[svn-r9523] Purpose:

Added data transform example

Description:
Added example code for the data dtransform

Solution:
This code both illustrates how data transform works and shows how to use it.
Examples of data transform on read, write, and both at the same time.
Also shows usage of H5Pget_data_transform

Platforms tested:
eirene + copper

Misc. update:

1 files changed, 185 insertions, 0 deletions

diff --git a/examples/h5_dtransform.c b/examples/h5_dtransform.c
new file mode 100644
index 0000000..d013ecf
--- /dev/null
+++ b/examples/h5_dtransform.c
@@ -0,0 +1,185 @@
+
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * 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://hdf.ncsa.uiuc.edu/HDF5/doc/Copyright.html.  If you do not have     *
+ * access to either file, you may request a copy from hdfhelp@ncsa.uiuc.edu. *
+ * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
+
+/*  
+ *  This example demonstrates how the data transform features of 
+ *  HDF5 works.
+ *
+ * (1)
+ *  The test first writes out data, with no data transform set.
+ *  Then, the test reads back this data with a data transform applied.
+ *
+ * (2)
+ *  Then, the test writes a new set of data, with a data transform set.
+ *  Then, the test reads this new set of data, without a data set.
+ *
+ * (3)
+ *  Lastly, the test reads the previous set of data (that was written out
+ *  with a data transform) with a data transform set for the read.
+ *
+ *  (4)
+ *  Get the transform from the property using H5Pget_data_transform.
+ */
+ 
+#include "hdf5.h"
+
+#define ROWS    12
+#define COLS    18
+
+const float windchillF[ROWS][COLS] =
+    {   {36.0, 31.0, 25.0, 19.0, 13.0, 7.0, 1.0, -5.0, -11.0, -16.0, -22.0, -28.0, -34.0, -40.0, -46.0, -52.0, -57.0, -63.0 },
+        {34.0, 27.0, 21.0, 15.0, 9.0, 3.0, -4.0, -10.0, -16.0, -22.0, -28.0, -35.0, -41.0, -47.0, -53.0, -59.0, -66.0, -72.0 } ,
+        {32.0, 25.0, 19.0, 13.0, 6.0, 0.0, -7.0, -13.0, -19.0, -26.0, -32.0, -39.0, -45.0, -51.0, -58.0, -64.0, -71.0, -77.0 },
+        {30.0, 24.0, 17.0, 11.0, 4.0, -2.0, -9.0, -15.0, -22.0, -29.0, -35.0, -42.0, -48.0, -55.0, -61.0, -68.0, -74.0, -81.0 },
+        {29.0, 23.0, 16.0, 9.0, 3.0, -4.0, -11.0, -17.0, -24.0, -31.0, -37.0, -44.0, -51.0, -58.0, -64.0, -71.0, -78.0, -84.0 },
+        {28.0, 22.0, 15.0, 8.0, 1.0, -5.0, -12.0, -19.0, -26.0, -33.0, -39.0, -46.0, -53.0, -60.0, -67.0, -73.0, -80.0, -87.0 },
+        {28.0, 21.0, 14.0, 7.0, 0.0, -7.0, -14.0, -21.0, -27.0, -34.0, -41.0, -48.0, -55.0, -62.0, -69.0, -76.0, -82.0, -89.0 },
+        {27.0, 20.0, 13.0, 6.0, -1.0, -8.0, -15.0, -22.0, -29.0, -36.0, -43.0, -50.0, -57.0, -64.0, -71.0, -78.0, -84.0, -91.0 },
+        {26.0, 19.0, 12.0, 5.0, -2.0, -9.0, -16.0, -23.0, -30.0, -37.0, -44.0, -51.0, -58.0, -65.0, -72.0, -79.0, -86.0, -93.0 },
+        {26.0, 19.0, 12.0, 4.0, -3.0, -10.0, -17.0, -24.0, -31.0, -38.0, -45.0, -52.0, -60.0, -67.0, -74.0, -81.0, -88.0, -95.0},
+        {25.0, 18.0, 11.0, 4.0, -3.0, -11.0, -18.0, -25.0, -32.0, -39.0, -46.0, -54.0, -61.0, -68.0, -75.0, -82.0, -89.0, -97.0},
+        {25.0, 17.0, 10.0, 3.0, -4.0, -11.0, -19.0, -26.0, -33.0, -40.0, -48.0, -55.0, -62.0, -69.0, -76.0, -84.0, -91.0, -98.0}
+    };
+
+#define PRINT(array)				\
+{						\
+    for(i=0; i<ROWS; i++)			\
+    {						\
+	for(j=0; j<COLS; j++)			\
+	    printf("%6.2f ", array[i][j]);	\
+	printf("\n");				\
+    }						\
+}
+
+
+	
+
+int
+main (void)
+{
+    hid_t       file, dataset;         /* file and dataset handles */
+    hid_t       dataspace;   /* handles */
+    hsize_t     dimsf[2];              /* dataset dimensions */
+    herr_t      status;      
+    hid_t	dxpl_id_f_to_c, dxpl_id_c_to_f;	/* data transform handles */                       
+    const char* f_to_c = "(5/9.0)*(x-32)";
+    const char* c_to_f =  "(9/5.0)*x + 32";
+    char*	transform;
+    float	windchillC[ROWS][COLS];
+    int 	i,j, transform_size;
+
+    /*
+     * Create a new file using H5F_ACC_TRUNC access,
+     * default file creation properties, and default file
+     * access properties.
+     */
+    file = H5Fcreate("dtransform.h5", H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT);
+
+    /*
+     * Describe the size of the array and create the data space for fixed
+     * size dataset. 
+     */
+    dimsf[0] = ROWS;
+    dimsf[1] = COLS;
+    dataspace = H5Screate_simple(2, dimsf, NULL); 
+
+    /*
+     * Create a new dataset within the file using defined dataspace and
+     * datatype and default dataset creation properties.
+     */
+    dataset = H5Dcreate(file, "data_no_trans", H5T_NATIVE_FLOAT, dataspace, H5P_DEFAULT);
+    printf("\nOriginal Data: \n");
+
+    PRINT(windchillF);
+
+
+
+
+/****************  PART 1 **************/
+    /*
+     * Write the data to the dataset using default transfer properties (ie, no transform set)
+     */
+    status = H5Dwrite(dataset, H5T_NATIVE_FLOAT, H5S_ALL, H5S_ALL,
+		      H5P_DEFAULT, windchillF);
+
+    /* Create the dataset transfer property list */
+    dxpl_id_f_to_c = H5Pcreate(H5P_DATASET_XFER);
+
+    /* Set the data transform */
+    H5Pset_data_transform(dxpl_id_f_to_c, f_to_c);
+
+    /* Read out the data with the data transform */
+    H5Dread(dataset, H5T_NATIVE_FLOAT, H5S_ALL, H5S_ALL, dxpl_id_f_to_c, windchillC);
+
+    /* Print the data from the read*/
+    printf("\nData with no write transform, but a read transform: \n");
+    PRINT(windchillC);
+    
+
+/****************  PART 2 **************/
+    /*
+     * Write the data to the dataset with the f_to_c transform set 
+     */
+    status = H5Dwrite(dataset, H5T_NATIVE_FLOAT, H5S_ALL, H5S_ALL,
+		      dxpl_id_f_to_c, windchillF);
+
+    /* Read out the data with the default transfer list (ie, no transform set) */
+    H5Dread(dataset, H5T_NATIVE_FLOAT, H5S_ALL, H5S_ALL, H5P_DEFAULT, windchillC);
+
+    /* Print the data from the read*/
+    printf("\nData with write transform, but no read transform: \n");
+    PRINT(windchillC);
+
+/************** PART 3 ***************/
+ 
+ 
+    /* Create the dataset transfer property list */
+    dxpl_id_c_to_f = H5Pcreate(H5P_DATASET_XFER);
+
+    /* Set the data transform to be used on the read*/
+    H5Pset_data_transform(dxpl_id_c_to_f, c_to_f);
+
+
+    /*
+     * Write the data to the dataset using the f_to_c transform
+     */
+    status = H5Dwrite(dataset, H5T_NATIVE_FLOAT, H5S_ALL, H5S_ALL,
+		      dxpl_id_f_to_c, windchillF);
+    
+    /* Read the data with the c_to_f data transform */
+    H5Dread(dataset, H5T_NATIVE_FLOAT, H5S_ALL, H5S_ALL, dxpl_id_c_to_f, windchillC);
+
+    /* Print the data from the read*/
+    printf("\nData with both read and write data transform: \n");
+    PRINT(windchillC);
+
+/************** PART 4 **************/
+    transform_size = H5Pget_data_transform(dxpl_id_f_to_c, NULL, 0);
+    transform = (char*) malloc(transform_size);
+    H5Pget_data_transform(dxpl_id_f_to_c, transform, transform_size);
+    
+    printf("\nTransform string (from dxpl_id_f_to_c) is: %s\n", transform);
+    
+    /*
+     * Close/release resources.
+     */
+    H5Pclose(dxpl_id_c_to_f);
+    H5Pclose(dxpl_id_f_to_c);
+    H5Sclose(dataspace);
+    H5Dclose(dataset);
+    H5Fclose(file);
+ 
+    return 0;
+}