80 lines
2.4 KiB
C
80 lines
2.4 KiB
C
/* Macros and inline functions to swap the order of bytes in integer values.
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Copyright (C) 1997-2022 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#if !defined _BYTESWAP_H && !defined _NETINET_IN_H && !defined _ENDIAN_H
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# error "Never use <bits/byteswap.h> directly; include <byteswap.h> instead."
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#endif
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#ifndef _BITS_BYTESWAP_H
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#define _BITS_BYTESWAP_H 1
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#include <features.h>
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#include <bits/types.h>
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/* Swap bytes in 16-bit value. */
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#define __bswap_constant_16(x) \
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((__uint16_t) ((((x) >> 8) & 0xff) | (((x) & 0xff) << 8)))
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static __inline __uint16_t
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__bswap_16 (__uint16_t __bsx)
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{
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#if __GNUC_PREREQ (4, 8)
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return __builtin_bswap16 (__bsx);
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#else
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return __bswap_constant_16 (__bsx);
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#endif
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}
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/* Swap bytes in 32-bit value. */
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#define __bswap_constant_32(x) \
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((((x) & 0xff000000u) >> 24) | (((x) & 0x00ff0000u) >> 8) \
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| (((x) & 0x0000ff00u) << 8) | (((x) & 0x000000ffu) << 24))
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static __inline __uint32_t
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__bswap_32 (__uint32_t __bsx)
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{
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#if __GNUC_PREREQ (4, 3)
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return __builtin_bswap32 (__bsx);
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#else
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return __bswap_constant_32 (__bsx);
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#endif
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}
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/* Swap bytes in 64-bit value. */
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#define __bswap_constant_64(x) \
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((((x) & 0xff00000000000000ull) >> 56) \
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| (((x) & 0x00ff000000000000ull) >> 40) \
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| (((x) & 0x0000ff0000000000ull) >> 24) \
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| (((x) & 0x000000ff00000000ull) >> 8) \
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| (((x) & 0x00000000ff000000ull) << 8) \
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| (((x) & 0x0000000000ff0000ull) << 24) \
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| (((x) & 0x000000000000ff00ull) << 40) \
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| (((x) & 0x00000000000000ffull) << 56))
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__extension__ static __inline __uint64_t
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__bswap_64 (__uint64_t __bsx)
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{
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#if __GNUC_PREREQ (4, 3)
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return __builtin_bswap64 (__bsx);
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#else
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return __bswap_constant_64 (__bsx);
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#endif
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}
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#endif /* _BITS_BYTESWAP_H */
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