/*
This file is part of GNUnet.
Copyright (C) 2008 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 .
SPDX-License-Identifier: AGPL3.0-or-later
*/
/**
* @file util/container_multihashmap32.c
* @brief a version of hash map implemented in container_multihashmap.c but with
* uint32_t as keys
* @author Christian Grothoff
* @author Sree Harsha Totakura
*/
#include "platform.h"
#include "gnunet_container_lib.h"
#define LOG(kind,...) GNUNET_log_from (kind, "util-container-multihashmap32", __VA_ARGS__)
/**
* Maximum recursion depth for callbacks of
* #GNUNET_CONTAINER_multihashmap_get_multiple() themselves
* 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.
*/
struct MapEntry
{
/**
* Key for the entry.
*/
uint32_t key;
/**
* Value of the entry.
*/
void *value;
/**
* If there is a hash collision, we create a linked list.
*/
struct MapEntry *next;
};
/**
* Internal representation of the hash map.
*/
struct GNUNET_CONTAINER_MultiHashMap32
{
/**
* All of our buckets.
*/
struct MapEntry **map;
/**
* Number of entries in the map.
*/
unsigned int size;
/**
* Length of the @e map array.
*/
unsigned int map_length;
/**
* 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.
*/
struct 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_MultiHashMap32Iterator
{
/**
* Position in the bucket @e idx
*/
struct 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_MultiHashMap32 *map;
};
/**
* Create a multi hash map.
*
* @param len initial size (map will grow as needed)
* @return NULL on error
*/
struct GNUNET_CONTAINER_MultiHashMap32 *
GNUNET_CONTAINER_multihashmap32_create (unsigned int len)
{
struct GNUNET_CONTAINER_MultiHashMap32 *ret;
GNUNET_assert (len > 0);
ret = GNUNET_new (struct GNUNET_CONTAINER_MultiHashMap32);
ret->map = GNUNET_malloc_large (len *
sizeof (struct MapEntry *));
if (NULL == ret->map)
{
GNUNET_free (ret);
return NULL;
}
ret->map_length = len;
return ret;
}
/**
* Destroy a hash map. Will not free any values
* stored in the hash map!
*
* @param map the map
*/
void
GNUNET_CONTAINER_multihashmap32_destroy (struct GNUNET_CONTAINER_MultiHashMap32 *map)
{
struct MapEntry *e;
for (unsigned int i = 0; i < map->map_length; i++)
{
while (NULL != (e = map->map[i]))
{
map->map[i] = e->next;
GNUNET_free (e);
}
}
GNUNET_free (map->map);
GNUNET_free (map);
}
/**
* Compute the index of the bucket for the given key.
*
* @param m 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 "m"
*/
static unsigned int
idx_of (const struct GNUNET_CONTAINER_MultiHashMap32 *m,
const uint32_t key)
{
GNUNET_assert (NULL != m);
return ((unsigned int) key) % m->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_multihashmap32_size (const struct GNUNET_CONTAINER_MultiHashMap32 *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_multihashmap32_get (const struct GNUNET_CONTAINER_MultiHashMap32 *map,
uint32_t key)
{
struct MapEntry *e;
e = map->map[idx_of (map, key)];
while (NULL != e)
{
if (key == e->key)
return e->value;
e = e->next;
}
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_multihashmap32_iterate (struct GNUNET_CONTAINER_MultiHashMap32 *map,
GNUNET_CONTAINER_HashMapIterator32 it,
void *it_cls)
{
int count;
struct MapEntry **ce;
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++)
{
struct MapEntry *e;
*ce = map->map[i];
while (NULL != (e = *ce))
{
*ce = e->next;
if (NULL != it)
{
if (GNUNET_OK != it (it_cls,
e->key,
e->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 (struct GNUNET_CONTAINER_MultiHashMap32 *map,
const struct MapEntry *me)
{
for (unsigned int i=0;inext_cache_off;i++)
if (map->next_cache[i] == me)
map->next_cache[i] = me->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_multihashmap32_remove (struct GNUNET_CONTAINER_MultiHashMap32 *map,
uint32_t key,
const void *value)
{
struct MapEntry *e;
struct MapEntry *p;
unsigned int i;
map->modification_counter++;
i = idx_of (map, key);
p = NULL;
e = map->map[i];
while (e != NULL)
{
if ( (key == e->key) && (value == e->value) )
{
if (p == NULL)
map->map[i] = e->next;
else
p->next = e->next;
update_next_cache (map,
e);
GNUNET_free (e);
map->size--;
return GNUNET_YES;
}
p = e;
e = e->next;
}
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_multihashmap32_remove_all (struct GNUNET_CONTAINER_MultiHashMap32 *map,
uint32_t key)
{
struct MapEntry *e;
struct MapEntry *p;
unsigned int i;
int ret;
map->modification_counter++;
ret = 0;
i = idx_of (map, key);
p = NULL;
e = map->map[i];
while (e != NULL)
{
if (key == e->key)
{
if (p == NULL)
map->map[i] = e->next;
else
p->next = e->next;
update_next_cache (map,
e);
GNUNET_free (e);
map->size--;
if (p == NULL)
e = map->map[i];
else
e = p->next;
ret++;
}
else
{
p = e;
e = e->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_multihashmap32_contains (const struct GNUNET_CONTAINER_MultiHashMap32 *map,
uint32_t key)
{
struct MapEntry *e;
e = map->map[idx_of (map, key)];
while (e != NULL)
{
if (key == e->key)
return GNUNET_YES;
e = e->next;
}
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_multihashmap32_contains_value (const struct GNUNET_CONTAINER_MultiHashMap32 *map,
uint32_t key,
const void *value)
{
struct MapEntry *e;
e = map->map[idx_of (map, key)];
while (e != NULL)
{
if ( (key == e->key) && (e->value == value) )
return GNUNET_YES;
e = e->next;
}
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_MultiHashMap32 *map)
{
struct MapEntry **old_map;
struct MapEntry **new_map;
struct MapEntry *e;
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 (struct 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++)
{
while (NULL != (e = old_map[i]))
{
old_map[i] = e->next;
idx = idx_of (map, e->key);
e->next = new_map[idx];
new_map[idx] = e;
}
}
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 UNIQUE_ONLY was the option and the
* value already exists
*/
int
GNUNET_CONTAINER_multihashmap32_put (struct GNUNET_CONTAINER_MultiHashMap32
*map, uint32_t key, void *value,
enum GNUNET_CONTAINER_MultiHashMapOption
opt)
{
struct MapEntry *e;
unsigned int i;
i = idx_of (map, key);
if ((opt != GNUNET_CONTAINER_MULTIHASHMAPOPTION_MULTIPLE) &&
(opt != GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_FAST))
{
e = map->map[i];
while (e != NULL)
{
if (key == e->key)
{
if (opt == GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY)
return GNUNET_SYSERR;
e->value = value;
return GNUNET_NO;
}
e = e->next;
}
}
if (map->size / 3 >= map->map_length / 4)
{
grow (map);
i = idx_of (map, key);
}
e = GNUNET_new (struct MapEntry);
e->key = key;
e->value = value;
e->next = map->map[i];
map->map[i] = e;
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_multihashmap32_get_multiple (struct GNUNET_CONTAINER_MultiHashMap32 *map,
uint32_t key,
GNUNET_CONTAINER_HashMapIterator32 it,
void *it_cls)
{
int count;
struct MapEntry *e;
struct MapEntry **ce;
count = 0;
ce = &map->next_cache[map->next_cache_off];
GNUNET_assert (++map->next_cache_off < NEXT_CACHE_SIZE);
*ce = map->map[idx_of (map, key)];
while (NULL != (e = *ce))
{
*ce = e->next;
if (key != e->key)
continue;
if ( (NULL != it) &&
(GNUNET_OK != it (it_cls,
key,
e->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;
}
/**
* 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 @a map
*/
struct GNUNET_CONTAINER_MultiHashMap32Iterator *
GNUNET_CONTAINER_multihashmap32_iterator_create (const struct GNUNET_CONTAINER_MultiHashMap32 *map)
{
struct GNUNET_CONTAINER_MultiHashMap32Iterator *iter;
iter = GNUNET_new (struct GNUNET_CONTAINER_MultiHashMap32Iterator);
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_multihashmap32_iterator_next (struct GNUNET_CONTAINER_MultiHashMap32Iterator *iter,
uint32_t *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 (NULL != iter->me)
{
if (NULL != key)
*key = iter->me->key;
if (NULL != value)
*value = iter->me->value;
iter->me = iter->me->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_multihashmap32_iterator_destroy (struct GNUNET_CONTAINER_MultiHashMapIterator *iter)
{
GNUNET_free (iter);
}
/* end of container_multihashmap.c */