vchoi_fork

/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *

 * 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 files COPYING and Copyright.html.  COPYING can be found at the root   *

 * of the source code distribution tree; Copyright.html can be found at the  *

 * root level of an installed copy of the electronic HDF5 document set and   *

 * is linked from the top-level documents page.  It can also be found at     *

 * http://hdfgroup.org/HDF5/doc/Copyright.html.  If you do not have          *

 * access to either file, you may request a copy from help@hdfgroup.org.     *

 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

​

/*

 * Module Info: This module contains the functionality for setting & querying

 *      the datatype offset for the H5T interface.

 */

​

#include "H5Tmodule.h"          /* This source code file is part of the H5T module */

​

​

#include "H5private.h"      /* Generic Functions            */

#include "H5Eprivate.h"     /* Error handling           */

#include "H5Iprivate.h"     /* IDs                  */

#include "H5Tpkg.h"     /* Datatypes                */

​

/* Static local functions */

static herr_t H5T_set_offset(const H5T_t *dt, size_t offset);

​

​

•

/*-------------------------------------------------------------------------

 * Function:    H5Tget_offset

 *

 * Purpose: Retrieves the bit offset of the first significant bit.  The

 *      signficant bits of an atomic datum can be offset from the

 *      beginning of the memory for that datum by an amount of

 *      padding. The `offset' property specifies the number of bits

 *      of padding that appear to the "right of" the value.  That is,

 *      if we have a 32-bit datum with 16-bits of precision having

 *      the value 0x1122 then it will be layed out in memory as (from

 *      small byte address toward larger byte addresses):

 *

 *          Big      Big       Little   Little

 *          Endian   Endian    Endian   Endian

 *          offset=0 offset=16 offset=0 offset=16

 *

 *      0:  [ pad]   [0x11]    [0x22]   [ pad]

 *      1:  [ pad]   [0x22]    [0x11]   [ pad]