panda/examples/can_unique.py

#!/usr/bin/env python3

# Given an interesting CSV file of CAN messages and a list of background CAN
# messages, print which bits in the interesting file have never appeared
# in the background files.

# Expects the CSV file to be in the format from can_logger.py
# Bus,MessageID,Message,MessageLength
# 0,0x292,0x040000001068,6

# The old can_logger.py format is also supported:
# Bus,MessageID,Message
# 0,344,c000c00000000000


import binascii
import csv
import sys
from panda import Panda

class Message():
  """Details about a specific message ID."""
  def __init__(self, message_id):
    self.message_id = message_id
    self.data = {}  # keyed by hex string encoded message data
    self.ones = [0] * 8   # bit set if 1 is seen
    self.zeros = [0] * 8  # bit set if 0 has been seen

  def printBitDiff(self, other):
    """Prints bits that are set or cleared compared to other background."""
    for i in range(len(self.ones)):
      new_ones = ((~other.ones[i]) & 0xff) & self.ones[i]
      if new_ones:
        print 'id %s new one  at byte %d bitmask %d' % (
            self.message_id, i, new_ones)
      new_zeros = ((~other.zeros[i]) & 0xff) & self.zeros[i]
      if new_zeros:
        print 'id %s new zero at byte %d bitmask %d' % (
            self.message_id, i, new_zeros)


class Info():
  """A collection of Messages."""

  def __init__(self):
    self.messages = {}  # keyed by MessageID

  def load(self, filename):
    """Given a CSV file, adds information about message IDs and their values."""
    with open(filename, 'rb') as input:
      reader = csv.reader(input)
      next(reader, None)  # skip the CSV header
      for row in reader:
        bus = row[0]
        if row[1].startswith('0x'):
          message_id = row[1][2:]  # remove leading '0x'
        else:
          message_id = hex(int(row[1]))[2:]  # old message IDs are in decimal
        message_id = '%s:%s' % (bus, message_id)
        if row[1].startswith('0x'):
          data = row[2][2:]  # remove leading '0x'
        else:
          data = row[2]
        if message_id not in self.messages:
          self.messages[message_id] = Message(message_id)
        message = self.messages[message_id]
        if data not in self.messages[message_id].data:
          message.data[data] = True
        bytes = bytearray.fromhex(data)
        for i in range(len(bytes)):
          message.ones[i] = message.ones[i] | int(bytes[i])
          # Inverts the data and masks it to a byte to get the zeros as ones.
          message.zeros[i] = message.zeros[i] | ( (~int(bytes[i])) & 0xff)

def PrintUnique(interesting_file, background_files):
  background = Info()
  for background_file in background_files:
    background.load(background_file)
  interesting = Info()
  interesting.load(interesting_file)
  for message_id in sorted(interesting.messages):
    if message_id not in background.messages:
      print 'New message_id: %s' % message_id
    else:
      interesting.messages[message_id].printBitDiff(
          background.messages[message_id])


if __name__ == "__main__":
  if len(sys.argv) < 3:
    print 'Usage:\n%s interesting.csv background*.csv' % sys.argv[0]
    sys.exit(0)
  PrintUnique(sys.argv[1], sys.argv[2:])