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Diffstat (limited to 'HDF5Examples/C/H5T/h5ex_t_cmpdatt.c')
-rw-r--r-- | HDF5Examples/C/H5T/h5ex_t_cmpdatt.c | 171 |
1 files changed, 171 insertions, 0 deletions
diff --git a/HDF5Examples/C/H5T/h5ex_t_cmpdatt.c b/HDF5Examples/C/H5T/h5ex_t_cmpdatt.c new file mode 100644 index 0000000..246537b --- /dev/null +++ b/HDF5Examples/C/H5T/h5ex_t_cmpdatt.c @@ -0,0 +1,171 @@ +/************************************************************ + + This example shows how to read and write compound + datatypes to an attribute. The program first writes + compound structures to an attribute with a dataspace of + DIM0, then closes the file. Next, it reopens the file, + reads back the data, and outputs it to the screen. + + ************************************************************/ + +#include "hdf5.h" +#include <stdio.h> +#include <stdlib.h> + +#define FILE "h5ex_t_cmpdatt.h5" +#define DATASET "DS1" +#define ATTRIBUTE "A1" +#define DIM0 4 + +typedef struct { + int serial_no; + char *location; + double temperature; + double pressure; +} sensor_t; /* Compound type */ + +int +main(void) +{ + hid_t file, filetype, memtype, strtype, space, dset, attr; + /* Handles */ + herr_t status; + hsize_t dims[1] = {DIM0}; + sensor_t wdata[DIM0], /* Write buffer */ + *rdata; /* Read buffer */ + int ndims; + hsize_t i; + + /* + * Initialize data. + */ + wdata[0].serial_no = 1153; + wdata[0].location = "Exterior (static)"; + wdata[0].temperature = 53.23; + wdata[0].pressure = 24.57; + wdata[1].serial_no = 1184; + wdata[1].location = "Intake"; + wdata[1].temperature = 55.12; + wdata[1].pressure = 22.95; + wdata[2].serial_no = 1027; + wdata[2].location = "Intake manifold"; + wdata[2].temperature = 103.55; + wdata[2].pressure = 31.23; + wdata[3].serial_no = 1313; + wdata[3].location = "Exhaust manifold"; + wdata[3].temperature = 1252.89; + wdata[3].pressure = 84.11; + + /* + * Create a new file using the default properties. + */ + file = H5Fcreate(FILE, H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT); + + /* + * Create variable-length string datatype. + */ + strtype = H5Tcopy(H5T_C_S1); + status = H5Tset_size(strtype, H5T_VARIABLE); + + /* + * Create the compound datatype for memory. + */ + memtype = H5Tcreate(H5T_COMPOUND, sizeof(sensor_t)); + status = H5Tinsert(memtype, "Serial number", HOFFSET(sensor_t, serial_no), H5T_NATIVE_INT); + status = H5Tinsert(memtype, "Location", HOFFSET(sensor_t, location), strtype); + status = H5Tinsert(memtype, "Temperature (F)", HOFFSET(sensor_t, temperature), H5T_NATIVE_DOUBLE); + status = H5Tinsert(memtype, "Pressure (inHg)", HOFFSET(sensor_t, pressure), H5T_NATIVE_DOUBLE); + + /* + * Create the compound datatype for the file. Because the standard + * types we are using for the file may have different sizes than + * the corresponding native types, we must manually calculate the + * offset of each member. + */ + filetype = H5Tcreate(H5T_COMPOUND, 8 + sizeof(hvl_t) + 8 + 8); + status = H5Tinsert(filetype, "Serial number", 0, H5T_STD_I64BE); + status = H5Tinsert(filetype, "Location", 8, strtype); + status = H5Tinsert(filetype, "Temperature (F)", 8 + sizeof(hvl_t), H5T_IEEE_F64BE); + status = H5Tinsert(filetype, "Pressure (inHg)", 8 + sizeof(hvl_t) + 8, H5T_IEEE_F64BE); + + /* + * Create dataset with a null dataspace. + */ + space = H5Screate(H5S_NULL); + dset = H5Dcreate(file, DATASET, H5T_STD_I32LE, space, H5P_DEFAULT, H5P_DEFAULT, 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 compound data to it. + */ + attr = H5Acreate(dset, ATTRIBUTE, filetype, space, H5P_DEFAULT, H5P_DEFAULT); + status = H5Awrite(attr, memtype, wdata); + + /* + * Close and release resources. + */ + status = H5Aclose(attr); + status = H5Dclose(dset); + status = H5Sclose(space); + status = H5Tclose(filetype); + 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(). For simplicity, we do not rebuild memtype. + */ + + /* + * Open file, dataset, and attribute. + */ + file = H5Fopen(FILE, H5F_ACC_RDONLY, H5P_DEFAULT); + dset = H5Dopen(file, DATASET, H5P_DEFAULT); + attr = H5Aopen(dset, ATTRIBUTE, H5P_DEFAULT); + + /* + * Get dataspace and allocate memory for read buffer. + */ + space = H5Aget_space(attr); + ndims = H5Sget_simple_extent_dims(space, dims, NULL); + rdata = (sensor_t *)malloc(dims[0] * sizeof(sensor_t)); + + /* + * Read the data. + */ + status = H5Aread(attr, memtype, rdata); + + /* + * Output the data to the screen. + */ + for (i = 0; i < dims[0]; i++) { + printf("%s[%llu]:\n", ATTRIBUTE, i); + printf("Serial number : %d\n", rdata[i].serial_no); + printf("Location : %s\n", rdata[i].location); + printf("Temperature (F) : %f\n", rdata[i].temperature); + printf("Pressure (inHg) : %f\n\n", rdata[i].pressure); + } + + /* + * Close and release resources. H5Dvlen_reclaim will automatically + * traverse the structure and free any vlen data (strings in this + * case). + */ + status = H5Dvlen_reclaim(memtype, space, H5P_DEFAULT, rdata); + free(rdata); + status = H5Aclose(attr); + status = H5Dclose(dset); + status = H5Sclose(space); + status = H5Tclose(memtype); + status = H5Tclose(strtype); + status = H5Fclose(file); + + return 0; +} |