Re: packed structs

From	Ian Collins <ian-news@hotmail.com>
Newsgroups	comp.lang.c
Subject	Re: packed structs
Date	2012-09-23 13:32 +1200
Message-ID	<ac7757Fbr7hU2@mid.individual.net> (permalink)
References	(2 earlier) <e5a6fdcf-0343-4ea9-bfa8-5464c8d355a4@ib4g2000vbb.googlegroups.com> <k3jua2$l2e$1@reader1.panix.com> <slrnk5ri4f.1d3.grahn+nntp@frailea.sa.invalid> <lnobkxu6mx.fsf@nuthaus.mib.org> <k3lkhr$85u$1@reader1.panix.com>

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On 09/23/12 12:19 PM, JohnF wrote:

>     Finally, regarding Ian's remarks, pack/unpack would be
> a>>lightweight<<  alternative to accomplish this kind of
> task. Ian's way involves importing additional tool dependencies,
> possibly turning what could be just a few lines of code
> into a subtask unto itself.

The up front effort is much the same.  In your case you have to code the 
pack and unpack functions, in mine I had to write a simple code 
generator.  In both cases, once it's done it's done.  While the code 
generator can be simple, mine has evolved to support enum types and 
inheritance, but its still only a couple of hundred lines of code.  A 
colleague on a previous project write all the transforms in XLST, but 
that made my head explode.

In coding, I add a table to an OpenOffice document (part of the project 
documentation, so it's dual use) while you write a format string. 
Probably similar effort although I'd say the table approach is less 
error prone.

At run time, I have optimised code to perform the packing and unpacking 
while your functions have to interpret the format string each time they 
are called.  If you have to handle a lot of traffic, especially on a low 
powered device, that can be a killer.

-- 
Ian Collins

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packed structs JohnF <john@please.see.sig.for.email.com> - 2012-09-22 01:54 +0000
  Re: packed structs Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-09-21 23:22 -0400
    Re: packed structs JohnF <john@please.see.sig.for.email.com> - 2012-09-22 06:37 +0000
      Re: packed structs "BartC" <bc@freeuk.com> - 2012-09-22 13:47 +0100
        Re: packed structs Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-09-22 14:00 +0100
        Re: packed structs JohnF <john@please.see.sig.for.email.com> - 2012-09-22 15:42 +0000
      Re: packed structs Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-09-22 09:13 -0400
      Re: packed structs Johann Klammer <klammerj@NOSPAM.a1.net> - 2012-09-23 03:10 +0200
        Re: packed structs JohnF <john@please.see.sig.for.email.com> - 2012-09-23 02:10 +0000
      Re: packed structs Stephen Sprunk <stephen@sprunk.org> - 2012-09-23 11:44 -0500
        Re: packed structs JohnF <john@please.see.sig.for.email.com> - 2012-09-23 23:23 +0000
          Re: packed structs Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-09-24 01:59 +0100
            Re: packed structs JohnF <john@please.see.sig.for.email.com> - 2012-09-24 02:54 +0000
              Re: packed structs Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-09-24 04:38 +0100
                Re: packed structs JohnF <john@please.see.sig.for.email.com> - 2012-09-24 04:07 +0000
                Re: packed structs Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-09-24 12:16 +0100
                Re: packed structs JohnF <john@please.see.sig.for.email.com> - 2012-09-24 11:45 +0000
              Re: packed structs "BartC" <bc@freeuk.com> - 2012-09-24 10:18 +0100
                Re: packed structs JohnF <john@please.see.sig.for.email.com> - 2012-09-24 11:04 +0000
                Re: packed structs Stephen Sprunk <stephen@sprunk.org> - 2012-09-30 14:21 -0500
                Re: packed structs JohnF <john@please.see.sig.for.email.com> - 2012-10-01 07:34 +0000
          Re: packed structs Stephen Sprunk <stephen@sprunk.org> - 2012-09-30 13:52 -0500
    Re: packed structs Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-09-22 01:31 -0700
      Re: packed structs JohnF <john@please.see.sig.for.email.com> - 2012-09-22 08:53 +0000
        Re: packed structs Jorgen Grahn <grahn+nntp@snipabacken.se> - 2012-09-22 14:17 +0000
          Re: packed structs JohnF <john@please.see.sig.for.email.com> - 2012-09-22 15:33 +0000
            Re: packed structs Jorgen Grahn <grahn+nntp@snipabacken.se> - 2012-09-22 20:43 +0000
            Re: packed structs "BartC" <bc@freeuk.com> - 2012-09-22 22:52 +0100
          Re: packed structs Keith Thompson <kst-u@mib.org> - 2012-09-22 13:47 -0700
            Re: packed structs JohnF <john@forkosh.com.com> - 2012-09-23 00:19 +0000
              Re: packed structs Ian Collins <ian-news@hotmail.com> - 2012-09-23 13:32 +1200
                Re: packed structs JohnF <john@please.see.sig.for.email.com> - 2012-09-23 02:16 +0000
        Re: packed structs Ian Collins <ian-news@hotmail.com> - 2012-09-23 10:33 +1200
          Re: packed structs Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-09-23 01:38 -0700
  Re: packed structs The Great Firewall of China Blue <chine.bleu@yahoo.com> - 2012-09-21 21:29 -0700

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