1  /* byteswap.h - Byte swapping
       2     Copyright (C) 2005, 2007, 2009-2022 Free Software Foundation, Inc.
       3     Written by Oskar Liljeblad <oskar@osk.mine.nu>, 2005.
       4  
       5     This file is free software: you can redistribute it and/or modify
       6     it under the terms of the GNU Lesser General Public License as
       7     published by the Free Software Foundation; either version 2.1 of the
       8     License, or (at your option) any later version.
       9  
      10     This file 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 Lesser General Public License for more details.
      14  
      15     You should have received a copy of the GNU Lesser General Public License
      16     along with this program.  If not, see <https://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 */