hashset.h

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/* -*- Mode: C; tab-width: 4; c-basic-offset: 4; indent-tabs-mode: nil -*- */
/*
 *     Copyright 2012 Couchbase, 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 HASHSET_H
#define HASHSET_H 1

#include <stdlib.h>

#ifdef __cplusplus
extern "C" {
#endif

    struct hashset_st {
        size_t nbits;
        size_t mask;

        size_t capacity;
        size_t *items;
        size_t nitems;
        size_t n_deleted_items;
    };

    typedef struct hashset_st *hashset_t;

    /* create hashset instance */
    hashset_t hashset_create(void);

    /* destroy hashset instance */
    void hashset_destroy(hashset_t set);

    size_t hashset_num_items(hashset_t set);

    /* add item into the hashset.
     *
     * @note 0 and 1 is special values, meaning nil and deleted items. the
     *       function will return -1 indicating error.
     *
     * returns zero if the item already in the set and non-zero otherwise
     */
    int hashset_add(hashset_t set, void *item);

    /* remove item from the hashset
     *
     * returns non-zero if the item was removed and zero if the item wasn't
     * exist
     */
    int hashset_remove(hashset_t set, void *item);

    /* check if existence of the item
     *
     * returns non-zero if the item exists and zero otherwise
     */
    int hashset_is_member(hashset_t set, void *item);

#ifdef __cplusplus
}
#endif

#endif