/*
This file is part of GNUnet.
- (C) 2008, 2012 Christian Grothoff (and other contributing authors)
+ Copyright (C) 2008, 2012 GNUnet e.V.
- GNUnet 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, or (at your
- option) any later version.
+ GNUnet is free software: you can redistribute it and/or modify it
+ under the terms of the GNU Affero General Public License as published
+ by the Free Software Foundation, either version 3 of the License,
+ or (at your option) any later version.
GNUnet 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.
+ Affero General Public License for more details.
- You should have received a copy of the GNU General Public License
- along with GNUnet; see the file COPYING. If not, write to the
- Free Software Foundation, Inc., 59 Temple Place - Suite 330,
- Boston, MA 02111-1307, USA.
+ You should have received a copy of the GNU Affero General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+ SPDX-License-Identifier: AGPL3.0-or-later
*/
/**
* @file util/container_multihashmap.c
*/
#include "platform.h"
-#include "gnunet_common.h"
#include "gnunet_container_lib.h"
-#include "gnunet_crypto_lib.h"
-#define LOG(kind,...) GNUNET_log_from (kind, "util", __VA_ARGS__)
+#define LOG(kind,...) GNUNET_log_from (kind, "util-container-multihashmap", __VA_ARGS__)
+
+/**
+ * Maximum recursion depth for callbacks of
+ * #GNUNET_CONTAINER_multihashmap_get_multiple() themselve s
+ * again calling #GNUNET_CONTAINER_multihashmap_get_multiple().
+ * Should be totally excessive, but if violated we die.
+ */
+#define NEXT_CACHE_SIZE 16
+
/**
* An entry in the hash map with the full key.
* If there is a hash collision, we create a linked list.
*/
struct SmallMapEntry *next;
-
+
/**
* Key for the entry.
*/
*/
struct GNUNET_CONTAINER_MultiHashMap
{
-
/**
* All of our buckets.
*/
unsigned int map_length;
/**
- * GNUNET_NO if the map entries are of type 'struct BigMapEntry',
- * GNUNET_YES if the map entries are of type 'struct SmallMapEntry'.
+ * #GNUNET_NO if the map entries are of type 'struct BigMapEntry',
+ * #GNUNET_YES if the map entries are of type 'struct SmallMapEntry'.
*/
int use_small_entries;
+
+ /**
+ * Counts the destructive modifications (grow, remove)
+ * to the map, so that iterators can check if they are still valid.
+ */
+ unsigned int modification_counter;
+
+ /**
+ * Map entries indicating iteration positions currently
+ * in use by #GNUNET_CONTAINER_multihashmap_get_multiple().
+ * Only used up to @e next_cache_off.
+ */
+ union MapEntry next_cache[NEXT_CACHE_SIZE];
+
+ /**
+ * Offset of @e next_cache entries in use, must be smaller
+ * than #NEXT_CACHE_SIZE.
+ */
+ unsigned int next_cache_off;
+};
+
+
+/**
+ * Cursor into a multihashmap.
+ * Allows to enumerate elements asynchronously.
+ */
+struct GNUNET_CONTAINER_MultiHashMapIterator
+{
+ /**
+ * Position in the bucket @e idx
+ */
+ union MapEntry me;
+
+ /**
+ * Current bucket index.
+ */
+ unsigned int idx;
+
+ /**
+ * Modification counter as observed on the map when the iterator
+ * was created.
+ */
+ unsigned int modification_counter;
+
+ /**
+ * Map that we are iterating over.
+ */
+ const struct GNUNET_CONTAINER_MultiHashMap *map;
};
* Create a multi hash map.
*
* @param len initial size (map will grow as needed)
- * @param do_not_copy_keys GNUNET_NO is always safe and should be used by default;
- * GNUNET_YES means that on 'put', the 'key' does not have
- * to be copied as the destination of the pointer is
+ * @param do_not_copy_keys #GNUNET_NO is always safe and should be used by default;
+ * #GNUNET_YES means that on 'put', the 'key' does not have
+ * to be copied as the destination of the pointer is
* guaranteed to be life as long as the value is stored in
- * the hashmap. This can significantly reduce memory
- * consumption, but of course is also a recipie for
+ * the hashmap. This can significantly reduce memory
+ * consumption, but of course is also a recipie for
* heap corruption if the assumption is not true. Only
* use this if (1) memory use is important in this case and
* (2) you have triple-checked that the invariant holds
GNUNET_CONTAINER_multihashmap_create (unsigned int len,
int do_not_copy_keys)
{
- struct GNUNET_CONTAINER_MultiHashMap *map;
+ struct GNUNET_CONTAINER_MultiHashMap *hm;
GNUNET_assert (len > 0);
- map = GNUNET_malloc (sizeof (struct GNUNET_CONTAINER_MultiHashMap));
- map->map = GNUNET_malloc (len * sizeof (union MapEntry));
- map->map_length = len;
- map->use_small_entries = do_not_copy_keys;
- return map;
+ hm = GNUNET_new (struct GNUNET_CONTAINER_MultiHashMap);
+ if (len * sizeof (union MapEntry) > GNUNET_MAX_MALLOC_CHECKED)
+ {
+ size_t s;
+ /* application *explicitly* requested very large map, hopefully
+ it checks the return value... */
+ s = len * sizeof (union MapEntry);
+ if ( (s / sizeof (union MapEntry)) != len)
+ return NULL; /* integer overflow on multiplication */
+ if (NULL == (hm->map = GNUNET_malloc_large (s)))
+ {
+ /* out of memory */
+ GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
+ "Out of memory allocating large hash map (%u entries)\n",
+ len);
+ GNUNET_free (hm);
+ return NULL;
+ }
+ }
+ else
+ {
+ hm->map = GNUNET_new_array (len,
+ union MapEntry);
+ }
+ hm->map_length = len;
+ hm->use_small_entries = do_not_copy_keys;
+ return hm;
}
/**
- * Destroy a hash map. Will not free any values
- * stored in the hash map!
+ * Destroy a hash map. Will not free any values stored in the hash
+ * map!
*
* @param map the map
*/
void
-GNUNET_CONTAINER_multihashmap_destroy (struct GNUNET_CONTAINER_MultiHashMap
- *map)
+GNUNET_CONTAINER_multihashmap_destroy (struct GNUNET_CONTAINER_MultiHashMap *map)
{
- unsigned int i;
- union MapEntry me;
-
- for (i = 0; i < map->map_length; i++)
+ GNUNET_assert (0 == map->next_cache_off);
+ for (unsigned int i = 0; i < map->map_length; i++)
{
+ union MapEntry me;
+
me = map->map[i];
if (map->use_small_entries)
{
* @return the number of key value pairs
*/
unsigned int
-GNUNET_CONTAINER_multihashmap_size (const struct GNUNET_CONTAINER_MultiHashMap
- *map)
+GNUNET_CONTAINER_multihashmap_size (const struct GNUNET_CONTAINER_MultiHashMap *map)
{
return map->size;
}
* key-value pairs with value NULL
*/
void *
-GNUNET_CONTAINER_multihashmap_get (const struct GNUNET_CONTAINER_MultiHashMap
- *map, const struct GNUNET_HashCode *key)
+GNUNET_CONTAINER_multihashmap_get (const struct GNUNET_CONTAINER_MultiHashMap *map,
+ const struct GNUNET_HashCode *key)
{
union MapEntry me;
struct SmallMapEntry *sme;
for (sme = me.sme; NULL != sme; sme = sme->next)
- if (0 == memcmp (key, sme->key, sizeof (struct GNUNET_HashCode)))
+ if (0 == memcmp (key,
+ sme->key,
+ sizeof (struct GNUNET_HashCode)))
return sme->value;
}
else
struct BigMapEntry *bme;
for (bme = me.bme; NULL != bme; bme = bme->next)
- if (0 == memcmp (key, &bme->key, sizeof (struct GNUNET_HashCode)))
+ if (0 == memcmp (key,
+ &bme->key,
+ sizeof (struct GNUNET_HashCode)))
return bme->value;
}
return NULL;
*
* @param map the map
* @param it function to call on each entry
- * @param it_cls extra argument to it
+ * @param it_cls extra argument to @a it
* @return the number of key value pairs processed,
- * GNUNET_SYSERR if it aborted iteration
+ * #GNUNET_SYSERR if it aborted iteration
*/
int
-GNUNET_CONTAINER_multihashmap_iterate (const struct
- GNUNET_CONTAINER_MultiHashMap *map,
+GNUNET_CONTAINER_multihashmap_iterate (struct GNUNET_CONTAINER_MultiHashMap *map,
GNUNET_CONTAINER_HashMapIterator it,
void *it_cls)
{
int count;
- unsigned int i;
union MapEntry me;
+ union MapEntry *ce;
struct GNUNET_HashCode kc;
- count = 0;
GNUNET_assert (NULL != map);
- for (i = 0; i < map->map_length; i++)
+ ce = &map->next_cache[map->next_cache_off];
+ GNUNET_assert (++map->next_cache_off < NEXT_CACHE_SIZE);
+ count = 0;
+ for (unsigned i = 0; i < map->map_length; i++)
{
me = map->map[i];
if (map->use_small_entries)
{
struct SmallMapEntry *sme;
- struct SmallMapEntry *nxt;
- nxt = me.sme;
- while (NULL != (sme = nxt))
+ ce->sme = me.sme;
+ while (NULL != (sme = ce->sme))
{
- nxt = sme->next;
+ ce->sme = sme->next;
if (NULL != it)
{
- if (GNUNET_OK != it (it_cls, sme->key, sme->value))
+ if (GNUNET_OK != it (it_cls,
+ sme->key,
+ sme->value))
+ {
+ GNUNET_assert (--map->next_cache_off < NEXT_CACHE_SIZE);
return GNUNET_SYSERR;
+ }
}
count++;
}
else
{
struct BigMapEntry *bme;
- struct BigMapEntry *nxt;
- nxt = me.bme;
- while (NULL != (bme = nxt))
+ ce->bme = me.bme;
+ while (NULL != (bme = ce->bme))
{
- nxt = bme->next;
+ ce->bme = bme->next;
if (NULL != it)
{
kc = bme->key;
- if (GNUNET_OK != it (it_cls, &kc, bme->value))
+ if (GNUNET_OK != it (it_cls,
+ &kc,
+ bme->value))
+ {
+ GNUNET_assert (--map->next_cache_off < NEXT_CACHE_SIZE);
return GNUNET_SYSERR;
+ }
}
count++;
}
}
}
+ GNUNET_assert (--map->next_cache_off < NEXT_CACHE_SIZE);
return count;
}
+/**
+ * We are about to free() the @a bme, make sure it is not in
+ * the list of next values for any iterator in the @a map's next_cache.
+ *
+ * @param map the map to check
+ * @param bme the entry that is about to be free'd
+ */
+static void
+update_next_cache_bme (struct GNUNET_CONTAINER_MultiHashMap *map,
+ const struct BigMapEntry *bme)
+{
+ for (unsigned int i=0;i<map->next_cache_off;i++)
+ if (map->next_cache[i].bme == bme)
+ map->next_cache[i].bme = bme->next;
+}
+
+
+/**
+ * We are about to free() the @a sme, make sure it is not in
+ * the list of next values for any iterator in the @a map's next_cache.
+ *
+ * @param map the map to check
+ * @param sme the entry that is about to be free'd
+ */
+static void
+update_next_cache_sme (struct GNUNET_CONTAINER_MultiHashMap *map,
+ const struct SmallMapEntry *sme)
+{
+ for (unsigned int i=0;i<map->next_cache_off;i++)
+ if (map->next_cache[i].sme == sme)
+ map->next_cache[i].sme = sme->next;
+}
+
+
/**
* Remove the given key-value pair from the map. Note that if the
* key-value pair is in the map multiple times, only one of the pairs
* @param map the map
* @param key key of the key-value pair
* @param value value of the key-value pair
- * @return GNUNET_YES on success, GNUNET_NO if the key-value pair
+ * @return #GNUNET_YES on success, #GNUNET_NO if the key-value pair
* is not in the map
*/
int
GNUNET_CONTAINER_multihashmap_remove (struct GNUNET_CONTAINER_MultiHashMap *map,
- const struct GNUNET_HashCode *key,
- void *value)
+ const struct GNUNET_HashCode *key,
+ const void *value)
{
union MapEntry me;
unsigned int i;
+ map->modification_counter++;
+
i = idx_of (map, key);
me = map->map[i];
if (map->use_small_entries)
- {
- struct SmallMapEntry *sme;
+ {
struct SmallMapEntry *p;
p = NULL;
- for (sme = me.sme; NULL != sme; sme = sme->next)
+ for (struct SmallMapEntry *sme = me.sme; NULL != sme; sme = sme->next)
{
- if ((0 == memcmp (key, sme->key, sizeof (struct GNUNET_HashCode))) &&
- (value == sme->value))
+ if ( (0 == memcmp (key,
+ sme->key,
+ sizeof (struct GNUNET_HashCode))) &&
+ (value == sme->value) )
{
if (NULL == p)
map->map[i].sme = sme->next;
else
p->next = sme->next;
+ update_next_cache_sme (map,
+ sme);
GNUNET_free (sme);
map->size--;
return GNUNET_YES;
}
else
{
- struct BigMapEntry *bme;
struct BigMapEntry *p;
p = NULL;
- for (bme = me.bme; NULL != bme; bme = bme->next)
+ for (struct BigMapEntry *bme = me.bme; NULL != bme; bme = bme->next)
{
- if ((0 == memcmp (key, &bme->key, sizeof (struct GNUNET_HashCode))) &&
- (value == bme->value))
+ if ( (0 == memcmp (key,
+ &bme->key,
+ sizeof (struct GNUNET_HashCode))) &&
+ (value == bme->value) )
{
if (NULL == p)
map->map[i].bme = bme->next;
else
p->next = bme->next;
+ update_next_cache_bme (map,
+ bme);
GNUNET_free (bme);
map->size--;
return GNUNET_YES;
* @return number of values removed
*/
int
-GNUNET_CONTAINER_multihashmap_remove_all (struct GNUNET_CONTAINER_MultiHashMap
- *map, const struct GNUNET_HashCode *key)
+GNUNET_CONTAINER_multihashmap_remove_all (struct GNUNET_CONTAINER_MultiHashMap *map,
+ const struct GNUNET_HashCode *key)
{
union MapEntry me;
unsigned int i;
int ret;
+ map->modification_counter++;
+
ret = 0;
i = idx_of (map, key);
me = map->map[i];
if (map->use_small_entries)
- {
+ {
struct SmallMapEntry *sme;
struct SmallMapEntry *p;
sme = me.sme;
while (NULL != sme)
{
- if (0 == memcmp (key, sme->key, sizeof (struct GNUNET_HashCode)))
+ if (0 == memcmp (key,
+ sme->key,
+ sizeof (struct GNUNET_HashCode)))
{
if (NULL == p)
map->map[i].sme = sme->next;
else
p->next = sme->next;
+ update_next_cache_sme (map,
+ sme);
GNUNET_free (sme);
map->size--;
if (NULL == p)
sme = map->map[i].sme;
else
sme = p->next;
- ret++;
+ ret++;
}
else
{
bme = me.bme;
while (NULL != bme)
{
- if (0 == memcmp (key, &bme->key, sizeof (struct GNUNET_HashCode)))
+ if (0 == memcmp (key,
+ &bme->key,
+ sizeof (struct GNUNET_HashCode)))
{
if (NULL == p)
map->map[i].bme = bme->next;
else
p->next = bme->next;
+ update_next_cache_bme (map,
+ bme);
GNUNET_free (bme);
map->size--;
if (NULL == p)
}
+/**
+ * Callback used to remove all entries from the map.
+ *
+ * @param cls the `struct GNUNET_CONTAINER_MultiHashMap`
+ * @param key the key
+ * @param value the value
+ * @return #GNUNET_OK (continue to iterate)
+ */
+static int
+remove_all (void *cls,
+ const struct GNUNET_HashCode *key,
+ void *value)
+{
+ struct GNUNET_CONTAINER_MultiHashMap *map = cls;
+
+ GNUNET_CONTAINER_multihashmap_remove (map,
+ key,
+ value);
+ return GNUNET_OK;
+}
+
+
+/**
+ * @ingroup hashmap
+ * Remove all entries from the map.
+ * Note that the values would not be "freed".
+ *
+ * @param map the map
+ * @return number of values removed
+ */
+unsigned int
+GNUNET_CONTAINER_multihashmap_clear (struct GNUNET_CONTAINER_MultiHashMap *map)
+{
+ unsigned int ret;
+
+ ret = map->size;
+ GNUNET_CONTAINER_multihashmap_iterate (map,
+ &remove_all,
+ map);
+ return ret;
+}
+
+
/**
* Check if the map contains any value under the given
* key (including values that are NULL).
*
* @param map the map
* @param key the key to test if a value exists for it
- * @return GNUNET_YES if such a value exists,
- * GNUNET_NO if not
+ * @return #GNUNET_YES if such a value exists,
+ * #GNUNET_NO if not
*/
int
GNUNET_CONTAINER_multihashmap_contains (const struct
* @param map the map
* @param key the key to test if a value exists for it
* @param value value to test for
- * @return GNUNET_YES if such a value exists,
- * GNUNET_NO if not
+ * @return #GNUNET_YES if such a value exists,
+ * #GNUNET_NO if not
*/
int
-GNUNET_CONTAINER_multihashmap_contains_value (const struct
- GNUNET_CONTAINER_MultiHashMap
- *map, const struct GNUNET_HashCode *key,
+GNUNET_CONTAINER_multihashmap_contains_value (const struct GNUNET_CONTAINER_MultiHashMap *map,
+ const struct GNUNET_HashCode *key,
const void *value)
{
union MapEntry me;
struct SmallMapEntry *sme;
for (sme = me.sme; NULL != sme; sme = sme->next)
- if ( (0 == memcmp (key, sme->key, sizeof (struct GNUNET_HashCode))) &&
+ if ( (0 == memcmp (key,
+ sme->key,
+ sizeof (struct GNUNET_HashCode))) &&
(sme->value == value) )
return GNUNET_YES;
}
struct BigMapEntry *bme;
for (bme = me.bme; NULL != bme; bme = bme->next)
- if ( (0 == memcmp (key, &bme->key, sizeof (struct GNUNET_HashCode))) &&
+ if ( (0 == memcmp (key,
+ &bme->key,
+ sizeof (struct GNUNET_HashCode))) &&
(bme->value == value) )
return GNUNET_YES;
}
unsigned int old_len;
unsigned int new_len;
unsigned int idx;
- unsigned int i;
old_map = map->map;
old_len = map->map_length;
+ GNUNET_assert (0 != old_len);
new_len = old_len * 2;
- new_map = GNUNET_malloc (sizeof (union MapEntry) * new_len);
+ if (0 == new_len) /* 2^31 * 2 == 0 */
+ new_len = old_len; /* never use 0 */
+ if (new_len == old_len)
+ return; /* nothing changed */
+ new_map = GNUNET_malloc_large (new_len *
+ sizeof (union MapEntry));
+ if (NULL == new_map)
+ return; /* grow not possible */
+ map->modification_counter++;
map->map_length = new_len;
map->map = new_map;
- for (i = 0; i < old_len; i++)
+ for (unsigned int i = 0; i < old_len; i++)
{
if (map->use_small_entries)
{
struct BigMapEntry *bme;
while (NULL != (bme = old_map[i].bme))
- {
+ {
old_map[i].bme = bme->next;
idx = idx_of (map, &bme->key);
bme->next = new_map[idx].bme;
* @param key key to use
* @param value value to use
* @param opt options for put
- * @return GNUNET_OK on success,
- * GNUNET_NO if a value was replaced (with REPLACE)
- * GNUNET_SYSERR if UNIQUE_ONLY was the option and the
+ * @return #GNUNET_OK on success,
+ * #GNUNET_NO if a value was replaced (with REPLACE)
+ * #GNUNET_SYSERR if UNIQUE_ONLY was the option and the
* value already exists
*/
int
GNUNET_CONTAINER_multihashmap_put (struct GNUNET_CONTAINER_MultiHashMap *map,
- const struct GNUNET_HashCode *key,
+ const struct GNUNET_HashCode *key,
void *value,
enum GNUNET_CONTAINER_MultiHashMapOption opt)
{
{
struct SmallMapEntry *sme;
- for (sme = me.sme; NULL != sme; sme = sme->next)
+ for (sme = me.sme; NULL != sme; sme = sme->next)
if (0 == memcmp (key, sme->key, sizeof (struct GNUNET_HashCode)))
{
if (opt == GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY)
{
struct BigMapEntry *bme;
- for (bme = me.bme; NULL != bme; bme = bme->next)
+ for (bme = me.bme; NULL != bme; bme = bme->next)
if (0 == memcmp (key, &bme->key, sizeof (struct GNUNET_HashCode)))
{
if (opt == GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY)
if (map->use_small_entries)
{
struct SmallMapEntry *sme;
-
- sme = GNUNET_malloc (sizeof (struct SmallMapEntry));
+
+ sme = GNUNET_new (struct SmallMapEntry);
sme->key = key;
sme->value = value;
sme->next = map->map[i].sme;
else
{
struct BigMapEntry *bme;
-
- bme = GNUNET_malloc (sizeof (struct BigMapEntry));
+
+ bme = GNUNET_new (struct BigMapEntry);
bme->key = *key;
bme->value = value;
bme->next = map->map[i].bme;
* @param it function to call on each entry
* @param it_cls extra argument to it
* @return the number of key value pairs processed,
- * GNUNET_SYSERR if it aborted iteration
+ * #GNUNET_SYSERR if it aborted iteration
*/
int
-GNUNET_CONTAINER_multihashmap_get_multiple (const struct
- GNUNET_CONTAINER_MultiHashMap *map,
+GNUNET_CONTAINER_multihashmap_get_multiple (struct GNUNET_CONTAINER_MultiHashMap *map,
const struct GNUNET_HashCode *key,
GNUNET_CONTAINER_HashMapIterator it,
void *it_cls)
{
int count;
- union MapEntry me;
+ union MapEntry *me;
+ union MapEntry *ce;
+ ce = &map->next_cache[map->next_cache_off];
+ GNUNET_assert (++map->next_cache_off < NEXT_CACHE_SIZE);
count = 0;
- me = map->map[idx_of (map, key)];
+ me = &map->map[idx_of (map, key)];
if (map->use_small_entries)
{
- struct SmallMapEntry *sme;
- struct SmallMapEntry *nxt;
-
- nxt = me.sme;
- while (NULL != (sme = nxt))
+ struct SmallMapEntry *sme;
+
+ ce->sme = me->sme;
+ while (NULL != (sme = ce->sme))
{
- nxt = sme->next;
- if (0 != memcmp (key, sme->key, sizeof (struct GNUNET_HashCode)))
+ ce->sme = sme->next;
+ if (0 != memcmp (key,
+ sme->key,
+ sizeof (struct GNUNET_HashCode)))
continue;
- if ((it != NULL) && (GNUNET_OK != it (it_cls, key, sme->value)))
+ if ( (NULL != it) &&
+ (GNUNET_OK != it (it_cls,
+ key,
+ sme->value)))
+ {
+ GNUNET_assert (--map->next_cache_off < NEXT_CACHE_SIZE);
return GNUNET_SYSERR;
+ }
count++;
}
}
else
{
- struct BigMapEntry *bme;
- struct BigMapEntry *nxt;
-
- nxt = me.bme;
- while (NULL != (bme = nxt))
+ struct BigMapEntry *bme;
+
+ ce->bme = me->bme;
+ while (NULL != (bme = ce->bme))
{
- nxt = bme->next;
- if (0 != memcmp (key, &bme->key, sizeof (struct GNUNET_HashCode)))
+ ce->bme = bme->next;
+ if (0 != memcmp (key,
+ &bme->key,
+ sizeof (struct GNUNET_HashCode)))
continue;
- if ((it != NULL) && (GNUNET_OK != it (it_cls, key, bme->value)))
+ if ( (NULL != it) &&
+ (GNUNET_OK != it (it_cls,
+ key,
+ bme->value)))
+ {
+ GNUNET_assert (--map->next_cache_off < NEXT_CACHE_SIZE);
return GNUNET_SYSERR;
+ }
count++;
}
}
+ GNUNET_assert (--map->next_cache_off < NEXT_CACHE_SIZE);
return count;
}
+/**
+ * @ingroup hashmap
+ * Call @a it on a random value from the map, or not at all
+ * if the map is empty. Note that this function has linear
+ * complexity (in the size of the map).
+ *
+ * @param map the map
+ * @param it function to call on a random entry
+ * @param it_cls extra argument to @a it
+ * @return the number of key value pairs processed, zero or one.
+ */
+unsigned int
+GNUNET_CONTAINER_multihashmap_get_random (const struct GNUNET_CONTAINER_MultiHashMap *map,
+ GNUNET_CONTAINER_HashMapIterator it,
+ void *it_cls)
+{
+ unsigned int off;
+ unsigned int idx;
+ union MapEntry me;
+
+ if (0 == map->size)
+ return 0;
+ if (NULL == it)
+ return 1;
+ off = GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_NONCE,
+ map->size);
+ for (idx = 0; idx < map->map_length; idx++)
+ {
+ me = map->map[idx];
+ if (map->use_small_entries)
+ {
+ struct SmallMapEntry *sme;
+ struct SmallMapEntry *nxt;
+
+ nxt = me.sme;
+ while (NULL != (sme = nxt))
+ {
+ nxt = sme->next;
+ if (0 == off)
+ {
+ if (GNUNET_OK != it (it_cls,
+ sme->key,
+ sme->value))
+ return GNUNET_SYSERR;
+ return 1;
+ }
+ off--;
+ }
+ }
+ else
+ {
+ struct BigMapEntry *bme;
+ struct BigMapEntry *nxt;
+
+ nxt = me.bme;
+ while (NULL != (bme = nxt))
+ {
+ nxt = bme->next;
+ if (0 == off)
+ {
+ if (GNUNET_OK != it (it_cls,
+ &bme->key, bme->value))
+ return GNUNET_SYSERR;
+ return 1;
+ }
+ off--;
+ }
+ }
+ }
+ GNUNET_break (0);
+ return GNUNET_SYSERR;
+}
+
+
+/**
+ * Create an iterator for a multihashmap.
+ * The iterator can be used to retrieve all the elements in the multihashmap
+ * one by one, without having to handle all elements at once (in contrast to
+ * GNUNET_CONTAINER_multihashmap_iterate()). Note that the iterator can not be
+ * used anymore if elements have been removed from 'map' after the creation of
+ * the iterator, or 'map' has been destroyed. Adding elements to 'map' may
+ * result in skipped or repeated elements.
+ *
+ * @param map the map to create an iterator for
+ * @return an iterator over the given multihashmap 'map'
+ */
+struct GNUNET_CONTAINER_MultiHashMapIterator *
+GNUNET_CONTAINER_multihashmap_iterator_create (const struct GNUNET_CONTAINER_MultiHashMap *map)
+{
+ struct GNUNET_CONTAINER_MultiHashMapIterator *iter;
+
+ iter = GNUNET_new (struct GNUNET_CONTAINER_MultiHashMapIterator);
+ iter->map = map;
+ iter->modification_counter = map->modification_counter;
+ iter->me = map->map[0];
+ return iter;
+}
+
+
+/**
+ * Retrieve the next element from the hash map at the iterator's position.
+ * If there are no elements left, GNUNET_NO is returned, and 'key' and 'value'
+ * are not modified.
+ * This operation is only allowed if no elements have been removed from the
+ * multihashmap since the creation of 'iter', and the map has not been destroyed.
+ * Adding elements may result in repeating or skipping elements.
+ *
+ * @param iter the iterator to get the next element from
+ * @param key pointer to store the key in, can be NULL
+ * @param value pointer to store the value in, can be NULL
+ * @return #GNUNET_YES we returned an element,
+ * #GNUNET_NO if we are out of elements
+ */
+int
+GNUNET_CONTAINER_multihashmap_iterator_next (struct GNUNET_CONTAINER_MultiHashMapIterator *iter,
+ struct GNUNET_HashCode *key,
+ const void **value)
+{
+ /* make sure the map has not been modified */
+ GNUNET_assert (iter->modification_counter == iter->map->modification_counter);
+
+ /* look for the next entry, skipping empty buckets */
+ while (1)
+ {
+ if (iter->idx >= iter->map->map_length)
+ return GNUNET_NO;
+ if (GNUNET_YES == iter->map->use_small_entries)
+ {
+ if (NULL != iter->me.sme)
+ {
+ if (NULL != key)
+ *key = *iter->me.sme->key;
+ if (NULL != value)
+ *value = iter->me.sme->value;
+ iter->me.sme = iter->me.sme->next;
+ return GNUNET_YES;
+ }
+ }
+ else
+ {
+ if (NULL != iter->me.bme)
+ {
+ if (NULL != key)
+ *key = iter->me.bme->key;
+ if (NULL != value)
+ *value = iter->me.bme->value;
+ iter->me.bme = iter->me.bme->next;
+ return GNUNET_YES;
+ }
+ }
+ iter->idx += 1;
+ if (iter->idx < iter->map->map_length)
+ iter->me = iter->map->map[iter->idx];
+ }
+}
+
+
+/**
+ * Destroy a multihashmap iterator.
+ *
+ * @param iter the iterator to destroy
+ */
+void
+GNUNET_CONTAINER_multihashmap_iterator_destroy (struct GNUNET_CONTAINER_MultiHashMapIterator *iter)
+{
+ GNUNET_free (iter);
+}
+
+
/* end of container_multihashmap.c */