Re: [boost] Review Request: Algorithm.Sorting

Subject: Re: [boost] Review Request: Algorithm.Sorting
From: Ross Levine (ross.levine_at_[hidden])
Date: 2009-05-08 13:33:06

Maybe instead of a static assert, do some sort of conditional compilation or
template metaprogramming, such that if
std::numeric_limits<Data_type>::is_iec559 is false, it just defaults to
std::sort? That would be more cross-platform.
Also, couldn't you just use reinterpret_cast instead of memcpy? Or is there
a problem with that?

I must say that this sort of thing could be very useful.

On Wed, May 6, 2009 at 10:43 PM, Steven Ross <spreadsort_at_[hidden]> wrote:

> Does this ease your mind?  float_sort shouldn't compile if the float type
> isn't correct, and this is the code I've been using for casting floats to
> integers:
>    BOOST_STATIC_ASSERT(sizeof(Cast_type) == sizeof(Data_type));
>    BOOST_STATIC_ASSERT(std::numeric_limits<Data_type>::is_iec559);
>    BOOST_STATIC_ASSERT(std::numeric_limits<Cast_type>::is_integer);
>    Cast_type result;
>    std::memcpy(&result, &(*floatiter), sizeof(Data_type));
>
> Also, the mostly-sorted performance issue is resolved; performance is now
> comparable on Windows between integer_sort and std::sort on mostly-sorted
> data, without any platform-specific edits.
> That should resolve all outstanding concerns I am aware of.
>
> On Wed, May 6, 2009 at 1:26 PM, Ross Levine <ross.levine_at_[hidden]> wrote:
>
> > On Mon, Apr 27, 2009 at 10:32 AM, Steven Ross <spreadsort_at_[hidden]>
> > wrote:
> >
> > > float_sort, which sorts IEEE floating-point numbers as integers
> >
> >
> > This worries me a little. C++ floating-point format is
> > implementation-defined, and is not necessarily in IEEE 754.
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