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Adding CAN FD 64 frame support to blf reader #568

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Merged
merged 3 commits into from
May 13, 2019
Merged

Adding CAN FD 64 frame support to blf reader #568

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8a09725
Adding CAN FD 64 frame support to blf reader
May 3, 2019
765206d
Merge branch 'develop' into BFL-CAN-FD-64
felixdivo May 12, 2019
3c34e1f
Merge branch 'develop' into BFL-CAN-FD-64
felixdivo May 13, 2019
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39 changes: 39 additions & 0 deletions can/io/blf.py
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Original file line number Diff line number Diff line change
Expand Up @@ -66,6 +66,13 @@ class BLFParseError(Exception):
# valid data bytes, data
CAN_FD_MSG_STRUCT = struct.Struct("<HBBLLBBB5x64s")

# channel, dlc, valid payload length of data, tx count, arbitration id,
# frame length, flags, bit rate used in arbitration phase,
# bit rate used in data phase, time offset of brs field,
# time offset of crc delimiter field, bit count, direction,
# offset if extDataOffset is used, crc
CAN_FD_MSG_64_STRUCT = struct.Struct("<BBBBLLLLLLLHBBL")

# channel, length, flags, ecc, position, dlc, frame length, id, flags ext, data
CAN_ERROR_EXT_STRUCT = struct.Struct("<HHLBBBxLLH2x8s")

Expand All @@ -81,6 +88,7 @@ class BLFParseError(Exception):
CAN_MESSAGE2 = 86
GLOBAL_MARKER = 96
CAN_FD_MESSAGE = 100
CAN_FD_MESSAGE_64 = 101

NO_COMPRESSION = 0
ZLIB_DEFLATE = 2
Expand All @@ -91,6 +99,12 @@ class BLFParseError(Exception):
BRS = 0x2
ESI = 0x4

# CAN FD 64 Flags
REMOTE_FLAG_64 = 0x0010
EDL_64 = 0x1000
BRS_64 = 0x2000
ESI_64 = 0x4000

TIME_TEN_MICS = 0x00000001
TIME_ONE_NANS = 0x00000002

Expand Down Expand Up @@ -236,6 +250,29 @@ def __iter__(self):
data=can_data[:length],
channel=channel - 1)
yield msg
elif obj_type == CAN_FD_MESSAGE_64:
(
channel, dlc, _, _, can_id, _, fd_flags
) = CAN_FD_MSG_64_STRUCT.unpack_from(data, pos)[:7]
length = dlc2len(dlc)
can_data = struct.unpack_from(
"<{}s".format(length),
data,
pos + CAN_FD_MSG_64_STRUCT.size
)[0]
msg = Message(
timestamp=timestamp,
arbitration_id=can_id & 0x1FFFFFFF,
is_extended_id=bool(can_id & CAN_MSG_EXT),
is_remote_frame=bool(fd_flags & REMOTE_FLAG_64),
is_fd=bool(fd_flags & EDL_64),
bitrate_switch=bool(fd_flags & BRS_64),
error_state_indicator=bool(fd_flags & ESI_64),
dlc=length,
data=can_data[:length],
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It would probably be more efficient something like this instead of unpacking the raw data above:

data_offset = pos + CAN_FD_MSG_64_STRUCT.size

data[data_offset:data_offset + length]

Also I've realized it should really be the valid payload length and not the DLC to support remote frames correctly, but it is more of a sanity thing.

channel=channel - 1
)
yield msg
elif obj_type == CAN_ERROR_EXT:
(channel, _, _, _, _, dlc, _, can_id, _,
can_data) = CAN_ERROR_EXT_STRUCT.unpack_from(data, pos)
Expand All @@ -247,6 +284,8 @@ def __iter__(self):
data=can_data[:dlc],
channel=channel - 1)
yield msg
# else:
# LOG.warning("Unknown object type (%d)", obj_type)

pos = next_pos

Expand Down