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