h5ex_t_enumatt.c

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

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

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

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

#define FILE          "h5ex_t_enumatt.h5"
#define DATASET       "DS1"
#define ATTRIBUTE     "A1"
#define DIM0          4
#define DIM1          7
#define F_BASET       H5T_STD_I16BE  /* File base type */
#define M_BASET       H5T_NATIVE_INT /* Memory base type */
#define NAME_BUF_SIZE 16

typedef enum { SOLID, LIQUID, GAS, PLASMA } phase_t; /* Enumerated type */

int
main(void)
{
    hid_t file, filetype, memtype, space, dset, attr;
    /* Handles */
    herr_t  status;
    hsize_t dims[2] = {DIM0, DIM1};
    phase_t wdata[DIM0][DIM1], /* Write buffer */
        **rdata,               /* Read buffer */
        val;
    char   *names[4] = {"SOLID", "LIQUID", "GAS", "PLASMA"}, name[NAME_BUF_SIZE];
    int     ndims;
    hsize_t i, j;

    /*
     * Initialize data.
     */
    for (i = 0; i < DIM0; i++)
        for (j = 0; j < DIM1; j++)
            wdata[i][j] = (phase_t)((i + 1) * j - j) % (int)(PLASMA + 1);

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

    /*
     * Create the enumerated datatypes for file and memory.  This
     * process is simplified if native types are used for the file,
     * as only one type must be defined.
     */
    filetype = H5Tenum_create(F_BASET);
    memtype  = H5Tenum_create(M_BASET);

    for (i = (int)SOLID; i <= (int)PLASMA; i++) {
        /*
         * Insert enumerated value for memtype.
         */
        val    = (phase_t)i;
        status = H5Tenum_insert(memtype, names[i], &val);
        /*
         * Insert enumerated value for filetype.  We must first convert
         * the numerical value val to the base type of the destination.
         */
        status = H5Tconvert(M_BASET, F_BASET, 1, &val, NULL, H5P_DEFAULT);
        status = H5Tenum_insert(filetype, names[i], &val);
    }

    /*
     * Create dataset with a null dataspace.
     */
    space  = H5Screate(H5S_NULL);
    dset   = H5Dcreate(file, DATASET, H5T_STD_I32LE, space, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT);
    status = H5Sclose(space);

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

    /*
     * Create the attribute and write the enumerated data to it.
     */
    attr   = H5Acreate(dset, ATTRIBUTE, filetype, space, H5P_DEFAULT, H5P_DEFAULT);
    status = H5Awrite(attr, memtype, wdata[0]);

    /*
     * Close and release resources.
     */
    status = H5Aclose(attr);
    status = H5Dclose(dset);
    status = H5Sclose(space);
    status = H5Tclose(filetype);
    status = H5Fclose(file);

    /*
     * Now we begin the read section of this example.  Here we assume
     * the attribute has the same name and rank, but can have any size.
     * Therefore we must allocate a new array to read in data using
     * malloc().  For simplicity, we do not rebuild memtype.
     */

    /*
     * Open file, dataset, and attribute.
     */
    file = H5Fopen(FILE, H5F_ACC_RDONLY, H5P_DEFAULT);
    dset = H5Dopen(file, DATASET, H5P_DEFAULT);
    attr = H5Aopen(dset, ATTRIBUTE, H5P_DEFAULT);

    /*
     * Get dataspace and allocate memory for read buffer.  This is a
     * two dimensional attribute so the dynamic allocation must be done
     * in steps.
     */
    space = H5Aget_space(attr);
    ndims = H5Sget_simple_extent_dims(space, dims, NULL);

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

    /*
     * Allocate space for enumerated data.
     */
    rdata[0] = (phase_t *)malloc(dims[0] * dims[1] * sizeof(phase_t));

    /*
     * 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 = H5Aread(attr, memtype, rdata[0]);

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

            /*
             * Get the name of the enumeration member.
             */
            status = H5Tenum_nameof(memtype, &rdata[i][j], name, NAME_BUF_SIZE);
            printf(" %-6s", name);
        }
        printf("]\n");
    }

    /*
     * Close and release resources.
     */
    free(rdata[0]);
    free(rdata);
    status = H5Aclose(attr);
    status = H5Dclose(dset);
    status = H5Sclose(space);
    status = H5Tclose(memtype);
    status = H5Fclose(file);

    return 0;
}