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[eos/hostdependARM64MAC64.git] / share / hdf5_examples / c / h5_compound.c

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+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * Copyright by The HDF Group.                                               *
+ * Copyright by the Board of Trustees of the University of Illinois.         *
+ * All rights reserved.                                                      *
+ *                                                                           *
+ * This file is part of HDF5.  The full HDF5 copyright notice, including     *
+ * terms governing use, modification, and redistribution, is contained in    *
+ * the COPYING file, which can be found at the root of the source code       *
+ * distribution tree, or in https://www.hdfgroup.org/licenses.               *
+ * If you do not have access to either file, you may request a copy from     *
+ * help@hdfgroup.org.                                                        *
+ * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
+
+/*
+ * 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 H5FILE_NAME "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(H5FILE_NAME, 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 = H5Dcreate2(file, DATASETNAME, s1_tid, space, H5P_DEFAULT, H5P_DEFAULT, 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(H5FILE_NAME, H5F_ACC_RDONLY, H5P_DEFAULT);
+
+    dataset = H5Dopen2(file, DATASETNAME, H5P_DEFAULT);
+
+    /*
+     * 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;
+}