text: # -*- coding: utf-8 -*-
  """Common routines and base driver class for serial-based meters.
  """
  
  __author__ = 'Diego Elio Pettenò'
  __email__ = 'flameeyes@flameeyes.eu'
  __copyright__ = 'Copyright © 2017, Diego Elio Pettenò'
  __license__ = 'MIT'
  
  import logging
  
  import serial
  
  from glucometerutils import exceptions
  
  
  class SerialDevice(object):
      """A Serial-connected glucometer driver base.
  
      This class does not implement an actual driver by itself, but provides an
      easier access to the boilerplate code required for pyserial.
  
      This helper assumes that communication happens on a standard 8n1
      configuration, with variable baudrate and no hardware flow control.
  
      The actual drivers should set the following parameters:
  
        BAUDRATE: (int) the speed the serial port should be opened at.
        DEFAULT_CABLE_ID: (string) USB Vendor/Product ID pair, in format
          abcd:abcd, of the default cable for the meter, in case the user
          didn't pass an explicit device driver.
  
      Optional parameters available:
  
        TIMEOUT: (float, default: 1) the read timeout in seconds as defined by
          pyserial.
  
      After initialization, the following attributes can be used by the driver:
        serial_: (serial.Serial) the open Serial object.
  
      """
  
      BAUDRATE = None
      DEFAULT_CABLE_ID = None
  
      TIMEOUT = 1
  
      def __init__(self, device):
          assert self.BAUDRATE is not None
  
          if not device and self.DEFAULT_CABLE_ID:
              logging.info(
                  'No --device parameter provided, looking for default cable.')
              device = 'hwgrep://' + self.DEFAULT_CABLE_ID
  
          if not device:
              raise exceptions.CommandLineError(
                  'No --device parameter provided, and no default cable known.')
  
          self.serial_ = serial.serial_for_url(
              device,
              baudrate=self.BAUDRATE,
              timeout=self.TIMEOUT,
              writeTimeout=None,
              bytesize=serial.EIGHTBITS, parity=serial.PARITY_NONE,
              stopbits=serial.STOPBITS_ONE,
              xonxoff=False, rtscts=False, dsrdtr=False)
  