[Mono-dev] Trivial Enumerable Optimizations

[Jonathan Pryor]

On Fri, 2008-05-09 at 08:53 -0400, Avery Pennarun wrote:
> On 5/9/08, Jonathan Pryor <jonpryor at vt.edu> wrote:
> >            catch {
> >                // ignore; collection has > int.MaxValue elements,
> >                // so count manually below.
> >            }
> [...]
> >  This will suffer an obvious performance penalty if the collection has
> >  over int.MaxValue elements (assuming .Count throws an exception when
> >  that happens), but as most (currently all?) collections will have less
> >  than int.MaxValue elements, this should be a performance win.
> 
> Hmm, are you sure you really want to count them all manually when
> there are greater than 2 billion elements in the data structure?

If the developer asks for a count, we have an obligation to provide a
count.  Throwing an exception claiming "You're a moron to ask about size
on a collection this big" should not be acceptable.

 - Jon