/*
 * compound.c
 *
 * A small test file to demonstrate the data transfer function
 * with scientific notation.
 * 
 */

#include <string.h>
#include <stdio.h>
#include <stdlib.h>

#include "hdf5.h"

#define LENGTH 101

typedef struct {
  char name[64];
  char unit[64];
} att_t;

int main(int argc, char** argv)
{
    hsize_t dims[]  = { LENGTH }; // Approximately 9.2 Gbytes of data.

    /* Compound datatype */
    att_t *atts = malloc(sizeof(att_t));
    strcpy(atts[0].name, "Name");
    strcpy(atts[0].unit, "Unit");

    /* String type */
    hid_t str_dtyp_id = H5Tcopy(H5T_C_S1);
    H5Tset_size(str_dtyp_id, 64);

    /* Attribute type */
    hid_t att_dtyp_id = H5Tcreate(H5T_COMPOUND, sizeof(att_t));
    H5Tinsert(att_dtyp_id, "NAME", HOFFSET(att_t, name), str_dtyp_id);
    H5Tinsert(att_dtyp_id, "UNIT", HOFFSET(att_t, unit), str_dtyp_id);

    /* Create file. */
    hid_t file_id = H5Fcreate("compound.h5", H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT);

    /* Create file dataspace. */
    hid_t fspace_id = H5Screate_simple(1, dims, NULL);

    /* Create dataset. */
    hid_t dset_id = H5Dcreate2(file_id, "test_dset", H5T_NATIVE_FLOAT, fspace_id, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT);

    /* Write the attribute (compound) to the dataset */
    hsize_t dima[] = { 1 };
    hid_t att_dspc_id = H5Screate_simple(1, dima, NULL);
    hid_t att_attr_id = H5Acreate2(dset_id, "ATTRIBUTES", att_dtyp_id, att_dspc_id, H5P_DEFAULT, H5P_DEFAULT);
    int status = H5Awrite(att_attr_id, att_dtyp_id, atts);
    if (status < 0) {
      fprintf(stderr, "*** ERROR: H5Awrite");
    }

    /* Create dataset transfer property list */
    const char *expr = "2*x";
    hid_t dxpl_id = H5Pcreate(H5P_DATASET_XFER);
    status = H5Pset_data_transform(dxpl_id, expr);
    if (status < 0) {
      fprintf(stderr, "*** ERROR: H5Pset_data_transform (expression: %s)\n", expr);
    }

    float *data = malloc(LENGTH * sizeof(float));
    for (unsigned i = 0; i < LENGTH; i++) {
      data[i] = 10.f;
    }

    /* Write the data */
    status = H5Dwrite(dset_id, H5T_NATIVE_FLOAT, H5S_ALL, H5S_ALL, dxpl_id, data);
    if (status < 0) {
      fprintf(stderr, "*** ERROR: H5Dwrite\n");
    }
    free(data);

    /* Close all identifiers. */
    H5Pclose(dxpl_id);
    H5Aclose(att_attr_id);
    H5Sclose(att_dspc_id);
    H5Dclose(dset_id);
    H5Sclose(fspace_id);
    H5Fclose(file_id);
    H5Tclose(att_dtyp_id);
    H5Tclose(str_dtyp_id);

    return 0;
}