Method TryRead

generator/osm_source.cpp:128–184

{}

bool ProcessorOsmElementsFromO5M::TryRead(OsmElement & element)
{
  if (m_pos == m_dataset.end())
    return false;

  using Type = osm::O5MSource::EntityType;
  auto const translate = [](Type t) -> OsmElement::EntityType
  {
    switch (t)
    {
    case Type::Node: return OsmElement::EntityType::Node;
    case Type::Way: return OsmElement::EntityType::Way;
    case Type::Relation: return OsmElement::EntityType::Relation;
    default: return OsmElement::EntityType::Unknown;
    }
  };

  // Be careful, we could call Nodes(), Members(), Tags() from O5MSource::Entity
  // only once (!). Because these functions read data from file simultaneously with
  // iterating in loop. Furthermore, into Tags() method calls Nodes.Skip() and Members.Skip(),
  // thus first call of Nodes (Members) after Tags() will not return any results.
  // So don not reorder the "for" loops (!).
  auto const & entity = *m_pos;
  element.m_id = entity.id;
  switch (entity.type)
  {
  case Type::Node:
  {
    element.m_type = OsmElement::EntityType::Node;
    element.m_lat = entity.lat;
    element.m_lon = entity.lon;
    break;
  }
  case Type::Way:
  {
    element.m_type = OsmElement::EntityType::Way;
    for (uint64_t nd : entity.Nodes())
      element.AddNd(nd);
    break;
  }
  case Type::Relation:
  {
    element.m_type = OsmElement::EntityType::Relation;
    for (auto const & member : entity.Members())
      element.AddMember(member.ref, translate(member.type), member.role);
    break;
  }
  default: break;
  }

  for (auto const & tag : entity.Tags())
    element.AddTag(tag.key, tag.value);

  element.Validate();
  ++m_pos;
  return true;
}