Method writeFrame

app/src/IO/Drivers/SeeedCanBackend.cpp:261–302

* @brief Encodes a QCanBusFrame as a variable-length analyzer packet and writes it. */

 * @brief Encodes a QCanBusFrame as a variable-length analyzer packet and writes it.
 */
bool IO::Drivers::SeeedCanBackend::writeFrame(const QCanBusFrame& frame)
{
  if (!m_port || !m_port->isOpen()) {
    setError(tr("USB-CAN Analyzer is not open for writing."), QCanBusDevice::WriteError);
    return false;
  }

  if (!frame.isValid())
    return false;

  const bool extended = frame.hasExtendedFrameFormat();
  const bool remote   = frame.frameType() == QCanBusFrame::RemoteRequestFrame;
  const int idLen     = extended ? 4 : 2;

  const QByteArray payload = frame.payload();
  const int dlc            = qMin(payload.size(), 8);

  std::uint8_t typeByte = kTypeBase | static_cast<std::uint8_t>(dlc);
  if (extended)
    typeByte |= kTypeExtBit;

  if (remote)
    typeByte |= kTypeRtrBit;

  QByteArray packet;
  packet.append(static_cast<char>(kFrameStart));
  packet.append(static_cast<char>(typeByte));

  const std::uint32_t id = frame.frameId();
  for (int i = 0; i < idLen; ++i)
    packet.append(static_cast<char>((id >> (8 * i)) & 0xff));

  packet.append(payload.left(dlc));
  packet.append(static_cast<char>(kFrameEnd));

  if (m_port->write(packet) != packet.size())
    return false;

  m_port->flush();
  Q_EMIT framesWritten(1);
  return true;
}

/**
 * @brief Produces a human-readable description for a CAN error frame.