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emacs/lib/byteswap.in.h
2024-01-02 09:47:10 +08:00

45 lines
2.0 KiB
C

/* byteswap.h - Byte swapping
Copyright (C) 2005, 2007, 2009-2024 Free Software Foundation, Inc.
Written by Oskar Liljeblad <oskar@osk.mine.nu>, 2005.
This file 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.
This file 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 this program. If not, see <https://www.gnu.org/licenses/>. */
#ifndef _GL_BYTESWAP_H
#define _GL_BYTESWAP_H
/* Given an unsigned 16-bit argument X, return the value corresponding to
X with reversed byte order. */
#define bswap_16(x) ((((x) & 0x00FF) << 8) | \
(((x) & 0xFF00) >> 8))
/* Given an unsigned 32-bit argument X, return the value corresponding to
X with reversed byte order. */
#define bswap_32(x) ((((x) & 0x000000FF) << 24) | \
(((x) & 0x0000FF00) << 8) | \
(((x) & 0x00FF0000) >> 8) | \
(((x) & 0xFF000000) >> 24))
/* Given an unsigned 64-bit argument X, return the value corresponding to
X with reversed byte order. */
#define bswap_64(x) ((((x) & 0x00000000000000FFULL) << 56) | \
(((x) & 0x000000000000FF00ULL) << 40) | \
(((x) & 0x0000000000FF0000ULL) << 24) | \
(((x) & 0x00000000FF000000ULL) << 8) | \
(((x) & 0x000000FF00000000ULL) >> 8) | \
(((x) & 0x0000FF0000000000ULL) >> 24) | \
(((x) & 0x00FF000000000000ULL) >> 40) | \
(((x) & 0xFF00000000000000ULL) >> 56))
#endif /* _GL_BYTESWAP_H */