Re: [boost] [boost::endian] Summary of discussion #1

Subject: Re: [boost] [boost::endian] Summary of discussion #1
From: Scott McMurray (me22.ca+boost_at_[hidden])
Date: 2010-06-03 12:44:33

On 3 June 2010 12:30, Terry Golubiewski <tjgolubi_at_[hidden]> wrote:
> Tom wrote:
>>
>> endian::cast<big_to_host>() Â //explicit direction
>> endian::cast<from_litle>() Â  //"to_host" is implicit
>> endian::cast<to_big>() Â  Â  Â  //"from_host" is implicit
>>
>
> Is it imporant that these names are templated? Â What are the advantages of
> this templated-tagged design over..
>

I also find it odd that the direction is mixed in with the endianness.
 I'd expect something like to_host_endian and from_host_endian, with a
policy type for the endianness.  (Perhaps the big and little types
could be formalized policies, in a way that there could be a
custom<1,3,0,4> endian type for very strange endians, with big and
little just being instances thereof, perhaps with specializations for
speed if needed.)

The only advantage I see of the explicit one is that it theoretically
allows cast<big_to_little>, but that would mean defining a number of
types quadratic in the number of endiannesses.  It clearly has no
speed benefit over to_host then from_host on typical machines.  I'm
also not certain that it's even a useful operation.