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Diffstat (limited to 'HDF5Examples/C/H5T/16/h5ex_t_objrefatt.c')
| -rw-r--r-- | HDF5Examples/C/H5T/16/h5ex_t_objrefatt.c | 175 |
1 files changed, 175 insertions, 0 deletions
diff --git a/HDF5Examples/C/H5T/16/h5ex_t_objrefatt.c b/HDF5Examples/C/H5T/16/h5ex_t_objrefatt.c new file mode 100644 index 0000000..95d86dc --- /dev/null +++ b/HDF5Examples/C/H5T/16/h5ex_t_objrefatt.c @@ -0,0 +1,175 @@ +/************************************************************ + + This example shows how to read and write object references + to an attribute. The program first creates objects in the + file and writes references to those objects to an + attribute with a dataspace of DIM0, then closes the file. + Next, it reopens the file, dereferences the references, + and outputs the names of their targets 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_objrefatt.h5" +#define DATASET "DS1" +#define ATTRIBUTE "A1" +#define DIM0 2 + +int +main(void) +{ + hid_t file; /* File Handle */ + hid_t space; /* Dataspace Handle */ + hid_t dset; /* Dataset Handle */ + hid_t obj; /* Object Handle */ + herr_t status; + hsize_t dims[1] = {DIM0}; + hobj_ref_t wdata[DIM0]; /* Write buffer */ + hobj_ref_t *rdata = NULL; /* Read buffer */ + H5G_obj_t objtype; + ssize_t size; + char *name = NULL; + int ndims; + int i; + + /* + * Create a new file using the default properties. + */ + file = H5Fcreate(FILE, H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT); + + /* + * Create a dataset with a scalar dataspace. + */ + space = H5Screate(H5S_SCALAR); + obj = H5Dcreate(file, "DS2", H5T_STD_I32LE, space, H5P_DEFAULT); + status = H5Dclose(obj); + status = H5Sclose(space); + + /* + * Create a group. + */ + obj = H5Gcreate(file, "G1", H5P_DEFAULT); + status = H5Gclose(obj); + + /* + * Create references to the previously created objects. Passing -1 + * as space_id causes this parameter to be ignored. Other values + * besides valid dataspaces result in an error. + */ + status = H5Rcreate(&wdata[0], file, "G1", H5R_OBJECT, -1); + status = H5Rcreate(&wdata[1], file, "DS2", H5R_OBJECT, -1); + + /* + * 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 object references to it. + */ + attr = H5Acreate(dset, ATTRIBUTE, H5T_STD_REF_OBJ, space, H5P_DEFAULT); + status = H5Awrite(attr, H5T_STD_REF_OBJ, wdata); + + /* + * Close and release resources. + */ + status = H5Aclose(attr); + status = H5Dclose(dset); + 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 = (hobj_ref_t *)malloc(dims[0] * sizeof(hobj_ref_t)); + + /* + * Read the data. + */ + status = H5Aread(attr, H5T_STD_REF_OBJ, rdata); + + /* + * Output the data to the screen. + */ + for (i = 0; i < dims[0]; i++) { + printf("%s[%d]:\n ->", ATTRIBUTE, i); + + /* + * Open the referenced object, get its name and type. + */ + obj = H5Rdereference(dset, H5R_OBJECT, &rdata[i]); + objtype = H5Rget_obj_type(dset, H5R_OBJECT, &rdata[i]); + + /* + * Get the length of the name, allocate space, then retrieve + * the name. + */ + size = 1 + H5Iget_name(obj, NULL, 0); + name = (char *)malloc(size); + size = H5Iget_name(obj, name, size); + + /* + * Print the object type and close the object. + */ + switch (objtype) { + case H5G_GROUP: + printf("Group"); + status = H5Gclose(obj); + break; + case H5G_DATASET: + printf("Dataset"); + status = H5Dclose(obj); + break; + case H5G_TYPE: + printf("Named Datatype"); + status = H5Tclose(obj); + } + + /* + * Print the name and deallocate space for the name. + */ + printf(": %s\n", name); + free(name); + } + + /* + * Close and release resources. + */ + free(rdata); + status = H5Aclose(attr); + status = H5Dclose(dset); + status = H5Sclose(space); + status = H5Fclose(file); + + return 0; +} |