pb to map (c++)

message_to_map.cc

// not tested yet
//
std::multimap<std::string, std::string> MessageToMap(
    const google::protobuf::Message& message) {
  std::multimap<std::string, std::string> params;

  auto* descriptor = message.GetDescriptor();
  auto* reflection = message.GetReflection();

  int field_count = descriptor->field_count();
  for (int i = 0; i < field_count; ++i) {
    const google::protobuf::FieldDescriptor* field_descriptor =
        descriptor->field(i);

    switch (field_descriptor->cpp_type()) {
      case google::protobuf::FieldDescriptor::CPPTYPE_INT32: {
        params.emplace(
            field_descriptor->name(),
            std::to_string(reflection->GetInt32(message, field_descriptor)));
        break;
      }
      case google::protobuf::FieldDescriptor::CPPTYPE_INT64: {
        params.emplace(
            field_descriptor->name(),
            std::to_string(reflection->GetInt64(message, field_descriptor)));
        break;
      }
      case google::protobuf::FieldDescriptor::CPPTYPE_UINT32: {
        params.emplace(
            field_descriptor->name(),
            std::to_string(reflection->GetUInt32(message, field_descriptor)));
        break;
      }
      case google::protobuf::FieldDescriptor::CPPTYPE_UINT64: {
        params.emplace(
            field_descriptor->name(),
            std::to_string(reflection->GetUInt64(message, field_descriptor)));
        break;
      }
      case google::protobuf::FieldDescriptor::CPPTYPE_FLOAT: {
        params.emplace(
            field_descriptor->name(),
            std::to_string(reflection->GetFloat(message, field_descriptor)));
        break;
      }
      case google::protobuf::FieldDescriptor::CPPTYPE_DOUBLE: {
        params.emplace(
            field_descriptor->name(),
            std::to_string(reflection->GetDouble(message, field_descriptor)));
        break;
      }
      case google::protobuf::FieldDescriptor::CPPTYPE_ENUM: {
        params.emplace(field_descriptor->name(),
                       reflection->GetEnum(message, field_descriptor)->name());
        break;
      }
      case google::protobuf::FieldDescriptor::CPPTYPE_STRING: {
        params.emplace(field_descriptor->name(),
                       reflection->GetString(message, field_descriptor));
        break;
      }
      case google::protobuf::FieldDescriptor::CPPTYPE_MESSAGE: {
        break;  // no-op
      }
      default:
        break;
    }
  }

  return params;
}