/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * 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://support.hdfgroup.org/ftp/HDF5/releases.  *
 * If you do not have access to either file, you may request a copy from     *
 * help@hdfgroup.org.                                                        *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

/************************************************************
  This example shows how to read and write floating point
  datatypes to an attribute.  The program first writes
  floating point numbers 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.
 ************************************************************/

package examples.datatypes;

import java.text.DecimalFormat;

import hdf.hdf5lib.H5;
import hdf.hdf5lib.HDF5Constants;

public class H5Ex_T_FloatAttribute {
    private static String FILENAME = "H5Ex_T_FloatAttribute.h5";
    private static String DATASETNAME = "DS1";
    private static String ATTRIBUTENAME = "A1";
    private static final int DIM0 = 4;
    private static final int DIM1 = 7;
    private static final int RANK = 2;

    private static void CreateDataset() {
        long file_id = -1;
        long dataspace_id = -1;
        long dataset_id = -1;
        long attribute_id = -1;
        long[] dims = { DIM0, DIM1 };
        double[][] dset_data = new double[DIM0][DIM1];

        // Initialize data.
        for (int indx = 0; indx < DIM0; indx++)
            for (int jndx = 0; jndx < DIM1; jndx++) {
                dset_data[indx][jndx] = indx / (jndx + 0.5) + jndx;
            }

        // Create a new file using default properties.
        try {
            file_id = H5.H5Fcreate(FILENAME, HDF5Constants.H5F_ACC_TRUNC, HDF5Constants.H5P_DEFAULT,
                    HDF5Constants.H5P_DEFAULT);
        }
        catch (Exception e) {
            e.printStackTrace();
        }

        // Create dataset with a scalar dataspace.
        try {
            dataspace_id = H5.H5Screate(HDF5Constants.H5S_SCALAR);
            if (dataspace_id >= 0) {
                dataset_id = H5.H5Dcreate(file_id, DATASETNAME, HDF5Constants.H5T_STD_I32LE, dataspace_id,
                        HDF5Constants.H5P_DEFAULT, HDF5Constants.H5P_DEFAULT, HDF5Constants.H5P_DEFAULT);
                H5.H5Sclose(dataspace_id);
                dataspace_id = -1;
            }
        }
        catch (Exception e) {
            e.printStackTrace();
        }

        // Create dataspace. Setting maximum size to NULL sets the maximum
        // size to be the current size.
        try {
            dataspace_id = H5.H5Screate_simple(RANK, dims, null);
        }
        catch (Exception e) {
            e.printStackTrace();
        }

        // Create the attribute and write the array data to it.
        try {
            if ((dataset_id >= 0) && (dataspace_id >= 0))
                attribute_id = H5.H5Acreate(dataset_id, ATTRIBUTENAME, HDF5Constants.H5T_IEEE_F64LE, dataspace_id,
                        HDF5Constants.H5P_DEFAULT, HDF5Constants.H5P_DEFAULT);
        }
        catch (Exception e) {
            e.printStackTrace();
        }

        // Write the dataset.
        try {
            if (attribute_id >= 0)
                H5.H5Awrite(attribute_id, HDF5Constants.H5T_NATIVE_DOUBLE, dset_data);
        }
        catch (Exception e) {
            e.printStackTrace();
        }

        // End access to the dataset and release resources used by it.
        try {
            if (attribute_id >= 0)
                H5.H5Aclose(attribute_id);
        }
        catch (Exception e) {
            e.printStackTrace();
        }

        try {
            if (dataset_id >= 0)
                H5.H5Dclose(dataset_id);
        }
        catch (Exception e) {
            e.printStackTrace();
        }

        // Terminate access to the data space.
        try {
            if (dataspace_id >= 0)
                H5.H5Sclose(dataspace_id);
        }
        catch (Exception e) {
            e.printStackTrace();
        }

        // Close the file.
        try {
            if (file_id >= 0)
                H5.H5Fclose(file_id);
        }
        catch (Exception e) {
            e.printStackTrace();
        }

    }

    private static void ReadDataset() {
        long file_id = -1;
        long dataspace_id = -1;
        long dataset_id = -1;
        long attribute_id = -1;
        long[] dims = { DIM0, DIM1 };
        double[][] dset_data;

        // Open an existing file.
        try {
            file_id = H5.H5Fopen(FILENAME, HDF5Constants.H5F_ACC_RDONLY, HDF5Constants.H5P_DEFAULT);
        }
        catch (Exception e) {
            e.printStackTrace();
        }

        // Open an existing dataset.
        try {
            if (file_id >= 0)
                dataset_id = H5.H5Dopen(file_id, DATASETNAME, HDF5Constants.H5P_DEFAULT);
        }
        catch (Exception e) {
            e.printStackTrace();
        }

        try {
            if (dataset_id >= 0)
                attribute_id = H5.H5Aopen_by_name(dataset_id, ".", ATTRIBUTENAME, HDF5Constants.H5P_DEFAULT,
                        HDF5Constants.H5P_DEFAULT);
        }
        catch (Exception e) {
            e.printStackTrace();
        }

        // Get dataspace and allocate memory for read buffer.
        try {
            if (attribute_id >= 0)
                dataspace_id = H5.H5Aget_space(attribute_id);
        }
        catch (Exception e) {
            e.printStackTrace();
        }

        try {
            if (dataspace_id >= 0)
                H5.H5Sget_simple_extent_dims(dataspace_id, dims, null);
        }
        catch (Exception e) {
            e.printStackTrace();
        }

        // Allocate array of pointers to two-dimensional arrays (the
        // elements of the dataset.
        dset_data = new double[(int) dims[0]][(int) (dims[1])];

        // Read data.
        try {
            if (attribute_id >= 0)
                H5.H5Aread(attribute_id, HDF5Constants.H5T_NATIVE_DOUBLE, dset_data);
        }
        catch (Exception e) {
            e.printStackTrace();
        }

        // Output the data to the screen.
        DecimalFormat df = new DecimalFormat("#,##0.0000");
        System.out.println(ATTRIBUTENAME + ":");
        for (int indx = 0; indx < dims[0]; indx++) {
            System.out.print(" [");
            for (int jndx = 0; jndx < dims[1]; jndx++) {
                System.out.print(" " + df.format(dset_data[indx][jndx]));
            }
            System.out.println("]");
        }
        System.out.println();

        // End access to the dataset and release resources used by it.
        try {
            if (attribute_id >= 0)
                H5.H5Aclose(attribute_id);
        }
        catch (Exception e) {
            e.printStackTrace();
        }

        try {
            if (dataset_id >= 0)
                H5.H5Dclose(dataset_id);
        }
        catch (Exception e) {
            e.printStackTrace();
        }

        // Terminate access to the data space.
        try {
            if (dataspace_id >= 0)
                H5.H5Sclose(dataspace_id);
        }
        catch (Exception e) {
            e.printStackTrace();
        }

        // Close the file.
        try {
            if (file_id >= 0)
                H5.H5Fclose(file_id);
        }
        catch (Exception e) {
            e.printStackTrace();
        }

    }

    public static void main(String[] args) {
        H5Ex_T_FloatAttribute.CreateDataset();
        // Now we begin the read section of this example. Here we assume
        // the dataset and array have the same name and rank, but can have
        // any size. Therefore we must allocate a new array to read in
        // data using malloc().
        H5Ex_T_FloatAttribute.ReadDataset();
    }

}
