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/*
* Copyright (c) 2002-2003 Erik Fears
* Copyright (c) 2014-2021 ircd-hybrid development team
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* 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, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301
* USA
*/
/*! \file list.c
* \brief Maintains doubly-linked lists.
* \version $Id$
*/
#include <stdlib.h>
#include <assert.h>
#include "memory.h"
#include "list.h"
node_t *
node_create(void)
{
node_t *node = xcalloc(sizeof *node);
return node;
}
void
node_free(node_t *node)
{
xfree(node);
}
node_t *
list_add(void *data, node_t *node, list_t *list)
{
node->data = data;
node->prev = NULL;
node->next = list->head;
/* Assumption: If list->tail != NULL, list->head != NULL */
if (list->head)
list->head->prev = node;
else if (list->tail == NULL)
list->tail = node;
list->head = node;
list->elements++;
return node;
}
node_t *
list_remove(node_t *node, list_t *list)
{
/* Assumption: If node->next == NULL, then list->tail == node
* and: If node->prev == NULL, then list->head == node
*/
if (node->next)
node->next->prev = node->prev;
else
{
assert(list->tail == node);
list->tail = node->prev;
}
if (node->prev)
node->prev->next = node->next;
else
{
assert(list->head == node);
list->head = node->next;
}
/* Set this to NULL does matter */
node->next = NULL;
node->prev = NULL;
list->elements--;
return node;
}
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