size_t
SerialPort::Write(const void *data, size_t length)
{
DWORD NumberOfBytesWritten;
if (hPort == INVALID_HANDLE_VALUE)
return 0;
OverlappedEvent osWriter;
// Start reading data
if (::WriteFile(hPort, data, length, &NumberOfBytesWritten, osWriter.GetPointer()))
return NumberOfBytesWritten;
if (::GetLastError() != ERROR_IO_PENDING)
return 0;
// Let's wait for ReadFile() to finish
unsigned timeout_ms = 1000 + length * 10;
switch (osWriter.Wait(timeout_ms)) {
case OverlappedEvent::FINISHED:
// Get results
::GetOverlappedResult(hPort, osWriter.GetPointer(), &NumberOfBytesWritten, FALSE);
return NumberOfBytesWritten;
default:
::CancelIo(hPort);
::SetCommMask(hPort, 0);
osWriter.Wait();
return 0;
}
}
size_t
SerialPort::Write(const void *data, size_t length)
{
DWORD NumberOfBytesWritten;
if (hPort == INVALID_HANDLE_VALUE)
return 0;
#ifdef _WIN32_WCE
#if 0
/* this workaround is currently disabled because it causes major
problems with some of our device drivers, causing timeouts; this
may be a regression on the bugged HP31x, but I prefer to support
sane platforms any day */
if (IsWindowsCE() && !IsAltair())
/* this is needed to work around a driver bug on the HP31x -
without it, the second consecutive write without a task switch
will hang the whole PNA; this Sleep() call enforces a task
switch */
Sleep(100);
#endif
// lpNumberOfBytesWritten : This parameter can be NULL only when the lpOverlapped parameter is not NULL.
if (!::WriteFile(hPort, data, length, &NumberOfBytesWritten, NULL))
return 0;
return NumberOfBytesWritten;
#else
OverlappedEvent osWriter;
// Start reading data
if (::WriteFile(hPort, data, length, &NumberOfBytesWritten, osWriter.GetPointer()))
return NumberOfBytesWritten;
if (::GetLastError() != ERROR_IO_PENDING)
return 0;
// Let's wait for ReadFile() to finish
unsigned timeout_ms = 1000 + length * 10;
switch (osWriter.Wait(timeout_ms)) {
case OverlappedEvent::FINISHED:
// Get results
::GetOverlappedResult(hPort, osWriter.GetPointer(), &NumberOfBytesWritten, FALSE);
return NumberOfBytesWritten;
default:
::CancelIo(hPort);
::SetCommMask(hPort, 0);
osWriter.Wait();
return 0;
}
#endif
}
Port::WaitResult
SerialPort::WaitDataPending(OverlappedEvent &overlapped,
unsigned timeout_ms) const
{
int nbytes = GetDataPending();
if (nbytes > 0)
return WaitResult::READY;
else if (nbytes < 0)
return WaitResult::FAILED;
::SetCommMask(hPort, EV_RXCHAR);
DWORD dwCommModemStatus;
if (!::WaitCommEvent(hPort, &dwCommModemStatus, overlapped.GetPointer())) {
if (::GetLastError() != ERROR_IO_PENDING)
return WaitResult::FAILED;
switch (overlapped.Wait(timeout_ms)) {
case OverlappedEvent::FINISHED:
break;
case OverlappedEvent::TIMEOUT:
/* the operation may still be running, we have to cancel it */
::CancelIo(hPort);
::SetCommMask(hPort, 0);
overlapped.Wait();
return WaitResult::TIMEOUT;
case OverlappedEvent::CANCELED:
/* the operation may still be running, we have to cancel it */
::CancelIo(hPort);
::SetCommMask(hPort, 0);
overlapped.Wait();
return WaitResult::CANCELLED;
}
DWORD result;
if (!::GetOverlappedResult(hPort, overlapped.GetPointer(), &result, FALSE))
return WaitResult::FAILED;
}
if ((dwCommModemStatus & EV_RXCHAR) == 0)
return WaitResult::FAILED;
return GetDataPending() > 0
? WaitResult::READY
: WaitResult::FAILED;
}
