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126 lines
4.3 KiB
C
126 lines
4.3 KiB
C
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
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* Copyright by The HDF Group. *
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* Copyright by the Board of Trustees of the University of Illinois. *
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* All rights reserved. *
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* *
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* This file is part of HDF5. The full HDF5 copyright notice, including *
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* terms governing use, modification, and redistribution, is contained in *
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* the files COPYING and Copyright.html. COPYING can be found at the root *
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* of the source code distribution tree; Copyright.html can be found at the *
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* root level of an installed copy of the electronic HDF5 document set and *
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* is linked from the top-level documents page. It can also be found at *
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* http://hdfgroup.org/HDF5/doc/Copyright.html. If you do not have *
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* access to either file, you may request a copy from help@hdfgroup.org. *
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* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
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/*
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* This example illustrates how to create a compressed dataset.
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* It is used in the HDF5 Tutorial.
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*/
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#include "hdf5.h"
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#define FILE "cmprss.h5"
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#define RANK 2
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#define DIM0 100
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#define DIM1 20
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int main () {
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hid_t file_id, dataset_id, dataspace_id; /* identifiers */
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hid_t plist_id;
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size_t nelmts;
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unsigned flags, filter_info;
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H5Z_filter_t filter_type;
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herr_t status;
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hsize_t dims[2];
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hsize_t cdims[2];
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int idx;
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int i,j, numfilt;
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int buf[DIM0][DIM1];
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int rbuf [DIM0][DIM1];
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/* Uncomment these variables to use SZIP compression
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unsigned szip_options_mask;
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unsigned szip_pixels_per_block;
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*/
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/* Create a file. */
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file_id = H5Fcreate (FILE, H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT);
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/* Create dataset "Compressed Data" in the group using absolute name. */
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dims[0] = DIM0;
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dims[1] = DIM1;
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dataspace_id = H5Screate_simple (RANK, dims, NULL);
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plist_id = H5Pcreate (H5P_DATASET_CREATE);
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/* Dataset must be chunked for compression */
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cdims[0] = 20;
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cdims[1] = 20;
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status = H5Pset_chunk (plist_id, 2, cdims);
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/* Set ZLIB / DEFLATE Compression using compression level 6.
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* To use SZIP Compression comment out these lines.
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*/
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status = H5Pset_deflate (plist_id, 6);
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/* Uncomment these lines to set SZIP Compression
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szip_options_mask = H5_SZIP_NN_OPTION_MASK;
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szip_pixels_per_block = 16;
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status = H5Pset_szip (plist_id, szip_options_mask, szip_pixels_per_block);
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*/
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dataset_id = H5Dcreate2 (file_id, "Compressed_Data", H5T_STD_I32BE,
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dataspace_id, H5P_DEFAULT, plist_id, H5P_DEFAULT);
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for (i = 0; i< DIM0; i++)
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for (j=0; j<DIM1; j++)
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buf[i][j] = i+j;
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status = H5Dwrite (dataset_id, H5T_NATIVE_INT, H5S_ALL, H5S_ALL, H5P_DEFAULT, buf);
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status = H5Sclose (dataspace_id);
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status = H5Dclose (dataset_id);
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status = H5Pclose (plist_id);
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status = H5Fclose (file_id);
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/* Now reopen the file and dataset in the file. */
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file_id = H5Fopen (FILE, H5F_ACC_RDWR, H5P_DEFAULT);
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dataset_id = H5Dopen2 (file_id, "Compressed_Data", H5P_DEFAULT);
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/* Retrieve filter information. */
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plist_id = H5Dget_create_plist (dataset_id);
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numfilt = H5Pget_nfilters (plist_id);
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printf ("Number of filters associated with dataset: %i\n", numfilt);
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for (i=0; i<numfilt; i++) {
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nelmts = 0;
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filter_type = H5Pget_filter2 (plist_id, 0, &flags, &nelmts, NULL, 0, NULL,
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&filter_info);
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printf ("Filter Type: ");
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switch (filter_type) {
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case H5Z_FILTER_DEFLATE:
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printf ("H5Z_FILTER_DEFLATE\n");
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break;
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case H5Z_FILTER_SZIP:
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printf ("H5Z_FILTER_SZIP\n");
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break;
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default:
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printf ("Other filter type included.\n");
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}
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}
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status = H5Dread (dataset_id, H5T_NATIVE_INT, H5S_ALL, H5S_ALL,
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H5P_DEFAULT, rbuf);
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status = H5Dclose (dataset_id);
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status = H5Pclose (plist_id);
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status = H5Fclose (file_id);
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}
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