On Sat, 24 Mar 2007 12:31:41 +0100, Kevin Sopp <baraclese@googlemail.com> wrote:
do you mean that it's possible to use std::allocator methods in order to grow allocated space without the need to initialize it again with old data ?
No, I meant that you can use the realloc() function throughout the library without having to worry about whether the user passed in an allocator with std::allocator interface or an allocator that supports realloc(). By specializing a struct on the allocator type, it will act as a proxy and you call the struct's realloc() in the library. If the user passes in std::allocator the proxy realloc() function will still do an alloc/copy/destroy.
Ok, now I understand what you meant.
I don't know if checking for states doesn't matter compared to the complexity of multi precision algorithms. It's possible, I should try.
parametrization for infinity, NaN and exception it's ok; anyway what I wanted to point out it's that in the case there is a performance loss, managing infinity and undefined states, then it is better to implement different classes and it's so even using template parameters: for instance classes big_integer<WITH_INF> and big_integer<WITHOUT_INF> ( WITH_INF = true, WITHOUT_INF = false, and I've omitted the other template parameters ) will exdend a common class in such a way to share as much as possible, but they will be two different template specialization of <bool use_inf>.
It sounds like this will make things more complex than necessary.
I agree with you
I just looked at the GMP manual [http://gmplib.org/manual/] and it looks like they don't support infinities etc. in fact they don't handle division by zero either because "This lets a program handle arithmetic exceptions in these functions the same way as for normal C int arithmetic."
well, anyway even if a division by zero throws an exception, a program could handle it in two way: the classical one checking the denominator argument before passing it to the division operator, and the one offered by the library by sourrounding the division operation with a try/catch block; the two methods are not exclusive. Marco -- Using Opera's revolutionary e-mail client: http://www.opera.com/mail/