1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
|
/*
* Circular list for shared mem.
*
* Copyright (c) 2009 Marko Kreen
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
/**
* @file
*
* Circular list for shared mem.
*
* Instead of pointers, it uses offsets from list head.
*/
#ifndef _USUAL_SHLIST_H_
#define _USUAL_SHLIST_H_
#include <usual/base.h>
/* clang: pointers are hard */
#if defined(__clang__)
#define __shlist_clang_workaround__ volatile
#else
#define __shlist_clang_workaround__
#endif
/** List node/head. Uses offsets from current node instead of direct pointers. */
struct SHList {
ptrdiff_t next;
ptrdiff_t prev;
};
/*
* Calculate offset relative to base.
*
* Instead of using some third pointer (eg. shmem start) as base,
* we use node itself as base. This results in simpler APi
* and also means that empty node appears as zero-filled.
*/
/** Get next element in list */
static inline struct SHList *shlist_get_next(const struct SHList *node)
{
char *p = (char *)node + node->next;
return (struct SHList *)p;
}
/** Get prev element in list */
static inline struct SHList *shlist_get_prev(const struct SHList *node)
{
char *p = (char *)node + node->prev;
return (struct SHList *)p;
}
static inline void _shlist_set_next(__shlist_clang_workaround__
struct SHList *node, const struct SHList *next)
{
node->next = (char *)next - (char *)node;
}
static inline void _shlist_set_prev(__shlist_clang_workaround__
struct SHList *node, const struct SHList *prev)
{
node->prev = (char *)prev - (char *)node;
}
/*
* List operations.
*/
/** Initialize list head */
static inline void shlist_init(struct SHList *list)
{
list->next = 0;
list->prev = 0;
}
/** Insert as last element */
static inline void shlist_append(struct SHList *list, struct SHList *node)
{
struct SHList *last;
last = shlist_get_prev(list);
_shlist_set_next(node, list);
_shlist_set_prev(node, last);
_shlist_set_next(last, node);
_shlist_set_prev(list, node);
}
/** Insert as first element */
static inline void shlist_prepend(struct SHList *list, struct SHList *node)
{
struct SHList *first;
first = shlist_get_next(list);
_shlist_set_next(node, first);
_shlist_set_prev(node, list);
_shlist_set_next(list, node);
_shlist_set_prev(first, node);
}
/** Remove an node */
static inline void shlist_remove(struct SHList *node)
{
struct SHList *next = shlist_get_next(node);
struct SHList *prev = shlist_get_prev(node);
_shlist_set_prev(next, prev);
_shlist_set_next(prev, next);
shlist_init(node);
}
/** No elements? */
static inline bool shlist_empty(const struct SHList *list)
{
return list->next == 0;
}
/** Return first elem */
static inline struct SHList *shlist_first(const struct SHList *list)
{
if (shlist_empty(list))
return NULL;
return shlist_get_next(list);
}
/** Return last elem */
static inline struct SHList *shlist_last(const struct SHList *list)
{
if (shlist_empty(list))
return NULL;
return shlist_get_prev(list);
}
/** Remove first elem */
static inline struct SHList *shlist_pop(struct SHList *list)
{
struct SHList *node = shlist_first(list);
if (node)
shlist_remove(node);
return node;
}
/** Remove and return specific type of elem */
#define shlist_pop_type(list, type, field) ( \
shlist_empty(list) ? NULL : container_of(shlist_pop(list), type, field))
/** Loop over list */
#define shlist_for_each(node, list) \
for ((node) = shlist_get_next(list); \
(node) != (list); \
(node) = shlist_get_next(node))
/** Loop over list and allow removing node */
#define shlist_for_each_safe(node, list, tmp) \
for ((node) = shlist_get_next(list), (tmp) = shlist_get_next(node); \
(node) != (list); \
(node) = (tmp), (tmp) = shlist_get_next(node))
#endif
|
