30-Oct-2013 22:02, Andrei Alexandrescu пишет:
Well actually there are things that can be done at the allocator level
to explicitly help reference counting:
1. The refcount could be an affix to the allocated block.
Yup. I seriously underappreciated this one.
2. Small refcounts can be kept together in a compact block a la HeapBlock.
That would entail some work to tie-up refcounts and bigint internal
array, but it sounds interesting.
3. Or refcounts can be kept in a freelist.
Doubtful. That would amount to extra pointer stored per BigInt AND extra
indirection to get at ref-count unless I'm missing the details completely.
So refounting can be helped by an allocator built especially for it.
Agreed.
BTW AffixAllocator is quite a feat, I think I wanted it countless times
while working on std.regex/std.uni. I expect massive code performance
and clarity improvements when {core,std}.allocator comes in.
Andrei
--
Dmitry Olshansky
