/// <summary>
/// Reads the in configuration.
/// </summary>
/// <param name="config_file">The configuration file.</param>
void Analyze::readInConfig( istream& config_file ) {
  // create stringstream
  stringstream localStream;

  localStream << config_file.rdbuf ();

  enum {VT, WIDTH, PULSE_DELTA, DROP_RATIO, BELOW_DROP_RATIO, NUM_FIELDS};
  vector<string> field_names {"vt", "width", "pulse_delta", "drop_ratio", "below_drop_ratio"};
  map<string, string> properties {};

  string line;
  while ( localStream && getline ( localStream, line, '='  ) ) {
    // lower case the line
    STRING_HELPER.lower ( line );
    auto property { line };

    // ignore comments
    auto skip { false };
    while ( property.find_first_of ( '#' ) != string::npos ) {
      auto const comment_end { property.find_first_of ( '\n' ) + 1 };
      property = property.substr ( comment_end, property.length ());
      if ( property.empty () )
        skip = true;
    }

    if ( skip ) continue;

    property = STRING_HELPER.trim ( property );

    getline ( localStream, line, '\n');
    auto value { line };

    properties.insert ( {property, value} );
  }

  auto fail { false };

  for ( auto const& name : field_names) {
    auto it = properties.find ( name );
    if (it == properties.end ()) {
      throw runtime_error ( "Config file is missing a required property." );
    }
  }

  if (properties.size () != NUM_FIELDS) throw runtime_error ( "Config file contains an invalid property." );

  try {
    config_.below_drop_ratio = stod ( properties.find ( field_names [static_cast< int >( BELOW_DROP_RATIO )] )->second );
    config_.drop_ratio = stod ( properties.find ( field_names [static_cast< int >( DROP_RATIO )] )->second );
    config_.pulse_delta = stod ( properties.find ( field_names [static_cast< int >( PULSE_DELTA )] )->second );
    config_.threshold = stod ( properties.find ( field_names [static_cast< int >( VT )] )->second );
    config_.width = stod ( properties.find ( field_names [static_cast< int >( WIDTH )] )->second );
  }
  catch ( invalid_argument const& )
  {
    throw runtime_error ( "Config file contains illegal characters."  );
  }
  catch ( out_of_range const& ) {
    throw runtime_error ( "Config file contains illegal characters." );
  }
}