Zabbix

/*

** Copyright (C) 2001-2025 Zabbix SIA

**

** This program 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, version 3.

**

** This program 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 <https://www.gnu.org/licenses/>.

**/

​

#include "zbxalgo.h"

​

/******************************************************************************

 *                                                                            *

 * Purpose: calculates the number of values in queue                          *

 *                                                                            *

 * Parameters: queue - [IN]                                                   *

 *                                                                            *

 * Return value: The number of values in queue                                *

 *                                                                            *

 ******************************************************************************/

int zbx_queue_ptr_values_num(zbx_queue_ptr_t *queue)

{

    int values_num;

​

    values_num = queue->head_pos - queue->tail_pos;

    if (0 > values_num)

        values_num += queue->alloc_num;

​

    return values_num;

}

​

/******************************************************************************

 *                                                                            *

 * Purpose: reserves space in queue for additional values                     *

 *                                                                            *

 * Parameters: queue - [IN]                                                   *

 *             num   - [IN] number of additional values to reserve            *

 *                                                                            *

 ******************************************************************************/

void    zbx_queue_ptr_reserve(zbx_queue_ptr_t *queue, int num)

{

    int values_num, alloc_num, resize_num;

​

    values_num = zbx_queue_ptr_values_num(queue);

​

    if (values_num + num + 1 <= queue->alloc_num)

        return;

​

    alloc_num = queue->alloc_num + MAX(num + 1, queue->alloc_num / 2);

​

    queue->values = (void **)zbx_realloc(queue->values, alloc_num * sizeof(*queue->values));

​

    if (queue->tail_pos > queue->head_pos)

    {

        resize_num = alloc_num - queue->alloc_num;

        memmove(queue->values + queue->tail_pos + resize_num, queue->values + queue->tail_pos,

                (queue->alloc_num - queue->tail_pos) * sizeof(*queue->values));

        queue->tail_pos += resize_num;