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- /*
- This file is part of GNUnet.
- 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 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
- Affero General Public License for more details.
- 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_multishortmap.c
- * @brief hash map where the same key may be present multiple times
- * @author Christian Grothoff
- */
- #include "platform.h"
- #include "gnunet_util_lib.h"
- #define LOG(kind, ...) \
- GNUNET_log_from (kind, "util-container-multishortmap", __VA_ARGS__)
- /**
- * Maximum recursion depth for callbacks of
- * #GNUNET_CONTAINER_multihashmap_get_multiple() themselves 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.
- */
- struct BigMapEntry
- {
- /**
- * Value of the entry.
- */
- void *value;
- /**
- * If there is a hash collision, we create a linked list.
- */
- struct BigMapEntry *next;
- /**
- * Key for the entry.
- */
- struct GNUNET_ShortHashCode key;
- };
- /**
- * An entry in the hash map with just a pointer to the key.
- */
- struct SmallMapEntry
- {
- /**
- * Value of the entry.
- */
- void *value;
- /**
- * If there is a hash collision, we create a linked list.
- */
- struct SmallMapEntry *next;
- /**
- * Key for the entry.
- */
- const struct GNUNET_ShortHashCode *key;
- };
- /**
- * Entry in the map.
- */
- union MapEntry
- {
- /**
- * Variant used if map entries only contain a pointer to the key.
- */
- struct SmallMapEntry *sme;
- /**
- * Variant used if map entries contain the full key.
- */
- struct BigMapEntry *bme;
- };
- /**
- * Internal representation of the hash map.
- */
- struct GNUNET_CONTAINER_MultiShortmap
- {
- /**
- * All of our buckets.
- */
- union MapEntry *map;
- /**
- * Number of entries in the map.
- */
- unsigned int size;
- /**
- * Length of the "map" array.
- */
- 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'.
- */
- 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 multishortmap.
- * Allows to enumerate elements asynchronously.
- */
- struct GNUNET_CONTAINER_MultiShortmapIterator
- {
- /**
- * Position in the bucket '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_MultiShortmap *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
- * 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 recipe 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
- * @return NULL on error
- */
- struct GNUNET_CONTAINER_MultiShortmap *
- GNUNET_CONTAINER_multishortmap_create (unsigned int len, int do_not_copy_keys)
- {
- struct GNUNET_CONTAINER_MultiShortmap *map;
- GNUNET_assert (len > 0);
- map = GNUNET_new (struct GNUNET_CONTAINER_MultiShortmap);
- map->map = GNUNET_malloc_large (len * sizeof(union MapEntry));
- if (NULL == map->map)
- {
- GNUNET_free (map);
- return NULL;
- }
- map->map_length = len;
- map->use_small_entries = do_not_copy_keys;
- return map;
- }
- /**
- * Destroy a hash map. Will not free any values
- * stored in the hash map!
- *
- * @param map the map
- */
- void
- GNUNET_CONTAINER_multishortmap_destroy (
- struct GNUNET_CONTAINER_MultiShortmap *map)
- {
- 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)
- {
- struct SmallMapEntry *sme;
- struct SmallMapEntry *nxt;
- nxt = me.sme;
- while (NULL != (sme = nxt))
- {
- nxt = sme->next;
- GNUNET_free (sme);
- }
- me.sme = NULL;
- }
- else
- {
- struct BigMapEntry *bme;
- struct BigMapEntry *nxt;
- nxt = me.bme;
- while (NULL != (bme = nxt))
- {
- nxt = bme->next;
- GNUNET_free (bme);
- }
- me.bme = NULL;
- }
- }
- GNUNET_free (map->map);
- GNUNET_free (map);
- }
- /**
- * Compute the index of the bucket for the given key.
- *
- * @param map hash map for which to compute the index
- * @param key what key should the index be computed for
- * @return offset into the "map" array of "map"
- */
- static unsigned int
- idx_of (const struct GNUNET_CONTAINER_MultiShortmap *map,
- const struct GNUNET_ShortHashCode *key)
- {
- unsigned int kx;
- GNUNET_assert (NULL != map);
- GNUNET_memcpy (&kx, key, sizeof(kx));
- return kx % map->map_length;
- }
- /**
- * Get the number of key-value pairs in the map.
- *
- * @param map the map
- * @return the number of key value pairs
- */
- unsigned int
- GNUNET_CONTAINER_multishortmap_size (
- const struct GNUNET_CONTAINER_MultiShortmap *map)
- {
- return map->size;
- }
- /**
- * Given a key find a value in the map matching the key.
- *
- * @param map the map
- * @param key what to look for
- * @return NULL if no value was found; note that
- * this is indistinguishable from values that just
- * happen to be NULL; use "contains" to test for
- * key-value pairs with value NULL
- */
- void *
- GNUNET_CONTAINER_multishortmap_get (
- const struct GNUNET_CONTAINER_MultiShortmap *map,
- const struct GNUNET_ShortHashCode *key)
- {
- union MapEntry me;
- me = map->map[idx_of (map, key)];
- if (map->use_small_entries)
- {
- for (struct SmallMapEntry *sme = me.sme; NULL != sme; sme = sme->next)
- if (0 == GNUNET_memcmp (key, sme->key))
- return sme->value;
- }
- else
- {
- for (struct BigMapEntry *bme = me.bme; NULL != bme; bme = bme->next)
- if (0 == GNUNET_memcmp (key, &bme->key))
- return bme->value;
- }
- return NULL;
- }
- /**
- * Iterate over all entries in the map.
- *
- * @param map the map
- * @param it function to call on each entry
- * @param it_cls extra argument to @a it
- * @return the number of key value pairs processed,
- * #GNUNET_SYSERR if it aborted iteration
- */
- int
- GNUNET_CONTAINER_multishortmap_iterate (
- struct GNUNET_CONTAINER_MultiShortmap *map,
- GNUNET_CONTAINER_ShortmapIterator it,
- void *it_cls)
- {
- int count;
- union MapEntry me;
- union MapEntry *ce;
- struct GNUNET_ShortHashCode kc;
- count = 0;
- GNUNET_assert (NULL != map);
- ce = &map->next_cache[map->next_cache_off];
- GNUNET_assert (++map->next_cache_off < NEXT_CACHE_SIZE);
- for (unsigned int i = 0; i < map->map_length; i++)
- {
- me = map->map[i];
- if (map->use_small_entries)
- {
- struct SmallMapEntry *sme;
- ce->sme = me.sme;
- while (NULL != (sme = ce->sme))
- {
- ce->sme = sme->next;
- if ((NULL != it) && (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;
- ce->bme = me.bme;
- while (NULL != (bme = ce->bme))
- {
- ce->bme = bme->next;
- if (NULL != it)
- {
- kc = bme->key;
- 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_MultiShortmap *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_MultiShortmap *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
- * will be removed.
- *
- * @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
- * is not in the map
- */
- int
- GNUNET_CONTAINER_multishortmap_remove (
- struct GNUNET_CONTAINER_MultiShortmap *map,
- const struct GNUNET_ShortHashCode *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 *p = NULL;
- for (struct SmallMapEntry *sme = me.sme; NULL != sme; sme = sme->next)
- {
- if ((0 == GNUNET_memcmp (key, sme->key)) && (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;
- }
- p = sme;
- }
- }
- else
- {
- struct BigMapEntry *p = NULL;
- for (struct BigMapEntry *bme = me.bme; NULL != bme; bme = bme->next)
- {
- if ((0 == GNUNET_memcmp (key, &bme->key)) && (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;
- }
- p = bme;
- }
- }
- return GNUNET_NO;
- }
- /**
- * Remove all entries for the given key from the map.
- * Note that the values would not be "freed".
- *
- * @param map the map
- * @param key identifies values to be removed
- * @return number of values removed
- */
- int
- GNUNET_CONTAINER_multishortmap_remove_all (
- struct GNUNET_CONTAINER_MultiShortmap *map,
- const struct GNUNET_ShortHashCode *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;
- p = NULL;
- sme = me.sme;
- while (NULL != sme)
- {
- if (0 == GNUNET_memcmp (key, sme->key))
- {
- 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++;
- }
- else
- {
- p = sme;
- sme = sme->next;
- }
- }
- }
- else
- {
- struct BigMapEntry *bme;
- struct BigMapEntry *p;
- p = NULL;
- bme = me.bme;
- while (NULL != bme)
- {
- if (0 == GNUNET_memcmp (key, &bme->key))
- {
- 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)
- bme = map->map[i].bme;
- else
- bme = p->next;
- ret++;
- }
- else
- {
- p = bme;
- bme = bme->next;
- }
- }
- }
- 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
- */
- int
- GNUNET_CONTAINER_multishortmap_contains (
- const struct GNUNET_CONTAINER_MultiShortmap *map,
- const struct GNUNET_ShortHashCode *key)
- {
- union MapEntry me;
- me = map->map[idx_of (map, key)];
- if (map->use_small_entries)
- {
- for (struct SmallMapEntry *sme = me.sme; NULL != sme; sme = sme->next)
- if (0 == GNUNET_memcmp (key, sme->key))
- return GNUNET_YES;
- }
- else
- {
- for (struct BigMapEntry *bme = me.bme; NULL != bme; bme = bme->next)
- if (0 == GNUNET_memcmp (key, &bme->key))
- return GNUNET_YES;
- }
- return GNUNET_NO;
- }
- /**
- * Check if the map contains the given value under the given
- * key.
- *
- * @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
- */
- int
- GNUNET_CONTAINER_multishortmap_contains_value (
- const struct GNUNET_CONTAINER_MultiShortmap *map,
- const struct GNUNET_ShortHashCode *key,
- const void *value)
- {
- union MapEntry me;
- me = map->map[idx_of (map, key)];
- if (map->use_small_entries)
- {
- for (struct SmallMapEntry *sme = me.sme; NULL != sme; sme = sme->next)
- if ((0 == GNUNET_memcmp (key, sme->key)) && (sme->value == value))
- return GNUNET_YES;
- }
- else
- {
- for (struct BigMapEntry *bme = me.bme; NULL != bme; bme = bme->next)
- if ((0 == GNUNET_memcmp (key, &bme->key)) && (bme->value == value))
- return GNUNET_YES;
- }
- return GNUNET_NO;
- }
- /**
- * Grow the given map to a more appropriate size.
- *
- * @param map the hash map to grow
- */
- static void
- grow (struct GNUNET_CONTAINER_MultiShortmap *map)
- {
- union MapEntry *old_map;
- union MapEntry *new_map;
- unsigned int old_len;
- unsigned int new_len;
- unsigned int idx;
- old_map = map->map;
- old_len = map->map_length;
- new_len = old_len * 2;
- 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 (unsigned int i = 0; i < old_len; i++)
- {
- if (map->use_small_entries)
- {
- struct SmallMapEntry *sme;
- while (NULL != (sme = old_map[i].sme))
- {
- old_map[i].sme = sme->next;
- idx = idx_of (map, sme->key);
- sme->next = new_map[idx].sme;
- new_map[idx].sme = sme;
- }
- }
- else
- {
- 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;
- new_map[idx].bme = bme;
- }
- }
- }
- GNUNET_free (old_map);
- }
- /**
- * Store a key-value pair in the map.
- *
- * @param map the map
- * @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 #GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY was the option and the
- * value already exists
- */
- int
- GNUNET_CONTAINER_multishortmap_put (
- struct GNUNET_CONTAINER_MultiShortmap *map,
- const struct GNUNET_ShortHashCode *key,
- void *value,
- enum GNUNET_CONTAINER_MultiHashMapOption opt)
- {
- union MapEntry me;
- unsigned int i;
- i = idx_of (map, key);
- if ((opt != GNUNET_CONTAINER_MULTIHASHMAPOPTION_MULTIPLE) &&
- (opt != GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_FAST))
- {
- me = map->map[i];
- if (map->use_small_entries)
- {
- for (struct SmallMapEntry *sme = me.sme; NULL != sme; sme = sme->next)
- if (0 == GNUNET_memcmp (key, sme->key))
- {
- if (opt == GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY)
- return GNUNET_SYSERR;
- sme->value = value;
- return GNUNET_NO;
- }
- }
- else
- {
- for (struct BigMapEntry *bme = me.bme; NULL != bme; bme = bme->next)
- if (0 == GNUNET_memcmp (key, &bme->key))
- {
- if (opt == GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY)
- return GNUNET_SYSERR;
- bme->value = value;
- return GNUNET_NO;
- }
- }
- }
- if (map->size / 3 >= map->map_length / 4)
- {
- grow (map);
- i = idx_of (map, key);
- }
- if (map->use_small_entries)
- {
- struct SmallMapEntry *sme;
- sme = GNUNET_new (struct SmallMapEntry);
- sme->key = key;
- sme->value = value;
- sme->next = map->map[i].sme;
- map->map[i].sme = sme;
- }
- else
- {
- struct BigMapEntry *bme;
- bme = GNUNET_new (struct BigMapEntry);
- bme->key = *key;
- bme->value = value;
- bme->next = map->map[i].bme;
- map->map[i].bme = bme;
- }
- map->size++;
- return GNUNET_OK;
- }
- /**
- * Iterate over all entries in the map that match a particular key.
- *
- * @param map the map
- * @param key key that the entries must correspond to
- * @param it function to call on each entry
- * @param it_cls extra argument to @a it
- * @return the number of key value pairs processed,
- * #GNUNET_SYSERR if it aborted iteration
- */
- int
- GNUNET_CONTAINER_multishortmap_get_multiple (
- struct GNUNET_CONTAINER_MultiShortmap *map,
- const struct GNUNET_ShortHashCode *key,
- GNUNET_CONTAINER_ShortmapIterator it,
- void *it_cls)
- {
- int count;
- 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)];
- if (map->use_small_entries)
- {
- struct SmallMapEntry *sme;
- ce->sme = me.sme;
- while (NULL != (sme = ce->sme))
- {
- ce->sme = sme->next;
- if (0 != GNUNET_memcmp (key, sme->key))
- continue;
- 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;
- ce->bme = me.bme;
- while (NULL != (bme = ce->bme))
- {
- ce->bme = bme->next;
- if (0 != GNUNET_memcmp (key, &bme->key))
- continue;
- 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_multishortmap_get_random (
- const struct GNUNET_CONTAINER_MultiShortmap *map,
- GNUNET_CONTAINER_ShortmapIterator it,
- void *it_cls)
- {
- unsigned int off;
- 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 (unsigned int idx = 0; idx < map->map_length; idx++)
- {
- me = map->map[idx];
- if (map->use_small_entries)
- {
- for (struct SmallMapEntry *sme = me.sme; NULL != sme; sme = sme->next)
- {
- if (0 == off)
- {
- if (GNUNET_OK != it (it_cls, sme->key, sme->value))
- return GNUNET_SYSERR;
- return 1;
- }
- off--;
- }
- }
- else
- {
- for (struct BigMapEntry *bme = me.bme; NULL != bme; bme = 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 multishortmap.
- * The iterator can be used to retrieve all the elements in the multishortmap
- * one by one, without having to handle all elements at once (in contrast to
- * #GNUNET_CONTAINER_multishortmap_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 multishortmap 'map'
- */
- struct GNUNET_CONTAINER_MultiShortmapIterator *
- GNUNET_CONTAINER_multishortmap_iterator_create (
- const struct GNUNET_CONTAINER_MultiShortmap *map)
- {
- struct GNUNET_CONTAINER_MultiShortmapIterator *iter;
- iter = GNUNET_new (struct GNUNET_CONTAINER_MultiShortmapIterator);
- 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
- * multishortmap 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_multishortmap_iterator_next (
- struct GNUNET_CONTAINER_MultiShortmapIterator *iter,
- struct GNUNET_ShortHashCode *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 multishortmap iterator.
- *
- * @param iter the iterator to destroy
- */
- void
- GNUNET_CONTAINER_multishortmap_iterator_destroy (
- struct GNUNET_CONTAINER_MultiShortmapIterator *iter)
- {
- GNUNET_free (iter);
- }
- /* end of container_multishortmap.c */
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