# -*- coding: utf-8 -*-

########################################################################

# #

# python-OBD: A python OBD-II serial module derived from pyobd #

# #

# Copyright 2004 Donour Sizemore (donour@uchicago.edu) #

# Copyright 2009 Secons Ltd. (www.obdtester.com) #

# Copyright 2009 Peter J. Creath #

# Copyright 2016 Brendan Whitfield (brendan-w.com) #

# #

########################################################################

# #

# OBDCommand.py #

# #

# This file is part of python-OBD (a derivative of pyOBD) #

# #

# python-OBD is free software: you can redistribute it and/or modify #

# it under the terms of the GNU General Public License as published by #

# the Free Software Foundation, either version 2 of the License, or #

# (at your option) any later version. #

# #

# python-OBD is distributed in the hope that it will be useful, #

# but WITHOUT ANY WARRANTY; without even the implied warranty of #

# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the #

# GNU General Public License for more details. #

# #

# You should have received a copy of the GNU General Public License #

# along with python-OBD. If not, see <http://www.gnu.org/licenses/>. #

# #

########################################################################

from .utils import *

from .protocols import ECU

from .OBDResponse import OBDResponse

import logging

logger = logging.getLogger(__name__)

class OBDCommand():

def __init__(self,

name,

desc,

command,

_bytes,

decoder,

ecu=ECU.ALL,

fast=False):

self.name = name # human readable name (also used as key in commands dict)

self.desc = desc # human readable description

self.command = command # command string

self.bytes = _bytes # number of bytes expected in return

self.decode = decoder # decoding function

self.ecu = ecu # ECU ID from which this command expects messages from

self.fast = fast # can an extra digit be added to the end of the command? (to make the ELM return early)

def clone(self):

return OBDCommand(self.name,

self.desc,

self.command,

self.bytes,

self.decode,

self.ecu,

self.fast)

@property

def mode(self):

if len(self.command) >= 2 and \

isHex(self.command.decode()):

return int(self.command[:2], 16)

else:

return None

@property

def pid(self):

if len(self.command) > 2 and \

isHex(self.command.decode()):

return int(self.command[2:], 16)

else:

return None

def __call__(self, messages):

# filter for applicable messages (from the right ECU(s))

for_us = lambda m: (self.ecu & m.ecu) > 0

messages = list(filter(for_us, messages))

# guarantee data size for the decoder

for m in messages:

self.__constrain_message_data(m)

# create the response object with the raw data recieved

# and reference to original command

r = OBDResponse(self, messages)

if messages:

r.value = self.decode(messages)

else:

logger.info(str(self) + " did not recieve any acceptable messages")

return r

def __constrain_message_data(self, message):

""" pads or chops the data field to the size specified by this command """

if self.bytes > 0:

if len(message.data) > self.bytes:

# chop off the right side

message.data = message.data[:self.bytes]

logger.debug("Message was longer than expected. Trimmed message: " + repr(message.data))

elif len(message.data) < self.bytes:

# pad the right with zeros

message.data += (b'\x00' * (self.bytes - len(message.data)))

logger.debug("Message was shorter than expected. Padded message: " + repr(message.data))

def __str__(self):

return "%s: %s" % (self.command, self.desc)

def __hash__(self):

# needed for using commands as keys in a dict (see async.py)

return hash(self.command)

def __eq__(self, other):

if isinstance(other, OBDCommand):

return (self.command == other.command)

else:

return False