1: /* Macros to swap the order of bytes in integer values.
    2:    Copyright (C) 1997,1998,2000,2001,2002,2005 Free Software Foundation, Inc.
    3:    This file is part of the GNU C Library.
    4: 
    5:    The GNU C Library is free software; you can redistribute it and/or
    6:    modify it under the terms of the GNU Lesser General Public
    7:    License as published by the Free Software Foundation; either
    8:    version 2.1 of the License, or (at your option) any later version.
    9: 
   10:    The GNU C Library 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 GNU
   13:    Lesser General Public License for more details.
   14: 
   15:    You should have received a copy of the GNU Lesser General Public
   16:    License along with the GNU C Library; if not, write to the Free
   17:    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   18:    02111-1307 USA.  */
   19: 
   20: #if !defined _BYTESWAP_H && !defined _NETINET_IN_H
   21: # error "Never use <bits/byteswap.h> directly; include <byteswap.h> instead."
   22: #endif
   23: 
   24: #ifndef _BITS_BYTESWAP_H
   25: #define _BITS_BYTESWAP_H 1
   26: 
   27: /* Swap bytes in 16 bit value.  */
   28: #define __bswap_constant_16(x) \
   29:      ((((x) >> 8) & 0xffu) | (((x) & 0xffu) << 8))
   30: 
   31: #ifdef __GNUC__
   32: # define __bswap_16(x) \
   33:     (__extension__                                                            \
   34:      ({ unsigned short int __bsx = (x); __bswap_constant_16 (__bsx); }))
   35: #else
   36: static __inline unsigned short int
   37: __bswap_16 (unsigned short int __bsx)
   38: {
   39:   return __bswap_constant_16 (__bsx);
   40: }
   41: #endif
   42: 
   43: /* Swap bytes in 32 bit value.  */
   44: #define __bswap_constant_32(x) \
   45:      ((((x) & 0xff000000u) >> 24) | (((x) & 0x00ff0000u) >>  8) |             \
   46:       (((x) & 0x0000ff00u) <<  8) | (((x) & 0x000000ffu) << 24))
   47: 
   48: #ifdef __GNUC__
   49: # define __bswap_32(x) \
   50:   (__extension__                                                              \
   51:    ({ register unsigned int __bsx = (x); __bswap_constant_32 (__bsx); }))
   52: #else
   53: static __inline unsigned int
   54: __bswap_32 (unsigned int __bsx)
   55: {
   56:   return __bswap_constant_32 (__bsx);
   57: }
   58: #endif
   59: 
   60: #if defined __GNUC__ && __GNUC__ >= 2
   61: /* Swap bytes in 64 bit value.  */
   62: # define __bswap_constant_64(x) \
   63:      ((((x) & 0xff00000000000000ull) >> 56)                                   \
   64:       | (((x) & 0x00ff000000000000ull) >> 40)                                 \
   65:       | (((x) & 0x0000ff0000000000ull) >> 24)                                 \
   66:       | (((x) & 0x000000ff00000000ull) >> 8)                                  \
   67:       | (((x) & 0x00000000ff000000ull) << 8)                                  \
   68:       | (((x) & 0x0000000000ff0000ull) << 24)                                 \
   69:       | (((x) & 0x000000000000ff00ull) << 40)                                 \
   70:       | (((x) & 0x00000000000000ffull) << 56))
   71: 
   72: # define __bswap_64(x) \
   73:      (__extension__                                                           \
   74:       ({ union { __extension__ unsigned long long int __ll;                   \
   75:                  unsigned int __l[2]; } __w, __r;                           \
   76:          if (__builtin_constant_p (x))                                        \
   77:            __r.__ll = __bswap_constant_64 (x);                               \
   78:          else                                                                \
   79:            {                                                                 \
   80:              __w.__ll = (x);                                                 \
   81:              __r.__l[0] = __bswap_32 (__w.__l[1]);                           \
   82:              __r.__l[1] = __bswap_32 (__w.__l[0]);                           \
   83:            }                                                                 \
   84:          __r.__ll; }))
   85: #endif
   86: 
   87: #endif /* _BITS_BYTESWAP_H */