threads: Check w32threads dependencies at the configure stage
[libav.git] / libavutil / atomic.c
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1/*
2 * Copyright (c) 2012 Ronald S. Bultje <rsbultje@gmail.com>
3 *
4 * This file is part of Libav.
5 *
6 * Libav 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 * Libav 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 Libav; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 */
20
e1b9de4f 21#include "config.h"
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22#include "atomic.h"
23
f9f6402e 24#if !HAVE_ATOMICS_NATIVE
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25
26#if HAVE_PTHREADS
27
28#include <pthread.h>
29
30static pthread_mutex_t atomic_lock = PTHREAD_MUTEX_INITIALIZER;
31
32int 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
43void 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
50int 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
62void *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
75int avpriv_atomic_int_get(volatile int *ptr)
76{
77 return *ptr;
78}
79
80void avpriv_atomic_int_set(volatile int *ptr, int val)
81{
82 *ptr = val;
83}
84
85int avpriv_atomic_int_add_and_fetch(volatile int *ptr, int inc)
86{
87 *ptr += inc;
88 return *ptr;
89}
90
91void *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
874c751c 100#else /* HAVE_THREADS */
65f1d45d 101
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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. */
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105#error "Threading is enabled, but there is no implementation of atomic operations available"
106
107#endif /* HAVE_PTHREADS */
108
e1b9de4f 109#endif /* !HAVE_ATOMICS_NATIVE */
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110
111#ifdef TEST
112#include <assert.h>
113
114int main(void)
115{
116 volatile int val = 1;
117 int res;
118
119 res = avpriv_atomic_int_add_and_fetch(&val, 1);
120 assert(res == 2);
121 avpriv_atomic_int_set(&val, 3);
122 res = avpriv_atomic_int_get(&val);
123 assert(res == 3);
124
125 return 0;
126}
127#endif