[svn-r17063] This example shows how to read and write bitfield

  datatypes to a dataset.  The program first writes bit
  fields to a dataset with a dataspace of DIM0xDIM1, then
  closes the file.  Next, it reopens the file, and extracts
  the bit field using a given starting bit and number
  of bits in the bit-field. The values are returned
  as a base-10 integer.

  Main illustrative function: H5LTread_bitfield_value

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diff --git a/hl/examples/ex_bitfield.c b/hl/examples/ex_bitfield.c
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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 bitfield
+  datatypes to a dataset.  The program first writes bit
+  fields to a dataset with a dataspace of DIM0xDIM1, then
+  closes the file.  Next, it reopens the file, and extracts
+  the bit field using a given starting bit and number
+  of bits in the bit-field. The values are returned
+  as a base-10 integer.
+
+  Main illustrative function: H5LTread_bitfield_value
+
+*/
+
+#include <stdlib.h>
+#include "hdf5.h"
+#include "hdf5_hl.h"
+
+#define filename "File.h5"
+#define DIM0            4
+#define DIM1            7
+#define num_flags       4
+
+int main(void)
+{
+  int qf_data[DIM0][DIM1][num_flags];  /* Read buffer */
+  unsigned int offset[4] = {0,2,4,6};  /* Starting bits to be extracted from element */
+  unsigned int length[4] = {2,2,2,2};  /* Number of bits to be extracted for each value */
+  hid_t file, space; /* Handles */
+  hid_t qf_dset;
+  int ndims;
+  herr_t status;
+  int rank = 2;
+  hsize_t dims[2] =  {DIM0,DIM1}; 
+  hid_t file_id;
+  unsigned char wdata[DIM0][DIM1]; /* Write buffer */
+  int i, j, k;
+  
+  /*
+   * Initialize data.  We will manually fill four 2-bit integers into
+   * each unsigned char data element.
+   */
+  for (i=0; i<DIM0; i++)
+    for (j=0; j<DIM1; j++) {
+      wdata[i][j] = 0;
+      wdata[i][j] |= (i * j - j) & 0x03;          /* Field "A" */
+      wdata[i][j] |= (i & 0x03) << 2;             /* Field "B" */
+      wdata[i][j] |= (j & 0x03) << 4;             /* Field "C" */
+      wdata[i][j] |= ( (i + j) & 0x03 ) <<6;      /* Field "D" */
+    }
+  /*
+   * Create file with default file access and file creation properties.
+   */
+  file_id = H5Fcreate(filename, H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT);
+  /*
+   * write the data.
+   */
+  status = H5LTmake_dataset ( file_id, "Granule 1", rank, dims, H5T_NATIVE_UCHAR, wdata );
+  /*
+   * close the resources.
+   */
+  status = H5Fclose(file_id);
+  
+  /*
+   * Open file.
+   */
+  file = H5Fopen (filename, H5F_ACC_RDONLY, H5P_DEFAULT);
+  /* 
+   * Open the data set
+   */
+  qf_dset = H5Dopen (file, "Granule 1",H5P_DEFAULT );
+  /*
+   * Get dataspace and allocate memory for read buffer. Quality flags dataset
+   * has the same dimensionality as corresponding product dataset;
+   * we are using its dimensions for illustration purposes only.
+   */
+  space = H5Dget_space (qf_dset);
+  ndims = H5Sget_simple_extent_dims (space, dims, NULL);
+  
+  status = H5Sclose (space);
+  
+  /*
+   * For each element read the value that takes first two bits and 
+   * store it in a char buffer. This selects all the elements (H5S_ALL)
+   */
+  status = H5LTread_bitfield_value(qf_dset, num_flags, offset, length,
+				   H5S_ALL, qf_data);
+  /* Print out the bit field */
+  printf("Bit Field:\n");
+  for (i = 0; i<DIM0; i++) {
+    printf (" [");
+    for (j = 0; j<DIM1; j++) {
+      printf(" {");
+      for (k = 0; k<num_flags; k++){
+	printf(" %d ", qf_data[i][j][k]);
+      }
+      printf("} ");
+    }
+    printf("]\n");
+  }
+
+  return 1;
+  
+}