hdf5/examples/h5_extend_write.c

/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * Copyright by The HDF Group.                                               *
 * 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 example shows how to work with extendible dataset.
 *   In the current version of the library dataset MUST be
 *   chunked.
 *
 */

#include "hdf5.h"

#define H5FILE_NAME "SDSextendible.h5"
#define DATASETNAME "ExtendibleArray"
#define RANK        2
#define NX          10
#define NY          5

int
main(void)
{
    hid_t   file; /* handles */
    hid_t   dataspace, dataset;
    hid_t   filespace;
    hid_t   cparms;
    hsize_t dims[2] = {3, 3};  /*
                                * dataset dimensions
                                * at the creation time
                                */
    hsize_t dims1[2] = {3, 3}; /* data1 dimensions */
    hsize_t dims2[2] = {7, 1}; /* data2 dimensions */
    hsize_t dims3[2] = {2, 2}; /* data3 dimensions */

    hsize_t maxdims[2]    = {H5S_UNLIMITED, H5S_UNLIMITED};
    hsize_t chunk_dims[2] = {2, 5};
    hsize_t size[2];
    hsize_t offset[2];

    herr_t status;

    int data1[3][3] = {{1, 1, 1}, /* data to write */
                       {1, 1, 1},
                       {1, 1, 1}};

    int data2[7] = {2, 2, 2, 2, 2, 2, 2};

    int data3[2][2] = {{3, 3}, {3, 3}};
    int fillvalue   = 0;

    /*
     * Create the data space with unlimited dimensions.
     */
    dataspace = H5Screate_simple(RANK, dims, maxdims);

    /*
     * Create a new file. If file exists its contents will be overwritten.
     */
    file = H5Fcreate(H5FILE_NAME, H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT);

    /*
     * Modify dataset creation properties, i.e. enable chunking.
     */
    cparms = H5Pcreate(H5P_DATASET_CREATE);
    status = H5Pset_chunk(cparms, RANK, chunk_dims);
    status = H5Pset_fill_value(cparms, H5T_NATIVE_INT, &fillvalue);

    /*
     * Create a new dataset within the file using cparms
     * creation properties.
     */
    dataset = H5Dcreate2(file, DATASETNAME, H5T_NATIVE_INT, dataspace, H5P_DEFAULT, cparms, H5P_DEFAULT);

    /*
     * Extend the dataset. This call assures that dataset is at least 3 x 3.
     */
    size[0] = 3;
    size[1] = 3;
    status  = H5Dset_extent(dataset, size);

    /*
     * Select a hyperslab.
     */
    filespace = H5Dget_space(dataset);
    offset[0] = 0;
    offset[1] = 0;
    status    = H5Sselect_hyperslab(filespace, H5S_SELECT_SET, offset, NULL, dims1, NULL);

    /*
     * Write the data to the hyperslab.
     */
    status = H5Dwrite(dataset, H5T_NATIVE_INT, dataspace, filespace, H5P_DEFAULT, data1);

    /*
     * Extend the dataset. Dataset becomes 10 x 3.
     */
    dims[0] = dims1[0] + dims2[0];
    size[0] = dims[0];
    size[1] = dims[1];
    status  = H5Dset_extent(dataset, size);

    /*
     * Select a hyperslab.
     */
    filespace = H5Dget_space(dataset);
    offset[0] = 3;
    offset[1] = 0;
    status    = H5Sselect_hyperslab(filespace, H5S_SELECT_SET, offset, NULL, dims2, NULL);

    /*
     * Define memory space
     */
    dataspace = H5Screate_simple(RANK, dims2, NULL);

    /*
     * Write the data to the hyperslab.
     */
    status = H5Dwrite(dataset, H5T_NATIVE_INT, dataspace, filespace, H5P_DEFAULT, data2);

    /*
     * Extend the dataset. Dataset becomes 10 x 5.
     */
    dims[1] = dims1[1] + dims3[1];
    size[0] = dims[0];
    size[1] = dims[1];
    status  = H5Dset_extent(dataset, size);

    /*
     * Select a hyperslab
     */
    filespace = H5Dget_space(dataset);
    offset[0] = 0;
    offset[1] = 3;
    status    = H5Sselect_hyperslab(filespace, H5S_SELECT_SET, offset, NULL, dims3, NULL);

    /*
     * Define memory space.
     */
    dataspace = H5Screate_simple(RANK, dims3, NULL);

    /*
     * Write the data to the hyperslab.
     */
    status = H5Dwrite(dataset, H5T_NATIVE_INT, dataspace, filespace, H5P_DEFAULT, data3);

    /*
     * Resulting dataset
     *
     *   1 1 1 3 3
     *   1 1 1 3 3
     *   1 1 1 0 0
     *	 2 0 0 0 0
     *	 2 0 0 0 0
     *	 2 0 0 0 0
     *	 2 0 0 0 0
     *	 2 0 0 0 0
     *	 2 0 0 0 0
     *	 2 0 0 0 0
     */
    /*
     * Close/release resources.
     */
    H5Dclose(dataset);
    H5Sclose(dataspace);
    H5Sclose(filespace);
    H5Pclose(cparms);
    H5Fclose(file);

    return 0;
}