Re: [PATCH] Add "@cjknarrow" modifier (was Re: [Fwd: [1.7] wcwidth failing configure tests])

[Corinna Vinschen <vinschen at redhat dot com>]

Jeff,

do you have any opinion about this change?  I would like to get it (or
some variation of it) into Cygwin 1.7.


Thanks,
Corinna

On Jun 15 10:44, Corinna Vinschen wrote:
> On Jun 14 22:18, IWAMURO Motonori wrote:
> > 2009/6/13 Corinna Vinschen 
> > > The problem appears to be that there is no standard for the handling
> > > of ambiguous characters.
> > 
> > Yes, but the guideline exists.
> > http://cygwin.com/ml/cygwin/2009-05/msg00444.html
> 
> A single mail in a single mailing list of a single project.  That's rather
> a suggestion than a guideline...
> 
> > > > Ambiguous characters behave like wide or narrow characters depending
> > > > on the context (language tag, script identification, associated
> > > > font, source of data, or explicit markup; all can provide the
> > > > context). If the context cannot be established reliably, they should
> > > > be treated as narrow characters by default.
> > 
> > > Define the default for ja, ko, and zh to use width = 2, with a
> > > @cjknarrow (or whatever) modifier to use width = 1.
> > 
> > I think it is good idea.
> 
> If everybody agrees to this suggestion, here's the patch.  Tested
> with various combinations like
> 
>   LANG=ja_JP.UTF-8@cjknarrow
>   LANG=ja_JP@cjknarrow
>   LANG=ja.UTF-8@cjknarrow
>   LANG=ja@cjknarrow
> 
> 
> Corinna
> 
> 
> 	* libc/locale/locale.c (loadlocale): Add handling of "@cjknarrow"
> 	modifier on _MB_CAPABLE targets.  Add comment to explain.
> 
> 
> Index: libc/locale/locale.c
> ===================================================================
> RCS file: /cvs/src/src/newlib/libc/locale/locale.c,v
> retrieving revision 1.20
> diff -u -p -r1.20 locale.c
> --- libc/locale/locale.c	3 Jun 2009 19:28:22 -0000	1.20
> +++ libc/locale/locale.c	15 Jun 2009 08:40:46 -0000
> @@ -397,6 +397,9 @@ loadlocale(struct _reent *p, int categor
>    int (*l_wctomb) (struct _reent *, char *, wchar_t, const char *, mbstate_t *);
>    int (*l_mbtowc) (struct _reent *, wchar_t *, const char *, size_t,
>  		   const char *, mbstate_t *);
> +#ifdef _MB_CAPABLE
> +  int cjknarrow = 0;
> +#endif
>    
>    /* "POSIX" is translated to "C", as on Linux. */
>    if (!strcmp (locale, "POSIX"))
> @@ -427,10 +430,14 @@ loadlocale(struct _reent *p, int categor
>        if (c[0] == '.')
>  	{
>  	  /* Charset */
> -	  strcpy (charset, c + 1);
> -	  if ((c = strchr (charset, '@')))
> +	  char *chp;
> +
> +	  ++c;
> +	  strcpy (charset, c);
> +	  if ((chp = strchr (charset, '@')))
>  	    /* Strip off modifier */
> -	    *c = '\0';
> +	    *chp = '\0';
> +	  c += strlen (charset);
>  	}
>        else if (c[0] == '\0' || c[0] == '@')
>  	/* End of string or just a modifier */
> @@ -442,6 +449,17 @@ loadlocale(struct _reent *p, int categor
>        else
>  	/* Invalid string */
>        	return NULL;
> +#ifdef _MB_CAPABLE
> +      if (c[0] == '@')
> +	{
> +	  /* Modifier */
> +	  /* Only one modifier is recognized right now.  "cjknarrow" is used
> +	     to modify the behaviour of wcwidth() for East Asian languages.
> +	     For details see the comment at the end of this function. */
> +	  if (!strcmp (c + 1, "cjknarrow"))
> +	    cjknarrow = 1;
> +	}
> +#endif
>      }
>    /* We only support this subset of charsets. */
>    switch (charset[0])
> @@ -604,13 +622,15 @@ loadlocale(struct _reent *p, int categor
>        __mbtowc = l_mbtowc;
>        __set_ctype (charset);
>        /* Check for the language part of the locale specifier.  In case
> -         of "ja", "ko", or "zh", assume the use of CJK fonts.  This is
> -	 stored in lc_ctype_cjk_lang and tested in wcwidth() to figure
> -	 out the width to return (1 or 2) for the "CJK Ambiguous Width"
> -	 category of characters. */
> -      lc_ctype_cjk_lang = (strncmp (locale, "ja", 2) == 0
> -			   || strncmp (locale, "ko", 2) == 0
> -			   || strncmp (locale, "zh", 2) == 0);
> +         of "ja", "ko", or "zh", assume the use of CJK fonts, unless the
> +	 "@cjknarrow" modifier has been specifed.
> +	 The result is stored in lc_ctype_cjk_lang and tested in wcwidth()
> +	 to figure out the width to return (1 or 2) for the "CJK Ambiguous
> +	 Width" category of characters. */
> +      lc_ctype_cjk_lang = !cjknarrow
> +			  && ((strncmp (locale, "ja", 2) == 0
> +			      || strncmp (locale, "ko", 2) == 0
> +			      || strncmp (locale, "zh", 2) == 0));
>  #endif
>      }
>    else if (category == LC_MESSAGES)
> 
> 
> -- 
> Corinna Vinschen                  Please, send mails regarding Cygwin to
> Cygwin Project Co-Leader          cygwin AT cygwin DOT com
> Red Hat

-- 
Corinna Vinschen
Cygwin Project Co-Leader
Red Hat