libavcodec/threadprogress.c

   1 /*
   2  * Copyright (c) 2022 Andreas Rheinhardt <andreas.rheinhardt@outlook.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 <limits.h>
  22 #include <stdatomic.h>
  23
  24 #include "pthread_internal.h"
  25 #include "threadprogress.h"
  26 #include "libavutil/attributes.h"
  27 #include "libavutil/thread.h"
  28
  29 DEFINE_OFFSET_ARRAY(ThreadProgress, thread_progress, init,
  30                     (offsetof(ThreadProgress, progress_mutex)),
  31                     (offsetof(ThreadProgress, progress_cond)));
  32
  33 av_cold int ff_thread_progress_init(ThreadProgress *pro, int init_mode)
  34 {
  35     atomic_init(&pro->progress, init_mode ? -1 : INT_MAX);
  36 #if HAVE_THREADS
  37     if (init_mode)
  38         return ff_pthread_init(pro, thread_progress_offsets);
  39 #endif
  40     pro->init = init_mode;
  41     return 0;
  42 }
  43
  44 av_cold void ff_thread_progress_destroy(ThreadProgress *pro)
  45 {
  46 #if HAVE_THREADS
  47     ff_pthread_free(pro, thread_progress_offsets);
  48 #else
  49     pro->init = 0;
  50 #endif
  51 }
  52
  53 void ff_thread_progress_report(ThreadProgress *pro, int n)
  54 {
  55     if (atomic_load_explicit(&pro->progress, memory_order_relaxed) >= n)
  56         return;
  57
  58     atomic_store_explicit(&pro->progress, n, memory_order_release);
  59
  60     ff_mutex_lock(&pro->progress_mutex);
  61     ff_cond_broadcast(&pro->progress_cond);
  62     ff_mutex_unlock(&pro->progress_mutex);
  63 }
  64
  65 void ff_thread_progress_await(const ThreadProgress *pro_c, int n)
  66 {
  67     /* Casting const away here is safe, because we only read from progress
  68      * and will leave pro_c in the same state upon leaving the function
  69      * as it had at the beginning. */
  70     ThreadProgress *pro = (ThreadProgress*)pro_c;
  71
  72     if (atomic_load_explicit(&pro->progress, memory_order_acquire) >= n)
  73         return;
  74
  75     ff_mutex_lock(&pro->progress_mutex);
  76     while (atomic_load_explicit(&pro->progress, memory_order_relaxed) < n)
  77         ff_cond_wait(&pro->progress_cond, &pro->progress_mutex);
  78     ff_mutex_unlock(&pro->progress_mutex);
  79 }