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Diffstat (limited to 'HDF5Examples/C/H5T/16/h5ex_t_regrefatt.c')
| -rw-r--r-- | HDF5Examples/C/H5T/16/h5ex_t_regrefatt.c | 182 |
1 files changed, 182 insertions, 0 deletions
diff --git a/HDF5Examples/C/H5T/16/h5ex_t_regrefatt.c b/HDF5Examples/C/H5T/16/h5ex_t_regrefatt.c new file mode 100644 index 0000000..1f993fb --- /dev/null +++ b/HDF5Examples/C/H5T/16/h5ex_t_regrefatt.c @@ -0,0 +1,182 @@ +/************************************************************ + + This example shows how to read and write region references + to an attribute. The program first creates a dataset + containing characters and writes references to region of + the dataset to a new attribute with a dataspace of DIM0, + then closes the file. Next, it reopens the file, + dereferences the references, and outputs the referenced + regions to the screen. + + This file is intended for use with HDF5 Library version 1.6 + + ************************************************************/ + +#include "hdf5.h" +#include <stdio.h> +#include <stdlib.h> + +#define FILE "h5ex_t_regrefatt.h5" +#define DATASET "DS1" +#define DATASET2 "DS2" +#define ATTRIBUTE "A1" +#define DIM0 2 +#define DS2DIM0 3 +#define DS2DIM1 16 + +int +main(void) +{ + hid_t file, space, memspace, dset, dset2, attr; + /* Handles */ + herr_t status; + hsize_t dims[1] = {DIM0}, dims2[2] = {DS2DIM0, DS2DIM1}, coords[4][2] = {{0, 1}, {2, 11}, {1, 0}, {2, 4}}, + start[2] = {0, 0}, stride[2] = {2, 11}, count[2] = {2, 2}, block[2] = {1, 3}; + hssize_t npoints; + hdset_reg_ref_t wdata[DIM0], /* Write buffer */ + *rdata; /* Read buffer */ + ssize_t size; + char wdata2[DS2DIM0][DS2DIM1] = {"The quick brown", "fox jumps over ", "the 5 lazy dogs"}, *rdata2, *name; + int ndims, i; + + /* + * Create a new file using the default properties. + */ + file = H5Fcreate(FILE, H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT); + + /* + * Create a dataset with character data. + */ + space = H5Screate_simple(2, dims2, NULL); + dset2 = H5Dcreate(file, DATASET2, H5T_STD_I8LE, space, H5P_DEFAULT); + status = H5Dwrite(dset2, H5T_NATIVE_CHAR, H5S_ALL, H5S_ALL, H5P_DEFAULT, wdata2); + + /* + * Create reference to a list of elements in dset2. + */ + status = H5Sselect_elements(space, H5S_SELECT_SET, 4, coords[0]); + status = H5Rcreate(&wdata[0], file, DATASET2, H5R_DATASET_REGION, space); + + /* + * Create reference to a hyperslab in dset2, close dataspace. + */ + status = H5Sselect_hyperslab(space, H5S_SELECT_SET, start, stride, count, block); + status = H5Rcreate(&wdata[1], file, DATASET2, H5R_DATASET_REGION, space); + status = H5Sclose(space); + + /* + * Create dataset with a scalar dataspace to serve as the parent + * for the attribute. + */ + space = H5Screate(H5S_SCALAR); + dset = H5Dcreate(file, DATASET, H5T_STD_I32LE, space, H5P_DEFAULT); + status = H5Sclose(space); + + /* + * Create dataspace. Setting maximum size to NULL sets the maximum + * size to be the current size. + */ + space = H5Screate_simple(1, dims, NULL); + + /* + * Create the attribute and write the region references to it. + */ + attr = H5Acreate(dset, ATTRIBUTE, H5T_STD_REF_DSETREG, space, H5P_DEFAULT); + status = H5Awrite(attr, H5T_STD_REF_DSETREG, wdata); + + /* + * Close and release resources. + */ + status = H5Aclose(attr); + status = H5Dclose(dset); + status = H5Dclose(dset2); + status = H5Sclose(space); + status = H5Fclose(file); + + /* + * Now we begin the read section of this example. Here we assume + * the attribute has the same name and rank, but can have any size. + * Therefore we must allocate a new array to read in data using + * malloc(). + */ + + /* + * Open file, dataset, and attribute. + */ + file = H5Fopen(FILE, H5F_ACC_RDONLY, H5P_DEFAULT); + dset = H5Dopen(file, DATASET); + attr = H5Aopen_name(dset, ATTRIBUTE); + + /* + * Get dataspace and allocate memory for read buffer. + */ + space = H5Aget_space(attr); + ndims = H5Sget_simple_extent_dims(space, dims, NULL); + rdata = (hdset_reg_ref_t *)malloc(dims[0] * sizeof(hdset_reg_ref_t)); + status = H5Sclose(space); + + /* + * Read the data. + */ + status = H5Aread(attr, H5T_STD_REF_DSETREG, rdata); + + /* + * Output the data to the screen. + */ + for (i = 0; i < dims[0]; i++) { + printf("%s[%d]:\n ->", ATTRIBUTE, i); + + /* + * Open the referenced object, retrieve its region as a + * dataspace selection. + */ + dset2 = H5Rdereference(dset, H5R_DATASET_REGION, &rdata[i]); + space = H5Rget_region(dset, H5R_DATASET_REGION, &rdata[i]); + + /* + * Get the length of the object's name, allocate space, then + * retrieve the name. + */ + size = 1 + H5Iget_name(dset2, NULL, 0); + name = (char *)malloc(size); + size = H5Iget_name(dset2, name, size); + if (size <= 1) + name[0] = '\0'; + + /* + * Allocate space for the read buffer. We will only allocate + * enough space for the selection, plus a null terminator. The + * read buffer will be 1-dimensional. + */ + npoints = H5Sget_select_npoints(space); + rdata2 = (char *)malloc(npoints + 1); + + /* + * Read the dataset region, and add a null terminator so we can + * print it as a string. + */ + memspace = H5Screate_simple(1, (hsize_t *)&npoints, NULL); + status = H5Dread(dset2, H5T_NATIVE_CHAR, memspace, space, H5P_DEFAULT, rdata2); + rdata2[npoints] = '\0'; + + /* + * Print the name and region data, close and release resources. + */ + printf(" %s: %s\n", name, rdata2); + free(rdata2); + free(name); + status = H5Sclose(space); + status = H5Sclose(memspace); + status = H5Dclose(dset2); + } + + /* + * Close and release resources. + */ + free(rdata); + status = H5Aclose(attr); + status = H5Dclose(dset); + status = H5Fclose(file); + + return 0; +} |