/************************************************************
  This example shows how to read and write data to a
  dataset by hyberslabs.  The program first writes integers
  in a hyperslab selection to a dataset with dataspace
  dimensions of DIM_XxDIM_Y, then closes the file.  Next, it
  reopens the file, reads back the data, and outputs it to
  the screen.  Finally it reads the data again using a
  different hyperslab selection, and outputs the result to
  the screen.
 ************************************************************/
package examples.datasets;

import ncsa.hdf.hdf5lib.H5;
import ncsa.hdf.hdf5lib.HDF5Constants;
import ncsa.hdf.object.Dataset;
import ncsa.hdf.object.Datatype;
import ncsa.hdf.object.FileFormat;
import ncsa.hdf.object.Group;
import ncsa.hdf.object.h5.H5Datatype;
import ncsa.hdf.object.h5.H5File;
import ncsa.hdf.object.h5.H5ScalarDS;

public class H5ObjectEx_D_Hyperslab {
	private static String FILENAME = "H5ObjectEx_D_Hyperslab.h5";
	private static String DATASETNAME = "DS1";
	private static final int DIM_X = 6;
	private static final int DIM_Y = 8;
	private static final int RANK = 2;
    private static final int DATATYPE_SIZE = 4;

	private static void writeHyperslab() {
        H5File file = null;
        Dataset dset = null;
		int file_id = -1;
		int filespace_id = -1;
		int dataset_id = -1;
        int type_id = -1;
		long[] dims = { DIM_X, DIM_Y };
		int[][] dset_data = new int[DIM_X][DIM_Y];
        final H5Datatype typeInt = new H5Datatype(Datatype.CLASS_INTEGER,
                DATATYPE_SIZE, Datatype.ORDER_LE, -1);

		// Initialize data to "1", to make it easier to see the selections.
		for (int indx = 0; indx < DIM_X; indx++)
			for (int jndx = 0; jndx < DIM_Y; jndx++)
				dset_data[indx][jndx] = 1;

		// Print the data to the screen.
		System.out.println("Original Data:");
		for (int indx = 0; indx < DIM_X; indx++) {
			System.out.print(" [ ");
			for (int jndx = 0; jndx < DIM_Y; jndx++)
				System.out.print(dset_data[indx][jndx] + " ");
			System.out.println("]");
		}
		System.out.println();

		// Create a new file using default properties.
		try {
            file = new H5File(FILENAME, FileFormat.CREATE);
            file_id = file.open();
		}
		catch (Exception e) {
			e.printStackTrace();
		}

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

		// Create the dataset. We will use all default properties for this example.
		try {
			if ((file_id >= 0) && (filespace_id >= 0))
				dataset_id = H5.H5Dcreate(file_id, DATASETNAME,
				        type_id, filespace_id,
						HDF5Constants.H5P_DEFAULT, HDF5Constants.H5P_DEFAULT, HDF5Constants.H5P_DEFAULT);
            dset = new H5ScalarDS(file, DATASETNAME, "/");
            Group pgroup = (Group) file.get("/");
            pgroup.addToMemberList(dset);
		}
		catch (Exception e) {
			e.printStackTrace();
		}

		// Define and select the first part of the hyperslab selection.
		long[] start = { 0, 0 };
		long[] stride = { 3, 3 };
		long[] count = { 2, 3 };
		long[] block = { 2, 2 };
		try {
			if ((filespace_id >= 0))
				H5.H5Sselect_hyperslab(filespace_id, HDF5Constants.H5S_SELECT_SET,
						start, stride, count, block);
		}
		catch (Exception e) {
			e.printStackTrace();
		}
		// Define and select the second part of the hyperslab selection,
		// which is subtracted from the first selection by the use of
		// H5S_SELECT_NOTB
		block[0] = 1;
		block[1] = 1;
		try {
			if ((filespace_id >= 0)) {
				H5.H5Sselect_hyperslab(filespace_id, HDF5Constants.H5S_SELECT_NOTB,
						start, stride, count, block);

				// Write the data to the dataset.
				if (dataset_id >= 0)
					H5.H5Dwrite(dataset_id, HDF5Constants.H5T_NATIVE_INT,
							HDF5Constants.H5S_ALL, filespace_id, HDF5Constants.H5P_DEFAULT,
							dset_data);
			}
		}
		catch (Exception e) {
			e.printStackTrace();
		}
        
		// End access to the dataset and release resources used by it.
        try {
            if (type_id >= 0)
                H5.H5Tclose(type_id);
        }
        catch (Exception e) {
            e.printStackTrace();
        }

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

		try {
			if (filespace_id >= 0)
				H5.H5Sclose(filespace_id);
		}
		catch (Exception e) {
			e.printStackTrace();
		}

		// Close the file.
		try {
            file.close();
		}
		catch (Exception e) {
			e.printStackTrace();
		}
	}

	private static void readHyperslab() {
        H5File file = null;
        Dataset dset = null;
		int filespace_id = -1;
		int dataset_id = -1;
		int dcpl_id = -1;
		int[] dset_data = new int[DIM_X*DIM_Y];

		// Open an existing file.
		try {
            file = new H5File(FILENAME, FileFormat.READ);
            file.open();
		}
		catch (Exception e) {
			e.printStackTrace();
		}

		// Open an existing dataset.
		try {
            dset = (Dataset) file.get(DATASETNAME);
            dataset_id = dset.open();
		}
		catch (Exception e) {
			e.printStackTrace();
		}

		// Read the data using the default properties.
		try {
            dset.init();
            dset_data = (int[]) dset.getData();
		}
		catch (Exception e) {
			e.printStackTrace();
		}

		// Output the data to the screen.
		System.out.println("Data as written to disk by hyberslabs:");
		for (int indx = 0; indx < DIM_X; indx++) {
			System.out.print(" [ ");
			for (int jndx = 0; jndx < DIM_Y; jndx++)
				System.out.print(dset_data[indx*DIM_Y+jndx] + " ");
			System.out.println("]");
		}
		System.out.println();

		// Initialize the read array.
		for (int indx = 0; indx < DIM_X; indx++)
			for (int jndx = 0; jndx < DIM_Y; jndx++)
				dset_data[indx*DIM_Y+jndx] = 0;

		// Define and select the hyperslab to use for reading.
		try {
			if (dataset_id >= 0) {
				filespace_id = H5.H5Dget_space(dataset_id);

				long[] start = { 0, 1 };
				long[] stride = { 4, 4 };
				long[] count = { 2, 2 };
				long[] block = { 2, 3 };

				if (filespace_id >= 0) {
					H5.H5Sselect_hyperslab(filespace_id, HDF5Constants.H5S_SELECT_SET,
							start, stride, count, block);

					// Read the data using the previously defined hyperslab.
					if ((dataset_id >= 0) && (filespace_id >= 0))
						H5.H5Dread(dataset_id, HDF5Constants.H5T_NATIVE_INT,
								HDF5Constants.H5S_ALL, filespace_id, HDF5Constants.H5P_DEFAULT,
								dset_data);
				}
			}
		}
		catch (Exception e) {
			e.printStackTrace();
		}

		// Output the data to the screen.
		System.out.println("Data as read from disk by hyberslab:");
		for (int indx = 0; indx < DIM_X; indx++) {
			System.out.print(" [ ");
			for (int jndx = 0; jndx < DIM_Y; jndx++)
				System.out.print(dset_data[indx*DIM_Y+jndx] + " ");
			System.out.println("]");
		}
		System.out.println();

		// End access to the dataset and release resources used by it.
		try {
			if (dcpl_id >= 0)
				H5.H5Pclose(dcpl_id);
		}
		catch (Exception e) {
			e.printStackTrace();
		}

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

		try {
			if (filespace_id >= 0)
				H5.H5Sclose(filespace_id);
		}
		catch (Exception e) {
			e.printStackTrace();
		}

		// Close the file.
		try {
            file.close();
		}
		catch (Exception e) {
			e.printStackTrace();
		}
	}

	public static void main(String[] args) {
		H5ObjectEx_D_Hyperslab.writeHyperslab();
		H5ObjectEx_D_Hyperslab.readHyperslab();
	}

}