/*
  * This file is part of FFmpeg.
  *
  * FFmpeg is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *
  * FFmpeg is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
 #include "internal.h"
 #include "libavutil/opt.h"
 #include "libavformat/avformat.h"
 
 int ff_alloc_input_device_context(AVFormatContext **avctx, AVInputFormat *iformat, const char *format)
 {
     AVFormatContext *s;
     int ret = 0;
 
     *avctx = NULL;
     if (!iformat && !format)
         return AVERROR(EINVAL);
     if (!(s = avformat_alloc_context()))
         return AVERROR(ENOMEM);
 
     if (!iformat)
         iformat = av_find_input_format(format);
     if (!iformat || !iformat->priv_class || !AV_IS_INPUT_DEVICE(iformat->priv_class->category)) {
         ret = AVERROR(EINVAL);
         goto error;
     }
     s->iformat = iformat;
     if (s->iformat->priv_data_size > 0) {
         s->priv_data = av_mallocz(s->iformat->priv_data_size);
         if (!s->priv_data) {
             ret = AVERROR(ENOMEM);
             goto error;
         }
         if (s->iformat->priv_class) {
             *(const AVClass**)s->priv_data= s->iformat->priv_class;
             av_opt_set_defaults(s->priv_data);
         }
     } else
         s->priv_data = NULL;
 
     *avctx = s;
     return 0;
   error:
     avformat_free_context(s);
     return ret;
 }