Re: [boost] stack-based std::containers

From: Thorsten Ottosen (thorsten.ottosen_at_[hidden])
Date: 2007-03-01 02:11:50

Michael Marcin wrote:
> I have functions like say a quartic equation solver that can return a 
> variable number of solutions.  It would be clean IMO to return or pass 
> by reference a std::vector or like container that store the solutions. 
> However heap allocation is fairly expensive here so the usual solution 
> is to have a local array with max solutions elements and pass that by 
> reference into the solver and return the number of solutions.  This is 
> ugly to use and read.  Is there a library for stack-based std-like 
> containers?  Alternatively is it possible to make an compatible 
> stack-based allocator for std::vector using alloca?

You can definitely make a stack-based version of allocators. The 
allocator would store a  pointer to the local array.
It's still fairly ugly though.

I suggest that you could look at STLSoft's auto_buffer:

http://synesis.com.au/software/stlsoft/help/classstlsoft_1_1auto__buffer.html

I suggested the construction of a similar class in boost for SoC last year.

-Thorsten