1 /**************************************************************************
2  *
3  * Copyright 2006 Tungsten Graphics, Inc., Bismarck, ND. USA.
4  * All Rights Reserved.
5  *
6  * Permission is hereby granted, free of charge, to any person obtaining a
7  * copy of this software and associated documentation files (the
8  * "Software"), to deal in the Software without restriction, including
9  * without limitation the rights to use, copy, modify, merge, publish,
10  * distribute, sub license, and/or sell copies of the Software, and to
11  * permit persons to whom the Software is furnished to do so, subject to
12  * the following conditions:
13  *
14  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16  * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
17  * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
18  * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
19  * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
20  * USE OR OTHER DEALINGS IN THE SOFTWARE.
21  *
22  * The above copyright notice and this permission notice (including the
23  * next paragraph) shall be included in all copies or substantial portions
24  * of the Software.
25  */
26 
27 /*
28  * List macros heavily inspired by the Linux kernel
29  * list handling. No list looping yet.
30  */
31 
32 #include <stddef.h>
33 
34 typedef struct _drmMMListHead
35 {
36     struct _drmMMListHead *prev;
37     struct _drmMMListHead *next;
38 } drmMMListHead;
39 
40 #define DRMINITLISTHEAD(__item)		       \
41   do{					       \
42     (__item)->prev = (__item);		       \
43     (__item)->next = (__item);		       \
44   } while (0)
45 
46 #define DRMLISTADD(__item, __list)		\
47   do {						\
48     (__item)->prev = (__list);			\
49     (__item)->next = (__list)->next;		\
50     (__list)->next->prev = (__item);		\
51     (__list)->next = (__item);			\
52   } while (0)
53 
54 #define DRMLISTADDTAIL(__item, __list)		\
55   do {						\
56     (__item)->next = (__list);			\
57     (__item)->prev = (__list)->prev;		\
58     (__list)->prev->next = (__item);		\
59     (__list)->prev = (__item);			\
60   } while(0)
61 
62 #define DRMLISTDEL(__item)			\
63   do {						\
64     (__item)->prev->next = (__item)->next;	\
65     (__item)->next->prev = (__item)->prev;	\
66   } while(0)
67 
68 #define DRMLISTDELINIT(__item)			\
69   do {						\
70     (__item)->prev->next = (__item)->next;	\
71     (__item)->next->prev = (__item)->prev;	\
72     (__item)->next = (__item);			\
73     (__item)->prev = (__item);			\
74   } while(0)
75 
76 #define DRMLISTENTRY(__type, __item, __field)   \
77     ((__type *)(((char *) (__item)) - offsetof(__type, __field)))
78 
79 #define DRMLISTEMPTY(__item) ((__item)->next == (__item))
80 
81 #define DRMLISTSINGLE(__list) \
82 	(!DRMLISTEMPTY(__list) && ((__list)->next == (__list)->prev))
83 
84 #define DRMLISTFOREACH(__item, __list)					\
85 	for ((__item) = (__list)->next;					\
86 	     (__item) != (__list); (__item) = (__item)->next)
87 
88 #define DRMLISTFOREACHSAFE(__item, __temp, __list)			\
89 	for ((__item) = (__list)->next, (__temp) = (__item)->next;	\
90 	     (__item) != (__list);					\
91 	     (__item) = (__temp), (__temp) = (__item)->next)
92 
93 #define DRMLISTFOREACHSAFEREVERSE(__item, __temp, __list)		\
94 	for ((__item) = (__list)->prev, (__temp) = (__item)->prev;	\
95 	     (__item) != (__list);					\
96 	     (__item) = (__temp), (__temp) = (__item)->prev)
97 
98 #define DRMLISTFOREACHENTRY(__item, __list, __head)                            \
99 	for ((__item) = DRMLISTENTRY(typeof(*__item), (__list)->next, __head); \
100 	     &(__item)->__head != (__list);                                    \
101 	     (__item) = DRMLISTENTRY(typeof(*__item),                          \
102 				     (__item)->__head.next, __head))
103 
104 #define DRMLISTFOREACHENTRYSAFE(__item, __temp, __list, __head)                \
105 	for ((__item) = DRMLISTENTRY(typeof(*__item), (__list)->next, __head), \
106 	     (__temp) = DRMLISTENTRY(typeof(*__item),                          \
107 				     (__item)->__head.next, __head);           \
108 	     &(__item)->__head != (__list);                                    \
109 	     (__item) = (__temp),                                              \
110 	     (__temp) = DRMLISTENTRY(typeof(*__item),                          \
111 				     (__temp)->__head.next, __head))
112 
113 #define DRMLISTJOIN(__list, __join) if (!DRMLISTEMPTY(__list)) {	\
114 	(__list)->next->prev = (__join);				\
115 	(__list)->prev->next = (__join)->next;				\
116 	(__join)->next->prev = (__list)->prev;				\
117 	(__join)->next = (__list)->next;				\
118 }
119