Re: [Boost-users] [statechart] [spirit] OSI delimited message framing

Subject: Re: [Boost-users] [statechart] [spirit] OSI delimited message framing
From: Larry Evans (cppljevans_at_[hidden])
Date: 2013-06-19 08:33:37

On 06/19/13 06:55, Michael Powell wrote:
> Hello,
> 
> I need to design a delimited message framing for TCP/IP sockets,
> probably using Asio to facilitate transport. Then build an OSI layer 7
> application vernier to handle framing.
> 
> I've dabbled a bit with Spirit and cooked up a couple of "simple"
> micro grammars throughout the code base. In a sense, I could see a
> delimited message framing strategy being a grammar of sorts, but this
> seems somewhat complex for a grammar to handle when you consider the
> overhead of verifying pass/fail (message or not a message), plus
> extracting the message within the delimiters.
> 
> Or, more likely approach the problem with statechart in mind. I've
> dealt with framed messages in the past more like this. One state is
> the escape byte, which can be followed by SOM, EOM, or another
> true-escape-byte (intended message byte). Plus other fields like
> message type, sub-type, how to handle payload, arguments, and so
> forth.
> 
> Anyone else dealt with things like this before? With Spirit? With Statechart?

Or with Lex?  I would think using just the lexer would work, since,
IIRC, lexers are a type of FSM, and I that's what StateChart is also.

OTOH, since you have to send and receive over a network.  Wouldn't
karma be a candidate for composing the message just as Spirit would
be a candidate for reading the message?

> 
> Regards,
> 
> Michael Powell
>