busybox/libbb/llist.c

/* vi: set sw=4 ts=4: */
/*
 * linked list helper functions.
 *
 * Copyright (C) 2003 Glenn McGrath
 * Copyright (C) 2005 Vladimir Oleynik
 * Copyright (C) 2005 Bernhard Reutner-Fischer
 * Copyright (C) 2006 Rob Landley <rob@landley.net>
 *
 * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
 */

#include "libbb.h"

/* Add data to the start of the linked list.  */
void FAST_FUNC 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;
}

/* Add data to the end of the linked list.  */
void FAST_FUNC 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;
	}
}

/* Remove first element from the list and return it */
void* FAST_FUNC llist_pop(llist_t **head)
{
	void *data, *next;

	if (!*head)
		return NULL;

	data = (*head)->data;
	next = (*head)->link;
	free(*head);
	*head = next;

	return data;
}

/* Unlink arbitrary given element from the list */
void FAST_FUNC llist_unlink(llist_t **head, llist_t *elm)
{
	llist_t *crt;

	if (!(elm && *head))
		return;

	if (elm == *head) {
		*head = (*head)->link;
		return;
	}

	for (crt = *head; crt; crt = crt->link) {
		if (crt->link == elm) {
			crt->link = elm->link;
			return;
		}
	}
}

/* Recursively free all elements in the linked list.  If freeit != NULL
 * call it on each datum in the list */
void FAST_FUNC llist_free(llist_t *elm, void (*freeit) (void *data))
{
	while (elm) {
		void *data = llist_pop(&elm);

		if (freeit)
			freeit(data);
	}
}

/* Reverse list order. */
llist_t* FAST_FUNC llist_rev(llist_t *list)
{
	llist_t *rev = NULL;

	while (list) {
		llist_t *next = list->link;

		list->link = rev;
		rev = list;
		list = next;
	}
	return rev;
}
1	niro	532	/* vi: set sw=4 ts=4: */
2			/*
3			* linked list helper functions.
4			*
5			* Copyright (C) 2003 Glenn McGrath
6			* Copyright (C) 2005 Vladimir Oleynik
7	niro	816	* Copyright (C) 2005 Bernhard Reutner-Fischer
8	niro	532	* Copyright (C) 2006 Rob Landley <rob@landley.net>
9			*
10			* Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
11			*/
12
13			#include "libbb.h"
14
15			/* Add data to the start of the linked list. */
16	niro	816	void FAST_FUNC llist_add_to(llist_t *old_head, void data)
17	niro	532	{
18			llist_t *new_head = xmalloc(sizeof(llist_t));
19	niro	816
20	niro	532	new_head->data = data;
21			new_head->link = *old_head;
22			*old_head = new_head;
23			}
24
25			/* Add data to the end of the linked list. */
26	niro	816	void FAST_FUNC llist_add_to_end(llist_t *list_head, void data)
27	niro	532	{
28			llist_t *new_item = xmalloc(sizeof(llist_t));
29	niro	816
30	niro	532	new_item->data = data;
31			new_item->link = NULL;
32
33	niro	816	if (!*list_head)
34			*list_head = new_item;
35	niro	532	else {
36			llist_t tail = list_head;
37	niro	816
38			while (tail->link)
39			tail = tail->link;
40	niro	532	tail->link = new_item;
41			}
42			}
43
44			/* Remove first element from the list and return it */
45	niro	816	void* FAST_FUNC llist_pop(llist_t **head)
46	niro	532	{
47	niro	816	void data, next;
48	niro	532
49	niro	816	if (!*head)
50			return NULL;
51	niro	532
52	niro	816	data = (*head)->data;
53			next = (*head)->link;
54			free(*head);
55			*head = next;
56
57	niro	532	return data;
58			}
59
60	niro	816	/* Unlink arbitrary given element from the list */
61			void FAST_FUNC llist_unlink(llist_t *head, llist_t elm)
62			{
63			llist_t *crt;
64
65			if (!(elm && *head))
66			return;
67
68			if (elm == *head) {
69			head = (head)->link;
70			return;
71			}
72
73			for (crt = *head; crt; crt = crt->link) {
74			if (crt->link == elm) {
75			crt->link = elm->link;
76			return;
77			}
78			}
79			}
80
81	niro	532	/* Recursively free all elements in the linked list. If freeit != NULL
82			* call it on each datum in the list */
83	niro	816	void FAST_FUNC llist_free(llist_t elm, void (freeit) (void *data))
84	niro	532	{
85			while (elm) {
86			void *data = llist_pop(&elm);
87	niro	816
88			if (freeit)
89			freeit(data);
90	niro	532	}
91			}
92
93	niro	816	/* Reverse list order. */
94			llist_t* FAST_FUNC llist_rev(llist_t *list)
95	niro	532	{
96	niro	816	llist_t *rev = NULL;
97
98	niro	532	while (list) {
99			llist_t *next = list->link;
100	niro	816
101			list->link = rev;
102			rev = list;
103	niro	532	list = next;
104			}
105	niro	816	return rev;
106	niro	532	}