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kamailio/endianness.h

139 lines
4.7 KiB

/*
* $Id$
*
* Copyright (C) 2008 iptelorg GmbH
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
/** @file
* endianness compile and runtime tests
*
* History:
* --------
* 2008-06-13 created by andrei
*
* Defines:
* - __IS_LITTLE_ENDIAN if the system is little endian and
* - __IS_BIG_ENDIAN if it's big endian
* Function/macros:
* - is_big_endian() - runtime test for big endian
* - is_little_endian() - runtime test for little endian
* - endianness_sanity_check() - returns 0 if the compile time
* detected endianness corresponds to
* the runtime detected one and -1 on
* error (recommended action: bail out)
*
* Implementation notes:
* Endian macro names/tests for different OSes:
* linux: __BYTE_ORDER == __LITTLE_ENDIAN | __BIG_ENDIAN
* BYTE_ORDER == LITTLE_ENDIAN | BIG_ENDIAN
* bsd: _BYTE_ORDER == _LITTLE_ENDIAN | _BIG_ENDIAN
* BYTE_ORDER == LITTLE_ENDIAN | BIG_ENDIAN
* solaris: _LITTLE_ENDIAN | _BIG_ENDIAN
*
* Include file for the endian macros:
* linux: <endian.h> (glibc), <sys/param.h>
* bsd: <sys/param.h>, <sys/endian.h>
* solaris: <sys/param.h>
*
* Note: BIG_ENDIAN, LITTLE_ENDIAN, _BIG_ENDIAN, _LITTLE_ENDIAN cannot be
* used always, some OSes define both of them for BYTE_ORDER use
* (e.g. linux defines both BIG_ENDIAN & LITTLE_ENDIAN, bsds define
* _BIG_ENDIAN, _LITTLE_ENDIAN, BIG_ENDIAN, LITTLE_ENDIAN)
*
*/
#ifndef _endianness_h
#define _endianness_h
/* use bsd includes: they work everywhere */
#include <sys/types.h>
#include <sys/param.h>
extern int _endian_test_int;
/* returns 1 for little endian, 0 for big endian */
#define endian_test() (*(char*)&_endian_test_int==1)
#define is_big_endian() (!endian_test())
#define is_little_endian() endian_test()
extern int endianness_sanity_check();
/* detect compile time endianess */
#if defined __BYTE_ORDER && defined __LITTLE_ENDIAN && defined __BIG_ENDIAN
/* linux */
#if __BYTE_ORDER == __LITTLE_ENDIAN && ! defined __IS_LITTLE_ENDIAN
#define __IS_LITTLE_ENDIAN 0x01020304
#endif
#if __BYTE_ORDER == __BIG_ENDIAN && ! defined __IS_BIG_ENDIAN
#define __IS_BIG_ENDIAN 0x01020304
#endif
#elif defined _BYTE_ORDER && defined _LITTLE_ENDIAN && defined _BIG_ENDIAN
/* bsd */
#if _BYTE_ORDER == _LITTLE_ENDIAN && ! defined __IS_LITTLE_ENDIAN
#define __IS_LITTLE_ENDIAN 0x01020304
#endif
#if _BYTE_ORDER == _BIG_ENDIAN && ! defined __IS_BIG_ENDIAN
#define __IS_BIG_ENDIAN 0x01020304
#endif
#elif defined BYTE_ORDER && defined LITTLE_ENDIAN && defined BIG_ENDIAN
/* bsd old/deprecated */
#if BYTE_ORDER == LITTLE_ENDIAN && ! defined __IS_LITTLE_ENDIAN
#define __IS_LITTLE_ENDIAN 0x01020304
#endif
#if BYTE_ORDER == BIG_ENDIAN && ! defined __IS_BIG_ENDIAN
#define __IS_BIG_ENDIAN 0x01020304
#endif
#elif !(defined _LITTLE_ENDIAN && defined _BIG_ENDIAN) && \
(defined _LITTLE_ENDIAN || defined _BIG_ENDIAN)
/* OSes that don't define BYTE_ORDER (sanity check above makes sure
* little & big endian are not defined in the same time )*/
/* solaris */
#if defined _LITTLE_ENDIAN && !defined __IS_LITTLE_ENDIAN
#define __IS_LITTLE_ENDIAN 0x01020304
#endif
#if defined _BIG_ENDIAN && !defined __IS_BIG_ENDIAN
#define __IS_BIG_ENDIAN 0x04030201
#endif
#elif !(defined LITTLE_ENDIAN && defined BIG_ENDIAN) && \
(defined LITTLE_ENDIAN || defined BIG_ENDIAN)
/* OSes that don't define BYTE_ORDER (sanity check above makes sure
* little & big endian are not defined in the same time )*/
#if defined LITTLE_ENDIAN && !defined __IS_LITTLE_ENDIAN
#define __IS_LITTLE_ENDIAN 0x01020304
#endif
#if defined BIG_ENDIAN && !defined __IS_BIG_ENDIAN
#define __IS_BIG_ENDIAN 0x04030201
#endif
#else
#error could not detect endianess
#endif
#if !defined __IS_LITTLE_ENDIAN && !defined __IS_BIG_ENDIAN
#error BUG: could not detect endianess
#endif
#if defined __IS_LITTLE_ENDIAN && defined __IS_BIG_ENDIAN
#error BUG: both little & big endian detected in the same time
#endif
#endif /* _endianness_h */