lib/byteswap.in.h

   1 /* byteswap.h - Byte swapping
   2    Copyright (C) 2005, 2007, 2009-2017 Free Software Foundation, Inc.
   3    Written by Oskar Liljeblad <oskar@osk.mine.nu>, 2005.
   4
   5    This program is free software: you can redistribute it and/or modify
   6    it under the terms of the GNU General Public License as published by
   7    the Free Software Foundation; either version 3 of the License, or
   8    (at your option) any later version.
   9
  10    This program 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
  13    GNU General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  17
  18 #ifndef _GL_BYTESWAP_H
  19 #define _GL_BYTESWAP_H
  20
  21 /* Given an unsigned 16-bit argument X, return the value corresponding to
  22    X with reversed byte order.  */
  23 #define bswap_16(x) ((((x) & 0x00FF) << 8) | \
  24                      (((x) & 0xFF00) >> 8))
  25
  26 /* Given an unsigned 32-bit argument X, return the value corresponding to
  27    X with reversed byte order.  */
  28 #define bswap_32(x) ((((x) & 0x000000FF) << 24) | \
  29                      (((x) & 0x0000FF00) << 8) | \
  30                      (((x) & 0x00FF0000) >> 8) | \
  31                      (((x) & 0xFF000000) >> 24))
  32
  33 /* Given an unsigned 64-bit argument X, return the value corresponding to
  34    X with reversed byte order.  */
  35 #define bswap_64(x) ((((x) & 0x00000000000000FFULL) << 56) | \
  36                      (((x) & 0x000000000000FF00ULL) << 40) | \
  37                      (((x) & 0x0000000000FF0000ULL) << 24) | \
  38                      (((x) & 0x00000000FF000000ULL) << 8) | \
  39                      (((x) & 0x000000FF00000000ULL) >> 8) | \
  40                      (((x) & 0x0000FF0000000000ULL) >> 24) | \
  41                      (((x) & 0x00FF000000000000ULL) >> 40) | \
  42                      (((x) & 0xFF00000000000000ULL) >> 56))
  43
  44 #endif /* _GL_BYTESWAP_H */