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/*
* Copyright (c) 2014, 2016 Nicira, Inc.
*
* 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.
*/
#ifndef CCMAP_H
#define CCMAP_H 1
#include <stdbool.h>
#include <stdint.h>
#include "ovs-rcu.h"
#include "util.h"
/* Concurrent hash map for numerical counts of given hash values.
* ==============================================================
*
* A single-writer, multiple-reader count hash table that efficiently supports
* duplicates.
*
*
* Thread-safety
* =============
*
* The general rules are:
*
* - Only a single thread may safely call into ccmap_inc(),
* or ccmap_dec() at any given time.
*
* - Any number of threads may use functions and macros that search
* a given ccmap, even in parallel with other threads
* calling ccmap_inc() or ccmap_dec().
*/
/* Concurrent hash map. */
struct ccmap {
OVSRCU_TYPE(struct ccmap_impl *) impl;
};
/* Initialization. */
void ccmap_init(struct ccmap *);
void ccmap_destroy(struct ccmap *);
/* Count. */
size_t ccmap_count(const struct ccmap *);
bool ccmap_is_empty(const struct ccmap *);
/* Insertion and deletion. Return the current count after the operation. */
uint32_t ccmap_inc(struct ccmap *, uint32_t hash);
uint32_t ccmap_dec(struct ccmap *, uint32_t hash);
uint32_t ccmap_find(const struct ccmap *, uint32_t hash);
#endif /* ccmap.h */
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