diff options
Diffstat (limited to 'c++/examples/h5tutr_cmprss.cpp')
| -rw-r--r-- | c++/examples/h5tutr_cmprss.cpp | 162 |
1 files changed, 162 insertions, 0 deletions
diff --git a/c++/examples/h5tutr_cmprss.cpp b/c++/examples/h5tutr_cmprss.cpp new file mode 100644 index 0000000..7db73c4 --- /dev/null +++ b/c++/examples/h5tutr_cmprss.cpp @@ -0,0 +1,162 @@ +/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * + * 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 <iostream> +#include <string> + +#include "H5Cpp.h" + +#ifndef H5_NO_NAMESPACE + using namespace H5; +#ifndef H5_NO_STD + using std::cout; + using std::endl; +#endif // H5_NO_STD +#endif + +const H5std_string FILE_NAME("cmprss.h5"); +const H5std_string DATASET_NAME("Compressed_Data"); +const int DIM0 = 100; +const int DIM1 = 20; + +int main (void) +{ + hsize_t dims[2] = { DIM0, DIM1 }; // dataset dimensions + hsize_t chunk_dims[2] = { 20, 20 }; // chunk dimensions + int i,j, buf[DIM0][DIM1]; + + // Try block to detect exceptions raised by any of the calls inside it + try + { + // Turn off the auto-printing when failure occurs so that we can + // handle the errors appropriately + Exception::dontPrint(); + + // Create a new file using the default property lists. + H5File file(FILE_NAME, H5F_ACC_TRUNC); + + // Create the data space for the dataset. + DataSpace *dataspace = new DataSpace(2, dims); + + // Modify dataset creation property to enable chunking + DSetCreatPropList *plist = new DSetCreatPropList; + plist->setChunk(2, chunk_dims); + + // Set ZLIB (DEFLATE) Compression using level 6. + // To use SZIP compression comment out this line. + plist->setDeflate(6); + + // Uncomment these lines to set SZIP Compression + // unsigned szip_options_mask = H5_SZIP_NN_OPTION_MASK; + // unsigned szip_pixels_per_block = 16; + // plist->setSzip(szip_options_mask, szip_pixels_per_block); + + // Create the dataset. + DataSet *dataset = new DataSet(file.createDataSet( DATASET_NAME, + PredType::STD_I32BE, *dataspace, *plist) ); + + for (i = 0; i< DIM0; i++) + for (j=0; j<DIM1; j++) + buf[i][j] = i+j; + + // Write data to dataset. + dataset->write(buf, PredType::NATIVE_INT); + + // Close objects and file. Either approach will close the HDF5 item. + delete dataspace; + delete dataset; + delete plist; + file.close(); + + // ----------------------------------------------- + // Re-open the file and dataset, retrieve filter + // information for dataset and read the data back. + // ----------------------------------------------- + + int rbuf[DIM0][DIM1]; + int numfilt; + size_t nelmts={1}, namelen={1}; + unsigned flags, filter_info, cd_values[1], idx; + char name[1]; + H5Z_filter_t filter_type; + + // Open the file and the dataset in the file. + file.openFile(FILE_NAME, H5F_ACC_RDONLY); + dataset = new DataSet(file.openDataSet( DATASET_NAME)); + + // Get the create property list of the dataset. + plist = new DSetCreatPropList(dataset->getCreatePlist ()); + + // Get the number of filters associated with the dataset. + numfilt = plist->getNfilters(); + cout << "Number of filters associated with dataset: " << numfilt << endl; + + for (idx=0; idx < numfilt; idx++) { + nelmts = 0; + + filter_type = plist->getFilter(idx, flags, nelmts, cd_values, namelen, name , filter_info); + + cout << "Filter Type: "; + + switch (filter_type) { + case H5Z_FILTER_DEFLATE: + cout << "H5Z_FILTER_DEFLATE" << endl; + break; + case H5Z_FILTER_SZIP: + cout << "H5Z_FILTER_SZIP" << endl; + break; + default: + cout << "Other filter type included." << endl; + } + } + + // Read data. + dataset->read(rbuf, PredType::NATIVE_INT); + + delete plist; + delete dataset; + file.close(); // can be skipped + + } // end of try block + + // catch failure caused by the H5File operations + catch(FileIException error) + { + error.printError(); + return -1; + } + + // catch failure caused by the DataSet operations + catch(DataSetIException error) + { + error.printError(); + return -1; + } + + // catch failure caused by the DataSpace operations + catch(DataSpaceIException error) + { + error.printError(); + return -1; + } + + return 0; // successfully terminated +} + |