/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * Copyright by The HDF Group.                                               *
 * Copyright by the Board of Trustees of the University of Illinois.         *
 * All rights reserved.                                                      *
 *                                                                           *
 * This file is part of HDF5.  The full HDF5 copyright notice, including     *
 * terms governing use, modification, and redistribution, is contained in    *
 * the COPYING file, which can be found at the root of the source code       *
 * distribution tree, or in https://www.hdfgroup.org/licenses.               *
 * If you do not have access to either file, you may request a copy from     *
 * help@hdfgroup.org.                                                        *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
/*
    This program shows how to create, store and dereference references
    to the dataset regions.

    It creates a file and writes a two dimensional integer dataset
    to it. Then it creates a dataset to store region references in. It
    stores references to a hyperslab and 3 points selected (for the
    integer dataset previously created).

    It then reopens the references dataset, reads and dereferences the
    region references, and then reads and displays the selected hyperslab
    and selected elements data from the integer dataset.
*/

#include "hdf5.h"

#define filename  "REF_REG.h5"
#define dsetnamev "MATRIX"
#define dsetnamer "REGION_REFERENCES"

int
main(void)
{
    hid_t           file_id;  /* file identifier */
    hid_t           space_id; /* dataspace identifiers */
    hid_t           spacer_id;
    hid_t           dsetv_id; /*dataset identifiers*/
    hid_t           dsetr_id;
    hsize_t         dims[2]  = {2, 9};
    hsize_t         dimsr[1] = {2};
    int             rank     = 2;
    int             rankr    = 1;
    herr_t          status;
    hdset_reg_ref_t ref[2];
    hdset_reg_ref_t ref_out[2];
    int             data[2][9]     = {{1, 1, 2, 3, 3, 4, 5, 5, 6}, {1, 2, 2, 3, 4, 4, 5, 6, 6}};
    int             data_out[2][9] = {{0, 0, 0, 0, 0, 0, 0, 0, 0}, {0, 0, 0, 0, 0, 0, 0, 0, 0}};
    hsize_t         start[2];
    hsize_t         count[2];
    hsize_t         coord[2][3] = {{0, 0, 1}, {6, 0, 8}};
    unsigned        num_points  = 3;
    int             i, j;
    size_t          name_size1, name_size2;
    char            buf1[10], buf2[10];

    /*
     * Create file with default file access and file creation properties.
     */
    file_id = H5Fcreate(filename, H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT);

    /*
     * Create dataspace for datasets.
     */
    space_id  = H5Screate_simple(rank, dims, NULL);
    spacer_id = H5Screate_simple(rankr, dimsr, NULL);

    /*
     * Create integer dataset.
     */
    dsetv_id =
        H5Dcreate2(file_id, dsetnamev, H5T_NATIVE_INT, space_id, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT);

    /*
     * Write data to the dataset.
     */
    status = H5Dwrite(dsetv_id, H5T_NATIVE_INT, H5S_ALL, H5S_ALL, H5P_DEFAULT, data);
    status = H5Dclose(dsetv_id);

    /*
     * Dataset with references.
     */
    dsetr_id =
        H5Dcreate2(file_id, dsetnamer, H5T_STD_REF_DSETREG, spacer_id, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT);

    /*
     * Create a reference to the hyperslab.
     */
    start[0] = 0;
    start[1] = 3;
    count[0] = 2;
    count[1] = 3;
    status   = H5Sselect_hyperslab(space_id, H5S_SELECT_SET, start, NULL, count, NULL);
    status   = H5Rcreate(&ref[0], file_id, dsetnamev, H5R_DATASET_REGION, space_id);

    /*
     * Create a reference to elements selection.
     */
    status = H5Sselect_none(space_id);
    status = H5Sselect_elements(space_id, H5S_SELECT_SET, num_points, (const hsize_t *)coord);
    status = H5Rcreate(&ref[1], file_id, dsetnamev, H5R_DATASET_REGION, space_id);

    /*
     * Write dataset with the references.
     */
    status = H5Dwrite(dsetr_id, H5T_STD_REF_DSETREG, H5S_ALL, H5S_ALL, H5P_DEFAULT, ref);

    /*
     * Close all objects.
     */
    status = H5Sclose(space_id);
    status = H5Sclose(spacer_id);
    status = H5Dclose(dsetr_id);
    status = H5Fclose(file_id);

    /*
     * Reopen the file to read selections back.
     */
    file_id = H5Fopen(filename, H5F_ACC_RDWR, H5P_DEFAULT);

    /*
     * Reopen the dataset with object references and read references
     * to the buffer.
     */
    dsetr_id = H5Dopen2(file_id, dsetnamer, H5P_DEFAULT);

    status = H5Dread(dsetr_id, H5T_STD_REF_DSETREG, H5S_ALL, H5S_ALL, H5P_DEFAULT, ref_out);

    /*
     * Dereference the first reference.
     */
    dsetv_id = H5Rdereference2(dsetr_id, H5P_DEFAULT, H5R_DATASET_REGION, &ref_out[0]);
    /*
     * Get name of the dataset the first region reference points to
     * using H5Rget_name
     */
    name_size1 = H5Rget_name(dsetr_id, H5R_DATASET_REGION, &ref_out[0], (char *)buf1, 10);
    printf(" Dataset's name (returned by H5Rget_name) the reference points to is %s, name length is %d\n",
           buf1, (int)name_size1);
    /*
     * Get name of the dataset the first region reference points to
     * using H5Iget_name
     */
    name_size2 = H5Iget_name(dsetv_id, (char *)buf2, 10);
    printf(" Dataset's name (returned by H5Iget_name) the reference points to is %s, name length is %d\n",
           buf2, (int)name_size2);

    space_id = H5Rget_region(dsetr_id, H5R_DATASET_REGION, &ref_out[0]);

    /*
     * Read and display hyperslab selection from the dataset.
     */

    status = H5Dread(dsetv_id, H5T_NATIVE_INT, H5S_ALL, space_id, H5P_DEFAULT, data_out);
    printf("Selected hyperslab: ");
    for (i = 0; i <= 1; i++) {
        printf("\n");
        for (j = 0; j <= 8; j++)
            printf("%d ", data_out[i][j]);
    }
    printf("\n");

    /*
     * Close dataspace and the dataset.
     */
    status = H5Sclose(space_id);
    status = H5Dclose(dsetv_id);

    /*
     * Initialize data_out array again to get point selection.
     */
    for (i = 0; i <= 1; i++)
        for (j = 0; j <= 8; j++)
            data_out[i][j] = 0;

    /*
     * Dereference the second reference.
     */
    dsetv_id = H5Rdereference2(dsetr_id, H5P_DEFAULT, H5R_DATASET_REGION, &ref_out[1]);
    space_id = H5Rget_region(dsetv_id, H5R_DATASET_REGION, &ref_out[1]);

    /*
     * Read selected data from the dataset.
     */

    status = H5Dread(dsetv_id, H5T_NATIVE_INT, H5S_ALL, space_id, H5P_DEFAULT, data_out);
    printf("Selected points: ");
    for (i = 0; i <= 1; i++) {
        printf("\n");
        for (j = 0; j <= 8; j++)
            printf("%d ", data_out[i][j]);
    }
    printf("\n");

    /*
     * Close dataspace and the dataset.
     */
    status = H5Sclose(space_id);
    status = H5Dclose(dsetv_id);
    status = H5Dclose(dsetr_id);
    status = H5Fclose(file_id);

    return 0;
}