Message 21 name + name_ext concatenation

[jwheare]

It would be nice to pre-concatenate name_ext onto name when decoding message type 21, perhaps on an attribute full_name: https://github.com/biiont/gpsd/blob/master/www/AIVDM.txt#L3690-L3693

The name field is up to 20 characters of 6-bit ASCII. If this field
is full (has no trailing @ characters) the decoder should interpret
the Name Extension field later in the message (no more than 14 6-bit
characters) and concatenate it to this one to obtain the full name.

Or at least provide a method that returns the full name.

e.g. in this example full_name would be NNG-OSS-S OFFSHORE WINDFARM

!AIVDM,1,1,,B,E>jHDL1W73nWaanah7S39T7a2h;wror=@5nL`A2AISd002CQ1PDS@0,4*39

print(pyais.decode('!AIVDM,1,1,,B,E>jHDL1W73nWaanah7S39T7a2h;wror=@5nL`A2AISd002CQ1PDS@0,4*39').to_json())

{
    "msg_type": 21,
    "repeat": 0,
    "mmsi": 992351344,
    "aid_type": 3,
    "name": "NNG-OSS-S OFFSHORE W",
    "accuracy": true,
    "lon": -2.239765,
    "lat": 56.243582,
    "to_bow": 17,
    "to_stern": 18,
    "to_port": 11,
    "to_starboard": 12,
    "epfd": 7,
    "second": 24,
    "off_position": false,
    "reserved_1": 0,
    "raim": false,
    "virtual_aid": false,
    "assigned": false,
    "spare_1": "AA==",
    "name_ext": "INDFARM"
}

[M0r13n]

Hey @jwheare,

that is a neat idea. Thank you for bringing this up. I have added a (cached) property, full_name, to message type 21 in v2.8.4 which should now be available on PyPi.

All the best,
Leon

[jwheare]

Brilliant, thank you!