busybox/libbb/llist.c

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/* vi: set sw=4 ts=4: */
/*
* linked list helper functions.
*
* Copyright (C) 2003 Glenn McGrath
* Copyright (C) 2005 Vladimir Oleynik
* Copyright (C) 2005 Bernhard Fischer
*
* Licensed under the GPL v2, see the file LICENSE in this tarball.
*/
#include <stdlib.h>
#include "libbb.h"
#ifdef L_llist_add_to
/* Add data to the start of the linked list. */
llist_t *llist_add_to(llist_t *old_head, char *new_item)
{
llist_t *new_head;
new_head = xmalloc(sizeof(llist_t));
new_head->data = new_item;
new_head->link = old_head;
return (new_head);
}
#endif
#ifdef L_llist_add_to_end
/* Add data to the end of the linked list. */
llist_t *llist_add_to_end(llist_t *list_head, char *data)
{
llist_t *new_item;
new_item = xmalloc(sizeof(llist_t));
new_item->data = data;
new_item->link = NULL;
if (list_head == NULL) {
list_head = new_item;
} else {
llist_t *tail = list_head;
while (tail->link)
tail = tail->link;
tail->link = new_item;
}
return list_head;
}
#endif
#ifdef L_llist_free_one
/* Free the current list element and advance to the next entry in the list.
* Returns a pointer to the next element. */
llist_t *llist_free_one(llist_t *elm)
{
llist_t *next = elm ? elm->link : NULL;
#if ENABLE_DMALLOC /* avoid warnings from dmalloc's error-free-null option */
if (elm)
#endif
free(elm);
elm = next;
return elm;
}
#endif
#ifdef L_llist_free
/* Recursively free all elements in the linked list. */
void llist_free(llist_t *elm)
{
while ((elm = llist_free_one(elm)));
}
#endif