/*
 *   This example copies subregions of the satellite data 'SatelliteZenithAngle'
 *   'SatelliteAzimuthAngle' and 'SatelliteRange' under '/All_Data/VIIRS-MOD-GTM-EDR-GEO_All'
 *    to one dataset,'Satellite', located at '/Data_Products/Subset' of the NPP
 *   file. 
 *   Main illustrative functions: H5LRcreate_region_references and H5LRmake_dataset
*/

#include <stdlib.h>
#include "hdf5.h"
#include "hdf5_hl.h"
#include "h5hl_region.h"

#define filename "GMGTO_npp_d20030125_t0657104_e0659047_b00014_c20090811150425926728_unkn_SCI.h5"

int main(void)
{
    hid_t file_id;  /* file identifier */
    hsize_t block_coord[12] = {3, 51, 7, 53, 3, 51, 7, 53, 3, 51, 7, 53}; /* hyperslab coordinates, (3,51)-(7,53), for
									     'SatelliteZenithAngle', 'SatelliteAzimuthAngle', 'SatelliteRange' */
    hdset_reg_ref_t ref_subset[3]; /* region references to hyperslabs of 'SatelliteZenithAngle', 'SatelliteAzimuthAngle', 'SatelliteRange' */
    const char *path[3];      /* full paths to the satellite target datasets for the region references*/
    hid_t file_id_array[3]; /* identifiers describing which HDF5 file the corresponding region reference belongs to*/
    herr_t status;
    int i;

    path[0]= "/All_Data/VIIRS-MOD-GTM-EDR-GEO_All/SatelliteZenithAngle";
    path[1]= "/All_Data/VIIRS-MOD-GTM-EDR-GEO_All/SatelliteAzimuthAngle";
    path[2]= "/All_Data/VIIRS-MOD-GTM-EDR-GEO_All/SatelliteRange";

    /*
     * Open the NPP file.
     */
    file_id = H5Fopen(filename, H5F_ACC_RDWR, H5P_DEFAULT);

    /*
     * We are creating the data set in the same file, so fill the file_id path with the same file id.
     */
    for (i = 0; i < 3; i++) 
      file_id_array[i] = file_id;
    
    /*
     * Create three region references pointing to hyperslabs with block coordinates (3,51)-(7,53) in
     * 'SatelliteZenithAngle', 'SatelliteAzimuthAngle' and 'SatelliteRange' datasets. 
     */
    status = H5LRcreate_region_references(file_id, 3, path, block_coord, ref_subset);

    /* 
     * Combine the three datasets into one dataset, 'Satellite', under '/Data_Products/Subset', 
     * resulting in a final dataset of size (0,0)-(14,2). Notice the group 'Subset' did not exist
     * so the function automatically created the necessary intermediate group.
     */

    status = H5LRmake_dataset(file_id, "/Data_Products/Subset/Satellite", H5T_NATIVE_FLOAT, 3, file_id_array, ( const hdset_reg_ref_t *)ref_subset);

    status = H5Fclose(file_id);

}