libavcodec/pthread_internal.h

   1 /*
   2  * This file is part of FFmpeg.
   3  *
   4  * FFmpeg is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Lesser General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2.1 of the License, or (at your option) any later version.
   8  *
   9  * FFmpeg is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Lesser General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General Public
  15  * License along with FFmpeg; if not, write to the Free Software
  16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  17  */
  18
  19 #ifndef AVCODEC_PTHREAD_INTERNAL_H
  20 #define AVCODEC_PTHREAD_INTERNAL_H
  21
  22 #include "avcodec.h"
  23
  24 /* H.264 slice threading seems to be buggy with more than 16 threads,
  25  * limit the number of threads to 16 for automatic detection */
  26 #define MAX_AUTO_THREADS 16
  27
  28 int ff_slice_thread_init(AVCodecContext *avctx);
  29 void ff_slice_thread_free(AVCodecContext *avctx);
  30
  31 int ff_frame_thread_init(AVCodecContext *avctx);
  32 void ff_frame_thread_free(AVCodecContext *avctx, int thread_count);
  33
  34 #define THREAD_SENTINEL 0 // This forbids putting a mutex/condition variable at the front.
  35 /**
  36  * Initialize/destroy a list of mutexes/conditions contained in a structure.
  37  * The positions of these mutexes/conditions in the structure are given by
  38  * their offsets. Because it is undefined behaviour to destroy
  39  * an uninitialized mutex/condition, ff_pthread_init() stores the number
  40  * of successfully initialized mutexes and conditions in the object itself
  41  * and ff_pthread_free() uses this number to destroy exactly the mutexes and
  42  * condition variables that have been successfully initialized.
  43  *
  44  * @param     obj     The object containing the mutexes/conditions.
  45  * @param[in] offsets An array of offsets. Its first member gives the offset
  46  *                    of the variable that contains the count of successfully
  47  *                    initialized mutexes/condition variables; said variable
  48  *                    must be an unsigned int. Two arrays of offsets, each
  49  *                    delimited by a THREAD_SENTINEL follow. The first
  50  *                    contains the offsets of all the mutexes, the second
  51  *                    contains the offsets of all the condition variables.
  52  */
  53 int  ff_pthread_init(void *obj, const unsigned offsets[]);
  54 void ff_pthread_free(void *obj, const unsigned offsets[]);
  55
  56 /**
  57  * Macros to help creating the above lists. mutexes and conds need
  58  * to be parentheses-enclosed lists of offsets in the containing structure.
  59  */
  60 #define OFFSET_ARRAY(...) __VA_ARGS__, THREAD_SENTINEL
  61 #define DEFINE_OFFSET_ARRAY(type, name, cnt_variable, mutexes, conds)         \
  62 static const unsigned name ## _offsets[] = { offsetof(type, cnt_variable),    \
  63                                              OFFSET_ARRAY mutexes,            \
  64                                              OFFSET_ARRAY conds }
  65
  66 #endif // AVCODEC_PTHREAD_INTERNAL_H