1 /* Interface to byteswapping functions. 2 Copyright (C) 2006-2022 Free Software Foundation, Inc. 3 4 This file is part of libctf. 5 6 libctf is free software; you can redistribute it and/or modify it under 7 the terms of the GNU General Public License as published by the Free 8 Software Foundation; either version 3, or (at your option) any later 9 version. 10 11 This program is distributed in the hope that it will be useful, but 12 WITHOUT ANY WARRANTY; without even the implied warranty of 13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 14 See the GNU General Public License for more details. 15 16 You should have received a copy of the GNU General Public License 17 along with this program; see the file COPYING. If not see 18 <http://www.gnu.org/licenses/>. */ 19 20 #ifndef _CTF_SWAP_H 21 #define _CTF_SWAP_H 22 23 #include "config.h" 24 #include <stdint.h> 25 #include <assert.h> 26 27 #ifdef HAVE_BYTESWAP_H 28 #include <byteswap.h> 29 #endif /* defined(HAVE_BYTESWAP_H) */ 30 31 /* Provide our own versions of the byteswap functions. */ 32 33 #if !HAVE_DECL_BSWAP_16 34 static inline uint16_t bswap_16(uint16_t v)35bswap_16 (uint16_t v) 36 { 37 return ((v >> 8) & 0xff) | ((v & 0xff) << 8); 38 } 39 #endif /* !HAVE_DECL_BSWAP16 */ 40 41 #if !HAVE_DECL_BSWAP_32 42 static inline uint32_t bswap_32(uint32_t v)43bswap_32 (uint32_t v) 44 { 45 return ( ((v & 0xff000000) >> 24) 46 | ((v & 0x00ff0000) >> 8) 47 | ((v & 0x0000ff00) << 8) 48 | ((v & 0x000000ff) << 24)); 49 } 50 #endif /* !HAVE_DECL_BSWAP32 */ 51 52 #if !HAVE_DECL_BSWAP_64 53 static inline uint64_t bswap_64(uint64_t v)54bswap_64 (uint64_t v) 55 { 56 return ( ((v & 0xff00000000000000ULL) >> 56) 57 | ((v & 0x00ff000000000000ULL) >> 40) 58 | ((v & 0x0000ff0000000000ULL) >> 24) 59 | ((v & 0x000000ff00000000ULL) >> 8) 60 | ((v & 0x00000000ff000000ULL) << 8) 61 | ((v & 0x0000000000ff0000ULL) << 24) 62 | ((v & 0x000000000000ff00ULL) << 40) 63 | ((v & 0x00000000000000ffULL) << 56)); 64 } 65 #endif /* !HAVE_DECL_BSWAP64 */ 66 67 /* < C11? define away static assertions. */ 68 69 #if !defined (__STDC_VERSION__) || __STDC_VERSION__ < 201112L 70 #define _Static_assert(cond, err) 71 #endif 72 73 /* Swap the endianness of something. */ 74 75 #define swap_thing(x) \ 76 do \ 77 { \ 78 _Static_assert (sizeof (x) == 1 || (sizeof (x) % 2 == 0 \ 79 && sizeof (x) <= 8), \ 80 "Invalid size, update endianness code"); \ 81 switch (sizeof (x)) { \ 82 case 2: x = bswap_16 (x); break; \ 83 case 4: x = bswap_32 (x); break; \ 84 case 8: x = bswap_64 (x); break; \ 85 case 1: /* Nothing needs doing */ \ 86 break; \ 87 } \ 88 } \ 89 while (0); 90 91 92 #endif /* !defined(_CTF_SWAP_H) */ 93