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authorAnthony G. Basile <blueness@gentoo.org>2014-08-05 19:22:24 -0400
committerAnthony G. Basile <blueness@gentoo.org>2014-08-05 19:22:24 -0400
commitb1ac60946d1625e14029ea9b7fa3aa4c06e0795f (patch)
tree28cdd75fec8c6c6a2cf69c9668add048c10370f8 /src/shared/hashmap.c
parent4b8733ffe9c0fe8e5a527186d323dab93e43fb37 (diff)
src/shared: refactor shared code
Signed-off-by: Anthony G. Basile <blueness@gentoo.org>
Diffstat (limited to 'src/shared/hashmap.c')
-rw-r--r--src/shared/hashmap.c550
1 files changed, 550 insertions, 0 deletions
diff --git a/src/shared/hashmap.c b/src/shared/hashmap.c
new file mode 100644
index 0000000000..b92c83202e
--- /dev/null
+++ b/src/shared/hashmap.c
@@ -0,0 +1,550 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+ 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 Lesser General Public License as published by
+ the Free Software Foundation; either version 2.1 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
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser 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"
+#include "siphash24.h"
+
+#define INITIAL_N_BUCKETS 31
+
+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;
+
+ struct hashmap_entry ** buckets;
+ unsigned n_buckets, n_entries;
+
+ uint8_t hash_key[HASH_KEY_SIZE];
+ bool from_pool:1;
+};
+
+struct pool {
+ struct pool *next;
+ unsigned n_tiles;
+ unsigned n_used;
+};
+
+static struct pool *first_hashmap_pool = NULL;
+static void *first_hashmap_tile = NULL;
+
+static struct pool *first_entry_pool = NULL;
+static void *first_entry_tile = NULL;
+
+static void* allocate_tile(struct pool **first_pool, void **first_tile, size_t tile_size, unsigned at_least) {
+ unsigned i;
+
+ /* When a tile is released we add it to the list and simply
+ * place the next pointer at its offset 0. */
+
+ assert(tile_size >= sizeof(void*));
+ assert(at_least > 0);
+
+ if (*first_tile) {
+ void *r;
+
+ r = *first_tile;
+ *first_tile = * (void**) (*first_tile);
+ return r;
+ }
+
+ if (_unlikely_(!*first_pool) || _unlikely_((*first_pool)->n_used >= (*first_pool)->n_tiles)) {
+ unsigned n;
+ size_t size;
+ struct pool *p;
+
+ n = *first_pool ? (*first_pool)->n_tiles : 0;
+ n = MAX(at_least, n * 2);
+ size = PAGE_ALIGN(ALIGN(sizeof(struct pool)) + n*tile_size);
+ n = (size - ALIGN(sizeof(struct pool))) / tile_size;
+
+ p = malloc(size);
+ if (!p)
+ return NULL;
+
+ p->next = *first_pool;
+ p->n_tiles = n;
+ p->n_used = 0;
+
+ *first_pool = p;
+ }
+
+ i = (*first_pool)->n_used++;
+
+ return ((uint8_t*) (*first_pool)) + ALIGN(sizeof(struct pool)) + i*tile_size;
+}
+
+static void deallocate_tile(void **first_tile, void *p) {
+ * (void**) p = *first_tile;
+ *first_tile = p;
+}
+
+unsigned long string_hash_func(const void *p, const uint8_t hash_key[HASH_KEY_SIZE]) {
+ uint64_t u;
+ siphash24((uint8_t*) &u, p, strlen(p), hash_key);
+ return (unsigned long) u;
+}
+
+int string_compare_func(const void *a, const void *b) {
+ return strcmp(a, b);
+}
+
+unsigned long trivial_hash_func(const void *p, const uint8_t hash_key[HASH_KEY_SIZE]) {
+ uint64_t u;
+ siphash24((uint8_t*) &u, &p, sizeof(p), hash_key);
+ return (unsigned long) u;
+}
+
+int trivial_compare_func(const void *a, const void *b) {
+ return a < b ? -1 : (a > b ? 1 : 0);
+}
+
+static unsigned bucket_hash(Hashmap *h, const void *p) {
+ return (unsigned) (h->hash_func(p, h->hash_key) % h->n_buckets);
+}
+
+static void get_hash_key(uint8_t hash_key[HASH_KEY_SIZE], bool reuse_is_ok) {
+ static uint8_t current[HASH_KEY_SIZE];
+ static bool current_initialized = false;
+
+ /* Returns a hash function key to use. In order to keep things
+ * fast we will not generate a new key each time we allocate a
+ * new hash table. Instead, we'll just reuse the most recently
+ * generated one, except if we never generated one or when we
+ * are rehashing an entire hash table because we reached a
+ * fill level */
+
+ if (!current_initialized || !reuse_is_ok) {
+ random_bytes(current, sizeof(current));
+ current_initialized = true;
+ }
+
+ memcpy(hash_key, current, sizeof(current));
+}
+
+Hashmap *hashmap_new(hash_func_t hash_func, compare_func_t compare_func) {
+ bool b;
+ Hashmap *h;
+ size_t size;
+
+ b = is_main_thread();
+
+ size = ALIGN(sizeof(Hashmap)) + INITIAL_N_BUCKETS * sizeof(struct hashmap_entry*);
+
+ if (b) {
+ h = allocate_tile(&first_hashmap_pool, &first_hashmap_tile, size, 8);
+ if (!h)
+ return NULL;
+
+ memzero(h, size);
+ } else {
+ h = malloc0(size);
+
+ if (!h)
+ return NULL;
+ }
+
+ h->hash_func = hash_func ? hash_func : trivial_hash_func;
+ h->compare_func = compare_func ? compare_func : trivial_compare_func;
+
+ h->n_buckets = INITIAL_N_BUCKETS;
+ h->n_entries = 0;
+ h->iterate_list_head = h->iterate_list_tail = NULL;
+
+ h->buckets = (struct hashmap_entry**) ((uint8_t*) h + ALIGN(sizeof(Hashmap)));
+
+ h->from_pool = b;
+
+ get_hash_key(h->hash_key, true);
+
+ return h;
+}
+
+static void link_entry(Hashmap *h, struct hashmap_entry *e, unsigned hash) {
+ assert(h);
+ assert(e);
+
+ /* Insert into hash table */
+ e->bucket_next = h->buckets[hash];
+ e->bucket_previous = NULL;
+ if (h->buckets[hash])
+ h->buckets[hash]->bucket_previous = e;
+ h->buckets[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);
+}
+
+static void unlink_entry(Hashmap *h, struct hashmap_entry *e, unsigned hash) {
+ 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
+ h->buckets[hash] = e->bucket_next;
+
+ assert(h->n_entries >= 1);
+ h->n_entries--;
+}
+
+static void remove_entry(Hashmap *h, struct hashmap_entry *e) {
+ unsigned hash;
+
+ assert(h);
+ assert(e);
+
+ hash = bucket_hash(h, e->key);
+ unlink_entry(h, e, hash);
+
+ if (h->from_pool)
+ deallocate_tile(&first_entry_tile, e);
+ else
+ free(e);
+}
+
+void hashmap_free(Hashmap*h) {
+
+ /* Free the hashmap, but nothing in it */
+
+ if (!h)
+ return;
+
+ hashmap_clear(h);
+
+ if (h->buckets != (struct hashmap_entry**) ((uint8_t*) h + ALIGN(sizeof(Hashmap))))
+ free(h->buckets);
+
+ if (h->from_pool)
+ deallocate_tile(&first_hashmap_tile, h);
+ else
+ free(h);
+}
+
+void hashmap_free_free(Hashmap *h) {
+
+ /* Free the hashmap and all data objects in it, but not the
+ * keys */
+
+ if (!h)
+ return;
+
+ hashmap_clear_free(h);
+ hashmap_free(h);
+}
+
+void hashmap_clear(Hashmap *h) {
+ if (!h)
+ return;
+
+ while (h->iterate_list_head)
+ remove_entry(h, h->iterate_list_head);
+}
+
+void hashmap_clear_free(Hashmap *h) {
+ void *p;
+
+ if (!h)
+ return;
+
+ while ((p = hashmap_steal_first(h)))
+ free(p);
+}
+
+static struct hashmap_entry *hash_scan(Hashmap *h, unsigned hash, const void *key) {
+ struct hashmap_entry *e;
+ assert(h);
+ assert(hash < h->n_buckets);
+
+ for (e = h->buckets[hash]; e; e = e->bucket_next)
+ if (h->compare_func(e->key, key) == 0)
+ return e;
+
+ return NULL;
+}
+
+static bool resize_buckets(Hashmap *h) {
+ struct hashmap_entry **n, *i;
+ unsigned m;
+ uint8_t nkey[HASH_KEY_SIZE];
+
+ assert(h);
+
+ if (_likely_(h->n_entries*4 < h->n_buckets*3))
+ return false;
+
+ /* Increase by four */
+ m = (h->n_entries+1)*4-1;
+
+ /* If we hit OOM we simply risk packed hashmaps... */
+ n = new0(struct hashmap_entry*, m);
+ if (!n)
+ return false;
+
+ /* Let's use a different randomized hash key for the
+ * extension, so that people cannot guess what we are using
+ * here forever */
+ get_hash_key(nkey, false);
+
+ for (i = h->iterate_list_head; i; i = i->iterate_next) {
+ unsigned long old_bucket, new_bucket;
+
+ old_bucket = h->hash_func(i->key, h->hash_key) % h->n_buckets;
+
+ /* First, drop from old bucket table */
+ if (i->bucket_next)
+ i->bucket_next->bucket_previous = i->bucket_previous;
+
+ if (i->bucket_previous)
+ i->bucket_previous->bucket_next = i->bucket_next;
+ else
+ h->buckets[old_bucket] = i->bucket_next;
+
+ /* Then, add to new backet table */
+ new_bucket = h->hash_func(i->key, nkey) % m;
+
+ i->bucket_next = n[new_bucket];
+ i->bucket_previous = NULL;
+ if (n[new_bucket])
+ n[new_bucket]->bucket_previous = i;
+ n[new_bucket] = i;
+ }
+
+ if (h->buckets != (struct hashmap_entry**) ((uint8_t*) h + ALIGN(sizeof(Hashmap))))
+ free(h->buckets);
+
+ h->buckets = n;
+ h->n_buckets = m;
+
+ memcpy(h->hash_key, nkey, HASH_KEY_SIZE);
+
+ return true;
+}
+
+int hashmap_put(Hashmap *h, const void *key, void *value) {
+ struct hashmap_entry *e;
+ unsigned hash;
+
+ assert(h);
+
+ hash = bucket_hash(h, key);
+ e = hash_scan(h, hash, key);
+ if (e) {
+ if (e->value == value)
+ return 0;
+ return -EEXIST;
+ }
+
+ if (resize_buckets(h))
+ hash = bucket_hash(h, key);
+
+ if (h->from_pool)
+ e = allocate_tile(&first_entry_pool, &first_entry_tile, sizeof(struct hashmap_entry), 64U);
+ else
+ e = new(struct hashmap_entry, 1);
+
+ if (!e)
+ return -ENOMEM;
+
+ e->key = key;
+ e->value = value;
+
+ link_entry(h, e, hash);
+
+ return 1;
+}
+
+void* hashmap_get(Hashmap *h, const void *key) {
+ unsigned hash;
+ struct hashmap_entry *e;
+
+ if (!h)
+ return NULL;
+
+ hash = bucket_hash(h, key);
+ e = hash_scan(h, hash, key);
+ if (!e)
+ return NULL;
+
+ return e->value;
+}
+
+bool hashmap_contains(Hashmap *h, const void *key) {
+ unsigned hash;
+
+ if (!h)
+ return false;
+
+ hash = bucket_hash(h, key);
+ return !!hash_scan(h, hash, key);
+}
+
+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_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;
+}
+
+char **hashmap_get_strv(Hashmap *h) {
+ char **sv;
+ Iterator it;
+ char *item;
+ int n;
+
+ sv = new(char*, h->n_entries+1);
+ if (!sv)
+ return NULL;
+
+ n = 0;
+ HASHMAP_FOREACH(item, h, it)
+ sv[n++] = item;
+ sv[n] = NULL;
+
+ return sv;
+}