circ_list.h

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/*
 *  OpenVPN -- An application to securely tunnel IP networks
 *             over a single UDP port, with support for SSL/TLS-based
 *             session authentication and key exchange,
 *             packet encryption, packet authentication, and
 *             packet compression.
 *
 *  Copyright (C) 2002-2025 OpenVPN Inc <sales@openvpn.net>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 2
 *  as published by the Free Software Foundation.
 *
 *  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 General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, see <https://www.gnu.org/licenses/>.
 */
 
#ifndef CIRC_LIST_H
#define CIRC_LIST_H
 
#include "basic.h"
#include "integer.h"
#include "error.h"
 
#define CIRC_LIST(name, type) \
    struct name               \
    {                         \
        int x_head;           \
        int x_size;           \
        int x_cap;            \
        int x_sizeof;         \
        type x_list[];        \
    }
 
#define CIRC_LIST_PUSH(obj, item)                                    \
    {                                                                \
        (obj)->x_head = modulo_add((obj)->x_head, -1, (obj)->x_cap); \
        (obj)->x_list[(obj)->x_head] = (item);                       \
        (obj)->x_size = min_int((obj)->x_size + 1, (obj)->x_cap);    \
    }
 
#define CIRC_LIST_SIZE(obj) ((obj)->x_size)
 
#define CIRC_LIST_INDEX(obj, index)                                                     \
    modulo_add((obj)->x_head, index_verify((index), (obj)->x_size, __FILE__, __LINE__), \
               (obj)->x_cap)
 
#define CIRC_LIST_ITEM(obj, index) ((obj)->x_list[CIRC_LIST_INDEX((obj), (index))])
 
#define CIRC_LIST_RESET(obj) \
    {                        \
        (obj)->x_head = 0;   \
        (obj)->x_size = 0;   \
    }
 
#define CIRC_LIST_ALLOC(dest, list_type, size)                                 \
    {                                                                          \
        const int so = sizeof(list_type) + sizeof((dest)->x_list[0]) * (size); \
        (dest) = (list_type *)malloc(so);                                      \
        check_malloc_return(dest);                                             \
        memset((dest), 0, so);                                                 \
        (dest)->x_cap = size;                                                  \
        (dest)->x_sizeof = so;                                                 \
    }
 
#define CIRC_LIST_FREE(dest) free(dest)
 
#endif /* ifndef CIRC_LIST_H */