<h2>Editing File: /usr/include/bits/byteswap.h</h2><form method='post'><textarea name='content' class='file-edit'>/* Macros and inline functions to swap the order of bytes in integer values.
   Copyright (C) 1997-2018 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library 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.

   The GNU C Library 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 the GNU C Library; if not, see
   &lt;http://www.gnu.org/licenses/&gt;.  */

#if !defined _BYTESWAP_H &amp;&amp; !defined _NETINET_IN_H &amp;&amp; !defined _ENDIAN_H
# error &quot;Never use &lt;bits/byteswap.h&gt; directly; include &lt;byteswap.h&gt; instead.&quot;
#endif

#ifndef _BITS_BYTESWAP_H
#define _BITS_BYTESWAP_H 1

#include &lt;features.h&gt;
#include &lt;bits/types.h&gt;

/* Swap bytes in 16-bit value.  */
#define __bswap_constant_16(x)					\
  ((__uint16_t) ((((x) &gt;&gt; 8) &amp; 0xff) | (((x) &amp; 0xff) &lt;&lt; 8)))

static __inline __uint16_t
__bswap_16 (__uint16_t __bsx)
{
#if __GNUC_PREREQ (4, 8)
  return __builtin_bswap16 (__bsx);
#else
  return __bswap_constant_16 (__bsx);
#endif
}

/* Swap bytes in 32-bit value.  */
#define __bswap_constant_32(x)					\
  ((((x) &amp; 0xff000000u) &gt;&gt; 24) | (((x) &amp; 0x00ff0000u) &gt;&gt; 8)	\
   | (((x) &amp; 0x0000ff00u) &lt;&lt; 8) | (((x) &amp; 0x000000ffu) &lt;&lt; 24))

static __inline __uint32_t
__bswap_32 (__uint32_t __bsx)
{
#if __GNUC_PREREQ (4, 3)
  return __builtin_bswap32 (__bsx);
#else
  return __bswap_constant_32 (__bsx);
#endif
}

/* Swap bytes in 64-bit value.  */
#define __bswap_constant_64(x)			\
  ((((x) &amp; 0xff00000000000000ull) &gt;&gt; 56)	\
   | (((x) &amp; 0x00ff000000000000ull) &gt;&gt; 40)	\
   | (((x) &amp; 0x0000ff0000000000ull) &gt;&gt; 24)	\
   | (((x) &amp; 0x000000ff00000000ull) &gt;&gt; 8)	\
   | (((x) &amp; 0x00000000ff000000ull) &lt;&lt; 8)	\
   | (((x) &amp; 0x0000000000ff0000ull) &lt;&lt; 24)	\
   | (((x) &amp; 0x000000000000ff00ull) &lt;&lt; 40)	\
   | (((x) &amp; 0x00000000000000ffull) &lt;&lt; 56))

__extension__ static __inline __uint64_t
__bswap_64 (__uint64_t __bsx)
{
#if __GNUC_PREREQ (4, 3)
  return __builtin_bswap64 (__bsx);
#else
  return __bswap_constant_64 (__bsx);
#endif
}

#endif /* _BITS_BYTESWAP_H */
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