hdf5/hl/examples/ptExampleFL.c

/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * 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.                                                        *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

#include "hdf5_hl.h"
#include <stdlib.h>

/*-------------------------------------------------------------------------
 * Packet Table Fixed-Length Example
 *
 * Example program that creates a packet table and performs
 * writes and reads.
 *
 *-------------------------------------------------------------------------
 */

int
main(void)
{
    hid_t fid;    /* File identifier */
    hid_t ptable; /* Packet table identifier */

    herr_t  err;   /* Function return status */
    hsize_t count; /* Number of records in the table */

    int x; /* Loop variable */

    /* Buffers to hold data */
    int writeBuffer[5];
    int readBuffer[5];

    /* Initialize buffers */
    for (x = 0; x < 5; x++) {
        writeBuffer[x] = x;
        readBuffer[x]  = -1;
    }

    /* Create a file using default properties */
    fid = H5Fcreate("packet_table_FLexample.h5", H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT);

    /* Create a fixed-length packet table within the file */
    /* This table's "packets" will be simple integers and it will use compression
     * level 5. */
    ptable = H5PTcreate_fl(fid, "Packet Test Dataset", H5T_NATIVE_INT, (hsize_t)100, 5);
    if (ptable == H5I_INVALID_HID)
        goto out;

    /* Write one packet to the packet table */
    err = H5PTappend(ptable, (hsize_t)1, &(writeBuffer[0]));
    if (err < 0)
        goto out;

    /* Write several packets to the packet table */
    err = H5PTappend(ptable, (hsize_t)4, &(writeBuffer[1]));
    if (err < 0)
        goto out;

    /* Get the number of packets in the packet table.  This should be five. */
    err = H5PTget_num_packets(ptable, &count);
    if (err < 0)
        goto out;

    printf("Number of packets in packet table after five appends: %d\n", (int)count);

    /* Initialize packet table's "current record" */
    err = H5PTcreate_index(ptable);
    if (err < 0)
        goto out;

    /* Iterate through packets, read each one back */
    for (x = 0; x < 5; x++) {
        err = H5PTget_next(ptable, (hsize_t)1, &(readBuffer[x]));
        if (err < 0)
            goto out;

        printf("Packet %d's value is %d\n", x, readBuffer[x]);
    }

    /* Close the packet table */
    err = H5PTclose(ptable);
    if (err < 0)
        goto out;

    /* Close the file */
    H5Fclose(fid);

    return 0;

out: /* An error has occurred.  Clean up and exit. */
    H5PTclose(ptable);
    H5Fclose(fid);
    return -1;
}