Re: [gpsd-dev] devtools/ais.py type25 parsing bug

[Christian Gagneraud]

On 27/07/12 04:29, KIU Shueng Chuan wrote:
> Hi,
>
> In devtools/ais.py from gpsd release 3.7, the bitfield definition of
> "type25" is causing a TypeError exception in aivdm_unpack().
>
> type25 = {
>      bitfield("addressed", ...),
>      bitfield("structured", ..."Dimension to Bow"),     # legend field
> should be "Binary Data Flag"
>      ...
>      bitfield("data", None, ...)                                 #
> width field set to None causes the exception
> }
>
> One of the last few lines of aivdm_unpack() does
> offset += inst.width
> which chokes on width==None
>
> Changing None to 0 in the bitfield definition makes it work.

Hi Kiu,

Thanks for pointing that out. I will fix that shortly.
Please note, that the gpsd program itself handle this sentence correctly.

Any reason you are using devtools/ais.py?
This script has not been tested as thoroughly as gpsd.
If you want a sand alone stdin-to-stdout decoder use gpsdecode instead.


> For reference, the following was the sentence that triggered it:
> !AIVDM,1,1,,B,I9NS<Lh01dWK:UN0bOM2MR2d0<<K,0*58

Chris

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Christian Gagneraud,
Embedded systems engineer.
Techworks Marine
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