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Groups > comp.lang.c > #55527

Re: Pointer to structure

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On 21-Dec-14 07:55, Siri Crews wrote:
> You could require all strings be UTF-8 encoded, and store 0x80+n in
> the first byte, where n is the number of length bytes, maximum
> length, current length, and UTF-8 characters. And a string that
> starts with a zero byte is an empty string; a string that starts with
> any other valid UTF-8 byte is a zero terminated string. And all pass
> around as char*. That would let you use legacy ASCII and UTF-8
> strings and new counted length strings transparently.

There are only two invalid code units for UTF-8, so how are you supposed
to know by examining the first byte whether the string is NUL-terminated
UTF-8 or "counted length"?

Even ignoring that, there are many other character encodings, and many
of them have _no_ invalid values that you could hijack.  The world is
not all UTF-8, unfortunately, and ASCII is pretty much irrelevant these
days.  (Much of the world is now "UTF-16", though a large fraction of
that is actually UCS-2; even "UTF-8" is often CESU-8, though that's
mostly a result of broken "UTF-16" systems.)

In-band signaling is nearly always a bad idea; if you want to use
counted length strings, just use the struct hack, and then you don't
have to worry about accidentally passing one to a function that is
expecting a NUL-terminated string or vice versa.

S

-- 
Stephen Sprunk         "God does not play dice."  --Albert Einstein
CCIE #3723         "God is an inveterate gambler, and He throws the
K5SSS        dice at every possible opportunity." --Stephen Hawking

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Pointer to structure Dexterr <dejangru@gmail.com> - 2014-12-21 03:16 -0800
  Re: Pointer to structure BartC <bc@freeuk.com> - 2014-12-21 12:09 +0000
    Re: Pointer to structure Siri Crews <chine.bleu@yahoo.com> - 2014-12-21 04:39 -0800
      Re: Pointer to structure BartC <bc@freeuk.com> - 2014-12-21 12:59 +0000
        Re: Pointer to structure Siri Crews <chine.bleu@yahoo.com> - 2014-12-21 05:05 -0800
          Re: Pointer to structure BartC <bc@freeuk.com> - 2014-12-21 13:12 +0000
            Re: Pointer to structure Siri Crews <chine.bleu@yahoo.com> - 2014-12-21 05:55 -0800
              Re: Pointer to structure BartC <bc@freeuk.com> - 2014-12-21 14:31 +0000
                Re: Pointer to structure Siri Crews <chine.bleu@yahoo.com> - 2014-12-21 06:47 -0800
                Re: Pointer to structure BartC <bc@freeuk.com> - 2014-12-21 20:10 +0000
                Re: Pointer to structure Geoff <geoff@invalid.invalid> - 2014-12-21 10:00 -0800
                Re: Pointer to structure Ben Bacarisse <ben.usenet@bsb.me.uk> - 2014-12-21 22:44 +0000
                Re: Pointer to structure raltbos@xs4all.nl (Richard Bos) - 2014-12-21 18:01 +0000
                Re: Pointer to structure BartC <bc@freeuk.com> - 2014-12-21 21:21 +0000
                Re: Pointer to structure raltbos@xs4all.nl (Richard Bos) - 2014-12-22 12:11 +0000
                Re: Pointer to structure Ben Bacarisse <ben.usenet@bsb.me.uk> - 2014-12-21 22:36 +0000
              Re: Pointer to structure Stephen Sprunk <stephen@sprunk.org> - 2014-12-27 17:56 -0600
                Re: Pointer to structure Siri Crews <chine.bleu@yahoo.com> - 2014-12-27 16:33 -0800
                Re: Pointer to structure Stephen Sprunk <stephen@sprunk.org> - 2015-01-15 12:29 -0600
            Re: Pointer to structure glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2014-12-22 00:50 +0000
              Re: Pointer to structure Richard Damon <Richard@Damon-Family.org> - 2014-12-21 20:19 -0500
                Re: Pointer to structure glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2014-12-22 06:23 +0000
                Re: Pointer to structure gazelle@shell.xmission.com (Kenny McCormack) - 2014-12-22 12:03 +0000
          Re: Pointer to structure gazelle@shell.xmission.com (Kenny McCormack) - 2014-12-21 13:20 +0000
            Re: Pointer to structure Siri Crews <chine.bleu@yahoo.com> - 2014-12-21 05:40 -0800
  Re: Pointer to structure Ben Bacarisse <ben.usenet@bsb.me.uk> - 2014-12-21 13:16 +0000
  Re: Pointer to structure Barry Schwarz <schwarzb@dqel.com> - 2014-12-21 10:02 -0800
  Re: Pointer to structure Keith Thompson <kst-u@mib.org> - 2014-12-21 12:25 -0800
    Re: Pointer to structure Dexterr <dejangru@gmail.com> - 2014-12-21 15:07 -0800

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