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/*
* Copyright (c) 2014 Nicira, Inc.
* Copyright (c) 2014 Netronome.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <config.h>
#include "id-pool.h"
#include "openvswitch/hmap.h"
#include "hash.h"
struct id_node {
struct hmap_node node;
uint32_t id;
};
struct id_pool {
struct hmap map;
uint32_t base; /* IDs in the range of [base, base + n_ids). */
uint32_t n_ids; /* Total number of ids in the pool. */
uint32_t next_free_id; /* Possible next free id. */
};
static void id_pool_init(struct id_pool *pool,
uint32_t base, uint32_t n_ids);
static void id_pool_uninit(struct id_pool *pool);
static struct id_node *id_pool_find(struct id_pool *pool, uint32_t id);
struct id_pool *
id_pool_create(uint32_t base, uint32_t n_ids)
{
struct id_pool *pool;
pool = xmalloc(sizeof *pool);
id_pool_init(pool, base, n_ids);
return pool;
}
void
id_pool_destroy(struct id_pool *pool)
{
if (pool) {
id_pool_uninit(pool);
free(pool);
}
}
static void
id_pool_init(struct id_pool *pool, uint32_t base, uint32_t n_ids)
{
pool->base = base;
pool->n_ids = n_ids;
pool->next_free_id = base;
hmap_init(&pool->map);
}
static void
id_pool_uninit(struct id_pool *pool)
{
struct id_node *id_node;
HMAP_FOR_EACH_POP(id_node, node, &pool->map) {
free(id_node);
}
hmap_destroy(&pool->map);
}
static struct id_node *
id_pool_find(struct id_pool *pool, uint32_t id)
{
size_t hash;
struct id_node *id_node;
hash = hash_int(id, 0);
HMAP_FOR_EACH_WITH_HASH(id_node, node, hash, &pool->map) {
if (id == id_node->id) {
return id_node;
}
}
return NULL;
}
void
id_pool_add(struct id_pool *pool, uint32_t id)
{
struct id_node *id_node = xmalloc(sizeof *id_node);
size_t hash;
id_node->id = id;
hash = hash_int(id, 0);
hmap_insert(&pool->map, &id_node->node, hash);
}
bool
id_pool_alloc_id(struct id_pool *pool, uint32_t *id_)
{
uint32_t id;
if (pool->n_ids == 0) {
return false;
}
if (!(id_pool_find(pool, pool->next_free_id))) {
id = pool->next_free_id;
goto found_free_id;
}
for(id = pool->base; id < pool->base + pool->n_ids; id++) {
if (!id_pool_find(pool, id)) {
goto found_free_id;
}
}
/* Not available. */
return false;
found_free_id:
id_pool_add(pool, id);
if (id + 1 < pool->base + pool->n_ids) {
pool->next_free_id = id + 1;
} else {
pool->next_free_id = pool->base;
}
*id_ = id;
return true;
}
void
id_pool_free_id(struct id_pool *pool, uint32_t id)
{
struct id_node *id_node;
if (id >= pool->base && (id < pool->base + pool->n_ids)) {
id_node = id_pool_find(pool, id);
if (id_node) {
hmap_remove(&pool->map, &id_node->node);
if (id < pool->next_free_id) {
pool->next_free_id = id;
}
free(id_node);
}
}
}
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