[C++ PATCH] Plural forms for count != eltscnt structured binding diagnostics

[Jakub Jelinek]

On Thu, Nov 30, 2017 at 01:33:48PM +0100, Jakub Jelinek wrote:
> On Thu, Nov 30, 2017 at 01:01:58PM +0100, Jakub Jelinek wrote:
> > I just followed:
> > https://www.gnu.org/savannah-checkouts/gnu/gettext/manual/html_node/Plural-forms.html
> > 
> > "About larger integer types, such as ‘uintmax_t’ or ‘unsigned long long’: they can be
> > handled by reducing the value to a range that fits in an ‘unsigned long’. Simply
> > casting the value to ‘unsigned long’ would not do the right thing, since it would
> > treat ULONG_MAX + 1 like zero, ULONG_MAX + 2 like singular, and the like. Here you
> > can exploit the fact that all mentioned plural form formulas eventually become periodic,
> > with a period that is a divisor of 100 (or 1000 or 1000000). So, when you reduce a large
> > value to another one in the range [1000000, 1999999] that ends in the same 6 decimal
> > digits, you can assume that it will lead to the same plural form selection. This code
> > does this:
> > 
> > #include <inttypes.h>
> > uintmax_t nbytes = ...;
> > printf (ngettext ("The file has %"PRIuMAX" byte.",
> >                   "The file has %"PRIuMAX" bytes.",
> >                   (nbytes > ULONG_MAX
> >                    ? (nbytes % 1000000) + 1000000
> >                    : nbytes)),
> >         nbytes);"
> > 
> > I can surely add a comment about that.
> > 
> > Note the patch depends on the https://gcc.gnu.org/ml/gcc-patches/2017-11/msg02521.html
> > patch.
> 
> Though, looking at our *_n diagnostic routines, the n argument is actually
> int there, not unsigned long for some reason.  So, either we should fix
> that (seems ngettext has unsigned long), or the above would need to be
> (unsigned HOST_WIDE_INT) (int) eltscnt != eltscnt || (int) eltscnt < 0 

Of course better eltscnt > INT_MAX

	Jakub