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Diffstat (limited to 'examples/h5_cmprss.c')
| -rw-r--r-- | examples/h5_cmprss.c | 125 |
1 files changed, 125 insertions, 0 deletions
diff --git a/examples/h5_cmprss.c b/examples/h5_cmprss.c new file mode 100644 index 0000000..4a2f982 --- /dev/null +++ b/examples/h5_cmprss.c @@ -0,0 +1,125 @@ +/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * 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 illustrates how to create a compressed dataset.
+ * It is used in the HDF5 Tutorial.
+ */
+
+#include "hdf5.h"
+
+#define FILE "cmprss.h5"
+#define RANK 2
+#define DIM0 100
+#define DIM1 20
+
+int main () {
+
+ hid_t file_id, dataset_id, dataspace_id; /* identifiers */
+ hid_t plist_id;
+
+ size_t nelmts;
+ unsigned flags, filter_info;
+ H5Z_filter_t filter_type;
+
+ herr_t status;
+ hsize_t dims[2];
+ hsize_t cdims[2];
+
+ int idx;
+ int i,j, numfilt;
+ int buf[DIM0][DIM1];
+ int rbuf [DIM0][DIM1];
+
+ /* Uncomment these variables to use SZIP compression
+ unsigned szip_options_mask;
+ unsigned szip_pixels_per_block;
+ */
+
+ /* Create a file. */
+ file_id = H5Fcreate (FILE, H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT);
+
+
+ /* Create dataset "Compressed Data" in the group using absolute name. */
+ dims[0] = DIM0;
+ dims[1] = DIM1;
+ dataspace_id = H5Screate_simple (RANK, dims, NULL);
+
+ plist_id = H5Pcreate (H5P_DATASET_CREATE);
+
+ /* Dataset must be chunked for compression */
+ cdims[0] = 20;
+ cdims[1] = 20;
+ status = H5Pset_chunk (plist_id, 2, cdims);
+
+ /* Set ZLIB / DEFLATE Compression using compression level 6.
+ * To use SZIP Compression comment out these lines.
+ */
+ status = H5Pset_deflate (plist_id, 6);
+
+ /* Uncomment these lines to set SZIP Compression
+ szip_options_mask = H5_SZIP_NN_OPTION_MASK;
+ szip_pixels_per_block = 16;
+ status = H5Pset_szip (plist_id, szip_options_mask, szip_pixels_per_block);
+ */
+
+ dataset_id = H5Dcreate2 (file_id, "Compressed_Data", H5T_STD_I32BE,
+ dataspace_id, H5P_DEFAULT, plist_id, H5P_DEFAULT);
+
+ for (i = 0; i< DIM0; i++)
+ for (j=0; j<DIM1; j++)
+ buf[i][j] = i+j;
+
+ status = H5Dwrite (dataset_id, H5T_NATIVE_INT, H5S_ALL, H5S_ALL, H5P_DEFAULT, buf);
+
+ status = H5Sclose (dataspace_id);
+ status = H5Dclose (dataset_id);
+ status = H5Pclose (plist_id);
+ status = H5Fclose (file_id);
+
+ /* Now reopen the file and dataset in the file. */
+ file_id = H5Fopen (FILE, H5F_ACC_RDWR, H5P_DEFAULT);
+ dataset_id = H5Dopen2 (file_id, "Compressed_Data", H5P_DEFAULT);
+
+ /* Retrieve filter information. */
+ plist_id = H5Dget_create_plist (dataset_id);
+
+ numfilt = H5Pget_nfilters (plist_id);
+ printf ("Number of filters associated with dataset: %i\n", numfilt);
+
+ for (i=0; i<numfilt; i++) {
+ nelmts = 0;
+ filter_type = H5Pget_filter2 (plist_id, 0, &flags, &nelmts, NULL, 0, NULL,
+ &filter_info);
+ printf ("Filter Type: ");
+ switch (filter_type) {
+ case H5Z_FILTER_DEFLATE:
+ printf ("H5Z_FILTER_DEFLATE\n");
+ break;
+ case H5Z_FILTER_SZIP:
+ printf ("H5Z_FILTER_SZIP\n");
+ break;
+ default:
+ printf ("Other filter type included.\n");
+ }
+ }
+
+ status = H5Dread (dataset_id, H5T_NATIVE_INT, H5S_ALL, H5S_ALL,
+ H5P_DEFAULT, rbuf);
+
+ status = H5Dclose (dataset_id);
+ status = H5Pclose (plist_id);
+ status = H5Fclose (file_id);
+}
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