macros.h

/* macros.h
 *
 */

/* nettle, low-level cryptographics library
 *
 * Copyright (C) 2001 Niels Mller
 *  
 * The nettle 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 nettle 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 nettle library; see the file COPYING.LIB.  If not, write to
 * the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
 * MA 02111-1307, USA.
 */

#ifndef NETTLE_MACROS_H_INCLUDED
#define NETTLE_MACROS_H_INCLUDED

/* Reads a 32-bit integer, in network, big-endian, byte order */
#define READ_UINT32(p)				\
(  (((uint32_t) (p)[0]) << 24)			\
 | (((uint32_t) (p)[1]) << 16)			\
 | (((uint32_t) (p)[2]) << 8)			\
 |  ((uint32_t) (p)[3]))

#define WRITE_UINT32(p, i)			\
do {						\
  (p)[0] = ((i) >> 24) & 0xff;			\
  (p)[1] = ((i) >> 16) & 0xff;			\
  (p)[2] = ((i) >> 8) & 0xff;			\
  (p)[3] = (i) & 0xff;				\
} while(0)

/* Analogous macros, for 24 and 16 bit numbers */
#define READ_UINT24(p)				\
(  (((uint32_t) (p)[0]) << 16)			\
 | (((uint32_t) (p)[1]) << 8)			\
 |  ((uint32_t) (p)[2]))

#define WRITE_UINT24(p, i)			\
do {						\
  (p)[0] = ((i) >> 16) & 0xff;			\
  (p)[1] = ((i) >> 8) & 0xff;			\
  (p)[2] = (i) & 0xff;				\
} while(0)

#define READ_UINT16(p)				\
(  (((uint32_t) (p)[0]) << 8)			\
 |  ((uint32_t) (p)[1]))

#define WRITE_UINT16(p, i)			\
do {						\
  (p)[0] = ((i) >> 8) & 0xff;			\
  (p)[1] = (i) & 0xff;				\
} while(0)

/* And the other, little-endian, byteorder */
#define LE_READ_UINT32(p)			\
(  (((uint32_t) (p)[3]) << 24)			\
 | (((uint32_t) (p)[2]) << 16)			\
 | (((uint32_t) (p)[1]) << 8)			\
 |  ((uint32_t) (p)[0]))

#define LE_WRITE_UINT32(p, i)			\
do {						\
  (p)[3] = ((i) >> 24) & 0xff;			\
  (p)[2] = ((i) >> 16) & 0xff;			\
  (p)[1] = ((i) >> 8) & 0xff;			\
  (p)[0] = (i) & 0xff;				\
} while(0)

/* Macro to make it easier to loop over several blocks. */
#define FOR_BLOCKS(length, dst, src, blocksize)	\
  assert( !((length) % (blocksize)));           \
  for (; (length); ((length) -= (blocksize),	\
		  (dst) += (blocksize),		\
		  (src) += (blocksize)) )

#endif /* NETTLE_MACROS_H_INCLUDED */