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Diffstat (limited to 'HDF5Examples/C/H5D/h5ex_d_shuffle.c')
| -rw-r--r-- | HDF5Examples/C/H5D/h5ex_d_shuffle.c | 204 |
1 files changed, 204 insertions, 0 deletions
diff --git a/HDF5Examples/C/H5D/h5ex_d_shuffle.c b/HDF5Examples/C/H5D/h5ex_d_shuffle.c new file mode 100644 index 0000000..6e2fb5c --- /dev/null +++ b/HDF5Examples/C/H5D/h5ex_d_shuffle.c @@ -0,0 +1,204 @@ +/************************************************************ + + This example shows how to read and write data to a dataset + using the shuffle filter with gzip compression. The + program first checks if the shuffle and gzip filters are + available, then if they are it writes integers to a + dataset using shuffle+gzip, then closes the file. Next, + it reopens the file, reads back the data, and outputs the + types of filters and the maximum value in the dataset to + the screen. + + This file is intended for use with HDF5 Library version 1.8 + + ************************************************************/ + +#include "hdf5.h" +#include <stdio.h> +#include <stdlib.h> + +#define FILE "h5ex_d_shuffle.h5" +#define DATASET "DS1" +#define DIM0 32 +#define DIM1 64 +#define CHUNK0 4 +#define CHUNK1 8 + +int +main(void) +{ + hid_t file = H5I_INVALID_HID; + hid_t space = H5I_INVALID_HID; + hid_t dset = H5I_INVALID_HID; + hid_t dcpl = H5I_INVALID_HID; + herr_t status; + htri_t avail; + H5Z_filter_t filter_type; + hsize_t dims[2] = {DIM0, DIM1}; + hsize_t chunk[2] = {CHUNK0, CHUNK1}; + size_t nelmts; + unsigned int flags; + unsigned int filter_info; + int wdata[DIM0][DIM1]; /* Write buffer */ + int rdata[DIM0][DIM1]; /* Read buffer */ + int max, nfilters; + int i, j; + + /* + * Check if gzip compression is available and can be used for both + * compression and decompression. Normally we do not perform error + * checking in these examples for the sake of clarity, but in this + * case we will make an exception because this filter is an + * optional part of the hdf5 library. + */ + avail = H5Zfilter_avail(H5Z_FILTER_DEFLATE); + if (!avail) { + printf("gzip filter not available.\n"); + return 1; + } + status = H5Zget_filter_info(H5Z_FILTER_DEFLATE, &filter_info); + if (!(filter_info & H5Z_FILTER_CONFIG_ENCODE_ENABLED) || + !(filter_info & H5Z_FILTER_CONFIG_DECODE_ENABLED)) { + printf("gzip filter not available for encoding and decoding.\n"); + return 1; + } + + /* + * Similarly, check for availability of the shuffle filter. + */ + avail = H5Zfilter_avail(H5Z_FILTER_SHUFFLE); + if (!avail) { + printf("Shuffle filter not available.\n"); + return 1; + } + status = H5Zget_filter_info(H5Z_FILTER_SHUFFLE, &filter_info); + if (!(filter_info & H5Z_FILTER_CONFIG_ENCODE_ENABLED) || + !(filter_info & H5Z_FILTER_CONFIG_DECODE_ENABLED)) { + printf("Shuffle filter not available for encoding and decoding.\n"); + return 1; + } + + /* + * Initialize data. + */ + for (i = 0; i < DIM0; i++) + for (j = 0; j < DIM1; j++) + wdata[i][j] = i * j - j; + + /* + * Create a new file using the default properties. + */ + file = H5Fcreate(FILE, H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT); + + /* + * Create dataspace. Setting maximum size to NULL sets the maximum + * size to be the current size. + */ + space = H5Screate_simple(2, dims, NULL); + + /* + * Create the dataset creation property list, add the shuffle + * filter and the gzip compression filter and set the chunk size. + * The order in which the filters are added here is significant - + * we will see much greater results when the shuffle is applied + * first. The order in which the filters are added to the property + * list is the order in which they will be invoked when writing + * data. + */ + dcpl = H5Pcreate(H5P_DATASET_CREATE); + status = H5Pset_shuffle(dcpl); + status = H5Pset_deflate(dcpl, 9); + status = H5Pset_chunk(dcpl, 2, chunk); + + /* + * Create the dataset. + */ + dset = H5Dcreate(file, DATASET, H5T_STD_I32LE, space, H5P_DEFAULT, dcpl, H5P_DEFAULT); + + /* + * Write the data to the dataset. + */ + status = H5Dwrite(dset, H5T_NATIVE_INT, H5S_ALL, H5S_ALL, H5P_DEFAULT, wdata[0]); + + /* + * Close and release resources. + */ + status = H5Pclose(dcpl); + status = H5Dclose(dset); + status = H5Sclose(space); + status = H5Fclose(file); + + /* + * Now we begin the read section of this example. + */ + + /* + * Open file and dataset using the default properties. + */ + file = H5Fopen(FILE, H5F_ACC_RDONLY, H5P_DEFAULT); + dset = H5Dopen(file, DATASET, H5P_DEFAULT); + + /* + * Retrieve dataset creation property list. + */ + dcpl = H5Dget_create_plist(dset); + + /* + * Retrieve the number of filters, and retrieve and print the + * type of each. + */ + nfilters = H5Pget_nfilters(dcpl); + for (i = 0; i < nfilters; i++) { + nelmts = 0; + filter_type = H5Pget_filter(dcpl, i, &flags, &nelmts, NULL, 0, NULL, &filter_info); + printf("Filter %d: Type is: ", i); + switch (filter_type) { + case H5Z_FILTER_DEFLATE: + printf("H5Z_FILTER_DEFLATE\n"); + break; + case H5Z_FILTER_SHUFFLE: + printf("H5Z_FILTER_SHUFFLE\n"); + break; + case H5Z_FILTER_FLETCHER32: + printf("H5Z_FILTER_FLETCHER32\n"); + break; + case H5Z_FILTER_SZIP: + printf("H5Z_FILTER_SZIP\n"); + break; + case H5Z_FILTER_NBIT: + printf("H5Z_FILTER_NBIT\n"); + break; + case H5Z_FILTER_SCALEOFFSET: + printf("H5Z_FILTER_SCALEOFFSET\n"); + } + } + + /* + * Read the data using the default properties. + */ + status = H5Dread(dset, H5T_NATIVE_INT, H5S_ALL, H5S_ALL, H5P_DEFAULT, rdata[0]); + + /* + * Find the maximum value in the dataset, to verify that it was + * read correctly. + */ + max = rdata[0][0]; + for (i = 0; i < DIM0; i++) + for (j = 0; j < DIM1; j++) + if (max < rdata[i][j]) + max = rdata[i][j]; + + /* + * Print the maximum value. + */ + printf("Maximum value in %s is: %d\n", DATASET, max); + + /* + * Close and release resources. + */ + status = H5Pclose(dcpl); + status = H5Dclose(dset); + status = H5Fclose(file); + + return 0; +} |