gmio/src/gmio_core/internal/byte_swap.h

/****************************************************************************
** GeomIO Library
** Copyright FougSys (2 Mar. 2015)
** contact@fougsys.fr
**
** This software is a reusable library whose purpose is to provide complete
** I/O support for various CAD file formats (eg. STL)
**
** This software is governed by the CeCILL-B license under French law and
** abiding by the rules of distribution of free software.  You can  use,
** modify and/ or redistribute the software under the terms of the CeCILL-B
** license as circulated by CEA, CNRS and INRIA at the following URL
** "http://www.cecill.info/licences/Licence_CeCILL-B_V1-en.html".
****************************************************************************/

/* WARNING :
 *     this header has no multi-inclusion guard. It must be included only once
 *     in the translation unit of use. The reason is that all functions
 *     defined here are meant to be inlined for performance purpose
 */

#include "../global.h"

#ifdef GMIO_HAVE_MSVC_BUILTIN_BSWAP_FUNC
#  include <stdlib.h>
#endif

/*! Returns \p val with the order of bytes reversed, uses compiler builtin
 *  functions if available */
GMIO_INLINE static uint16_t gmio_uint16_bswap(uint16_t val)
{
#ifdef GMIO_HAVE_GCC_BUILTIN_BSWAP16_FUNC
    return __builtin_bswap16(val);
#elif defined(GMIO_HAVE_MSVC_BUILTIN_BSWAP_FUNC)
    return _byteswap_ushort(val);
#else
    return ((val & 0x00FF) << 8) | ((val >> 8) & 0x00FF);
#endif
}

/*! Returns \p val with the order of bytes reversed, uses compiler builtin
 *  functions if available */
GMIO_INLINE static uint32_t gmio_uint32_bswap(uint32_t val)
{
#ifdef GMIO_HAVE_GCC_BUILTIN_BSWAP32_FUNC
    return __builtin_bswap32(val);
#elif defined(GMIO_HAVE_MSVC_BUILTIN_BSWAP_FUNC)
    return _byteswap_ulong(val);
#else
    return
            ((val & 0x000000FF) << 24)
            | ((val & 0x0000FF00) << 8)
            | ((val >> 8) & 0x0000FF00)
            | ((val >> 24) & 0x000000FF);
#endif
}