!
!   This example copies a hyperslab region of 'SatelliteRange' under
!   '/All_Data/VIIRS-MOD-GTM-EDR-GEO_All/' to another hyperslab region 
!   '/SatelliteRange_Subset' under '/All_Data'. It then reads back
!   the newly created hyperslab region.
!    Main illustrative functions: H5LTread_region_f, H5LTcopy_region_f
!

PROGRAM main
  
  USE ISO_C_BINDING
  USE HDF5 ! module of HDF5 library
  USE H5LT ! module of H5LT
  USE H5HL_REGION
  
  IMPLICIT NONE
  
  CHARACTER(LEN=78), PARAMETER :: filename = &
       "GMGTO_npp_d20030125_t0657104_e0659047_b00014_c20090811150425926728_unkn_SCI.h5"
  
  CHARACTER(LEN=78), PARAMETER :: PATH_DEST = &
       "/Data_Products/SatelliteRange_Subset" ! Full path of the source dataset
  
  CHARACTER(LEN=78), PARAMETER :: PATH_SRC = &
       "/All_Data/VIIRS-MOD-GTM-EDR-GEO_All/SatelliteRange" ! Full path to the destination dataset
  
  INTEGER, PARAMETER :: NRANK = 2 ! rank of source and destination dataset
  
  INTEGER(hid_t) :: file_id   ! file identifier 
  INTEGER(hid_t) :: dset_id   ! dataset identifier 
  INTEGER(hid_t) :: space_id  ! dataspace identifier 
  INTEGER(hsize_t), DIMENSION(1:4) :: block_coord_src = (/52,4,54,8/) ! source's block coordinates (52,4)-(54,8) 
  INTEGER(hsize_t), DIMENSION(1:4) :: block_coord_dest= (/2, 2, 4, 6/)   ! destination's BLOCK coordinates (2,2)-(4,6) 
  INTEGER(hsize_t), DIMENSION(1:NRANK) :: dims = (/5,7/) ! receiving dataset dimensions 
  REAL, DIMENSION(1:3,1:5), TARGET :: rdata                      ! buffer to read destination data into 
  INTEGER :: i, j
  INTEGER :: status
  TYPE(C_PTR) :: f_ptr
  
  !
  ! Initialize FORTRAN interface.
  !
  CALL H5open_f(status)
  !
  ! Open the NPP file.
  !
  CALL H5Fopen_f(filename, H5F_ACC_RDWR_F, file_id, status)
  ! 
  ! First create the destination dataset "SatelliteRange_Subset" since it does not exist.
  !
  ! NOTE: If the destination dataset does not already exist then H5LTcopy_region
  !       will automatically create a destination dataset that is the same size 
  !       and rank of the source data and will, additionally, fill the destination 
  !       block starting at (1,1) thus ignoring the destination's block coordinates.
  !
  CALL H5Screate_simple_f(NRANK, dims, space_id, status)
  CALL H5Dcreate_f(file_id, PATH_DEST, H5T_NATIVE_REAL, space_id, dset_id, status)
  
  CALL H5Sclose_f(space_id, status)
  CALL H5Fclose_f(file_id, status)
  !
  ! Copy a block of the "/All_Data/VIIRS-MOD-GTM-EDR-GEO_All/SatelliteRange"
  ! data with block corner coordinates of (52,4)-(54,8) to
  ! a subset of the "/Data_Products/SatelliteRange_Subset" with hyperslab
  ! coordinates (2,2)-(4,6).
  ! 
  !
  CALL H5LTcopy_region_f(filename, PATH_SRC, block_coord_src, filename, PATH_DEST, &
       block_coord_dest, status)
  ! 
  !
  ! Reads a subset region of "/Data_Products/SatelliteRange_Subset"
  ! specified by coordinates (2,2)-(4,6).
  !
  !

  f_ptr = C_LOC(rdata(1,1))
  CALL H5LTread_region_f(filename, PATH_DEST, block_coord_dest, H5T_NATIVE_REAL, &
       f_ptr, status)
  
  WRITE(*,'(/,"Subset of /Data_Products/SatelliteRange_Subset with coordinates (",i1,",",i1,")-(",i1,",",i1,"):")') block_coord_dest(1:4)
  
  DO i = 1, 3
     WRITE(*,'(A)', ADVANCE="NO") "["
     DO j = 1, 5
        WRITE(*,'(x,f12.4)', ADVANCE="NO") rdata(i,j)
     ENDDO
     WRITE(*,'(A)') " ]"
  ENDDO
  WRITE(*,'(/)')
  
END PROGRAM main