I had a similar need, but I think you are overthinking. No need to involve
any classes at all.
Try this:
inline hid_t hid_from_type(const char &) { return H5T_NATIVE_CHAR; }
inline hid_t hid_from_type(const signed char &) { return H5T_NATIVE_SCHAR; }
inline hid_t hid_from_type(const unsigned char &) { return
H5T_NATIVE_UCHAR; }
inline hid_t hid_from_type(const short &) { return H5T_NATIVE_SHORT; }
inline hid_t hid_from_type(const unsigned short &) { return
H5T_NATIVE_USHORT; }
inline hid_t hid_from_type(const int &) { return H5T_NATIVE_INT; }
inline hid_t hid_from_type(const unsigned &) { return H5T_NATIVE_UINT; }
inline hid_t hid_from_type(const long &) { return H5T_NATIVE_LONG; }
inline hid_t hid_from_type(const unsigned long &) { return
H5T_NATIVE_ULONG; }
inline hid_t hid_from_type(const long long &) { return H5T_NATIVE_LLONG; }
inline hid_t hid_from_type(const unsigned long long &) { return
H5T_NATIVE_ULLONG; }
inline hid_t hid_from_type(const float &) { return H5T_NATIVE_FLOAT; }
inline hid_t hid_from_type(const double &) { return H5T_NATIVE_DOUBLE; }
// And the coup de grace:
template <typename T>
inline hid_t hid_from_type() { return hid_from_type(T()); }
// Usage for your example:
hid_t dsid = H5Dcreate(fid, name, hid_from_type<T>(), spid, H5P_DEFAULT,
H5P_DEFAULT, H5P_DEFAULT);
Kevin
On Mon, Feb 5, 2018 at 9:03 AM, Miller, Mark C. <[email protected]> wrote:
> Hi All,
>
>
>
> I am wondering if anyone else in C++ coding of HDF5 has run into the
> following problem…
>
>
>
> I have a templatized function that writes an HDF5 dataset…
>
>
>
> template <class T> static void WriteVecToHDF5(hid_t fid, char const *name,
> std::vector<T> const &vec, int d2size)
>
> {
>
> hsize_t siz2d[2] = {(hsize_t) vec.size() / d2size, d2size};
>
> hid_t spid = H5Screate_simple(d2size>1?2:1, siz2d, 0);
>
> hid_t dsid = H5Dcreate(fid, name, *HDF5Type<T>().Type()*, spid,
> H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT);
>
> H5Dwrite(dsid, H5T_NATIVE_INT, H5S_ALL, H5S_ALL, H5P_DEFAULT, &vec[0]);
>
> H5Dclose(dsid);
>
> H5Sclose(spid);
>
> }
>
>
>
> I would like the template instantiation to then return the correct
> H5T_NATIVE_XXX type so WriteVecToHDF5<int>(…) produces a call to H5Dcreae,
> there in *bold red* with H5T_NATIVE_INT, etc.
>
>
>
> There does not appear to be any support in the HDF5 implementation for
> this. Am I missing something?
>
>
>
> Below is what I did (for int, float and double but can easily be expanded
> to cover all primitive types) and am wondering if others find this useful
> enough (or something like it) that it ought to be included in HDF5 C++
> interface?
>
>
>
>
>
> // base class
>
> template <class T> class HDF5TypeBase {
>
> public:
>
> HDF5TypeBase() {} ;
>
> virtual ~HDF5TypeBase() {};
>
> };
>
>
>
>
>
> // base class for type-specific template specializations to follow
>
> template <class T> class HDF5Type : public HDF5TypeBase<T> {
>
> public:
>
> HDF5Type() : HDF5TypeBase<T>() {};
>
> virtual ~HDF5Type() {};
>
> virtual hid_t Type() const { return H5T_NATIVE_HERR; };
>
> };
>
>
>
> // int, H5T_NATIVE_INT specialization
>
> template <> class HDF5Type<int> : public HDF5TypeBase<int> {
>
> public:
>
> HDF5Type() : HDF5TypeBase<int>() {};
>
> virtual ~HDF5Type() {};
>
> virtual hid_t Type() const { return H5T_NATIVE_INT; };
>
> };
>
>
>
> // float, H5T_NATIVE_FLOAT specialization
>
> template <> class HDF5Type<float> : public HDF5TypeBase<float> {
>
> public:
>
> HDF5Type() : HDF5TypeBase<float>() {};
>
> virtual ~HDF5Type() {};
>
> virtual hid_t Type() const { return H5T_NATIVE_FLOAT; };
>
> };
>
>
>
> // double, H5T_NATIVE_DOUBLE specialization
>
> template <> class HDF5Type<double> : public HDF5TypeBase<double> {
>
> public:
>
> HDF5Type() : HDF5TypeBase<double>() {};
>
> virtual ~HDF5Type() {};
>
> virtual hid_t Type() const { return H5T_NATIVE_DOUBLE; };
>
> };
>
>
>
> This permits in the HDF5Type<T>().Type(), *bold red*, in the snipit
> above, to actually work
>
>
>
> --
>
> Mark C. Miller, LLNL
>
>
>
> "In the end, we will remember not the words of
>
> our enemies but the silence of our friends" - MLK
>
> _______________________________________________
> Hdf-forum is for HDF software users discussion.
> [email protected]
> http://lists.hdfgroup.org/mailman/listinfo/hdf-forum_lists.hdfgroup.org
> Twitter: https://twitter.com/hdf5
>
--
Kevin B. McCarty
<[email protected]>
_______________________________________________
Hdf-forum is for HDF software users discussion.
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