Source code for

# coding: utf-8

Contains handling of ASC logging files.

Example .asc files:
    - under `test/data/logfile.asc`

from datetime import datetime
import time
import logging

from ..message import Message
from ..listener import Listener
from ..util import channel2int
from .generic import BaseIOHandler

CAN_MSG_EXT = 0x80000000

logger = logging.getLogger("")

[docs]class ASCReader(BaseIOHandler): """ Iterator of CAN messages from a ASC logging file. TODO: turn relative timestamps back to absolute form """ 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") @staticmethod def _extract_can_id(str_can_id): if str_can_id[-1:].lower() == "x": is_extended = True can_id = int(str_can_id[0:-1], 16) else: is_extended = False can_id = int(str_can_id, 16) return can_id, is_extended def __iter__(self): for line in self.file: # logger.debug("ASCReader: parsing line: '%s'", line.splitlines()[0]) temp = line.strip() if not temp or not temp[0].isdigit(): continue try: timestamp, channel, dummy = temp.split( None, 2 ) # , frameType, dlc, frameData except ValueError: # we parsed an empty comment continue timestamp = float(timestamp) try: # See ASCWriter channel = int(channel) - 1 except ValueError: pass if dummy.strip()[0:10].lower() == "errorframe": msg = Message(timestamp=timestamp, is_error_frame=True, channel=channel) yield msg elif ( not isinstance(channel, int) or dummy.strip()[0:10].lower() == "statistic:" ): pass elif dummy[-1:].lower() == "r": can_id_str, _ = dummy.split(None, 1) can_id_num, is_extended_id = self._extract_can_id(can_id_str) msg = Message( timestamp=timestamp, arbitration_id=can_id_num & CAN_ID_MASK, is_extended_id=is_extended_id, is_remote_frame=True, channel=channel, ) yield msg else: try: # this only works if dlc > 0 and thus data is availabe can_id_str, _, _, dlc, data = dummy.split(None, 4) except ValueError: # but if not, we only want to get the stuff up to the dlc can_id_str, _, _, dlc = dummy.split(None, 3) # and we set data to an empty sequence manually data = "" dlc = int(dlc) frame = bytearray() data = data.split() for byte in data[0:dlc]: frame.append(int(byte, 16)) can_id_num, is_extended_id = self._extract_can_id(can_id_str) yield Message( timestamp=timestamp, arbitration_id=can_id_num & CAN_ID_MASK, is_extended_id=is_extended_id, is_remote_frame=False, dlc=dlc, data=frame, channel=channel, ) self.stop()
[docs]class ASCWriter(BaseIOHandler, Listener): """Logs CAN data to an ASCII log file (.asc). The measurement starts with the timestamp of the first registered message. If a message has a timestamp smaller than the previous one 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. """ FORMAT_MESSAGE = "{channel} {id:<15} Rx {dtype} {data}" FORMAT_DATE = "%a %b %m %I:%M:%S.{} %p %Y" FORMAT_EVENT = "{timestamp: 9.6f} {message}\n" def __init__(self, file, channel=1): """ :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 """ super().__init__(file, mode="w") = channel # write start of file header now ="%a %b %m %I:%M:%S.%f %p %Y") self.file.write("date %s\n" % now) self.file.write("base hex timestamps absolute\n") self.file.write("internal events logged\n") # the last part is written with the timestamp of the first message self.header_written = False self.last_timestamp = None self.started = None
[docs] def stop(self): if not self.file.closed: self.file.write("End TriggerBlock\n") super().stop()
[docs] def log_event(self, message, timestamp=None): """Add a message to the log file. :param str message: an arbitrary message :param float timestamp: the absolute timestamp of the event """ if not message: # if empty or None logger.debug("ASCWriter: ignoring empty message") return # this is the case for the very first message: if not self.header_written: self.last_timestamp = timestamp or 0.0 self.started = self.last_timestamp mlsec = repr(self.last_timestamp).split(".")[1][:3] formatted_date = time.strftime( self.FORMAT_DATE.format(mlsec), time.localtime(self.last_timestamp) ) self.file.write("Begin Triggerblock %s\n" % formatted_date) self.header_written = True self.log_event("Start of measurement") # caution: this is a recursive call! # Use last known timestamp if unknown if timestamp is None: timestamp = self.last_timestamp # turn into relative timestamps if necessary if timestamp >= self.started: timestamp -= self.started line = self.FORMAT_EVENT.format(timestamp=timestamp, message=message) self.file.write(line)
[docs] def on_message_received(self, msg): if msg.is_error_frame: self.log_event("{} ErrorFrame".format(, msg.timestamp) return if msg.is_remote_frame: dtype = "r" data = [] else: dtype = "d {}".format(msg.dlc) data = ["{:02X}".format(byte) for byte in] arb_id = "{:X}".format(msg.arbitration_id) if msg.is_extended_id: arb_id += "x" channel = channel2int( if channel is None: channel = else: # Many interfaces start channel numbering at 0 which is invalid channel += 1 serialized = self.FORMAT_MESSAGE.format( channel=channel, id=arb_id, dtype=dtype, data=" ".join(data) ) self.log_event(serialized, msg.timestamp)