hdf5/c++/examples/writedata.cpp

/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * 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 the select_hyperslab and select_elements
 *  functions are used to write selected data from memory to the file.
 *  Program takes 48 elements from the linear buffer and writes them into
 *  the matrix using 3x2 blocks, (4,3) stride and (2,4) count.
 *  Then four elements  of the matrix are overwritten with the new values and
 *  file is closed. Program reopens the file and reads and displays the result.
 */

#include <iostream>
using std::cout;
using std::endl;

#include <string>
#include "H5Cpp.h"
using namespace H5;

const H5std_string FILE_NAME("Select.h5");
const H5std_string DATASET_NAME("Matrix in file");
const int          MSPACE1_RANK = 1;  // Rank of the first dataset in memory
const int          MSPACE1_DIM  = 50; // Dataset size in memory
const int          MSPACE2_RANK = 1;  // Rank of the second dataset in memory
const int          MSPACE2_DIM  = 4;  // Dataset size in memory
const int          FSPACE_RANK  = 2;  // Dataset rank as it is stored in the file
const int          FSPACE_DIM1  = 8;  // Dimension sizes of the dataset as it is
const int          FSPACE_DIM2  = 12; //      stored in the file
const int          MSPACE_RANK  = 2;  // Rank of the first dataset in memory
const int          MSPACE_DIM1  = 8;  // We will read dataset back from the file
const int          MSPACE_DIM2  = 9;  //      to the dataset in memory with these
                                      //      dataspace parameters
const int NPOINTS = 4;                // Number of points that will be selected
                                      //      and overwritten

int
main(void)
{
    int i, j; // loop indices */

    /*
     * Try block to detect exceptions raised by any of the calls inside it
     */
    try {
        /*
         * Turn off the auto-printing when failure occurs so that we can
         * handle the errors appropriately
         */
        Exception::dontPrint();

        /*
         * Create a file.
         */
        H5File *file = new H5File(FILE_NAME, H5F_ACC_TRUNC);

        /*
         * Create property list for a dataset and set up fill values.
         */
        int               fillvalue = 0; /* Fill value for the dataset */
        DSetCreatPropList plist;
        plist.setFillValue(PredType::NATIVE_INT, &fillvalue);

        /*
         * Create dataspace for the dataset in the file.
         */
        hsize_t   fdim[] = {FSPACE_DIM1, FSPACE_DIM2}; // dim sizes of ds (on disk)
        DataSpace fspace(FSPACE_RANK, fdim);

        /*
         * Create dataset and write it into the file.
         */
        DataSet *dataset =
            new DataSet(file->createDataSet(DATASET_NAME, PredType::NATIVE_INT, fspace, plist));

        /*
         * Select hyperslab for the dataset in the file, using 3x2 blocks,
         * (4,3) stride and (2,4) count starting at the position (0,1).
         */
        hsize_t start[2];  // Start of hyperslab
        hsize_t stride[2]; // Stride of hyperslab
        hsize_t count[2];  // Block count
        hsize_t block[2];  // Block sizes
        start[0]  = 0;
        start[1]  = 1;
        stride[0] = 4;
        stride[1] = 3;
        count[0]  = 2;
        count[1]  = 4;
        block[0]  = 3;
        block[1]  = 2;
        fspace.selectHyperslab(H5S_SELECT_SET, count, start, stride, block);

        /*
         * Create dataspace for the first dataset.
         */
        hsize_t dim1[] = {MSPACE1_DIM}; /* Dimension size of the first dataset
                                          (in memory) */
        DataSpace mspace1(MSPACE1_RANK, dim1);

        /*
         * Select hyperslab.
         * We will use 48 elements of the vector buffer starting at the
         * second element.  Selected elements are 1 2 3 . . . 48
         */
        start[0]  = 1;
        stride[0] = 1;
        count[0]  = 48;
        block[0]  = 1;
        mspace1.selectHyperslab(H5S_SELECT_SET, count, start, stride, block);

        /*
         * Write selection from the vector buffer to the dataset in the file.
         *
         * File dataset should look like this:
         *                    0  1  2  0  3  4  0  5  6  0  7  8
         *                    0  9 10  0 11 12  0 13 14  0 15 16
         *                    0 17 18  0 19 20  0 21 22  0 23 24
         *                    0  0  0  0  0  0  0  0  0  0  0  0
         *                    0 25 26  0 27 28  0 29 30  0 31 32
         *                    0 33 34  0 35 36  0 37 38  0 39 40
         *                    0 41 42  0 43 44  0 45 46  0 47 48
         *                    0  0  0  0  0  0  0  0  0  0  0  0
         */
        int vector[MSPACE1_DIM]; // vector buffer for dset

        /*
         * Buffer initialization.
         */
        vector[0] = vector[MSPACE1_DIM - 1] = -1;
        for (i = 1; i < MSPACE1_DIM - 1; i++)
            vector[i] = i;

        dataset->write(vector, PredType::NATIVE_INT, mspace1, fspace);

        /*
         * Reset the selection for the file dataspace fid.
         */
        fspace.selectNone();

        /*
         * Create dataspace for the second dataset.
         */
        hsize_t dim2[] = {MSPACE2_DIM}; /* Dimension size of the second dataset
                                          (in memory */
        DataSpace mspace2(MSPACE2_RANK, dim2);

        /*
         * Select sequence of NPOINTS points in the file dataspace.
         */
        hsize_t coord[NPOINTS][FSPACE_RANK]; /* Array to store selected points
                                                from the file dataspace */
        coord[0][0] = 0;
        coord[0][1] = 0;
        coord[1][0] = 3;
        coord[1][1] = 3;
        coord[2][0] = 3;
        coord[2][1] = 5;
        coord[3][0] = 5;
        coord[3][1] = 6;

        fspace.selectElements(H5S_SELECT_SET, NPOINTS, (const hsize_t *)coord);

        /*
         * Write new selection of points to the dataset.
         */
        int values[] = {53, 59, 61, 67}; /* New values to be written */
        dataset->write(values, PredType::NATIVE_INT, mspace2, fspace);

        /*
         * File dataset should look like this:
         *                   53  1  2  0  3  4  0  5  6  0  7  8
         *                    0  9 10  0 11 12  0 13 14  0 15 16
         *                    0 17 18  0 19 20  0 21 22  0 23 24
         *                    0  0  0 59  0 61  0  0  0  0  0  0
         *                    0 25 26  0 27 28  0 29 30  0 31 32
         *                    0 33 34  0 35 36 67 37 38  0 39 40
         *                    0 41 42  0 43 44  0 45 46  0 47 48
         *                    0  0  0  0  0  0  0  0  0  0  0  0
         *
         */

        /*
         * Close the dataset and the file.
         */
        delete dataset;
        delete file;

        /*
         * Open the file.
         */
        file = new H5File(FILE_NAME, H5F_ACC_RDONLY);

        /*
         * Open the dataset.
         */
        dataset = new DataSet(file->openDataSet(DATASET_NAME));

        /*
         * Get dataspace of the dataset.
         */
        fspace = dataset->getSpace();

        /*
         * Select first hyperslab for the dataset in the file. The following
         * elements are selected:
         *                     10  0 11 12
         *                     18  0 19 20
         *                      0 59  0 61
         *
         */
        start[0]  = 1;
        start[1]  = 2;
        block[0]  = 1;
        block[1]  = 1;
        stride[0] = 1;
        stride[1] = 1;
        count[0]  = 3;
        count[1]  = 4;
        fspace.selectHyperslab(H5S_SELECT_SET, count, start, stride, block);

        /*
         * Add second selected hyperslab to the selection.
         * The following elements are selected:
         *                    19 20  0 21 22
         *                     0 61  0  0  0
         *                    27 28  0 29 30
         *                    35 36 67 37 38
         *                    43 44  0 45 46
         *                     0  0  0  0  0
         * Note that two hyperslabs overlap. Common elements are:
         *                                              19 20
         *                                               0 61
         */
        start[0]  = 2;
        start[1]  = 4;
        block[0]  = 1;
        block[1]  = 1;
        stride[0] = 1;
        stride[1] = 1;
        count[0]  = 6;
        count[1]  = 5;
        fspace.selectHyperslab(H5S_SELECT_OR, count, start, stride, block);

        /*
         * Create memory dataspace.
         */
        hsize_t mdim[] = {MSPACE_DIM1, MSPACE_DIM2}; /* Dimension sizes of the
                                                   dataset in memory when we
                                                   read selection from the
                                                   dataset on the disk */
        DataSpace mspace(MSPACE_RANK, mdim);

        /*
         * Select two hyperslabs in memory. Hyperslabs has the same
         * size and shape as the selected hyperslabs for the file dataspace.
         */
        start[0]  = 0;
        start[1]  = 0;
        block[0]  = 1;
        block[1]  = 1;
        stride[0] = 1;
        stride[1] = 1;
        count[0]  = 3;
        count[1]  = 4;
        mspace.selectHyperslab(H5S_SELECT_SET, count, start, stride, block);
        start[0]  = 1;
        start[1]  = 2;
        block[0]  = 1;
        block[1]  = 1;
        stride[0] = 1;
        stride[1] = 1;
        count[0]  = 6;
        count[1]  = 5;
        mspace.selectHyperslab(H5S_SELECT_OR, count, start, stride, block);

        /*
         * Initialize data buffer.
         */
        int matrix_out[MSPACE_DIM1][MSPACE_DIM2];
        for (i = 0; i < MSPACE_DIM1; i++)
            for (j = 0; j < MSPACE_DIM2; j++)
                matrix_out[i][j] = 0;

        /*
         * Read data back to the buffer matrix.
         */
        dataset->read(matrix_out, PredType::NATIVE_INT, mspace, fspace);

        /*
         * Display the result.  Memory dataset is:
         *
         *                    10  0 11 12  0  0  0  0  0
         *                    18  0 19 20  0 21 22  0  0
         *                     0 59  0 61  0  0  0  0  0
         *                     0  0 27 28  0 29 30  0  0
         *                     0  0 35 36 67 37 38  0  0
         *                     0  0 43 44  0 45 46  0  0
         *                     0  0  0  0  0  0  0  0  0
         *                     0  0  0  0  0  0  0  0  0
         */
        for (i = 0; i < MSPACE_DIM1; i++) {
            for (j = 0; j < MSPACE_DIM2; j++)
                cout << matrix_out[i][j] << "  ";
            cout << endl;
        }

        /*
         * Close the dataset and the file.
         */
        delete dataset;
        delete file;
    } // end of try block

    // catch failure caused by the H5File operations
    catch (FileIException error) {
        error.printErrorStack();
        return -1;
    }

    // catch failure caused by the DataSet operations
    catch (DataSetIException error) {
        error.printErrorStack();
        return -1;
    }

    // catch failure caused by the DataSpace operations
    catch (DataSpaceIException error) {
        error.printErrorStack();
        return -1;
    }

    return 0;
}