For the first example, DSET1 is a two-dimensional chunked dataset with atomic type defined below: DATASET "DSET1" {
DATATYPE H5T_STD_I32LE
DATASPACE SIMPLE { ( 4, 13 ) / ( 60, 100 ) }
:
:
}
The following coding sample illustrates the reading of data elements appended to the dataset DSET1: /* open the HDF5 file */
fid = H5Fopen(FILE, H5F_ACC_RDWR, H5P_DEFAULT);
/* open the dataset */
did = H5Dopen2(fid, "DSET1", H5P_DEFAULT);
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:
/* define hsize_t dims[2]; */
/* define hsize_t new_dims[2]; */
/* get the dataset's current dimension sizes */
H5LDget_dset_dims(did, dims);
/* extend the dataset by 2 */
new_dims[0] = dims[0] + 2;
new_dims[1] = dims[1] + 2;
H5Dset_extent(did, new_dims)
/* write data to the extended dataset */
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:
/* get the size of the dataset's data type */
type_size = H5LDget_dset_type_size(did, NULL);
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:
/* allocate buffer for storing selected data elements from the dataset */
/* calculate # of selected elements from dims & new_dims */
/* buffer size = type_size * number of selected elements */
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:
/* read the selected elements from the dataset into buf */
H5LDget_dset_elmts(did, dims, new_dims, NULL, buf);
:
:
H5Dclose(did);
H5Fclose(fid);
The output buffer will contain data elements selected from DSET1 as follows: data for elements (0, 13), (0, 14)
data for elements (1, 13), (1, 14)
data for elements (2, 13), (2, 14)
data for elements (3, 13), (3, 14)
data for elements (4, 0), (4, 1), (4, 2)......................(4, 13), (4, 14)
data for elements (5, 0), (5, 1), (5, 2)......................(5, 13), (5, 14)
For the second example, DSET2 is a one-dimensional chunked dataset with compound type defined below: DATASET "DSET2" {
DATATYPE H5T_COMPOUND {
H5T_STD_I32LE "a";
H5T_STD_I32LE "b";
H5T_ARRAY { [4] H5T_STD_I32LE } "c";
H5T_STD_I32LE "d";
H5T_STD_I32LE "e";
H5T_COMPOUND {
H5T_STD_I32LE "a";
H5T_STD_I32LE "b";
H5T_ARRAY {[4] H5T_STD_I32LE} "c";
H5T_STD_I32LE "d";
H5T_STD_I32LE "e";
} "s2";
}
DATASPACE SIMPLE { ( 5 ) / ( 5 ) }
:
:
}
The following coding sample illustrates the reading of data elements appended to the dataset DSET2 with compound datatype This example selects only 2 fields: the fourth field d and a subfield of the sixth field s2.c: /* open the HDF5 file */
fid = H5Fopen(FILE, H5F_ACC_RDWR, H5P_DEFAULT);
/* open the dataset */
did = H5Dopen2(fid, "DSET2", H5P_DEFAULT);
/* define hsize_t dims[1]; */
/* define hsize_t new_dims[1]; */
:
:
/* get the dataset's current dimension size */
H5LDget_dset_dims(did, dims);
/* extend the dataset by 2 */
new_dims[0] = dims[0] + 2;
H5Dset_extent(did, new_dims);
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:
/* write data to the extended part of the dataset */
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:
/* #define fields "d,s2.c" */
/* get the size of the dataset's data type for the selected fields */
type_size = H5LDget_dset_type_size(did, fields);
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:
/* allocate buffer for storing selected data elements from the dataset */
/* calculate # of selected elements from dims & new_dims */
/* buffer size = type_size * number of selected elements */
:
:
/* read the selected elements from the dataset into buf */
H5LD_get_dset_elmts(did, dims, new_dims, fields, buf);
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:
H5Dclose(did);
H5Fclose(fid);
The output buffer will contain data for d and s2.c selected from DSET2 as follows: Data for element (5): integer value for "d", 4 integer values for array "s2.c"
Data for element (6): integer value for "d", 4 integer values for array "s2.c" | 