[Groff] Re: MSVC Port-- '-(unsigned)' Construct in font.cpp

[Werner LEMBERG]

[CCing to the groff list.]

> I notice in scale_round() in font.cpp, the sequence
> 
>     if (-(unsigned)n <= (-(unsigned)INT_MIN - y2)/x)
>       return (n*x - y2)/y;
>     return int(n*double(x)/double(y) - .5);
> 
> What is happening with the '-(unsigned)n' construct?  Is this a
> substitute for -abs(n)?  At least with MSVC, the unary minus has no
> effect on an unsigned value.  I notice the same construct is used in
> several other files as well.

I wonder whether we can replace this safely with

  if (n >= (INT_MIN + y2)/x)
    return (n*x - y2)/x;
  return int(n*double(x)/double(y) - .5);

Any comments or suggestions?  Is `>=' correct or should `>' be used
instead?  My knowledge is very limited with those border cases of
binary number representations...


    Werner