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/* bithelp.h - Some bit manipulation helpers
* Copyright (C) 1999, 2002 Free Software Foundation, Inc.
*
* This file is part of Libgcrypt.
*
* Libgcrypt 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.
*
* Libgcrypt 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, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
*/
#ifndef G10_BITHELP_H
#define G10_BITHELP_H
#include "types.h"
/****************
* Rotate the 32 bit unsigned integer X by N bits left/right
*/
static inline u32 rol(u32 x, int n)
{
return ( (x << (n&(32-1))) | (x >> ((32-n)&(32-1))) );
}
static inline u32 ror(u32 x, int n)
{
return ( (x >> (n&(32-1))) | (x << ((32-n)&(32-1))) );
}
/* Byte swap for 32-bit and 64-bit integers. If available, use compiler
provided helpers. */
#ifdef HAVE_BUILTIN_BSWAP32
# define _gcry_bswap32 __builtin_bswap32
#else
static inline u32
_gcry_bswap32(u32 x)
{
return ((rol(x, 8) & 0x00ff00ffL) | (ror(x, 8) & 0xff00ff00L));
}
#endif
#ifdef HAVE_U64_TYPEDEF
# ifdef HAVE_BUILTIN_BSWAP64
# define _gcry_bswap64 __builtin_bswap64
# else
static inline u64
_gcry_bswap64(u64 x)
{
return ((u64)_gcry_bswap32(x) << 32) | (_gcry_bswap32(x >> 32));
}
# endif
#endif
/* Endian dependent byte swap operations. */
#ifdef WORDS_BIGENDIAN
# define le_bswap32(x) _gcry_bswap32(x)
# define be_bswap32(x) ((u32)(x))
# ifdef HAVE_U64_TYPEDEF
# define le_bswap64(x) _gcry_bswap64(x)
# define be_bswap64(x) ((u64)(x))
# endif
#else
# define le_bswap32(x) ((u32)(x))
# define be_bswap32(x) _gcry_bswap32(x)
# ifdef HAVE_U64_TYPEDEF
# define le_bswap64(x) ((u64)(x))
# define be_bswap64(x) _gcry_bswap64(x)
# endif
#endif
#endif /*G10_BITHELP_H*/
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