On 5/9/15 3:38 PM, Timon Gehr wrote:
Thanks! Looks good, except:
106| if (!parent.expand(b, goodAllocSize(needed) - b.length))
Let's see, this is a tad tricky. "needed" is the needed size, i.e.
b.length + delta. We want to expand to a final size of
goodAllocSize(needed). So we need to pass the appropriate delta to
expand, i.e. goodAllocSize(needed) - b.length.
(recall that expand() takes the delta, not the new size)
142| return parent.reallocate(b, gs);
gs is precomputed at the top of the function to be goodAllocSize(s), so
this seems to be in good shape.
172| return parent.alignedReallocate(b, gs, a);
Same here, the intent is to reallocate to goodAllocSize(s), which is
precomputed in gs.
Those should be more like:
182| parent.deallocate(b.ptr[0 .. goodAllocSize(b.length)]);
Another point is that the documented/checked constraints on the rounding
function are too weak. A rounding function should be monotone increasing
and piecewise constant with one fixed point per piece.
Agreed, I see there's a bit of follow-up so I'll reply to that.
And then, there's this, of course:
size_t goodAllocSize(size_t n);
Returns roundingFunction(n). It is required that
roundingFunction(n) >= n. For efficiency reasons, this is only asserted
(checked in debug mode).
Is this meant to be a complete specification of 'assert'? :o)
What is 'debug mode'?
Good point. Fixed the docs:
https://github.com/andralex/phobos/blob/allocator/std/experimental/allocator/quantizer.d
Andrei
