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+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * 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 files COPYING and Copyright.html. COPYING can be found at the root *
+ * of the source code distribution tree; Copyright.html can be found at the *
+ * root level of an installed copy of the electronic HDF5 document set and *
+ * is linked from the top-level documents page. It can also be found at *
+ * http://hdfgroup.org/HDF5/doc/Copyright.html. 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 data to a dataset
+ using a data transform expression. The program first
+ writes integers to a dataset using the transform
+ expression TRANSFORM, then closes the file. Next, it
+ reopens the file, reads back the data without a transform,
+ and outputs the data to the screen. Finally it reads the
+ data using the transform expression RTRANSFORM and outputs
+ the results to the screen.
+ ************************************************************/
+package examples.datasets;
+
+import hdf.hdf5lib.H5;
+import hdf.hdf5lib.HDF5Constants;
+
+public class H5Ex_D_Transform {
+
+ private static String FILE = "H5Ex_D_Transform.h5";
+ private static String DATASET = "DS1";
+ private static final int DIM_X = 4;
+ private static final int DIM_Y = 7;
+ private static String TRANSFORM = "x+1";
+ private static String RTRANSFORM = "x-1";
+
+ private static void writeData() {
+ long file_id = -1;
+ long filespace_id = -1;
+ long dataset_id = -1;
+ long dxpl_id = -1;
+
+ long[] dims = { DIM_X, DIM_Y };
+ int[][] dset_data = new int[DIM_X][DIM_Y];
+
+ // Initialize data.
+ for (int i = 0; i < DIM_X; i++)
+ for (int j = 0; j < DIM_Y; j++)
+ dset_data[i][j] = i * j - j;
+
+ // Output the data to the screen.
+ System.out.println("Original Data:");
+ for (int i = 0; i < DIM_X; i++) {
+ System.out.print(" [");
+ for (int j = 0; j < DIM_Y; j++)
+ System.out.print(" " + dset_data[i][j] + " ");
+ System.out.println("]");
+ }
+
+ // Create a new file using the default properties.
+ try {
+ file_id = H5.H5Fcreate(FILE, HDF5Constants.H5F_ACC_TRUNC, HDF5Constants.H5P_DEFAULT,
+ HDF5Constants.H5P_DEFAULT);
+ }
+ 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(2, dims, null);
+ }
+ catch (Exception e) {
+ e.printStackTrace();
+ }
+
+ // Create the dataset transfer property list and define the transform expression.
+ try {
+ dxpl_id = H5.H5Pcreate(HDF5Constants.H5P_DATASET_XFER);
+ if (dxpl_id >= 0)
+ H5.H5Pset_data_transform(dxpl_id, TRANSFORM);
+ }
+ catch (Exception e) {
+ e.printStackTrace();
+ }
+
+ // Create the dataset using the default properties. Unfortunately we must save as
+ // a native type or the transform operation will fail.
+ try {
+ if ((file_id >= 0) && (filespace_id >= 0))
+ dataset_id = H5.H5Dcreate(file_id, DATASET, HDF5Constants.H5T_NATIVE_INT, filespace_id,
+ HDF5Constants.H5P_DEFAULT, HDF5Constants.H5P_DEFAULT, HDF5Constants.H5P_DEFAULT);
+ }
+ catch (Exception e) {
+ e.printStackTrace();
+ }
+
+ // Write the data to the dataset using the dataset transfer property list.
+ try {
+ if ((dataset_id >= 0) && (dxpl_id >= 0))
+ H5.H5Dwrite(dataset_id, HDF5Constants.H5T_NATIVE_INT, HDF5Constants.H5S_ALL, HDF5Constants.H5S_ALL,
+ dxpl_id, dset_data);
+ }
+ catch (Exception e) {
+ e.printStackTrace();
+ }
+
+ // End access to the dataset and release resources used by it.
+ try {
+ if (dxpl_id >= 0)
+ H5.H5Pclose(dxpl_id);
+ }
+ catch (Exception e) {
+ e.printStackTrace();
+ }
+
+ try {
+ if (dataset_id >= 0)
+ H5.H5Dclose(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 {
+ if (file_id >= 0)
+ H5.H5Fclose(file_id);
+ }
+ catch (Exception e) {
+ e.printStackTrace();
+ }
+ }
+
+ private static void readData() {
+
+ long file_id = -1;
+ long dataset_id = -1;
+ long dxpl_id = -1;
+ int[][] dset_data = new int[DIM_X][DIM_Y];
+
+ // Open an existing file using the default properties.
+ try {
+ file_id = H5.H5Fopen(FILE, HDF5Constants.H5F_ACC_RDONLY, HDF5Constants.H5P_DEFAULT);
+ }
+ catch (Exception e) {
+ e.printStackTrace();
+ }
+
+ // Open an existing dataset using the default properties.
+ try {
+ if (file_id >= 0)
+ dataset_id = H5.H5Dopen(file_id, DATASET, HDF5Constants.H5P_DEFAULT);
+ }
+ catch (Exception e) {
+ e.printStackTrace();
+ }
+
+ // Read the data using the default properties.
+ try {
+ if (dataset_id >= 0)
+ H5.H5Dread(dataset_id, HDF5Constants.H5T_NATIVE_INT, HDF5Constants.H5S_ALL, HDF5Constants.H5S_ALL,
+ HDF5Constants.H5P_DEFAULT, dset_data);
+ }
+ catch (Exception e) {
+ e.printStackTrace();
+ }
+
+ // Output the data to the screen.
+ System.out.println("Data as written with transform '" + TRANSFORM + "'");
+ for (int i = 0; i < DIM_X; i++) {
+ System.out.print(" [");
+ for (int j = 0; j < DIM_Y; j++)
+ System.out.print(" " + dset_data[i][j] + " ");
+ System.out.println("]");
+ }
+
+ // Create the dataset transfer property list and define the transform expression.
+ try {
+ dxpl_id = H5.H5Pcreate(HDF5Constants.H5P_DATASET_XFER);
+ if (dxpl_id >= 0)
+ H5.H5Pset_data_transform(dxpl_id, RTRANSFORM);
+ }
+ catch (Exception e) {
+ e.printStackTrace();
+ }
+
+ // Read the data using the dataset transfer property list.
+ try {
+ if ((dataset_id >= 0) && (dxpl_id >= 0))
+ H5.H5Dread(dataset_id, HDF5Constants.H5T_NATIVE_INT, HDF5Constants.H5S_ALL, HDF5Constants.H5S_ALL,
+ dxpl_id, dset_data);
+ }
+ catch (Exception e) {
+ e.printStackTrace();
+ }
+
+ // Output the data to the screen.
+
+ System.out.println("Data as written with transform '" + TRANSFORM + "' and read with transform '"
+ + RTRANSFORM + "'");
+ for (int i = 0; i < DIM_X; i++) {
+ System.out.print(" [");
+ for (int j = 0; j < DIM_Y; j++)
+ System.out.print(" " + dset_data[i][j] + " ");
+ System.out.println("]");
+ }
+
+ // Close and release resources.
+ try {
+ if (dxpl_id >= 0)
+ H5.H5Pclose(dxpl_id);
+ }
+ catch (Exception e) {
+ e.printStackTrace();
+ }
+ try {
+ if (dataset_id >= 0)
+ H5.H5Dclose(dataset_id);
+ }
+ catch (Exception e) {
+ e.printStackTrace();
+ }
+ try {
+ if (file_id >= 0)
+ H5.H5Fclose(file_id);
+ }
+ catch (Exception e) {
+ e.printStackTrace();
+ }
+ }
+
+ public static void main(String[] args) {
+ H5Ex_D_Transform.writeData();
+ H5Ex_D_Transform.readData();
+ }
+
+}
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