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systemd/hashmap.c

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/*-*- Mode: C; c-basic-offset: 8 -*-*/
/***
This file is part of systemd.
Copyright 2010 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <assert.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include "util.h"
#include "hashmap.h"
#include "macro.h"
#define NBUCKETS 127
struct hashmap_entry {
const void *key;
void *value;
struct hashmap_entry *bucket_next, *bucket_previous;
struct hashmap_entry *iterate_next, *iterate_previous;
};
struct Hashmap {
hash_func_t hash_func;
compare_func_t compare_func;
struct hashmap_entry *iterate_list_head, *iterate_list_tail;
unsigned n_entries;
};
#define BY_HASH(h) ((struct hashmap_entry**) ((uint8_t*) (h) + ALIGN(sizeof(Hashmap))))
unsigned string_hash_func(const void *p) {
unsigned hash = 0;
const char *c;
for (c = p; *c; c++)
hash = 31 * hash + (unsigned) *c;
return hash;
}
int string_compare_func(const void *a, const void *b) {
return strcmp(a, b);
}
unsigned trivial_hash_func(const void *p) {
return PTR_TO_UINT(p);
}
int trivial_compare_func(const void *a, const void *b) {
return a < b ? -1 : (a > b ? 1 : 0);
}
Hashmap *hashmap_new(hash_func_t hash_func, compare_func_t compare_func) {
Hashmap *h;
if (!(h = malloc0(ALIGN(sizeof(Hashmap)) + NBUCKETS * ALIGN(sizeof(struct hashmap_entry*)))))
return NULL;
h->hash_func = hash_func ? hash_func : trivial_hash_func;
h->compare_func = compare_func ? compare_func : trivial_compare_func;
h->n_entries = 0;
h->iterate_list_head = h->iterate_list_tail = NULL;
return h;
}
int hashmap_ensure_allocated(Hashmap **h, hash_func_t hash_func, compare_func_t compare_func) {
assert(h);
if (*h)
return 0;
if (!(*h = hashmap_new(hash_func, compare_func)))
return -ENOMEM;
return 0;
}
static void remove_entry(Hashmap *h, struct hashmap_entry *e) {
assert(h);
assert(e);
/* Remove from iteration list */
if (e->iterate_next)
e->iterate_next->iterate_previous = e->iterate_previous;
else
h->iterate_list_tail = e->iterate_previous;
if (e->iterate_previous)
e->iterate_previous->iterate_next = e->iterate_next;
else
h->iterate_list_head = e->iterate_next;
/* Remove from hash table bucket list */
if (e->bucket_next)
e->bucket_next->bucket_previous = e->bucket_previous;
if (e->bucket_previous)
e->bucket_previous->bucket_next = e->bucket_next;
else {
unsigned hash = h->hash_func(e->key) % NBUCKETS;
BY_HASH(h)[hash] = e->bucket_next;
}
free(e);
assert(h->n_entries >= 1);
h->n_entries--;
}
void hashmap_free(Hashmap*h) {
if (!h)
return;
hashmap_clear(h);
free(h);
}
void hashmap_clear(Hashmap *h) {
if (!h)
return;
while (h->iterate_list_head)
remove_entry(h, h->iterate_list_head);
}
static struct hashmap_entry *hash_scan(Hashmap *h, unsigned hash, const void *key) {
struct hashmap_entry *e;
assert(h);
assert(hash < NBUCKETS);
for (e = BY_HASH(h)[hash]; e; e = e->bucket_next)
if (h->compare_func(e->key, key) == 0)
return e;
return NULL;
}
int hashmap_put(Hashmap *h, const void *key, void *value) {
struct hashmap_entry *e;
unsigned hash;
assert(h);
hash = h->hash_func(key) % NBUCKETS;
if ((e = hash_scan(h, hash, key))) {
if (e->value == value)
return 0;
return -EEXIST;
}
if (!(e = new(struct hashmap_entry, 1)))
return -ENOMEM;
e->key = key;
e->value = value;
/* Insert into hash table */
e->bucket_next = BY_HASH(h)[hash];
e->bucket_previous = NULL;
if (BY_HASH(h)[hash])
BY_HASH(h)[hash]->bucket_previous = e;
BY_HASH(h)[hash] = e;
/* Insert into iteration list */
e->iterate_previous = h->iterate_list_tail;
e->iterate_next = NULL;
if (h->iterate_list_tail) {
assert(h->iterate_list_head);
h->iterate_list_tail->iterate_next = e;
} else {
assert(!h->iterate_list_head);
h->iterate_list_head = e;
}
h->iterate_list_tail = e;
h->n_entries++;
assert(h->n_entries >= 1);
return 0;
}
int hashmap_replace(Hashmap *h, const void *key, void *value) {
struct hashmap_entry *e;
unsigned hash;
assert(h);
hash = h->hash_func(key) % NBUCKETS;
if ((e = hash_scan(h, hash, key))) {
e->value = value;
return 0;
}
return hashmap_put(h, key, value);
}
void* hashmap_get(Hashmap *h, const void *key) {
unsigned hash;
struct hashmap_entry *e;
if (!h)
return NULL;
hash = h->hash_func(key) % NBUCKETS;
if (!(e = hash_scan(h, hash, key)))
return NULL;
return e->value;
}
void* hashmap_remove(Hashmap *h, const void *key) {
struct hashmap_entry *e;
unsigned hash;
void *data;
if (!h)
return NULL;
hash = h->hash_func(key) % NBUCKETS;
if (!(e = hash_scan(h, hash, key)))
return NULL;
data = e->value;
remove_entry(h, e);
return data;
}
void* hashmap_remove_value(Hashmap *h, const void *key, void *value) {
struct hashmap_entry *e;
unsigned hash;
if (!h)
return NULL;
hash = h->hash_func(key) % NBUCKETS;
if (!(e = hash_scan(h, hash, key)))
return NULL;
if (e->value != value)
return NULL;
remove_entry(h, e);
return value;
}
void *hashmap_iterate(Hashmap *h, Iterator *i, const void **key) {
struct hashmap_entry *e;
assert(i);
if (!h)
goto at_end;
if (*i == ITERATOR_LAST)
goto at_end;
if (*i == ITERATOR_FIRST && !h->iterate_list_head)
goto at_end;
e = *i == ITERATOR_FIRST ? h->iterate_list_head : (struct hashmap_entry*) *i;
if (e->iterate_next)
*i = (Iterator) e->iterate_next;
else
*i = ITERATOR_LAST;
if (key)
*key = e->key;
return e->value;
at_end:
*i = ITERATOR_LAST;
if (key)
*key = NULL;
return NULL;
}
void *hashmap_iterate_backwards(Hashmap *h, Iterator *i, const void **key) {
struct hashmap_entry *e;
assert(i);
if (!h)
goto at_beginning;
if (*i == ITERATOR_FIRST)
goto at_beginning;
if (*i == ITERATOR_LAST && !h->iterate_list_tail)
goto at_beginning;
e = *i == ITERATOR_LAST ? h->iterate_list_tail : (struct hashmap_entry*) *i;
if (e->iterate_previous)
*i = (Iterator) e->iterate_previous;
else
*i = ITERATOR_FIRST;
if (key)
*key = e->key;
return e->value;
at_beginning:
*i = ITERATOR_FIRST;
if (key)
*key = NULL;
return NULL;
}
void *hashmap_iterate_skip(Hashmap *h, const void *key, Iterator *i) {
unsigned hash;
struct hashmap_entry *e;
if (!h)
return NULL;
hash = h->hash_func(key) % NBUCKETS;
if (!(e = hash_scan(h, hash, key)))
return NULL;
*i = (Iterator) e;
return e->value;
}
void* hashmap_first(Hashmap *h) {
if (!h)
return NULL;
if (!h->iterate_list_head)
return NULL;
return h->iterate_list_head->value;
}
void* hashmap_last(Hashmap *h) {
if (!h)
return NULL;
if (!h->iterate_list_tail)
return NULL;
return h->iterate_list_tail->value;
}
void* hashmap_steal_first(Hashmap *h) {
void *data;
if (!h)
return NULL;
if (!h->iterate_list_head)
return NULL;
data = h->iterate_list_head->value;
remove_entry(h, h->iterate_list_head);
return data;
}
unsigned hashmap_size(Hashmap *h) {
if (!h)
return 0;
return h->n_entries;
}
bool hashmap_isempty(Hashmap *h) {
if (!h)
return true;
return h->n_entries == 0;
}
int hashmap_merge(Hashmap *h, Hashmap *other) {
struct hashmap_entry *e;
assert(h);
if (!other)
return 0;
for (e = other->iterate_list_head; e; e = e->iterate_next) {
int r;
if ((r = hashmap_put(h, e->key, e->value)) < 0)
if (r != -EEXIST)
return r;
}
return 0;
}
Hashmap *hashmap_copy(Hashmap *h) {
Hashmap *copy;
assert(h);
if (!(copy = hashmap_new(h->hash_func, h->compare_func)))
return NULL;
if (hashmap_merge(copy, h) < 0) {
hashmap_free(copy);
return NULL;
}
return copy;
}
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