Sandia National Laboratories recently changed management from the
Sandia Corporation to the National Technology & Engineering Solutions
of Sandia, LLC (NTESS). The copyright statements need to be updated
accordingly.
Previously once an ArrayHandle was stolen it was placed in an invalid state
where it could not used again by VTK-m. Now instead after being stolen it
is placed into a state where it is identical to memory allocated outside
of VTK-m and passed in.
The old templated array transfer mechanism generated a lot of code
that ended up doing a simple, type-agnostic memcpy for most devices.
This patch specialized array handles for basic storage and uses a
fast-path array transfer implementation. This reduces the size of the
vtkm_cont library by 27% on gcc (from 6.2MB to 4.5MB).
The basic storage has an implicit invariant that if the size of the
storage is 0 then the array is a null pointer. That invariant was broken
if the array was allocated and then Shrink or Allocate was called with
0. In that case, the array remained allocated by the size was set to 0.
This fixes the problem by making sure a Shrink(0) actually does an
Allocate(0) (to clear out the data) and that the basic storage always
frees its memory when allocating a 0 sized array.
