Re: [boost] Boost::Bigint header draft - suggestions are welcome!

From: Arseny Kapoulkine (arseny.kapoulkine_at_[hidden])
Date: 2007-05-07 10:59:08

>
> Date: Mon, 7 May 2007 09:31:28 -0400
> From: "Jarrad Waterloo" jwaterloo_at_[hidden]
>
> Could use constructors that take 64 bit integers

There wass a problem with this approach, but it seems that defining 4
constructors (int, unsigned int, uint64, int64) satisfies all needs. Will
do.

Yes, wchar_t and wstring support is required

Added to todo list.

conversion to and from string probably should go into static function; other
> people's preference

I followed the way things like stringstream and boost::format behave.
Suggestion noted though, I'd like to hear other opinions.

Could we have conversions to and from strings of different bases 2-36

Indeed, I don't know why I missed it. Added to todo list.

>From what I have read from other bigint and other boost api's serialization
> is prefered if it was in a seperate header so that it won't become part of
> the build if not used.

Sorry, that was indeed unclear. I merged 2 headers in 1 for posting here,
serialization is in a separate header.

On a side note sometimes people need bigger_ints that are not of infinite
> precision that could be created on the stack. Problem domains would
> include
> RFID and other identification schemes. As such it would be nice to have
> the
> following:
> Ability to created a stack allocated bigger_int<128> similar in design to
> the bitset

As I noted this will not be supported for all implementations because of
increased complexity. The library initially will contain 2 implementations,
one will be faster and will be based on GMP - this implementation will NOT
support stack-based allocation. Another implementation will allow for
arbitrary storage implementation that meets the interface constraints,
possible syntax will be

bigint_base<bigint_default_implementation<bigint_static_storage<256> > > (oh
wel, I guess I will need to provide a helper, something like
static_bigint<256>::type)

2nd to be able get and set sub integers for instance give me the integer at
> bit 7 and goes for 21 bits.

I don't quite get it, do you want the ability to fetch separate bits or
separate limbs (digits, etc. - the internal representation)? And anyway,
what do you need it for? What behavior do you want for it in case of for
example negative numbers?

> Other proposals out there for review are Proposal for an Infinite
> Precision
> Integer for Library Technical Report 2 Draft by M.Kronenburg_at_[hidden]

I'd be happy to look at it, but I found only the initial post that said the
pdf is in Boost Vault - but it seems it is not there any more.

Thank you for your answer!