Re: Reverse a string (with xchars)

From	Paul Rubin <no.email@nospam.invalid>
Newsgroups	comp.lang.forth
Subject	Re: Reverse a string (with xchars)
Date	2016-02-21 14:59 -0800
Organization	A noiseless patient Spider
Message-ID	<87d1rp4qlo.fsf@jester.gateway.pace.com> (permalink)
References	(3 earlier) <d1e1967f-6c07-4d04-867f-45133642a540@googlegroups.com> <874md16d46.fsf@jester.gateway.pace.com> <c8ba1573-77ce-49fb-a2f3-eb14a583ddc8@googlegroups.com> <87mvqt4wbd.fsf@jester.gateway.pace.com> <2a2f536b-cba7-4360-97e7-2d78e425aafb@googlegroups.com>

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Chris Curl <ccurl609@gmail.com> writes:
> The thing is ... a character may have more than one modifier, so for 
> chars that have >1, don't you need a way to keep the char and its 
> modifiers in the proper order? Perhaps what you are saying does that,
> I may just not be seeing it yet.

I don't think there can be unlimited numbers of modifiers, in fact
I thought there was at most 1.  It doesn't matter, you can do all
the reversals in place.  Algorithm:

  let p = start of buffer
  Until you reach the end of the buffer:
    scan forward from p til you reach the end of the end of
      the char including any modifiers
    let q = current position
    reverse the bytes in the range from p to q
    let p = q
  ( p now points to the end of the buffer )
  reverse bytes from start of buffer to p

So you've done the whole thing in place with no auxiliary buffers,
just a few temp variables for the loops and swaps.

Thread

Reverse a string (with xchars) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-02-19 09:00 +0000
  Re: Reverse a string (with xchars) mentificium@gmail.com - 2016-02-20 23:44 -0800
  Re: Reverse a string (with xchars) Chris Curl <ccurl609@gmail.com> - 2016-02-21 10:18 -0800
    Re: Reverse a string (with xchars) Chris Curl <ccurl609@gmail.com> - 2016-02-21 10:24 -0800
      Re: Reverse a string (with xchars) Chris Curl <ccurl609@gmail.com> - 2016-02-21 10:35 -0800
        Re: Reverse a string (with xchars) Paul Rubin <no.email@nospam.invalid> - 2016-02-21 12:07 -0800
          Re: Reverse a string (with xchars) Chris Curl <ccurl609@gmail.com> - 2016-02-21 12:40 -0800
            Re: Reverse a string (with xchars) Paul Rubin <no.email@nospam.invalid> - 2016-02-21 12:50 -0800
            Re: Reverse a string (with xchars) Paul Rubin <no.email@nospam.invalid> - 2016-02-21 12:56 -0800
              Re: Reverse a string (with xchars) Chris Curl <ccurl609@gmail.com> - 2016-02-21 14:43 -0800
                Re: Reverse a string (with xchars) Paul Rubin <no.email@nospam.invalid> - 2016-02-21 14:59 -0800
                Re: Reverse a string (with xchars) Chris Curl <ccurl609@gmail.com> - 2016-02-21 16:55 -0800
              Re: Reverse a string (with xchars) Albert van der Horst <albert@spenarnc.xs4all.nl> - 2016-02-22 09:37 +0000

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