Re: Field Header

From:
Jorgen Grahn <grahn+nntp@snipabacken.se>
Newsgroups:
comp.lang.c++
Date:
19 Nov 2010 14:14:42 GMT
Message-ID:
<slrnied1ii.1mn.grahn+nntp@frailea.sa.invalid>
On Thu, 2010-11-18, Andrea Crotti wrote:

I have a Stream class, which handles in short the manipulation of vector
of chars, and what I need also is something that creates a header.

Now I only have (now) two possibilities
- type + payload
- type + size + payload

And that's what I'm using:

class FieldHeader : public Stream
{
public:
    stream_t type;
    stream_t size;
    static const size_t TYPE = sizeof(stream_t);
    static const size_t SIZE = sizeof(stream_t);
    static const size_t TYPE_SIZE = TYPE + SIZE;

    FieldHeader(stream_t);
    FieldHeader(stream_t, stream_t);
    FieldHeader(const Stream&, bool full=true);

    static Stream createField(const Serializable&, stream_t, bool full=true);
};

it works and with "createField" I create the whole stream containing
payload and header, BUT

- the TYPE, SIZE, TYPE_SIZE are quite ugly
  I would like to use "sizeof(type)" for example if possible, but a
  static variable can't use a non-static variable (of course).
- if I want to add other fields is quite painful

Any suggestions to make this better?


To be blunt, you are probably overdesigning this A LOT. You have
asked a dozen or so questions here recently, all revolving around
run-time polymorphism. Concentrate on making the program do its job
instead.

I spent three years[1] maintaining an overdesigned protocol en/decoder
for the GTP protocol (which uses tag-value and tag-length-value
message attributes, just like yours) and I still hate the original
author. There were abstract factories, dynamic memory allocation,
std::multimap, templates, inheritance abuse in one big mix ... and it
was obviously not under its authors control.

I could prove, later, that none of that was needed, helpful, or even
harmless.

/Jorgen

[1] I had real work to do too, and the software had to work --
    or I would have rewritten it during the first year.

--
  // Jorgen Grahn <grahn@ Oo o. . .
\X/ snipabacken.se> O o .

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