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Diffstat (limited to 'HDF5Examples/C/H5T/16/h5ex_t_vlstring.c')
-rw-r--r-- | HDF5Examples/C/H5T/16/h5ex_t_vlstring.c | 126 |
1 files changed, 126 insertions, 0 deletions
diff --git a/HDF5Examples/C/H5T/16/h5ex_t_vlstring.c b/HDF5Examples/C/H5T/16/h5ex_t_vlstring.c new file mode 100644 index 0000000..f790424 --- /dev/null +++ b/HDF5Examples/C/H5T/16/h5ex_t_vlstring.c @@ -0,0 +1,126 @@ +/************************************************************ + + This example shows how to read and write variable-length + string datatypes to a dataset. The program first writes + variable-length strings to a dataset with a dataspace of + DIM0, then closes the file. Next, it reopens the file, + reads back the data, and outputs it 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_vlstring.h5" +#define DATASET "DS1" +#define DIM0 4 + +int +main(void) +{ + hid_t file, filetype, memtype, space, dset; + /* Handles */ + herr_t status; + hsize_t dims[1] = {DIM0}; + char *wdata[DIM0] = {"Parting", "is such", "sweet", "sorrow."}, + /* Write buffer */ + **rdata; /* Read buffer */ + int ndims, i; + + /* + * Create a new file using the default properties. + */ + file = H5Fcreate(FILE, H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT); + + /* + * Create file and memory datatypes. For this example we will save + * the strings as FORTRAN strings. + */ + filetype = H5Tcopy(H5T_FORTRAN_S1); + status = H5Tset_size(filetype, H5T_VARIABLE); + memtype = H5Tcopy(H5T_C_S1); + status = H5Tset_size(memtype, H5T_VARIABLE); + + /* + * Create dataspace. Setting maximum size to NULL sets the maximum + * size to be the current size. + */ + space = H5Screate_simple(1, dims, NULL); + + /* + * Create the dataset and write the variable-length string data to + * it. + */ + dset = H5Dcreate(file, DATASET, filetype, space, H5P_DEFAULT); + status = H5Dwrite(dset, memtype, H5S_ALL, H5S_ALL, H5P_DEFAULT, wdata); + + /* + * Close and release resources. + */ + status = H5Dclose(dset); + status = H5Sclose(space); + status = H5Tclose(filetype); + status = H5Tclose(memtype); + status = H5Fclose(file); + + /* + * Now we begin the read section of this example. Here we assume + * the dataset 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 and dataset. + */ + file = H5Fopen(FILE, H5F_ACC_RDONLY, H5P_DEFAULT); + dset = H5Dopen(file, DATASET); + + /* + * Get the datatype. + */ + filetype = H5Dget_type(dset); + + /* + * Get dataspace and allocate memory for read buffer. + */ + space = H5Dget_space(dset); + ndims = H5Sget_simple_extent_dims(space, dims, NULL); + rdata = (char **)malloc(dims[0] * sizeof(char *)); + + /* + * Create the memory datatype. + */ + memtype = H5Tcopy(H5T_C_S1); + status = H5Tset_size(memtype, H5T_VARIABLE); + + /* + * Read the data. + */ + status = H5Dread(dset, memtype, H5S_ALL, H5S_ALL, H5P_DEFAULT, rdata); + + /* + * Output the data to the screen. + */ + for (i = 0; i < dims[0]; i++) + printf("%s[%d]: %s\n", DATASET, i, rdata[i]); + + /* + * Close and release resources. Note that H5Dvlen_reclaim works + * for variable-length strings as well as variable-length arrays. + * Also note that we must still free the array of pointers stored + * in rdata, as H5Tvlen_reclaim only frees the data these point to. + */ + status = H5Dvlen_reclaim(memtype, space, H5P_DEFAULT, rdata); + free(rdata); + status = H5Dclose(dset); + status = H5Sclose(space); + status = H5Tclose(filetype); + status = H5Tclose(memtype); + status = H5Fclose(file); + + return 0; +} |