Re: Fix wrong character count in argp

[Vladimir 'φ-coder/phcoder' Serbinenko]

On 12.02.2012 22:59, Bruno Haible wrote:
> Hi Vladimir,
>
> Thank you for the proposed patch.
>
>> As already reported several years ago
> I cannot find it in my archives. Maybe that discussion already contained
> some useful thoughts or arguments? Can you please point me to it?
http://lists.gnu.org/archive/html/bug-tar/2009-09/msg00008.html
>> argp counts bytes even when
>> actually what matters is the display length. This patch improves the
>> situation by counting only leading and standalone UTF-8 bytes. It
>> doesn't handle the double-width characters like Chinese sinograms
> A program that needs to consider display length - for example for
> line wrapping - should
>   1) work with any locale encoding. Don't assume that the locale encoding
>      is UTF-8.
>   2) work with Chinese ideographs correctly, like it should also work
>      with Russian (single-width) letters.
Here you go. Tested on Cyrillic. Haven't tested with Chinese.
>
> The easiest way to satisfy these two requirements is to base the code on
> either
>   * the function mbswidth (gnulib module mbswidth) and possibly also mbiter
>     or mbuiter, or
>   * the gnulib module unilbrk/ulc-width-linebreaks, it contains a complete
>     line-breaking algorithm.
>
> Can you rewrite your patch to this effect?
>
> Also, such tricky issues should be checked in the test suite. Can you
> please also provide a test program, some input data, and the expected
> output for this data? We can then turn it into a gnulib test.
I can strip down one of our programs to keep just --help when time permits.
> Bruno
>
>


-- 
Regards
Vladimir 'φ-coder/phcoder' Serbinenko

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