/* gmp-glue.h */

/* nettle, low-level cryptographics library
 *
 * Copyright (C) 2013 Niels Möller
 *  
 * 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., 51 Franklin Street, Fifth Floor, Boston,
 * MA 02111-1301, USA.
 */

#ifndef NETTLE_GMP_GLUE_H_INCLUDED
#define NETTLE_GMP_GLUE_H_INCLUDED

#include <gmp.h>

#include "nettle-stdint.h"

#ifdef mpz_limbs_read
#define GMP_HAVE_mpz_limbs_read 1
#else
#define GMP_HAVE_mpz_limbs_read 0
#endif

#ifdef mpn_copyd
#define GMP_HAVE_mpn_copyd 1
#else
#define GMP_HAVE_mpn_copyd 0
#endif

/* Name mangling. */
#if !GMP_HAVE_mpz_limbs_read
#define mpz_limbs_read _nettle_mpz_limbs_read
#define mpz_limbs_write _nettle_mpz_limbs_write
#define mpz_limbs_modify _nettle_mpz_limbs_modify
#define mpz_limbs_finish _nettle_mpz_limbs_finish
#define mpz_roinit_n _nettle_mpz_roinit_n
#endif

#if !GMP_HAVE_mpn_copyd
#define mpn_copyd _nettle_mpn_copyd
#define mpn_copyi _nettle_mpn_copyi
#define mpn_zero  _nettle_mpn_zero
#endif

#ifndef mpn_sqr
#define mpn_sqr(rp, ap, n) mpn_mul_n((rp), (ap), (ap), (n))
#endif

#define mpz_limbs_cmp _nettle_mpz_limbs_cmp
#define mpz_limbs_read_n _nettle_mpz_limbs_read_n
#define mpz_limbs_copy _nettle_mpz_limbs_copy
#define mpz_set_n _nettle_mpz_set_n
#define mpn_set_base256 _nettle_mpn_set_base256
#define gmp_alloc_limbs _nettle_gmp_alloc_limbs
#define gmp_free_limbs _nettle_gmp_free_limbs

/* Use only in-place operations, so we can fall back to addmul_1/submul_1 */
#ifdef mpn_cnd_add_n
# define cnd_add_n(cnd, rp, ap, n) mpn_cnd_add_n ((cnd), (rp), (rp), (ap), (n))
# define cnd_sub_n(cnd, rp, ap, n) mpn_cnd_sub_n ((cnd), (rp), (rp), (ap), (n))
#else
# define cnd_add_n(cnd, rp, ap, n) mpn_addmul_1 ((rp), (ap), (n), (cnd) != 0)
# define cnd_sub_n(cnd, rp, ap, n) mpn_submul_1 ((rp), (ap), (n), (cnd) != 0)
#endif

/* Some functions for interfacing between mpz and mpn code. Signs of
   the mpz numbers are generally ignored. */

#if !GMP_HAVE_mpz_limbs_read
/* Read access to mpz numbers. */

/* Return limb pointer, for read-only operations. Use mpz_size to get
   the number of limbs. */
const mp_limb_t *
mpz_limbs_read (const mpz_srcptr x);

/* Write access to mpz numbers. */

/* Get a limb pointer for writing, previous contents may be
   destroyed. */
mp_limb_t *
mpz_limbs_write (mpz_ptr x, mp_size_t n);

/* Get a limb pointer for writing, previous contents is intact. */
mp_limb_t *
mpz_limbs_modify (mpz_ptr x, mp_size_t n);

/* Update size. */
void
mpz_limbs_finish (mpz_ptr x, mp_size_t n);

/* Using an mpn number as an mpz. Can be used for read-only access
   only. x must not be cleared or reallocated. */
mpz_srcptr
mpz_roinit_n (mpz_ptr x, const mp_limb_t *xp, mp_size_t xs);

#endif /* !GMP_HAVE_mpz_limbs_read */

#if !GMP_HAVE_mpn_copyd
/* Copy elements, backwards */
void
mpn_copyd (mp_ptr dst, mp_srcptr src, mp_size_t n);

/* Copy elements, forwards */
void
mpn_copyi (mp_ptr dst, mp_srcptr src, mp_size_t n);

/* Zero elements */
void
mpn_zero (mp_ptr ptr, mp_size_t n);
#endif /* !GMP_HAVE_mpn_copyd */

/* Convenience functions */
int
mpz_limbs_cmp (mpz_srcptr a, const mp_limb_t *bp, mp_size_t bn);

/* Get a pointer to an n limb area, for read-only operation. n must be
   greater or equal to the current size, and the mpz is zero-padded if
   needed. */
const mp_limb_t *
mpz_limbs_read_n (mpz_ptr x, mp_size_t n);

/* Copy limbs, with zero-padding. */
/* FIXME: Reorder arguments, on the theory that the first argument of
   an _mpz_* fucntion should be an mpz_t? Or rename to _mpz_get_limbs,
   with argument order consistent with mpz_get_*. */
void
mpz_limbs_copy (mp_limb_t *xp, mpz_srcptr x, mp_size_t n);

void
mpz_set_n (mpz_t r, const mp_limb_t *xp, mp_size_t xn);

/* Like mpn_set_str, but always writes rn limbs. If input is larger,
   higher bits are ignored. */
void
mpn_set_base256 (mp_limb_t *rp, mp_size_t rn,
		 const uint8_t *xp, size_t xn);


mp_limb_t *
gmp_alloc_limbs (mp_size_t n);

void
gmp_free_limbs (mp_limb_t *p, mp_size_t n);


#endif /* NETTLE_GMP_GLUE_H_INCLUDED */