Re: [Boost-users] Needs advices on design ( mpl or processor )

Subject: Re: [Boost-users] Needs advices on design ( mpl or processor )
From: Allan Nielsen (a_at_[hidden])
Date: 2012-01-07 04:27:19

> I have no see yet your implementation and how I can help you in, but I guess
> that you can find your own responses in the implementation of this library
>
> https://svn.boost.org/svn/boost/sandbox/SOC/2010/bit_masks/lib/integer/doc/html/index.html
Cool, I will have a look at it.

> In addition to what you want to do, I think that all this stuff can be
> generalized to a compressed_tuple.
>
> About compressed_tuple.
>
> Tuples of types can be compressed depending on the bits needed to store the
> underlying type of each one of the tuple elements. For example a
> compressed_tuple<month,day,weekday> would take 3 bytes, but month needs only
> 5 bits, day 3 bits and weekday 3 bits, that is 11 bits which can be
> represented using just 2 bytes.

It sounds interesting, and might be quite close to what I want, but not exactly:

Say I need to store 11 weekday ( encoded as an int 0-6 ) in a
compressed_tuple, then this would require 11 * 3 bits = 33 -> 5 bytes.

If I store 11 weekdays in a compressed_enum the only requirement is
that 7^11 < MAX_STORAGE_SIZE. 7^11 = 1977326743, which is less than
2^32 and would therefor require 4 bytes.

Best regards
Allan W. Nielsen