| 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 |