/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * 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 the concept of the virtual dataset. Percival use case. Every fifth 10x10 plane in VDS is stored in the corresponding 3D unlimited dataset. EIP: For now we will use finite dimension. There are 4 source datasets total. This file is intended for use with HDF5 Library version 1.10 ************************************************************/ /* EIP Add link to the picture */ #include "hdf5.h" #include #include #define FILE "vds-percival.h5" #define DATASET "VDS-Percival" /* later #define VDSDIM0 H5S_UNLIMITED */ #define VDSDIM0 40 #define VDSDIM1 10 #define VDSDIM2 10 /* later #define DIM0 H5S_UNLIMITED */ #define DIM0 10 #define DIM1 10 #define DIM2 10 #define RANK 3 #define PLANE_STRIDE 4 const char *SRC_FILE[] = {"a.h5", "b.h5", "c.h5", "d.h5"}; const char *SRC_DATASET[] = {"A", "B", "C", "D"}; int main(void) { hid_t file, src_space, vspace, dset; /* Handles */ hid_t dcpl; herr_t status; hsize_t vdsdims[3] = {VDSDIM0, VDSDIM1, VDSDIM2}, vdsdims_max[3] = {VDSDIM0, VDSDIM1, VDSDIM2}, dims[3] = {DIM0, DIM1, DIM2}, dims_max[3] = {DIM0, DIM1, DIM2}, start[3], /* Hyperslab start parameter for VDS */ stride[3], count[3], src_count[3], block[3]; hsize_t start_out[3], /* Hyperslab parameter out */ stride_out[3], count_out[3], block_out[3]; int i, j; H5D_layout_t layout; /* Storage layout */ size_t num_map; /* Number of mappings */ ssize_t len; /* Length of the string; also a return value */ char *filename; char *dsetname; int wdata[DIM0 * DIM1 * DIM2]; /* * Create source files and datasets. This step is optional. */ for (i = 0; i < PLANE_STRIDE; i++) { /* * Initialize data for i-th source dataset. */ for (j = 0; j < DIM0 * DIM1 * DIM2; j++) wdata[j] = i + 1; /* * Create the source files and datasets. Write data to each dataset and * close all resources. */ file = H5Fcreate(SRC_FILE[i], H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT); src_space = H5Screate_simple(RANK, dims, NULL); dset = H5Dcreate2(file, SRC_DATASET[i], H5T_NATIVE_INT, src_space, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT); status = H5Dwrite(dset, H5T_NATIVE_INT, H5S_ALL, H5S_ALL, H5P_DEFAULT, wdata); status = H5Sclose(src_space); status = H5Dclose(dset); status = H5Fclose(file); } file = H5Fcreate(FILE, H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT); /* Create VDS dataspace. */ vspace = H5Screate_simple(RANK, vdsdims, vdsdims_max); /* Create dataspaces for the source dataset. */ src_space = H5Screate_simple(RANK, dims, dims_max); /* Create VDS creation property */ dcpl = H5Pcreate(H5P_DATASET_CREATE); /* Initialize hyperslab values */ start[0] = 0; start[1] = 0; start[2] = 0; stride[0] = PLANE_STRIDE; /* we will select every fifth plane in VDS */ stride[1] = 1; stride[2] = 1; /* later count[0] = H5S_UNLIMITED; */ count[0] = VDSDIM0 / 4; count[1] = 1; count[2] = 1; /* later src_count[0] = H5S_UNLIMITED; */ src_count[0] = DIM0; src_count[1] = 1; src_count[2] = 1; block[0] = 1; block[1] = DIM1; block[2] = DIM2; /* * Build the mappings * */ status = H5Sselect_hyperslab(src_space, H5S_SELECT_SET, start, NULL, src_count, block); for (i = 0; i < PLANE_STRIDE; i++) { status = H5Sselect_hyperslab(vspace, H5S_SELECT_SET, start, stride, count, block); status = H5Pset_virtual(dcpl, vspace, SRC_FILE[i], SRC_DATASET[i], src_space); start[0]++; } H5Sselect_none(vspace); /* Create a virtual dataset */ dset = H5Dcreate2(file, DATASET, H5T_NATIVE_INT, vspace, H5P_DEFAULT, dcpl, H5P_DEFAULT); status = H5Sclose(vspace); status = H5Sclose(src_space); status = H5Dclose(dset); 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 = H5Dopen2(file, DATASET, H5P_DEFAULT); /* * Get creation property list and mapping properties. */ dcpl = H5Dget_create_plist(dset); /* * Get storage layout. */ layout = H5Pget_layout(dcpl); if (H5D_VIRTUAL == layout) printf(" Dataset has a virtual layout \n"); else printf(" Wrong layout found \n"); /* * Find number of mappings. */ status = H5Pget_virtual_count(dcpl, &num_map); printf(" Number of mappings is %lu\n", (unsigned long)num_map); /* * Get mapping parameters for each mapping. */ for (i = 0; i < (int)num_map; i++) { printf(" Mapping %d \n", i); printf(" Selection in the virtual dataset \n"); /* Get selection in the virtual dataset */ vspace = H5Pget_virtual_vspace(dcpl, (size_t)i); if (H5Sget_select_type(vspace) == H5S_SEL_HYPERSLABS) { if (H5Sis_regular_hyperslab(vspace)) { status = H5Sget_regular_hyperslab(vspace, start_out, stride_out, count_out, block_out); printf(" start = [%llu, %llu, %llu] \n", (unsigned long long)start_out[0], (unsigned long long)start_out[1], (unsigned long long)start_out[2]); printf(" stride = [%llu, %llu, %llu] \n", (unsigned long long)stride_out[0], (unsigned long long)stride_out[1], (unsigned long long)stride_out[2]); printf(" count = [%llu, %llu, %llu] \n", (unsigned long long)count_out[0], (unsigned long long)count_out[1], (unsigned long long)count_out[2]); printf(" block = [%llu, %llu, %llu] \n", (unsigned long long)block_out[0], (unsigned long long)block_out[1], (unsigned long long)block_out[2]); } } /* Get source file name */ len = H5Pget_virtual_filename(dcpl, (size_t)i, NULL, 0); filename = (char *)malloc((size_t)len * sizeof(char) + 1); H5Pget_virtual_filename(dcpl, (size_t)i, filename, len + 1); printf(" Source filename %s\n", filename); /* Get source dataset name */ len = H5Pget_virtual_dsetname(dcpl, (size_t)i, NULL, 0); dsetname = (char *)malloc((size_t)len * sizeof(char) + 1); H5Pget_virtual_dsetname(dcpl, (size_t)i, dsetname, len + 1); printf(" Source dataset name %s\n", dsetname); /* Get selection in the source dataset */ printf(" Selection in the source dataset \n"); src_space = H5Pget_virtual_srcspace(dcpl, (size_t)i); if (H5Sget_select_type(src_space) == H5S_SEL_HYPERSLABS) { if (H5Sis_regular_hyperslab(src_space)) { status = H5Sget_regular_hyperslab(src_space, start_out, stride_out, count_out, block_out); printf(" start = [%llu, %llu, %llu] \n", (unsigned long long)start_out[0], (unsigned long long)start_out[1], (unsigned long long)start_out[2]); printf(" stride = [%llu, %llu, %llu] \n", (unsigned long long)stride_out[0], (unsigned long long)stride_out[1], (unsigned long long)stride_out[2]); printf(" count = [%llu, %llu, %llu] \n", (unsigned long long)count_out[0], (unsigned long long)count_out[1], (unsigned long long)count_out[2]); printf(" block = [%llu, %llu, %llu] \n", (unsigned long long)block_out[0], (unsigned long long)block_out[1], (unsigned long long)block_out[2]); } } H5Sclose(vspace); H5Sclose(src_space); free(filename); free(dsetname); } /* * Close and release resources. */ status = H5Pclose(dcpl); status = H5Dclose(dset); status = H5Fclose(file); return 0; }