def read(self, size=1):
"""Read size bytes from the serial port. If a timeout is set it may
return less characters as requested. With no timeout it will block
until the requested number of bytes is read."""
if not self.hComPort: raise portNotOpenError
if size > 0:
win32.ResetEvent(self._overlappedRead.hEvent)
flags = win32.DWORD()
comstat = win32.COMSTAT()
if not win32.ClearCommError(self.hComPort, ctypes.byref(flags), ctypes.byref(comstat)):
raise SerialException('call to ClearCommError failed')
if self.timeout == 0:
n = min(comstat.cbInQue, size)
if n > 0:
buf = ctypes.create_string_buffer(n)
rc = win32.DWORD()
err = win32.ReadFile(self.hComPort, buf, n, ctypes.byref(rc), ctypes.byref(self._overlappedRead))
if not err and win32.GetLastError() != win32.ERROR_IO_PENDING:
raise SerialException("ReadFile failed (%r)" % ctypes.WinError())
err = win32.WaitForSingleObject(self._overlappedRead.hEvent, win32.INFINITE)
read = buf.raw[:rc.value]
else:
read = bytes()
else:
buf = ctypes.create_string_buffer(size)
rc = win32.DWORD()
err = win32.ReadFile(self.hComPort, buf, size, ctypes.byref(rc), ctypes.byref(self._overlappedRead))
if not err and win32.GetLastError() != win32.ERROR_IO_PENDING:
raise SerialException("ReadFile failed (%r)" % ctypes.WinError())
err = win32.GetOverlappedResult(self.hComPort, ctypes.byref(self._overlappedRead), ctypes.byref(rc), True)
read = buf.raw[:rc.value]
else:
read = bytes()
return bytes(read)
def read(self, size=1):
"""\
Read size bytes from the serial port. If a timeout is set it may
return less characters as requested. With no timeout it will block
until the requested number of bytes is read.
"""
if not self.is_open:
raise portNotOpenError
if size > 0:
win32.ResetEvent(self._overlapped_read.hEvent)
flags = win32.DWORD()
comstat = win32.COMSTAT()
if not win32.ClearCommError(self._port_handle, ctypes.byref(flags),
ctypes.byref(comstat)):
raise SerialException("ClearCommError failed ({!r})".format(
ctypes.WinError()))
n = min(comstat.cbInQue, size) if self.timeout == 0 else size
if n > 0:
buf = ctypes.create_string_buffer(n)
rc = win32.DWORD()
read_ok = win32.ReadFile(self._port_handle, buf, n,
ctypes.byref(rc),
ctypes.byref(self._overlapped_read))
if not read_ok and win32.GetLastError() not in (
win32.ERROR_SUCCESS, win32.ERROR_IO_PENDING):
raise SerialException("ReadFile failed ({!r})".format(
ctypes.WinError()))
result_ok = win32.GetOverlappedResult(
self._port_handle, ctypes.byref(self._overlapped_read),
ctypes.byref(rc), True)
if not result_ok:
if win32.GetLastError() != win32.ERROR_OPERATION_ABORTED:
raise SerialException(
"GetOverlappedResult failed ({!r})".format(
ctypes.WinError()))
read = buf.raw[:rc.value]
else:
read = bytes()
else:
read = bytes()
return bytes(read)