/************************************************************

  This example shows how to read and write float datatypes
  to a dataset.  The program first writes floats to a
  dataset with a dataspace of DIM0xDIM1, then closes the
  file.  Next, it reopens the file, reads back the data, and
  outputs it to the screen.

  This file is intended for use with HDF5 Library version 1.6

 ************************************************************/

#include "hdf5.h"
#include <stdio.h>
#include <stdlib.h>

#define FILE    "h5ex_t_float.h5"
#define DATASET "DS1"
#define DIM0    4
#define DIM1    7

int
main(void)
{
    hid_t   file, space, dset; /* Handles */
    herr_t  status;
    hsize_t dims[2] = {DIM0, DIM1};
    double  wdata[DIM0][DIM1], /* Write buffer */
        **rdata;               /* Read buffer */
    int ndims, i, j;

    /*
     * Initialize data.
     */
    for (i = 0; i < DIM0; i++)
        for (j = 0; j < DIM1; j++)
            wdata[i][j] = (double)i / (j + 0.5) + j;

    /*
     * Create a new file using the default properties.
     */
    file = H5Fcreate(FILE, H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT);

    /*
     * Create dataspace.  Setting maximum size to NULL sets the maximum
     * size to be the current size.
     */
    space = H5Screate_simple(2, dims, NULL);

    /*
     * Create the dataset and write the floating point data to it.  In
     * this example we will save the data as 64 bit little endian IEEE
     * floating point numbers, regardless of the native type.  The HDF5
     * library automatically converts between different floating point
     * types.
     */
    dset   = H5Dcreate(file, DATASET, H5T_IEEE_F64LE, space, H5P_DEFAULT);
    status = H5Dwrite(dset, H5T_NATIVE_DOUBLE, H5S_ALL, H5S_ALL, H5P_DEFAULT, wdata[0]);

    /*
     * Close and release resources.
     */
    status = H5Dclose(dset);
    status = H5Sclose(space);
    status = H5Fclose(file);

    /*
     * Now we begin the read section of this example.  Here we assume
     * the dataset has the same name and rank, but can have any size.
     * Therefore we must allocate a new array to read in data using
     * malloc().
     */

    /*
     * Open file and dataset.
     */
    file = H5Fopen(FILE, H5F_ACC_RDONLY, H5P_DEFAULT);
    dset = H5Dopen(file, DATASET);

    /*
     * Get dataspace and allocate memory for read buffer.  This is a
     * two dimensional dataset so the dynamic allocation must be done
     * in steps.
     */
    space = H5Dget_space(dset);
    ndims = H5Sget_simple_extent_dims(space, dims, NULL);

    /*
     * Allocate array of pointers to rows.
     */
    rdata = (double **)malloc(dims[0] * sizeof(double *));

    /*
     * Allocate space for floating point data.
     */
    rdata[0] = (double *)malloc(dims[0] * dims[1] * sizeof(double));

    /*
     * Set the rest of the pointers to rows to the correct addresses.
     */
    for (i = 1; i < dims[0]; i++)
        rdata[i] = rdata[0] + i * dims[1];

    /*
     * Read the data.
     */
    status = H5Dread(dset, H5T_NATIVE_DOUBLE, H5S_ALL, H5S_ALL, H5P_DEFAULT, rdata[0]);

    /*
     * Output the data to the screen.
     */
    printf("%s:\n", DATASET);
    for (i = 0; i < dims[0]; i++) {
        printf(" [");
        for (j = 0; j < dims[1]; j++)
            printf(" %6.4f", rdata[i][j]);
        printf("]\n");
    }

    /*
     * Close and release resources.
     */
    free(rdata[0]);
    free(rdata);
    status = H5Dclose(dset);
    status = H5Sclose(space);
    status = H5Fclose(file);

    return 0;
}
