add %class method

Author: scivision

API.md

@@ -68,6 +68,15 @@ character(*), intent(in) :: dataset_name
 integer(HSIZE_T), intent(out), allocatable :: dims(:)
 ```
 
+Dataset "dname" data class (i.e. integer, float, string, ...)
+
+```fortran
+integer :: class
+!! H5T_INTEGER_F, H5T_FLOAT_F, H5T_STRING_F
+class = h%class(dname)
+character(*), intent(in) :: dname
+```
+
 Dataset "dname" datatype
 
 ```fortran

src/interface.f90

@@ -6,6 +6,7 @@ module h5fortran
   H5S_ALL_F, H5S_SELECT_SET_F, &
   H5D_CONTIGUOUS_F, H5D_CHUNKED_F, H5D_COMPACT_F, &
   H5T_NATIVE_DOUBLE, H5T_NATIVE_REAL, H5T_NATIVE_INTEGER, H5T_NATIVE_CHARACTER, H5T_STD_I64LE, &
+  H5T_INTEGER_F, H5T_FLOAT_F, H5T_STRING_F, &
   H5F_SCOPE_GLOBAL_F, &
   h5open_f, h5close_f, &
   h5dopen_f, h5dclose_f, h5dget_space_f, &
@@ -22,6 +23,7 @@ module h5fortran
 public :: check, hdf_shape_check, hdf_rank_check, hdf_get_slice, hdf_wrapup
 !! for submodules only
 public :: HSIZE_T, HID_T, H5T_NATIVE_DOUBLE, H5T_NATIVE_REAL, H5T_NATIVE_INTEGER, H5T_NATIVE_CHARACTER, H5T_STD_I64LE
+public :: H5T_INTEGER_F, H5T_FLOAT_F, H5T_STRING_F
 !! HDF5 types for end users
 
 !> main type
@@ -50,7 +52,7 @@ module h5fortran
   flush => hdf_flush, &
   ndims => hdf_get_ndims, &
   shape => hdf_get_shape, layout => hdf_get_layout, chunks => hdf_get_chunk, &
-  dtype => get_native_dtype, &
+  class => get_class, dtype => get_native_dtype, &
   exist => hdf_check_exist, exists => hdf_check_exist, &
   is_contig => hdf_is_contig, is_chunked => hdf_is_chunked, is_compact => hdf_is_compact, &
   softlink => create_softlink
@@ -304,6 +306,11 @@ end subroutine h5write_7d
 
 interface !< read.f90
 
+module integer function get_class(self, dname)
+class(hdf5_file), intent(in) :: self
+character(*), intent(in) :: dname
+end function get_class
+
 module integer(hid_t) function get_native_dtype(self, dname, ds_id)
 class(hdf5_file), intent(in) :: self
 character(*), intent(in) :: dname

src/read/read.f90

@@ -3,7 +3,7 @@
 use hdf5, only : h5dget_create_plist_f, &
   h5pget_layout_f, h5pget_chunk_f, &
   h5dget_type_f, h5tget_native_type_f, h5tget_class_f, H5Tget_order_f, h5tclose_f, h5tget_size_f, &
-  H5T_DIR_ASCEND_F, H5T_INTEGER_F, H5T_FLOAT_F, H5T_STRING_F
+  H5T_DIR_ASCEND_F
 
 use H5LT, only : h5ltpath_valid_f
 
@@ -12,54 +12,79 @@
 contains
 
 
-module procedure get_native_dtype
-!! get the dataset variable type:
-!! {H5T_NATIVE_REAL, H5T_NATIVE_DOUBLE, H5T_NATIVE_INTEGER, H5T_NATIVE_CHARACTER, H5T_STD_I64LE}
+module procedure get_class
+
+call get_dset_class(self, dname, get_class)
+
+end procedure get_class
+
+
+subroutine get_dset_class(self, dname, class, ds_id, size_bytes)
+!! get the dataset class (integer, float, string, ...)
+!! {H5T_INTEGER_F, H5T_FLOAT_F, H5T_STRING_F}
+class(hdf5_file), intent(in) :: self
+character(*), intent(in) :: dname
+integer, intent(out) :: class
+integer(hid_t), intent(in), optional :: ds_id
+integer(size_t), intent(out), optional :: size_bytes
 
-integer(hid_t) :: dtype_id, native_dtype_id, dset_id
-integer :: class
 integer :: ierr
-! integer :: order, machine_order
-integer(size_t) :: size_bytes
+integer(hid_t) :: dtype_id, native_dtype_id, dset_id
 
 if(present(ds_id)) then
   dset_id = ds_id
 else
   call h5dopen_f(self%lid, dname, dset_id, ierr)
-  if(ierr/=0) error stop 'h5fortran:get_native_dtype: ' // dname // ' from ' // self%filename
+  if(ierr/=0) error stop 'h5fortran:get_class: ' // dname // ' from ' // self%filename
 endif
 
 call h5dget_type_f(dset_id, dtype_id, ierr)
-if(ierr/=0) error stop 'h5fortran:get_native_dtype: dtype_id ' // dname // ' from ' // self%filename
+if(ierr/=0) error stop 'h5fortran:get_class: dtype_id ' // dname // ' from ' // self%filename
 
 call h5tget_native_type_f(dtype_id, H5T_DIR_ASCEND_F, native_dtype_id, ierr)
-if(ierr/=0) error stop 'h5fortran:get_native_dtype: native_dtype_id ' // dname // ' from ' // self%filename
-
-!> endianness and within type casting is handled by HDF5
-! call h5tget_order_f(native_dtype_id, order, ierr)
-! if(ierr/=0) error stop 'h5fortran:reader: get endianness ' // dname // ' from ' // self%filename
-! !> check dataset endianness matches machine (in future, could swap endianness if needed)
-! call h5tget_order_f(H5T_NATIVE_INTEGER, machine_order, ierr)
-! if(order /= machine_order) error stop 'h5fortran:read: endianness /= machine native: ' &
-! // dname // ' from ' // self%filename
+if(ierr/=0) error stop 'h5fortran:get_class: native_dtype_id ' // dname // ' from ' // self%filename
 
 !> compose datatype inferred
 call h5tget_class_f(native_dtype_id, class, ierr)
-if(ierr/=0) error stop 'h5fortran:get_native_dtype: class ' // dname // ' from ' // self%filename
+if(ierr/=0) error stop 'h5fortran:get_class: class ' // dname // ' from ' // self%filename
 
-call h5tget_size_f(native_dtype_id, size_bytes, ierr)
-if(ierr/=0) error stop 'h5fortran:get_native_dtype: byte size ' // dname // ' from ' // self%filename
+if(present(size_bytes)) then
+  call h5tget_size_f(native_dtype_id, size_bytes, ierr)
+  if(ierr/=0) error stop 'h5fortran:get_class: byte size ' // dname // ' from ' // self%filename
+endif
 
 !> close to avoid memory leaks
-call h5tclose_f(dtype_id, ierr)
-if(ierr/=0) error stop 'h5fortran:get_native_dtype: closing dtype ' // dname // ' from ' // self%filename
 call h5tclose_f(native_dtype_id, ierr)
-if(ierr/=0) error stop 'h5fortran:get_native_dtype: closing native dtype ' // dname // ' from ' // self%filename
+if(ierr/=0) error stop 'h5fortran:get_class: closing native dtype ' // dname // ' from ' // self%filename
+
+call h5tclose_f(dtype_id, ierr)
+if(ierr/=0) error stop 'h5fortran:get_class: closing dtype ' // dname // ' from ' // self%filename
+
 if(.not.present(ds_id)) then
   call h5dclose_f(dset_id, ierr)
-  if(ierr/=0) error stop 'h5fortran:get_native_dtype: close dataset ' // dname // ' from ' // self%filename
+  if(ierr/=0) error stop 'h5fortran:get_class: close dataset ' // dname // ' from ' // self%filename
 endif
 
+end subroutine get_dset_class
+
+
+module procedure get_native_dtype
+!! get the dataset variable type:
+!! {H5T_NATIVE_REAL, H5T_NATIVE_DOUBLE, H5T_NATIVE_INTEGER, H5T_NATIVE_CHARACTER, H5T_STD_I64LE}
+
+integer :: class
+! integer :: order, machine_order
+integer(size_t) :: size_bytes
+
+call get_dset_class(self, dname, class, ds_id, size_bytes)
+
+!> endianness and within type casting is handled by HDF5
+! call h5tget_order_f(native_dtype_id, order, ierr)
+! if(ierr/=0) error stop 'h5fortran:reader: get endianness ' // dname // ' from ' // self%filename
+! !> check dataset endianness matches machine (in future, could swap endianness if needed)
+! call h5tget_order_f(H5T_NATIVE_INTEGER, machine_order, ierr)
+! if(order /= machine_order) error stop 'h5fortran:read: endianness /= machine native: ' &
+! // dname // ' from ' // self%filename
 
 if(class == H5T_INTEGER_F) then
   if(size_bytes == 4) then

src/tests/test_cast.f90

@@ -2,6 +2,7 @@ program test_cast
 !! test HDF5 built-in casting
 
 use h5fortran, only : hdf5_file, &
+ H5T_INTEGER_F, H5T_FLOAT_F, H5T_STRING_F, &
  H5T_NATIVE_REAL, H5T_NATIVE_DOUBLE, H5T_NATIVE_INTEGER, H5T_NATIVE_CHARACTER, H5T_STD_I64LE
 use, intrinsic :: iso_fortran_env, only : real32, real64, int32, int64
 
@@ -29,6 +30,13 @@ program test_cast
 call h%write('/1d_int32', i1_32)
 call h%write('/char', "hello")
 
+!> %class method
+if (h%class("/scalar_int32") /= H5T_INTEGER_F) error stop "int32 not integer"
+if (h%class("/scalar_int64") /= H5T_INTEGER_F) error stop "int64 not integer"
+if (h%class("/scalar_real32") /= H5T_FLOAT_F) error stop "real32 not float"
+if (h%class("/scalar_real64") /= H5T_FLOAT_F) error stop "real64 not float"
+if (h%class("/char") /= H5T_STRING_F) error stop "char not string"
+
 !> %dtype method
 if (h%dtype('/scalar_int32') /= H5T_NATIVE_INTEGER) error stop "int32 type"
 if (h%dtype("/scalar_int64") /= H5T_STD_I64LE) error stop "int64 type"