1/* Macros and inline functions to swap the order of bytes in integer values. 
2 Copyright (C) 1997-2020 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, see 
17 <https://www.gnu.org/licenses/>. */ 
18 
19#if !defined _BYTESWAP_H && !defined _NETINET_IN_H && !defined _ENDIAN_H 
20# error "Never use <bits/byteswap.h> directly; include <byteswap.h> instead." 
21#endif 
22 
23#ifndef _BITS_BYTESWAP_H 
24#define _BITS_BYTESWAP_H 1 
25 
26#include <features.h> 
27#include <bits/types.h> 
28 
29/* Swap bytes in 16-bit value. */ 
30#define __bswap_constant_16(x) \ 
31 ((__uint16_t) ((((x) >> 8) & 0xff) | (((x) & 0xff) << 8))) 
32 
33static __inline __uint16_t 
34__bswap_16 (__uint16_t __bsx) 
35{ 
36#if __GNUC_PREREQ (4, 8) 
37 return __builtin_bswap16 (__bsx); 
38#else 
39 return __bswap_constant_16 (__bsx); 
40#endif 
41} 
42 
43/* Swap bytes in 32-bit value. */ 
44#define __bswap_constant_32(x) \ 
45 ((((x) & 0xff000000u) >> 24) | (((x) & 0x00ff0000u) >> 8) \ 
46 | (((x) & 0x0000ff00u) << 8) | (((x) & 0x000000ffu) << 24)) 
47 
48static __inline __uint32_t 
49__bswap_32 (__uint32_t __bsx) 
50{ 
51#if __GNUC_PREREQ (4, 3) 
52 return __builtin_bswap32 (__bsx); 
53#else 
54 return __bswap_constant_32 (__bsx); 
55#endif 
56} 
57 
58/* Swap bytes in 64-bit value. */ 
59#define __bswap_constant_64(x) \ 
60 ((((x) & 0xff00000000000000ull) >> 56) \ 
61 | (((x) & 0x00ff000000000000ull) >> 40) \ 
62 | (((x) & 0x0000ff0000000000ull) >> 24) \ 
63 | (((x) & 0x000000ff00000000ull) >> 8) \ 
64 | (((x) & 0x00000000ff000000ull) << 8) \ 
65 | (((x) & 0x0000000000ff0000ull) << 24) \ 
66 | (((x) & 0x000000000000ff00ull) << 40) \ 
67 | (((x) & 0x00000000000000ffull) << 56)) 
68 
69__extension__ static __inline __uint64_t 
70__bswap_64 (__uint64_t __bsx) 
71{ 
72#if __GNUC_PREREQ (4, 3) 
73 return __builtin_bswap64 (__bsx); 
74#else 
75 return __bswap_constant_64 (__bsx); 
76#endif 
77} 
78 
79#endif /* _BITS_BYTESWAP_H */ 
80