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	/* 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	* Copyright (C) 2005 Bernhard Reutner-Fischer
8	* 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	void FAST_FUNC llist_add_to(llist_t *old_head, void data)
17	{
18	llist_t *new_head = xmalloc(sizeof(llist_t));
19
20	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	void FAST_FUNC llist_add_to_end(llist_t *list_head, void data)
27	{
28	llist_t *new_item = xmalloc(sizeof(llist_t));
29
30	new_item->data = data;
31	new_item->link = NULL;
32
33	if (!*list_head)
34	*list_head = new_item;
35	else {
36	llist_t tail = list_head;
37
38	while (tail->link)
39	tail = tail->link;
40	tail->link = new_item;
41	}
42	}
43
44	/* Remove first element from the list and return it */
45	void* FAST_FUNC llist_pop(llist_t **head)
46	{
47	void data, next;
48
49	if (!*head)
50	return NULL;
51
52	data = (*head)->data;
53	next = (*head)->link;
54	free(*head);
55	*head = next;
56
57	return data;
58	}
59
60	/* 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	/* Recursively free all elements in the linked list. If freeit != NULL
82	* call it on each datum in the list */
83	void FAST_FUNC llist_free(llist_t elm, void (freeit) (void *data))
84	{
85	while (elm) {
86	void *data = llist_pop(&elm);
87
88	if (freeit)
89	freeit(data);
90	}
91	}
92
93	/* Reverse list order. */
94	llist_t* FAST_FUNC llist_rev(llist_t *list)
95	{
96	llist_t *rev = NULL;
97
98	while (list) {
99	llist_t *next = list->link;
100
101	list->link = rev;
102	rev = list;
103	list = next;
104	}
105	return rev;
106	}