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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 "config.h" | |
22 | #include "atomic.h" | |
23 | ||
24 | #if !HAVE_ATOMICS_NATIVE | |
25 | ||
26 | #if HAVE_PTHREADS | |
27 | ||
28 | #include <pthread.h> | |
29 | ||
30 | static pthread_mutex_t atomic_lock = PTHREAD_MUTEX_INITIALIZER; | |
31 | ||
32 | int avpriv_atomic_int_get(volatile int *ptr) | |
33 | { | |
34 | int res; | |
35 | ||
36 | pthread_mutex_lock(&atomic_lock); | |
37 | res = *ptr; | |
38 | pthread_mutex_unlock(&atomic_lock); | |
39 | ||
40 | return res; | |
41 | } | |
42 | ||
43 | void avpriv_atomic_int_set(volatile int *ptr, int val) | |
44 | { | |
45 | pthread_mutex_lock(&atomic_lock); | |
46 | *ptr = val; | |
47 | pthread_mutex_unlock(&atomic_lock); | |
48 | } | |
49 | ||
50 | int avpriv_atomic_int_add_and_fetch(volatile int *ptr, int inc) | |
51 | { | |
52 | int res; | |
53 | ||
54 | pthread_mutex_lock(&atomic_lock); | |
55 | *ptr += inc; | |
56 | res = *ptr; | |
57 | pthread_mutex_unlock(&atomic_lock); | |
58 | ||
59 | return res; | |
60 | } | |
61 | ||
62 | void *avpriv_atomic_ptr_cas(void * volatile *ptr, void *oldval, void *newval) | |
63 | { | |
64 | void *ret; | |
65 | pthread_mutex_lock(&atomic_lock); | |
66 | ret = *ptr; | |
67 | if (*ptr == oldval) | |
68 | *ptr = newval; | |
69 | pthread_mutex_unlock(&atomic_lock); | |
70 | return ret; | |
71 | } | |
72 | ||
73 | #elif !HAVE_THREADS | |
74 | ||
75 | int avpriv_atomic_int_get(volatile int *ptr) | |
76 | { | |
77 | return *ptr; | |
78 | } | |
79 | ||
80 | void avpriv_atomic_int_set(volatile int *ptr, int val) | |
81 | { | |
82 | *ptr = val; | |
83 | } | |
84 | ||
85 | int avpriv_atomic_int_add_and_fetch(volatile int *ptr, int inc) | |
86 | { | |
87 | *ptr += inc; | |
88 | return *ptr; | |
89 | } | |
90 | ||
91 | void *avpriv_atomic_ptr_cas(void * volatile *ptr, void *oldval, void *newval) | |
92 | { | |
93 | if (*ptr == oldval) { | |
94 | *ptr = newval; | |
95 | return oldval; | |
96 | } | |
97 | return *ptr; | |
98 | } | |
99 | ||
100 | #else /* HAVE_THREADS */ | |
101 | ||
102 | /* This should never trigger, unless a new threading implementation | |
103 | * without correct atomics dependencies in configure or a corresponding | |
104 | * atomics implementation is added. */ | |
105 | #error "Threading is enabled, but there is no implementation of atomic operations available" | |
106 | ||
107 | #endif /* HAVE_PTHREADS */ | |
108 | ||
109 | #endif /* !HAVE_ATOMICS_NATIVE */ | |
110 | ||
111 | #ifdef TEST | |
112 | #include "avassert.h" | |
113 | ||
114 | int main(void) | |
115 | { | |
116 | volatile int val = 1; | |
117 | int res; | |
118 | ||
119 | res = avpriv_atomic_int_add_and_fetch(&val, 1); | |
120 | av_assert0(res == 2); | |
121 | avpriv_atomic_int_set(&val, 3); | |
122 | res = avpriv_atomic_int_get(&val); | |
123 | av_assert0(res == 3); | |
124 | ||
125 | return 0; | |
126 | } | |
127 | #endif |