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
* Copyright (C) 2006 Rob Landley <rob@landley.net>
*
* 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. */
void llist_add_to(llist_t **old_head, void *data)
{
llist_t *new_head = xmalloc(sizeof(llist_t));
new_head->data = data;
new_head->link = *old_head;
*old_head = new_head;
}
#endif
#ifdef L_llist_add_to_end
/* Add data to the end of the linked list. */
void llist_add_to_end(llist_t **list_head, void *data)
{
llist_t *new_item = xmalloc(sizeof(llist_t));
new_item->data = data;
new_item->link = NULL;
if (!*list_head) *list_head = new_item;
else {
llist_t *tail = *list_head;
while (tail->link) tail = tail->link;
tail->link = new_item;
}
}
#endif
#ifdef L_llist_pop
/* Remove first element from the list and return it */
void *llist_pop(llist_t **head)
{
void *data;
if(!*head) data = *head;
else {
void *next = (*head)->link;
data = (*head)->data;
free(*head);
*head = next;
}
return data;
}
#endif
#ifdef L_llist_free
/* Recursively free all elements in the linked list. If freeit != NULL
* call it on each datum in the list */
void llist_free(llist_t *elm, void (*freeit)(void *data))
{
while (elm) {
void *data = llist_pop(&elm);
if (freeit) freeit(data);
}
}
#endif