1/*
2   Unix SMB/CIFS implementation.
3   some simple double linked list macros
4   Copyright (C) Andrew Tridgell 1998
5
6   This program is free software; you can redistribute it and/or modify
7   it under the terms of the GNU General Public License as published by
8   the Free Software Foundation; either version 2 of the License, or
9   (at your option) any later version.
10
11   This program is distributed in the hope that it will be useful,
12   but WITHOUT ANY WARRANTY; without even the implied warranty of
13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14   GNU General Public License for more details.
15
16   You should have received a copy of the GNU General Public License
17   along with this program; if not, write to the Free Software
18   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
19*/
20
21/* To use these macros you must have a structure containing a next and
22   prev pointer */
23
24#ifndef _DLINKLIST_H
25#define _DLINKLIST_H
26
27
28/* hook into the front of the list */
29#define DLIST_ADD(list, p) \
30do { \
31        if (!(list)) { \
32		(list) = (p); \
33		(p)->next = (p)->prev = NULL; \
34	} else { \
35		(list)->prev = (p); \
36		(p)->next = (list); \
37		(p)->prev = NULL; \
38		(list) = (p); \
39	}\
40} while (0)
41
42/* remove an element from a list - element doesn't have to be in list. */
43#define DLIST_REMOVE(list, p) \
44do { \
45	if ((p) == (list)) { \
46		(list) = (p)->next; \
47		if (list) (list)->prev = NULL; \
48	} else { \
49		if ((p)->prev) (p)->prev->next = (p)->next; \
50		if ((p)->next) (p)->next->prev = (p)->prev; \
51	} \
52	if ((p) != (list)) (p)->next = (p)->prev = NULL; \
53} while (0)
54
55/* promote an element to the top of the list */
56#define DLIST_PROMOTE(list, p) \
57do { \
58          DLIST_REMOVE(list, p); \
59          DLIST_ADD(list, p); \
60} while (0)
61
62/* hook into the end of the list - needs the entry type */
63#define DLIST_ADD_END(list, p, type) \
64do { \
65		if (!(list)) { \
66			(list) = (p); \
67			(p)->next = (p)->prev = NULL; \
68		} else { \
69			type tmp; \
70			for (tmp = (list); tmp->next; tmp = tmp->next) ; \
71			tmp->next = (p); \
72			(p)->next = NULL; \
73			(p)->prev = tmp; \
74		} \
75} while (0)
76
77/* insert 'p' after the given element 'el' in a list. If el is NULL then
78   this is the same as a DLIST_ADD() */
79#define DLIST_ADD_AFTER(list, p, el) \
80do { \
81        if (!(list) || !(el)) { \
82		DLIST_ADD(list, p); \
83	} else { \
84		p->prev = el; \
85		p->next = el->next; \
86		el->next = p; \
87		if (p->next) p->next->prev = p; \
88	}\
89} while (0)
90
91/* demote an element to the end of the list, needs a tmp pointer */
92#define DLIST_DEMOTE(list, p, tmp) \
93do { \
94		DLIST_REMOVE(list, p); \
95		DLIST_ADD_END(list, p, tmp); \
96} while (0)
97
98/* concatenate two lists - putting all elements of the 2nd list at the
99   end of the first list */
100#define DLIST_CONCATENATE(list1, list2, type) \
101do { \
102		if (!(list1)) { \
103			(list1) = (list2); \
104		} else { \
105			type tmp; \
106			for (tmp = (list1); tmp->next; tmp = tmp->next) ; \
107			tmp->next = (list2); \
108			if (list2) { \
109				(list2)->prev = tmp;	\
110			} \
111		} \
112} while (0)
113
114#endif /* _DLINKLIST_H */
115