How do you remove/insert elements in a dynamic array without allocating?

[Jonathan M Davis]

On Wednesday, November 07, 2012 10:45:46 monarch_dodra wrote:
> Also, Array uses a deterministic memory model, just like vector,
> that releases content as soon as it goes out of scope. I could
> have done without that, personally, but to each their own.

Yes. The built-in arrays work extremely well as they are designed, but they 
are _not_ meant for cases where you need the array to have specific ownership.

It appears that Array is using malloc and free internally (including telling 
the GC about it so that it's scanned for references/pointers as appropriate), 
so it doesn't even have to worry about stuff like assumeSafeAppend. It's very 
much in line with std::vector and what should be used if you want something 
similar to std::vector.

By the way, monarch_dodra, since you've been messing around with Array 
recently, I would point out that it looks like setting the length doesn't work 
properly if you set it greater than the current length, let alone greater than 
the current capacity.  _capacity is not adjusted if newLength is greater than 
it, and no calls to GC.removeRange or GC.addRange are made, so it doesn't look 
like newly allocated memory is being tracked by the GC like it should if 
length is allocating it. And I find the whole length vs capacity bit in Array 
highly confusing, because it looks like the length of the payload is used for 
length, when I would have expected the length of the payload to be the 
capacity and for there to be a separate length for the actual number of 
elements. So, I really don't know what's going on with std.array.Array's 
implementation without studying it a lot more - hopefully you do. But at 
minimimu, I'd advise verifying that the GC.addRange and GC.removeRange calls 
are being correctly done, because regardless of what the deal is with capacity 
vs length, it seems seriously off to me that no GC functions are called when a 
realloc is made.

- Jonathan M Davis