|Subject:||Re: [Discuss-gnuradio] gr-ais: bit unstuffing bug?|
|Date:||Fri, 10 Aug 2012 12:43:55 -0700|
On 10/08/12 19:55, Nick Foster wrote:For what i understand, bit stuffing never generates framing code (that's the whole point), but the bit *un*stuffing can and will if the payload contains itself a byte which as the same value as the framing code.
You can do it either way since unstuffing will never generate a valid
HDLC framing code ("01111110"). Unstuffing before the deframing
Actually, while dumping data from ais_parse.cc, I found that gr-ais unstuffing code do generate framing codes. that has fooled get_tags_in_range (a stop was found because the AIS payload had a 01111110 in it).
Well, I think I found, I'm still scratching my head....Yes, I see the point. But you could unstuff inline, in place of the memcpy, just before calling parse().
correlators means my tags' sample numbers don't have to be modified for
the bits inserted by the unstuffing operation.
On Fri, Aug 10, 2012 at 11:47 AM, Christian Gagneraud<address@hidden <mailto:address@hidden>> wrote:Tel: + 353 (0) 1 236 5990 <tel:%2B%20353%20%280%29%201%20236%205990>
Hi all, Nick,
In gr-ais. the bit un-stuffing is done before the de-framing,
shouldn't it be done after instead?
Embedded systems engineer.
1 Harbour road
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