Checking if an Integer is an Exact Binary Power

Andrei Alexandrescu via Digitalmars-d digitalmars-d at puremagic.com
Sat Apr 23 06:41:35 PDT 2016


On 4/23/16 9:04 AM, Nordlöw wrote:
> Wanted: CT-trait and run-time predicate for checking whether its single
> integer parameter is an exact power of two.
>
> I guess
>
> https://dlang.org/phobos/std_math.html#.truncPow2
>
> or
>
> https://dlang.org/phobos/std_math.html#.nextPow2
>
> could be reused, but I bet there's a more efficient way of checking this.

There's stuff for that in e.g. 
https://github.com/dlang/phobos/blob/master/std/experimental/allocator/common.d#L462. 
They're package-private with the intent is to move those slowly into 
Phobos. -- Andrei


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