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struct hashmap_entry *cur, **prev_ptr; |
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if (!map->buckets) |
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return false; |
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for (prev_ptr = &map->buckets[hash], cur = *prev_ptr; |
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cur; |
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prev_ptr = &cur->next, cur = cur->next) { |
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if (map->equal_fn(cur->key, key, map->ctx)) { |
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if (pprev) |
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*pprev = prev_ptr; |
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*entry = cur; |
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return true; |
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} |
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} |
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return false; |
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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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{ |
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struct hashmap_entry *entry; |
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size_t h; |
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int err; |
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if (old_key) |
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*old_key = NULL; |
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if (old_value) |
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*old_value = NULL; |
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h = hash_bits(map->hash_fn(key, map->ctx), map->cap_bits); |
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if (strategy != HASHMAP_APPEND && |
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hashmap_find_entry(map, key, h, NULL, &entry)) { |
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if (old_key) |
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*old_key = entry->key; |
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if (old_value) |
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*old_value = entry->value; |
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if (strategy == HASHMAP_SET || strategy == HASHMAP_UPDATE) { |
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entry->key = key; |
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entry->value = value; |
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return 0; |
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} else if (strategy == HASHMAP_ADD) { |
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return -EEXIST; |
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} |
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} |
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if (strategy == HASHMAP_UPDATE) |
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return -ENOENT; |
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if (hashmap_needs_to_grow(map)) { |
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err = hashmap_grow(map); |
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if (err) |
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return err; |
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h = hash_bits(map->hash_fn(key, map->ctx), map->cap_bits); |
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} |
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entry = malloc(sizeof(struct hashmap_entry)); |
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if (!entry) |
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return -ENOMEM; |
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entry->key = key; |
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entry->value = value; |
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hashmap_add_entry(&map->buckets[h], entry); |
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map->sz++; |
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return 0; |
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} |
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bool hashmap__find(const struct hashmap *map, const void *key, void **value) |
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{ |
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struct hashmap_entry *entry; |
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size_t h; |
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h = hash_bits(map->hash_fn(key, map->ctx), map->cap_bits); |
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if (!hashmap_find_entry(map, key, h, NULL, &entry)) |
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return false; |
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if (value) |
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*value = entry->value; |
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return true; |
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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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{ |
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struct hashmap_entry **pprev, *entry; |
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size_t h; |
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h = hash_bits(map->hash_fn(key, map->ctx), map->cap_bits); |
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if (!hashmap_find_entry(map, key, h, &pprev, &entry)) |
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return false; |
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if (old_key) |
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*old_key = entry->key; |
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if (old_value) |
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*old_value = entry->value; |
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hashmap_del_entry(pprev, entry); |
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free(entry); |
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map->sz--; |
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return true; |
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} |
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