hdf5/tools/test/h5diff/dynlib_diff.c

/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * Copyright by The HDF Group.                                               *
 * 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.                                                        *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
/*
 * Purpose:    Tests the plugin module (H5PL)
 */

#include <stdlib.h>
#include <stdio.h>
#include "H5PLextern.h"

#define H5Z_FILTER_DYNLIBUD 300
#define MULTIPLIER          3

static size_t H5Z_filter_dynlibud(unsigned int flags, size_t cd_nelmts, const unsigned int *cd_values,
                                  size_t nbytes, size_t *buf_size, void **buf);

/* This message derives from H5Z */
const H5Z_class2_t H5Z_DYNLIBUD[1] = {{
    H5Z_CLASS_T_VERS,    /* H5Z_class_t version             */
    H5Z_FILTER_DYNLIBUD, /* Filter id number        */
    1, 1,                /* Encoding and decoding enabled   */
    "dynlibud",          /* Filter name for debugging    */
    NULL,                /* The "can apply" callback        */
    NULL,                /* The "set local" callback        */
    H5Z_filter_dynlibud, /* The actual filter function    */
}};

H5PL_type_t
H5PLget_plugin_type(void)
{
    return H5PL_TYPE_FILTER;
}
const void *
H5PLget_plugin_info(void)
{
    return H5Z_DYNLIBUD;
}

/*-------------------------------------------------------------------------
 * Function:    H5Z_filter_dynlibud
 *
 * Purpose:    A dynlib2 filter method that multiplies the original value
 *              during write and divide the original value during read. It
 *              will be built as a shared library.  plugin.c test will load
 *              and use this filter library.
 *
 * Return:    Success:    Data chunk size
 *
 *        Failure:    0
 *-------------------------------------------------------------------------
 */
static size_t
H5Z_filter_dynlibud(unsigned int flags, size_t cd_nelmts, const unsigned int *cd_values, size_t nbytes,
                    size_t *buf_size, void **buf)
{
    char * int_ptr  = (char *)*buf; /* Pointer to the data values */
    size_t buf_left = *buf_size;    /* Amount of data buffer left to process */

    /* Check for the correct number of parameters */
    if (cd_nelmts > 0)
        return (0);

    /* Assignment to eliminate unused parameter warning. */
    cd_values = cd_values;

    if (flags & H5Z_FLAG_REVERSE) { /*read*/
        /* Subtract the original value with MULTIPLIER */
        while (buf_left > 0) {
            char temp = *int_ptr;
            *int_ptr  = (int8_t)(temp - MULTIPLIER);
            int_ptr++;
            buf_left -= sizeof(*int_ptr);
        }  /* end while */
    }      /* end if */
    else { /*write*/
        /* Add the original value with MULTIPLIER */
        while (buf_left > 0) {
            char temp = *int_ptr;
            *int_ptr  = (int8_t)(temp + MULTIPLIER);
            int_ptr++;
            buf_left -= sizeof(*int_ptr);
        } /* end while */
    }     /* end else */

    return nbytes;
} /* end H5Z_filter_dynlibud() */