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.

examples/can_unique.py

@@ -0,0 +1,80 @@
+#!/usr/bin/env python
+
+# 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
+# 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 xrange(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:
+        message_id = row[1]
+        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 xrange(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 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:])