Currently, VTK-m is using C++11. However, it is often useful to use
features in the `std` namespace that are defined for C++14 or later. We
can provide our own versions (sometimes), but it is preferable to use
the version provided by the compiler if available.
There were already some examples of defining portable versions of C++14
and C++17 classes in a `vtkmstd` namespace, but these were sprinkled
around the source code.
There is now a top level `vtkmstd` directory and in it are header files
that provide portable versions of these future C++ classes. In each
case, preprocessor macros are used to select which version of the class
to use.
The ArrayPortalWrapper is used for both execution and control portals.
When it was wrapped around a control portal that does not work on CUDA
devices, we were getting ugly warnings even though the intention was
only to use it in the control environment.
Because ArrayPortalToken does not have an IteratorType,
ArrayPortalToIterators assumed it had to wrap it in an
IteratorFromArrayPortal object. Now it uses PortalSupportsIterators
(from ArrayPortalHelpers.h) to determine whether the iterators are
there. This does work with ArrayPortalToken.
The convenience functions `ArrayPortalToIteratorBegin()` and
`ArrayPortalToIteratorEnd()` wouldn't detect specializations of
`ArrayPortalToIterators<PortalType>` since the specializations aren't
visible when the `Begin`/`End` functions are declared.
Since the CUDA iterators rely on a specialization, the convenience
functions would not compile on CUDA.
Now, instead of specializing `ArrayPortalToIterators` to provide custom
iterators for a particular portal, the portal may advertise custom
iterators by defining `IteratorType`, `GetIteratorBegin()`, and
`GetIteratorEnd()`. `ArrayPortalToIterators` will detect such portals
and automatically switch to using the specialized portals.
This eliminates the need for the specializations to be visible to the
convenience functions and allows them to be usable on CUDA.
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.
Change the VTKM_CONT_EXPORT to VTKM_CONT. (Likewise for EXEC and
EXEC_CONT.) Remove the inline from these macros so that they can be
applied to everything, including implementations in a library.
Because inline is not declared in these modifies, you have to add the
keyword to functions and methods where the implementation is not inlined
in the class.
This moves the ability to get an iterator from an array portal out of
the portal itself. The next step is to move the GetIteratorBegin/End out
of ArrayPortal. This should make the implemenation a bit cleaner.
