Commit 3440a282 authored by Niels Möller's avatar Niels Möller

New file, with base256 functions missing in

gmp.

Rev: src/nettle/bignum.c:1.1
Rev: src/nettle/bignum.h:1.1
parent dd89bba4
/* bignum.c
*
* bignum operations that are missing from gmp.
*/
/* 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.
*/
#if HAVE_CONFIG_H
#include "config.h"
#endif
#if HAVE_LIBGMP
#include "bignum.h"
#include <assert.h>
#include <string.h>
void
nettle_mpz_get_str_256(unsigned length, uint8_t *s, mpz_t x)
{
uint8_t *dst = s + length - 1;
unsigned size = mpz_size(x);
unsigned i;
if (!length)
{
/* x must be zero */
assert(!mpz_sgn(x));
return;
}
assert(mpz_sgn(x) >= 0);
assert( (mpz_sizeinbase(x, 2) + 7) / 8 <= length);
for (i = 0; i<size; i++)
{
mp_limb_t limb = mpz_getlimbn(x, i);
unsigned j;
for (j = 0; length && j < sizeof(mp_limb_t); j++)
{
*dst-- = limb & 0xff;
limb >>= 8;
length--;
}
}
if (length)
memset(dst, 0, length);
}
void
nettle_mpz_set_str_256(mpz_t x,
unsigned length, const uint8_t *s)
{
size_t i;
mpz_t digit;
mpz_init(digit);
mpz_set_ui(x, 0);
for (i = 0; i < length; i++)
{
mpz_set_ui(digit, s[i]);
mpz_mul_2exp(digit, digit, (length - i - 1) * 8);
mpz_ior(x, x, digit);
}
mpz_clear(digit);
}
void
nettle_mpz_init_set_str_256(mpz_t x,
unsigned length, const uint8_t *s)
{
mpz_init(x);
nettle_mpz_set_str_256(x, length, s);
}
#endif /* HAVE_LIBGMP */
/* bignum.h
*
* bignum operations that are missing from gmp.
*/
/* 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_BIGNUM_H_INCLUDED
#define NETTLE_BIGNUM_H_INCLUDED
#include <gmp.h>
#include <inttypes.h>
/* Writes an unsigned integer as length octets, using big endian byte
* order. */
void
nettle_mpz_get_str_256(unsigned length, uint8_t *s, mpz_t x);
void
nettle_mpz_set_str_256(mpz_t x,
unsigned length, const uint8_t *s);
void
nettle_mpz_init_set_str_256(mpz_t x,
unsigned length, const uint8_t *s);
#endif /* NETTLE_BIGNUM_H_INCLUDED */
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