FFmpeg
Main Page
Related Pages
Modules
Namespaces
Data Structures
Files
Examples
File List
Globals
All
Data Structures
Namespaces
Files
Functions
Variables
Typedefs
Enumerations
Enumerator
Macros
Groups
Pages
libavutil
atomic.c
Go to the documentation of this file.
1
/*
2
* Copyright (c) 2012 Ronald S. Bultje <rsbultje@gmail.com>
3
*
4
* This file is part of FFmpeg.
5
*
6
* FFmpeg is free software; you can redistribute it and/or
7
* modify it under the terms of the GNU Lesser General Public
8
* License as published by the Free Software Foundation; either
9
* version 2.1 of the License, or (at your option) any later version.
10
*
11
* FFmpeg 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 GNU
14
* Lesser General Public License for more details.
15
*
16
* You should have received a copy of the GNU Lesser General Public
17
* License along with FFmpeg; if not, write to the Free Software
18
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19
*/
20
21
#include "
atomic.h
"
22
23
#if !HAVE_ATOMICS_NATIVE
24
25
#if HAVE_PTHREADS
26
27
#include <pthread.h>
28
29
static
pthread_mutex_t
atomic_lock = PTHREAD_MUTEX_INITIALIZER;
30
31
int
avpriv_atomic_int_get
(
volatile
int
*ptr)
32
{
33
int
res
;
34
35
pthread_mutex_lock
(&atomic_lock);
36
res = *ptr;
37
pthread_mutex_unlock
(&atomic_lock);
38
39
return
res
;
40
}
41
42
void
avpriv_atomic_int_set
(
volatile
int
*ptr,
int
val
)
43
{
44
pthread_mutex_lock
(&atomic_lock);
45
*ptr =
val
;
46
pthread_mutex_unlock
(&atomic_lock);
47
}
48
49
int
avpriv_atomic_int_add_and_fetch
(
volatile
int
*ptr,
int
inc)
50
{
51
int
res
;
52
53
pthread_mutex_lock
(&atomic_lock);
54
*ptr += inc;
55
res = *ptr;
56
pthread_mutex_unlock
(&atomic_lock);
57
58
return
res
;
59
}
60
61
void
*
avpriv_atomic_ptr_cas
(
void
*
volatile
*ptr,
void
*oldval,
void
*newval)
62
{
63
void
*
ret
;
64
pthread_mutex_lock
(&atomic_lock);
65
ret = *ptr;
66
if
(*ptr == oldval)
67
*ptr = newval;
68
pthread_mutex_unlock
(&atomic_lock);
69
return
ret
;
70
}
71
72
#elif !HAVE_THREADS
73
74
int
avpriv_atomic_int_get
(
volatile
int
*ptr)
75
{
76
return
*ptr;
77
}
78
79
void
avpriv_atomic_int_set
(
volatile
int
*ptr,
int
val
)
80
{
81
*ptr =
val
;
82
}
83
84
int
avpriv_atomic_int_add_and_fetch
(
volatile
int
*ptr,
int
inc)
85
{
86
*ptr += inc;
87
return
*ptr;
88
}
89
90
void
*
avpriv_atomic_ptr_cas
(
void
*
volatile
*ptr,
void
*oldval,
void
*newval)
91
{
92
if
(*ptr == oldval) {
93
*ptr = newval;
94
return
oldval;
95
}
96
return
*ptr;
97
}
98
99
#else
100
101
#error "Threading is enabled, but there is no implementation of atomic operations available"
102
103
#endif
/* HAVE_PTHREADS */
104
105
#endif
/* !HAVE_MEMORYBARRIER && !HAVE_SYNC_VAL_COMPARE_AND_SWAP && !HAVE_MACHINE_RW_BARRIER */
106
107
#ifdef TEST
108
#include "
avassert.h
"
109
110
int
main
(
void
)
111
{
112
volatile
int
val
= 1;
113
int
res
;
114
115
res =
avpriv_atomic_int_add_and_fetch
(&val, 1);
116
av_assert0
(res == 2);
117
avpriv_atomic_int_set
(&val, 3);
118
res =
avpriv_atomic_int_get
(&val);
119
av_assert0
(res == 3);
120
121
return
0;
122
}
123
#endif
Generated on Wed Jul 10 2013 23:48:15 for FFmpeg by
1.8.2