1 files changed, 148 insertions, 0 deletions
diff --git a/HDF5Examples/C/H5T/16/h5ex_t_bitatt.c b/HDF5Examples/C/H5T/16/h5ex_t_bitatt.c
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index 0000000..be19a28
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+++ b/HDF5Examples/C/H5T/16/h5ex_t_bitatt.c
@@ -0,0 +1,148 @@
+/************************************************************
+
+  This example shows how to read and write bitfield
+  datatypes to an attribute.  The program first writes bit
+  fields to an attribute with a dataspace of DIM0xDIM1, 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 version 1.6
+
+ ************************************************************/
+
+#include "hdf5.h"
+#include <stdio.h>
+#include <stdlib.h>
+
+#define FILE      "h5ex_t_bitatt.h5"
+#define DATASET   "DS1"
+#define ATTRIBUTE "A1"
+#define DIM0      4
+#define DIM1      7
+
+int
+main(void)
+{
+    hid_t         file, space, dset, attr; /* Handles */
+    herr_t        status;
+    hsize_t       dims[2] = {DIM0, DIM1};
+    unsigned char wdata[DIM0][DIM1], /* Write buffer */
+        **rdata;                     /* Read buffer */
+    int ndims, A, B, C, D, i, j;
+
+    /*
+     * Initialize data.  We will manually pack 4 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 a new file using the default properties.
+     */
+    file = H5Fcreate(FILE, H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT);
+
+    /*
+     * Create dataset with a scalar dataspace.
+     */
+    space  = H5Screate(H5S_SCALAR);
+    dset   = H5Dcreate(file, DATASET, H5T_STD_I32LE, space, H5P_DEFAULT);
+    status = H5Sclose(space);
+
+    /*
+     * Create dataspace.  Setting maximum size to NULL sets the maximum
+     * size to be the current size.
+     */
+    space = H5Screate_simple(2, dims, NULL);
+
+    /*
+     * Create the attribute and write the bitfield data to it.
+     */
+    attr   = H5Acreate(dset, ATTRIBUTE, H5T_STD_B8BE, space, H5P_DEFAULT);
+    status = H5Awrite(attr, H5T_NATIVE_B8, wdata[0]);
+
+    /*
+     * Close and release resources.
+     */
+    status = H5Aclose(attr);
+    status = H5Dclose(dset);
+    status = H5Sclose(space);
+    status = H5Fclose(file);
+
+    /*
+     * Now we begin the read section of this example.  Here we assume
+     * the attribute has the same name and rank, but can have any size.
+     * Therefore we must allocate a new array to read in data using
+     * malloc().
+     */
+
+    /*
+     * Open file, dataset, and attribute.
+     */
+    file = H5Fopen(FILE, H5F_ACC_RDONLY, H5P_DEFAULT);
+    dset = H5Dopen(file, DATASET);
+    attr = H5Aopen_name(dset, ATTRIBUTE);
+
+    /*
+     * Get dataspace and allocate memory for read buffer.  This is a
+     * two dimensional attribute so the dynamic allocation must be done
+     * in steps.
+     */
+    space = H5Aget_space(attr);
+    ndims = H5Sget_simple_extent_dims(space, dims, NULL);
+
+    /*
+     * Allocate array of pointers to rows.
+     */
+    rdata = (unsigned char **)malloc(dims[0] * sizeof(unsigned char *));
+
+    /*
+     * Allocate space for bitfield data.
+     */
+    rdata[0] = (unsigned char *)malloc(dims[0] * dims[1] * sizeof(unsigned char));
+
+    /*
+     * Set the rest of the pointers to rows to the correct addresses.
+     */
+    for (i = 1; i < dims[0]; i++)
+        rdata[i] = rdata[0] + i * dims[1];
+
+    /*
+     * Read the data.
+     */
+    status = H5Aread(attr, H5T_NATIVE_B8, rdata[0]);
+
+    /*
+     * Output the data to the screen.
+     */
+    printf("%s:\n", ATTRIBUTE);
+    for (i = 0; i < dims[0]; i++) {
+        printf(" [");
+        for (j = 0; j < dims[1]; j++) {
+            A = rdata[i][j] & 0x03;        /* Retrieve field "A" */
+            B = (rdata[i][j] >> 2) & 0x03; /* Retrieve field "B" */
+            C = (rdata[i][j] >> 4) & 0x03; /* Retrieve field "C" */
+            D = (rdata[i][j] >> 6) & 0x03; /* Retrieve field "D" */
+            printf(" {%d, %d, %d, %d}", A, B, C, D);
+        }
+        printf(" ]\n");
+    }
+
+    /*
+     * Close and release resources.
+     */
+    free(rdata[0]);
+    free(rdata);
+    status = H5Aclose(attr);
+    status = H5Dclose(dset);
+    status = H5Sclose(space);
+    status = H5Fclose(file);
+
+    return 0;
+}