Function header_check_ogg

src/file_ogg.c:108–136

@ @ requires buffer_size >= 0x78+7; @ requires separation: \separated(&file_hint_ogg, buffer+(..), file_recovery, file_recovery_new); @ requires valid_header_check_param(buffer, buffer_size, safe_header_only, file_recovery, file_recovery_new); @ ensures valid_header_check_result(\result, file_recovery_new); @*/

  @ ensures  valid_header_check_result(\result, file_recovery_new);
  @*/
static int header_check_ogg(const unsigned char *buffer, const unsigned int buffer_size, const unsigned int safe_header_only, const file_recovery_t *file_recovery, file_recovery_t *file_recovery_new)
{
  static const unsigned char sign_theora[7]= {0x80, 't', 'h', 'e', 'o', 'r', 'a'};
  /* http://en.wikipedia.org/wiki/Ogg#File_format */
  /* Return if not Beginning Of Stream and already saving the file */
  if((buffer[5]&0x02)!=0x02 &&
      file_recovery->file_stat!=NULL &&
      file_recovery->file_check!=NULL &&
      file_recovery->file_stat->file_hint==&file_hint_ogg)
  {
    header_ignored(file_recovery_new);
    return 0;
  }
  reset_file_recovery(file_recovery_new);
  file_recovery_new->calculated_file_size=0;
  if(file_recovery_new->blocksize > 27+255)
  {
    file_recovery_new->data_check=&data_check_ogg;
    file_recovery_new->file_check=&file_check_size;
  }
  /* Ogg data, Theora video */
  if(memcmp(&buffer[28], sign_theora, sizeof(sign_theora))==0)
    file_recovery_new->extension="ogv";
  else if(memcmp(&buffer[0x78], sign_theora, sizeof(sign_theora))==0)
    file_recovery_new->extension="ogv";
  else
    file_recovery_new->extension=file_hint_ogg.extension;
  return 1;
}

static void register_header_check_ogg(file_stat_t *file_stat)
{