From: Gennadiy Rozental (gennadiy.rozental_at_[hidden])
Date: 2006-08-07 12:19:14
"John Maddock" <john_at_[hidden]> wrote in message
news:00f101c6b86f$68577300$96f20352_at_fuji...
> Gennadiy Rozental wrote:
>> Could you try this?
>
> I sympathise, but there is a problem still: there are some std lib's
> (STLport springs to mind, plus some Borland versions) where
> numeric_limits<>::is_specialized is *not* a compile time constant. It
> doesn't effect all compilers/std lib's, and we have a config macro
> BOOST_NO_LIMITS_COMPILE_TIME_CONSTANTS for this, but then you're into
> applying workarounds on the workaround :-(
Ok how about this:
namespace tt_detail {
template<typename FPT>
struct fpt_limits {
FPT min_value()
{
return std::numeric_limits<FPT>::is_specialized
? (std::numeric_limits<FPT>::min)()
: 0;
}
FPT max_value()
{
return std::numeric_limits<FPT>::is_specialized
? (std::numeric_limits<FPT>::max)()
: static_cast<FPT>(1000000);
}
};
template<typename FPT>
inline FPT
safe_fpt_division( FPT f1, FPT f2 )
{
// Avoid overflow.
if( f2 < static_cast<FPT>(1) && f1 > f2*fpt_limits<FPT>::max_value() )
return fpt_limits<FPT>::max_value();
// Avoid underflow.
if( f1 == static_cast<FPT>(0) ||
f2 > static_cast<FPT>(1) && f1 < f2*fpt_limits<FPT>::min_value() )
return static_cast<FPT>(0);
return f1/f2;
}
} // namespace tt_detail
Gennadiy