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Diffstat (limited to 'examples/h5_subset.c')
| -rw-r--r-- | examples/h5_subset.c | 141 |
1 files changed, 141 insertions, 0 deletions
diff --git a/examples/h5_subset.c b/examples/h5_subset.c new file mode 100644 index 0000000..4df2091 --- /dev/null +++ b/examples/h5_subset.c @@ -0,0 +1,141 @@ +/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * + * Copyright by The HDF Group. * + * 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 COPYING file, which can be found at the root of the source code * + * distribution tree, or in https://www.hdfgroup.org/licenses. * + * If you do not have access to either file, you may request a copy from * + * help@hdfgroup.org. * + * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */ + +/* + * This example illustrates how to read/write a subset of data (a slab) + * from/to a dataset in an HDF5 file. It is used in the HDF5 Tutorial. + */ + +#include "hdf5.h" + +#define FILE "subset.h5" +#define DATASETNAME "IntArray" +#define RANK 2 + +#define DIM0_SUB 3 /* subset dimensions */ +#define DIM1_SUB 4 + +#define DIM0 8 /* size of dataset */ +#define DIM1 10 + +int +main(void) +{ + hsize_t dims[2], dimsm[2]; + int data[DIM0][DIM1]; /* data to write */ + int sdata[DIM0_SUB][DIM1_SUB]; /* subset to write */ + int rdata[DIM0][DIM1]; /* buffer for read */ + + hid_t file_id, dataset_id; /* handles */ + hid_t dataspace_id, memspace_id; + + herr_t status; + + hsize_t count[2]; /* size of subset in the file */ + hsize_t offset[2]; /* subset offset in the file */ + hsize_t stride[2]; + hsize_t block[2]; + int i, j; + + /***************************************************************** + * Create a new file with default creation and access properties.* + * Then create a dataset and write data to it and close the file * + * and dataset. * + *****************************************************************/ + + file_id = H5Fcreate(FILE, H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT); + + dims[0] = DIM0; + dims[1] = DIM1; + dataspace_id = H5Screate_simple(RANK, dims, NULL); + + dataset_id = + H5Dcreate2(file_id, DATASETNAME, H5T_STD_I32BE, dataspace_id, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT); + + for (j = 0; j < DIM0; j++) { + for (i = 0; i < DIM1; i++) + if (i < (DIM1 / 2)) + data[j][i] = 1; + else + data[j][i] = 2; + } + + status = H5Dwrite(dataset_id, H5T_NATIVE_INT, H5S_ALL, H5S_ALL, H5P_DEFAULT, data); + + printf("\nData Written to File:\n"); + for (i = 0; i < DIM0; i++) { + for (j = 0; j < DIM1; j++) + printf(" %i", data[i][j]); + printf("\n"); + } + status = H5Sclose(dataspace_id); + status = H5Dclose(dataset_id); + status = H5Fclose(file_id); + + /***************************************************** + * Reopen the file and dataset and write a subset of * + * values to the dataset. + *****************************************************/ + + file_id = H5Fopen(FILE, H5F_ACC_RDWR, H5P_DEFAULT); + dataset_id = H5Dopen2(file_id, DATASETNAME, H5P_DEFAULT); + + /* Specify size and shape of subset to write. */ + + offset[0] = 1; + offset[1] = 2; + + count[0] = DIM0_SUB; + count[1] = DIM1_SUB; + + stride[0] = 1; + stride[1] = 1; + + block[0] = 1; + block[1] = 1; + + /* Create memory space with size of subset. Get file dataspace + and select subset from file dataspace. */ + + dimsm[0] = DIM0_SUB; + dimsm[1] = DIM1_SUB; + memspace_id = H5Screate_simple(RANK, dimsm, NULL); + + dataspace_id = H5Dget_space(dataset_id); + status = H5Sselect_hyperslab(dataspace_id, H5S_SELECT_SET, offset, stride, count, block); + + /* Write a subset of data to the dataset, then read the + entire dataset back from the file. */ + + printf("\nWrite subset to file specifying:\n"); + printf(" offset=1x2 stride=1x1 count=3x4 block=1x1\n"); + for (j = 0; j < DIM0_SUB; j++) { + for (i = 0; i < DIM1_SUB; i++) + sdata[j][i] = 5; + } + + status = H5Dwrite(dataset_id, H5T_NATIVE_INT, memspace_id, dataspace_id, H5P_DEFAULT, sdata); + + status = H5Dread(dataset_id, H5T_NATIVE_INT, H5S_ALL, H5S_ALL, H5P_DEFAULT, rdata); + + printf("\nData in File after Subset is Written:\n"); + for (i = 0; i < DIM0; i++) { + for (j = 0; j < DIM1; j++) + printf(" %i", rdata[i][j]); + printf("\n"); + } + + status = H5Sclose(memspace_id); + status = H5Sclose(dataspace_id); + status = H5Dclose(dataset_id); + status = H5Fclose(file_id); +} |