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glibc/bits/byteswap.h
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/* Macros to swap the order of bytes in integer values. | |
Copyright (C) 1997,1998,2000-2002,2005,2008,2011 | |
Free Software Foundation, Inc. | |
This file is part of the GNU C Library. | |
The GNU C Library is free software; you can redistribute it and/or | |
modify it under the terms of the GNU Lesser General Public | |
License as published by the Free Software Foundation; either | |
version 2.1 of the License, or (at your option) any later version. | |
The GNU C Library is distributed in the hope that it will be useful, | |
but WITHOUT ANY WARRANTY; without even the implied warranty of | |
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
Lesser General Public License for more details. | |
You should have received a copy of the GNU Lesser General Public | |
License along with the GNU C Library; if not, see | |
<http://www.gnu.org/licenses/>. */ | |
#if !defined _BYTESWAP_H && !defined _NETINET_IN_H && !defined _ENDIAN_H | |
# error "Never use <bits/byteswap.h> directly; include <byteswap.h> instead." | |
#endif | |
#ifndef _BITS_BYTESWAP_H | |
#define _BITS_BYTESWAP_H 1 | |
/* Swap bytes in 16 bit value. */ | |
#define __bswap_constant_16(x) \ | |
((((x) >> 8) & 0xffu) | (((x) & 0xffu) << 8)) | |
#ifdef __GNUC__ | |
# define __bswap_16(x) \ | |
(__extension__ \ | |
({ unsigned short int __bsx = (x); __bswap_constant_16 (__bsx); })) | |
#else | |
static __inline unsigned short int | |
__bswap_16 (unsigned short int __bsx) | |
{ | |
return __bswap_constant_16 (__bsx); | |
} | |
#endif | |
/* Swap bytes in 32 bit value. */ | |
#define __bswap_constant_32(x) \ | |
((((x) & 0xff000000u) >> 24) | (((x) & 0x00ff0000u) >> 8) | \ | |
(((x) & 0x0000ff00u) << 8) | (((x) & 0x000000ffu) << 24)) | |
#ifdef __GNUC__ | |
# define __bswap_32(x) \ | |
(__extension__ \ | |
({ register unsigned int __bsx = (x); __bswap_constant_32 (__bsx); })) | |
#else | |
static __inline unsigned int | |
__bswap_32 (unsigned int __bsx) | |
{ | |
return __bswap_constant_32 (__bsx); | |
} | |
#endif | |
#if defined __GNUC__ && __GNUC__ >= 2 | |
/* Swap bytes in 64 bit value. */ | |
# define __bswap_constant_64(x) \ | |
(__extension__ ((((x) & 0xff00000000000000ull) >> 56) \ | |
| (((x) & 0x00ff000000000000ull) >> 40) \ | |
| (((x) & 0x0000ff0000000000ull) >> 24) \ | |
| (((x) & 0x000000ff00000000ull) >> 8) \ | |
| (((x) & 0x00000000ff000000ull) << 8) \ | |
| (((x) & 0x0000000000ff0000ull) << 24) \ | |
| (((x) & 0x000000000000ff00ull) << 40) \ | |
| (((x) & 0x00000000000000ffull) << 56))) | |
# define __bswap_64(x) \ | |
(__extension__ \ | |
({ union { __extension__ unsigned long long int __ll; \ | |
unsigned int __l[2]; } __w, __r; \ | |
if (__builtin_constant_p (x)) \ | |
__r.__ll = __bswap_constant_64 (x); \ | |
else \ | |
{ \ | |
__w.__ll = (x); \ | |
__r.__l[0] = __bswap_32 (__w.__l[1]); \ | |
__r.__l[1] = __bswap_32 (__w.__l[0]); \ | |
} \ | |
__r.__ll; })) | |
#endif | |
#endif /* _BITS_BYTESWAP_H */ |