Bit syntax frustrations, again
Thu Oct 3 21:39:37 CEST 2002
On Thu, Oct 03, 2002 at 08:39:31PM +0200, Tony Rogvall wrote:
> You need to give the emulator some hint on the length of Payload,
Point is I don't know. :)
> 1. The header contains the length of PayLoad
> <<Len:16, Header:16, Payload:Len/binary, Trailer:16>> = Packet
So therefore I can't do this.
> 2. The pattern search.
> Assume that Trailer is bound then the pattern
> <<Header:32, Payload/binary, Trailer:16>> = Packet
> Would be interpreted as "first get the header" then start search
> for a bit pattern "Trailer" when "Trailer" is found then bind the
> Payload to the bits(bytes).
> Something like that?
Yes, perfect. I just wrote a parser for a protocol where there is an
ascii STX (Start of Transmission) followed by a variable length data
string and then an ascii ETX (End of Transmission). It would nice if
<<?STX, Data/binary, ?ETX>>.
Motivity Telecom Inc.
+1 519 579 5816
More information about the erlang-questions