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/*
* netlink/hashtable.c Netlink hashtable Utilities
*
* This library 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 version 2.1
* of the License.
*
* Copyright (c) 2012 Cumulus Networks, Inc
*/
#include <string.h>
#include <netlink-local.h>
#include <netlink/object.h>
#include <netlink/hash.h>
#include <netlink/hashtable.h>
/**
* @ingroup core_types
* @defgroup hashtable Hashtable
*
* @{
*
* Header
* ------
* ~~~~{.c}
* #include <netlink/hashtable.h>
* ~~~~
*/
/**
* Allocate hashtable
* @arg size Size of hashtable in number of elements
*
* @return Allocated hashtable or NULL.
*/
nl_hash_table_t *nl_hash_table_alloc(int size)
{
nl_hash_table_t *ht;
ht = calloc(1, sizeof (*ht));
if (!ht)
goto errout;
ht->nodes = calloc(size, sizeof (*ht->nodes));
if (!ht->nodes) {
free(ht);
goto errout;
}
ht->size = size;
return ht;
errout:
return NULL;
}
/**
* Free hashtable including all nodes
* @arg ht Hashtable
*
* @note Reference counter of all objects in the hashtable will be decremented.
*/
void nl_hash_table_free(nl_hash_table_t *ht)
{
int i;
for(i = 0; i < ht->size; i++) {
nl_hash_node_t *node = ht->nodes[i];
nl_hash_node_t *saved_node;
while (node) {
saved_node = node;
node = node->next;
nl_object_put(saved_node->obj);
free(saved_node);
}
}
free(ht->nodes);
free(ht);
}
/**
* Lookup identical object in hashtable
* @arg ht Hashtable
* @arg obj Object to lookup
*
* Generates hashkey for `obj` and traverses the corresponding chain calling
* `nl_object_identical()` on each trying to find a match.
*
* @return Pointer to object if match was found or NULL.
*/
struct nl_object* nl_hash_table_lookup(nl_hash_table_t *ht,
struct nl_object *obj)
{
nl_hash_node_t *node;
uint32_t key_hash;
nl_object_keygen(obj, &key_hash, ht->size);
node = ht->nodes[key_hash];
while (node) {
if (nl_object_identical(node->obj, obj))
return node->obj;
node = node->next;
}
return NULL;
}
/**
* Add object to hashtable
* @arg ht Hashtable
* @arg obj Object to add
*
* Adds `obj` to the hashtable. Object type must support hashing, otherwise all
* objects will be added to the chain `0`.
*
* @note The reference counter of the object is incremented.
*
* @return 0 on success or a negative error code
* @retval -NLE_EXIST Identical object already present in hashtable
*/
int nl_hash_table_add(nl_hash_table_t *ht, struct nl_object *obj)
{
nl_hash_node_t *node;
uint32_t key_hash;
nl_object_keygen(obj, &key_hash, ht->size);
node = ht->nodes[key_hash];
while (node) {
if (nl_object_identical(node->obj, obj)) {
NL_DBG(2, "Warning: Add to hashtable found duplicate...\n");
return -NLE_EXIST;
}
node = node->next;
}
NL_DBG (5, "adding cache entry of obj %p in table %p, with hash 0x%x\n",
obj, ht, key_hash);
node = malloc(sizeof(nl_hash_node_t));
if (!node)
return -NLE_NOMEM;
nl_object_get(obj);
node->obj = obj;
node->key = key_hash;
node->key_size = sizeof(uint32_t);
node->next = ht->nodes[key_hash];
ht->nodes[key_hash] = node;
return 0;
}
/**
* Remove object from hashtable
* @arg ht Hashtable
* @arg obj Object to remove
*
* Remove `obj` from hashtable if it exists.
*
* @note Reference counter of object will be decremented.
*
* @return 0 on success or a negative error code.
* @retval -NLE_OBJ_NOTFOUND Object not present in hashtable.
*/
int nl_hash_table_del(nl_hash_table_t *ht, struct nl_object *obj)
{
nl_hash_node_t *node, *prev;
uint32_t key_hash;
nl_object_keygen(obj, &key_hash, ht->size);
prev = node = ht->nodes[key_hash];
while (node) {
if (nl_object_identical(node->obj, obj)) {
nl_object_put(obj);
NL_DBG (5, "deleting cache entry of obj %p in table %p, with"
" hash 0x%x\n", obj, ht, key_hash);
if (node == ht->nodes[key_hash])
ht->nodes[key_hash] = node->next;
else
prev->next = node->next;
free(node);
return 0;
}
prev = node;
node = node->next;
}
return -NLE_OBJ_NOTFOUND;
}
uint32_t nl_hash(void *k, size_t length, uint32_t initval)
{
return(__nl_hash(k, length, initval));
}
/** @} */
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