Re: [boost] Boost.Uuid and header-only support

Subject: Re: [boost] Boost.Uuid and header-only support
From: Peter Dimov (lists_at_[hidden])
Date: 2017-11-06 13:38:37

James E. King, III wrote:
> I'm planning to change random_generator to use the header-only 
> random_device based on points made in this discussion:
>
> 1. It is more secure.
> 2. I believe it is the most widely used use case: generating a uuid 
> relatively infrequently (i.e. not in bulk).

Thanks.

> Therefore it will look something like this:
>
> //
> // The default random_generator uses operating-system provided entropy,
> // is the most secure, and fastest random uuid generator for creating a
> // small number of uuids with a single generator because it does not need
> // expensive seeding to be effective like a PseudoRandomNumberGenerator
> // does.
> //
> typedef basic_random_generator<detail::random::random_device>
> random_generator;

I suggest

class random_generator {
public:
    typedef uuid result_type;

    random_generator();

    uuid operator()();
};

that is, not using basic_random_generator here at all. There is no need to 
go through a URNG in this case; random bytes can and should be obtained 
directly from the OS API.

> typedef basic_random_generator<mt19937> random_generator_bulk;

If we guarantee that this will always use mt19937, it might be better to 
just call it random_generator_mt19937.