Pass CollectionType when reading

[Flamefire]

HDF5 does datatype conversion when required (https://www.hdfgroup.org/HDF5/doc/UG/HDF5_Users_Guide-Responsive%20HTML5/index.html#t=HDF5_Users_Guide%2FDatatypes%2FHDF5_Datatypes.htm%23TOC_6_10_Data_Transferbc-26&rhtocid=6.5_2)
So the interfaces should accept a CollectionType when reading making the read/write signature almost the same.

Example:

    virtual void readAttribute(int32_t id,
            const CollectionType& type,
            const char *dataName,
            const char *attrName,
            void *buf,
            Dimensions *mpiPosition = NULL) = 0;
    virtual void writeAttribute(int32_t id,
            const CollectionType& type,
            const char *dataName,
            const char *attrName,
            const void *buf) = 0;

If one is really interested in the actual collection type, there is the readAttributeMeta function. One could also make the type a pointer, with NULL allowed which would be handy for strings.

[ax3l]

one general comment: a current design flaw is still, that native HDF5 types such as hid_t, hsize_t, ... are currently exposed in the public API of libSplash (see e.g., CollectionType, Dimensions, Serial&ParallelDataCollector, the new DCAttributeInfo). This leads to the problem, that booth <splash/splash.h> and <hdf5.h> need to be present in user code.

Ideally, <hdf5.h> and objects / types from it would not be visible in any of the user-included header files of libSplash.