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Diffstat (limited to 'doc/html/Tutor/examples/h5_compound.c')
-rw-r--r-- | doc/html/Tutor/examples/h5_compound.c | 153 |
1 files changed, 153 insertions, 0 deletions
diff --git a/doc/html/Tutor/examples/h5_compound.c b/doc/html/Tutor/examples/h5_compound.c new file mode 100644 index 0000000..4bb4ad1 --- /dev/null +++ b/doc/html/Tutor/examples/h5_compound.c @@ -0,0 +1,153 @@ +/* + * This example shows how to create a compound data type, + * write an array which has the compound data type to the file, + * and read back fields' subsets. + */ + +#include "hdf5.h" + +#define FILE "SDScompound.h5" +#define DATASETNAME "ArrayOfStructures" +#define LENGTH 10 +#define RANK 1 + +int +main(void) +{ + + /* First structure and dataset*/ + typedef struct s1_t { + int a; + float b; + double c; + } s1_t; + s1_t s1[LENGTH]; + hid_t s1_tid; /* File datatype identifier */ + + /* Second structure (subset of s1_t) and dataset*/ + typedef struct s2_t { + double c; + int a; + } s2_t; + s2_t s2[LENGTH]; + hid_t s2_tid; /* Memory datatype handle */ + + /* Third "structure" ( will be used to read float field of s1) */ + hid_t s3_tid; /* Memory datatype handle */ + float s3[LENGTH]; + + int i; + hid_t file, dataset, space; /* Handles */ + herr_t status; + hsize_t dim[] = {LENGTH}; /* Dataspace dimensions */ + + + /* + * Initialize the data + */ + for (i = 0; i< LENGTH; i++) { + s1[i].a = i; + s1[i].b = i*i; + s1[i].c = 1./(i+1); + } + + /* + * Create the data space. + */ + space = H5Screate_simple(RANK, dim, NULL); + + /* + * Create the file. + */ + file = H5Fcreate(FILE, H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT); + + /* + * Create the memory data type. + */ + s1_tid = H5Tcreate (H5T_COMPOUND, sizeof(s1_t)); + H5Tinsert(s1_tid, "a_name", HOFFSET(s1_t, a), H5T_NATIVE_INT); + H5Tinsert(s1_tid, "c_name", HOFFSET(s1_t, c), H5T_NATIVE_DOUBLE); + H5Tinsert(s1_tid, "b_name", HOFFSET(s1_t, b), H5T_NATIVE_FLOAT); + + /* + * Create the dataset. + */ + dataset = H5Dcreate(file, DATASETNAME, s1_tid, space, H5P_DEFAULT); + + /* + * Wtite data to the dataset; + */ + status = H5Dwrite(dataset, s1_tid, H5S_ALL, H5S_ALL, H5P_DEFAULT, s1); + + /* + * Release resources + */ + H5Tclose(s1_tid); + H5Sclose(space); + H5Dclose(dataset); + H5Fclose(file); + + /* + * Open the file and the dataset. + */ + file = H5Fopen(FILE, H5F_ACC_RDONLY, H5P_DEFAULT); + + dataset = H5Dopen(file, DATASETNAME); + + /* + * Create a data type for s2 + */ + s2_tid = H5Tcreate(H5T_COMPOUND, sizeof(s2_t)); + + H5Tinsert(s2_tid, "c_name", HOFFSET(s2_t, c), H5T_NATIVE_DOUBLE); + H5Tinsert(s2_tid, "a_name", HOFFSET(s2_t, a), H5T_NATIVE_INT); + + /* + * Read two fields c and a from s1 dataset. Fields in the file + * are found by their names "c_name" and "a_name". + */ + status = H5Dread(dataset, s2_tid, H5S_ALL, H5S_ALL, H5P_DEFAULT, s2); + + /* + * Display the fields + */ + printf("\n"); + printf("Field c : \n"); + for( i = 0; i < LENGTH; i++) printf("%.4f ", s2[i].c); + printf("\n"); + + printf("\n"); + printf("Field a : \n"); + for( i = 0; i < LENGTH; i++) printf("%d ", s2[i].a); + printf("\n"); + + /* + * Create a data type for s3. + */ + s3_tid = H5Tcreate(H5T_COMPOUND, sizeof(float)); + + status = H5Tinsert(s3_tid, "b_name", 0, H5T_NATIVE_FLOAT); + + /* + * Read field b from s1 dataset. Field in the file is found by its name. + */ + status = H5Dread(dataset, s3_tid, H5S_ALL, H5S_ALL, H5P_DEFAULT, s3); + + /* + * Display the field + */ + printf("\n"); + printf("Field b : \n"); + for( i = 0; i < LENGTH; i++) printf("%.4f ", s3[i]); + printf("\n"); + + /* + * Release resources + */ + H5Tclose(s2_tid); + H5Tclose(s3_tid); + H5Dclose(dataset); + H5Fclose(file); + + return 0; +} |