include/vlc_atomic.h

   1 /*****************************************************************************
   2  * vlc_atomic.h:
   3  *****************************************************************************
   4  * Copyright (C) 2010 Rémi Denis-Courmont
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU Lesser General Public License as published by
   8  * the Free Software Foundation; either version 2.1 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program 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
  14  * GNU Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public License
  17  * along with this program; if not, write to the Free Software Foundation,
  18  * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  19  *****************************************************************************/
  20
  21 #ifdef __cplusplus
  22 # error Not implemented in C++.
  23 #endif
  24
  25 #ifndef VLC_ATOMIC_H
  26 # define VLC_ATOMIC_H
  27
  28 /**
  29  * \file
  30  * Atomic operations do not require locking, but they are not very powerful.
  31  */
  32
  33 # include <stdatomic.h>
  34
  35 typedef atomic_uint_least32_t vlc_atomic_float;
  36
  37 static inline void vlc_atomic_init_float(vlc_atomic_float *var, float f)
  38 {
  39     union { float f; uint32_t i; } u;
  40     u.f = f;
  41     atomic_init(var, u.i);
  42 }
  43
  44 /** Helper to retrieve a single precision from an atom. */
  45 static inline float vlc_atomic_load_float(vlc_atomic_float *atom)
  46 {
  47     union { float f; uint32_t i; } u;
  48     u.i = atomic_load(atom);
  49     return u.f;
  50 }
  51
  52 /** Helper to store a single precision into an atom. */
  53 static inline void vlc_atomic_store_float(vlc_atomic_float *atom, float f)
  54 {
  55     union { float f; uint32_t i; } u;
  56     u.f = f;
  57     atomic_store(atom, u.i);
  58 }
  59
  60 #endif