1/* Macros to swap the order of bytes in integer values. 2 Copyright (C) 1997,1998,2000,2001,2002,2005 Free Software Foundation, Inc. 3 This file is part of the GNU C Library. 4 5 The GNU C Library is free software; you can redistribute it and/or 6 modify it under the terms of the GNU Lesser General Public 7 License as published by the Free Software Foundation; either 8 version 2.1 of the License, or (at your option) any later version. 9 10 The GNU C Library is distributed in the hope that it will be useful, 11 but WITHOUT ANY WARRANTY; without even the implied warranty of 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 13 Lesser General Public License for more details. 14 15 You should have received a copy of the GNU Lesser General Public 16 License along with the GNU C Library; if not, write to the Free 17 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 18 02111-1307 USA. */ 19 20#if !defined _BYTESWAP_H && !defined _NETINET_IN_H 21# error "Never use <bits/byteswap.h> directly; include <byteswap.h> instead." 22#endif 23 24#ifndef _BITS_BYTESWAP_H 25#define _BITS_BYTESWAP_H 1 26 27/* Swap bytes in 16 bit value. */ 28#define __bswap_constant_16(x) \ 29 ((((x) >> 8) & 0xffu) | (((x) & 0xffu) << 8)) 30 31#ifndef __bswap_non_constant_16 32# define __bswap_non_constant_16(x) __bswap_constant_16(x) 33#endif 34#ifdef __GNUC__ 35# define __bswap_16(x) \ 36 (__extension__ \ 37 ({ unsigned short int __bsv, __bsx = (x); \ 38 if (__builtin_constant_p (__bsx)) \ 39 __bsv = __bswap_constant_16 (__bsx); \ 40 else \ 41 __bsv = __bswap_non_constant_16 (__bsx); \ 42 __bsv; })) 43#else 44static __inline unsigned short int 45__bswap_16 (unsigned short int __bsx) 46{ 47 return __bswap_constant_16 (__bsx); 48} 49#endif 50 51/* Swap bytes in 32 bit value. */ 52#define __bswap_constant_32(x) \ 53 ((((x) & 0xff000000u) >> 24) | (((x) & 0x00ff0000u) >> 8) | \ 54 (((x) & 0x0000ff00u) << 8) | (((x) & 0x000000ffu) << 24)) 55 56#ifndef __bswap_non_constant_32 57# define __bswap_non_constant_32(x) __bswap_constant_32(x) 58#endif 59#ifdef __GNUC__ 60# define __bswap_32(x) \ 61 (__extension__ \ 62 ({ unsigned int __bsv, __bsx = (x); \ 63 if (__builtin_constant_p (__bsx)) \ 64 __bsv = __bswap_constant_32 (__bsx); \ 65 else \ 66 __bsv = __bswap_non_constant_32 (__bsx); \ 67 __bsv; })) 68#else 69static __inline unsigned int 70__bswap_32 (unsigned int __bsx) 71{ 72 return __bswap_constant_32 (__bsx); 73} 74#endif 75 76#if defined __GNUC__ && __GNUC__ >= 2 77/* Swap bytes in 64 bit value. */ 78# define __bswap_constant_64(x) \ 79 ((((x) & 0xff00000000000000ull) >> 56) \ 80 | (((x) & 0x00ff000000000000ull) >> 40) \ 81 | (((x) & 0x0000ff0000000000ull) >> 24) \ 82 | (((x) & 0x000000ff00000000ull) >> 8) \ 83 | (((x) & 0x00000000ff000000ull) << 8) \ 84 | (((x) & 0x0000000000ff0000ull) << 24) \ 85 | (((x) & 0x000000000000ff00ull) << 40) \ 86 | (((x) & 0x00000000000000ffull) << 56)) 87 88# ifndef __bswap_non_constant_64 89# define __bswap_non_constant_64(x) \ 90 (__extension__ \ 91 ({ union { __extension__ unsigned long long int __ll; \ 92 unsigned int __l[2]; } __w, __r; \ 93 __w.__ll = (x); \ 94 __r.__l[0] = __bswap_non_constant_32 (__w.__l[1]); \ 95 __r.__l[1] = __bswap_non_constant_32 (__w.__l[0]); \ 96 __r.__ll; })) 97# endif 98# define __bswap_64(x) \ 99 (__extension__ \ 100 ({ __extension__ unsigned long long int __ll; \ 101 if (__builtin_constant_p (x)) \ 102 __ll = __bswap_constant_64 (x); \ 103 else \ 104 __ll = __bswap_non_constant_64 (x); \ 105 __ll; })) 106#endif 107 108#endif /* _BITS_BYTESWAP_H */ 109