Source code for can.io.canutils

"""
This module works with CAN data in ASCII log files (*.log).
It is is compatible with "candump -L" from the canutils program
(https://github.com/linux-can/can-utils).
"""

import logging

from can.message import Message
from can.listener import Listener
from .generic import BaseIOHandler


log = logging.getLogger("can.io.canutils")

CAN_MSG_EXT = 0x80000000
CAN_ERR_FLAG = 0x20000000
CAN_ERR_BUSERROR = 0x00000080
CAN_ERR_DLC = 8


[docs]class CanutilsLogReader(BaseIOHandler): """ Iterator over CAN messages from a .log Logging File (candump -L). .. note:: .log-format looks for example like this: ``(0.0) vcan0 001#8d00100100820100`` """ def __init__(self, file): """ :param file: a path-like object or as file-like object to read from If this is a file-like object, is has to opened in text read mode, not binary read mode. """ super().__init__(file, mode="r") def __iter__(self): for line in self.file: # skip empty lines temp = line.strip() if not temp: continue timestamp, channel, frame = temp.split() timestamp = float(timestamp[1:-1]) canId, data = frame.split("#") if channel.isdigit(): channel = int(channel) isExtended = len(canId) > 3 canId = int(canId, 16) if data and data[0].lower() == "r": isRemoteFrame = True if len(data) > 1: dlc = int(data[1:]) else: dlc = 0 dataBin = None else: isRemoteFrame = False dlc = len(data) // 2 dataBin = bytearray() for i in range(0, len(data), 2): dataBin.append(int(data[i : (i + 2)], 16)) if canId & CAN_ERR_FLAG and canId & CAN_ERR_BUSERROR: msg = Message(timestamp=timestamp, is_error_frame=True) else: msg = Message( timestamp=timestamp, arbitration_id=canId & 0x1FFFFFFF, is_extended_id=isExtended, is_remote_frame=isRemoteFrame, dlc=dlc, data=dataBin, channel=channel, ) yield msg self.stop()
[docs]class CanutilsLogWriter(BaseIOHandler, Listener): """Logs CAN data to an ASCII log file (.log). This class is is compatible with "candump -L". If a message has a timestamp smaller than the previous one (or 0 or None), it gets assigned the timestamp that was written for the last message. It the first message does not have a timestamp, it is set to zero. """ def __init__(self, file, channel="vcan0", append=False): """ :param file: a path-like object or as file-like object to write to If this is a file-like object, is has to opened in text write mode, not binary write mode. :param channel: a default channel to use when the message does not have a channel set :param bool append: if set to `True` messages are appended to the file, else the file is truncated """ mode = "a" if append else "w" super().__init__(file, mode=mode) self.channel = channel self.last_timestamp = None
[docs] def on_message_received(self, msg): # this is the case for the very first message: if self.last_timestamp is None: self.last_timestamp = msg.timestamp or 0.0 # figure out the correct timestamp if msg.timestamp is None or msg.timestamp < self.last_timestamp: timestamp = self.last_timestamp else: timestamp = msg.timestamp channel = msg.channel if msg.channel is not None else self.channel if msg.is_error_frame: self.file.write( "(%f) %s %08X#0000000000000000\n" % (timestamp, channel, CAN_ERR_FLAG | CAN_ERR_BUSERROR) ) elif msg.is_remote_frame: if msg.is_extended_id: self.file.write( "(%f) %s %08X#R\n" % (timestamp, channel, msg.arbitration_id) ) else: self.file.write( "(%f) %s %03X#R\n" % (timestamp, channel, msg.arbitration_id) ) else: data = ["{:02X}".format(byte) for byte in msg.data] if msg.is_extended_id: self.file.write( "(%f) %s %08X#%s\n" % (timestamp, channel, msg.arbitration_id, "".join(data)) ) else: self.file.write( "(%f) %s %03X#%s\n" % (timestamp, channel, msg.arbitration_id, "".join(data)) )