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

  This example shows how to read and write opaque datatypes
  to an attribute.  The program first writes opaque data to
  an attribute with a dataspace of DIM0, 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 verion 1.6

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

package datatypes;

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

public class H5Ex_T_OpaqueAttribute {
	private static String FILENAME = "h5ex_t_opaqueatt.h5";
	private static String DATASETNAME = "DS1";
	private static String ATTRIBUTENAME = "A1";
	private static final int DIM0 = 4;
	private static final int LEN = 7;
	private static final int RANK = 1;

	private static void CreateDataset() {
		int file_id = -1;
		int dataspace_id = -1;
		int datatype_id = -1;
		int dataset_id = -1;
		int attribute_id = -1;
		long[] dims = { DIM0 };
		byte[] dset_data = new byte[DIM0 * LEN];
		byte[] str_data = { 'O', 'P', 'A', 'Q', 'U', 'E' };

		// Initialize data.
		for (int indx = 0; indx < DIM0; indx++) {
			for (int jndx = 0; jndx < LEN - 1; jndx++)
				dset_data[jndx + indx * LEN] = str_data[jndx];
			dset_data[LEN - 1 + indx * LEN] = (byte) (indx + '0');
		}

		// 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);
				H5.H5Sclose(dataspace_id);
				dataspace_id = -1;
			}
		}
		catch (Exception e) {
			e.printStackTrace();
		}

		// Create opaque datatype and set the tag to something appropriate.
		// For this example we will write and view the data as a character
		// array.
		try {
			datatype_id = H5.H5Tcreate(HDF5Constants.H5T_OPAQUE, LEN);
			if (datatype_id >= 0)
				H5.H5Tset_tag(datatype_id, "Character array");
		}
		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) && (datatype_id >= 0) && (dataspace_id >= 0))
				attribute_id = H5.H5Acreate(dataset_id, ATTRIBUTENAME, datatype_id,
						dataspace_id, HDF5Constants.H5P_DEFAULT);
		}
		catch (Exception e) {
			e.printStackTrace();
		}

		// Write the dataset.
		try {
			if ((attribute_id >= 0) && (datatype_id >= 0))
				H5.H5Awrite(attribute_id, datatype_id, 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();
		}

		try {
			if (datatype_id >= 0)
				H5.H5Tclose(datatype_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() {
		int file_id = -1;
		int datatype_id = -1;
		int dataspace_id = -1;
		int dataset_id = -1;
		int attribute_id = -1;
		int type_len = -1;
		long[] dims = { DIM0 };
		byte[] dset_data;
		String tag_name = null;

		// 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);
		}
		catch (Exception e) {
			e.printStackTrace();
		}

		try {
			if (dataset_id >= 0)
				attribute_id = H5.H5Aopen_name(dataset_id, ATTRIBUTENAME);
		}
		catch (Exception e) {
			e.printStackTrace();
		}

		// Get datatype and properties for the datatype.
		try {
			if (attribute_id >= 0)
				datatype_id = H5.H5Aget_type(attribute_id);
			if (datatype_id >= 0) {
				type_len = H5.H5Tget_size(datatype_id);
				tag_name = H5.H5Tget_tag(datatype_id);
			}
		}
		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 buffer.
		dset_data = new byte[(int) dims[0] * type_len];

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

		// Output the data to the screen.
		System.out.println("Datatype tag for " + ATTRIBUTENAME + " is: \""
				+ tag_name + "\"");
		for (int indx = 0; indx < dims[0]; indx++) {
			System.out.print(ATTRIBUTENAME + "[" + indx + "]: ");
			for (int jndx = 0; jndx < type_len; jndx++) {
				char temp = (char) dset_data[jndx + indx * type_len];
				System.out.print(temp);
			}
			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();
		}

		try {
			if (datatype_id >= 0)
				H5.H5Tclose(datatype_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_OpaqueAttribute.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_OpaqueAttribute.ReadDataset();
	}

}