text: #
  # This file is part of the PyMeasure package.
  #
  # Copyright (c) 2013-2020 PyMeasure Developers
  #
  # Permission is hereby granted, free of charge, to any person obtaining a copy
  # of this software and associated documentation files (the "Software"), to deal
  # in the Software without restriction, including without limitation the rights
  # to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  # copies of the Software, and to permit persons to whom the Software is
  # furnished to do so, subject to the following conditions:
  #
  # The above copyright notice and this permission notice shall be included in
  # all copies or substantial portions of the Software.
  #
  # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  # FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  # AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  # THE SOFTWARE.
  #
  import time
  
  import serial
  
  from .serial import SerialAdapter
  
  
  class PrologixAdapter(SerialAdapter):
      """ Encapsulates the additional commands necessary
      to communicate over a Prologix GPIB-USB Adapter,
      using the SerialAdapter.
  
      Each PrologixAdapter is constructed based on a serial port or
      connection and the GPIB address to be communicated to.
      Serial connection sharing is achieved by using the :meth:`.gpib`
      method to spawn new PrologixAdapters for different GPIB addresses.
  
      :param port: The Serial port name or a serial.Serial object
      :param address: Integer GPIB address of the desired instrument
      :param rw_delay: An optional delay to set between a write and read call for slow to respond instruments.
      :param preprocess_reply: optional callable used to preprocess strings
          received from the instrument. The callable returns the processed string.
      :param kwargs: Key-word arguments if constructing a new serial object
  
      :ivar address: Integer GPIB address of the desired instrument
  
      To allow user access to the Prologix adapter in Linux, create the file:
      :code:`/etc/udev/rules.d/51-prologix.rules`, with contents:
  
      .. code-block:: bash
  
          SUBSYSTEMS=="usb",ATTRS{idVendor}=="0403",ATTRS{idProduct}=="6001",MODE="0666"
  
      Then reload the udev rules with:
  
      .. code-block:: bash
  
          sudo udevadm control --reload-rules
          sudo udevadm trigger
  
      """
  
      def __init__(self, port, address=None, rw_delay=None, serial_timeout=0.5,
                   preprocess_reply=None, **kwargs):
          super().__init__(port, timeout=serial_timeout,
                           preprocess_reply=preprocess_reply, **kwargs)
          self.address = address
          self.rw_delay = rw_delay
          if not isinstance(port, serial.Serial):
              self.set_defaults()
  
      def set_defaults(self):
          """ Sets up the default behavior of the Prologix-GPIB
          adapter
          """
          self.write("++auto 0")  # Turn off auto read-after-write
          self.write("++eoi 1")  # Append end-of-line to commands
          self.write("++eos 2")  # Append line-feed to commands
  
      def ask(self, command):
          """ Ask the Prologix controller, include a forced delay for some instruments.
  
          :param command: SCPI command string to be sent to instrument
          """
  
          self.write(command)
          if self.rw_delay is not None:
              time.sleep(self.rw_delay)
          return self.read()
  
      def write(self, command):
          """ Writes the command to the GPIB address stored in the
          :attr:`.address`
  
          :param command: SCPI command string to be sent to the instrument
          """
          if self.address is not None:
              address_command = "++addr %d\n" % self.address
              self.connection.write(address_command.encode())
          command += "\n"
          self.connection.write(command.encode())
  
      def read(self):
          """ Reads the response of the instrument until timeout
  
          :returns: String ASCII response of the instrument
          """
          self.write("++read eoi")
          return b"\n".join(self.connection.readlines()).decode()
  
      def gpib(self, address, rw_delay=None):
          """ Returns and PrologixAdapter object that references the GPIB
          address specified, while sharing the Serial connection with other
          calls of this function
  
          :param address: Integer GPIB address of the desired instrument
          :param rw_delay: Set a custom Read/Write delay for the instrument
          :returns: PrologixAdapter for specific GPIB address
          """
          rw_delay = rw_delay or self.rw_delay
          return PrologixAdapter(self.connection, address, rw_delay=rw_delay)
  
      def wait_for_srq(self, timeout=25, delay=0.1):
          """ Blocks until a SRQ, and leaves the bit high
  
          :param timeout: Timeout duration in seconds
          :param delay: Time delay between checking SRQ in seconds
          """
          while int(self.ask("++srq")) != 1:  # TODO: Include timeout!
              time.sleep(delay)
  
      def __repr__(self):
          if self.address is not None:
              return "<PrologixAdapter(port='%s',address=%d)>" % (
                  self.connection.port, self.address)
          else:
              return "<PrologixAdapter(port='%s')>" % self.connection.port
  