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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 3 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, see <http://www.gnu.org/licenses/>.
18 */
19
20 /* To use these macros you must have a structure containing a next and
21 prev pointer */
22
23
24 /* hook into the front of the list */
25 #define DLIST_ADD(list, p) \
26 do { \
27 if (!(list)) { \
28 (list) = (p); \
29 (p)->next = (p)->prev = NULL; \
30 } else { \
31 (list)->prev = (p); \
32 (p)->next = (list); \
33 (p)->prev = NULL; \
34 (list) = (p); \
35 }\
36 } while (0)
37
38 /* remove an element from a list - element doesn't have to be in list. */
39 #ifndef DLIST_REMOVE
40 #define DLIST_REMOVE(list, p) \
41 do { \
42 if ((p) == (list)) { \
43 (list) = (p)->next; \
44 if (list) (list)->prev = NULL; \
45 } else { \
46 if ((p)->prev) (p)->prev->next = (p)->next; \
47 if ((p)->next) (p)->next->prev = (p)->prev; \
48 } \
49 if ((p) && ((p) != (list))) (p)->next = (p)->prev = NULL; \
50 } while (0)
51 #endif
52
53 /* promote an element to the top of the list */
54 #define DLIST_PROMOTE(list, p) \
55 do { \
56 DLIST_REMOVE(list, p); \
57 DLIST_ADD(list, p); \
58 } while (0)
59
60 /* hook into the end of the list - needs a tmp pointer */
61 #define DLIST_ADD_END(list, p, type) \
62 do { \
63 if (!(list)) { \
64 (list) = (p); \
65 (p)->next = (p)->prev = NULL; \
66 } else { \
67 type tmp; \
68 for (tmp = (list); tmp->next; tmp = tmp->next) ; \
69 tmp->next = (p); \
70 (p)->next = NULL; \
71 (p)->prev = tmp; \
72 } \
73 } while (0)
74
75 /* insert 'p' after the given element 'el' in a list. If el is NULL then
76 this is the same as a DLIST_ADD() */
77 #define DLIST_ADD_AFTER(list, p, el) \
78 do { \
79 if (!(list) || !(el)) { \
80 DLIST_ADD(list, p); \
81 } else { \
82 p->prev = el; \
83 p->next = el->next; \
84 el->next = p; \
85 if (p->next) p->next->prev = p; \
86 }\
87 } while (0)
88
89 /* demote an element to the end of the list, needs a tmp pointer */
90 #define DLIST_DEMOTE(list, p, tmp) \
91 do { \
92 DLIST_REMOVE(list, p); \
93 DLIST_ADD_END(list, p, tmp); \
94 } while (0)
95
96 /* concatenate two lists - putting all elements of the 2nd list at the
97 end of the first list */
98 #define DLIST_CONCATENATE(list1, list2, type) \
99 do { \
100 if (!(list1)) { \
101 (list1) = (list2); \
102 } else { \
103 type tmp; \
104 for (tmp = (list1); tmp->next; tmp = tmp->next) ; \
105 tmp->next = (list2); \
106 if (list2) { \
107 (list2)->prev = tmp; \
108 } \
109 } \
110 } while (0)