/*

 * gcrypt_missing.c - routines that are in OpenSSL but not in libgcrypt.

 *

 * This file is part of the SSH Library

 *

 * Copyright (c) 2003-2006 by Aris Adamantiadis

 *

 * The SSH 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 SSH 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 SSH Library; see the file COPYING.  If not, write to

 * the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,

 * MA 02111-1307, USA.

 */

#include "config.h"

#include <stdlib.h>

#include "libssh/priv.h"

#include "libssh/libgcrypt.h"

#ifdef HAVE_LIBGCRYPT

int ssh_gcry_dec2bn(bignum *bn, const char *data) {

  int count;

  *bn = bignum_new();

  if (*bn == NULL) {

    return 0;

  }

  gcry_mpi_set_ui(*bn, 0);

  for (count = 0; data[count]; count++) {

    gcry_mpi_mul_ui(*bn, *bn, 10);

    gcry_mpi_add_ui(*bn, *bn, data[count] - '0');

  }

  return count;

}

char *ssh_gcry_bn2dec(bignum bn) {

  bignum bndup, num, ten;

  char *ret;

  int count, count2;

  int size, rsize;

  char decnum;

  size = gcry_mpi_get_nbits(bn) * 3;

  rsize = size / 10 + size / 1000 + 2;

  ret = malloc(rsize + 1);

  if (ret == NULL) {

    return NULL;

  }

  if (!gcry_mpi_cmp_ui(bn, 0)) {

    strcpy(ret, "0");

  } else {

    ten = bignum_new();

    if (ten == NULL) {

      SAFE_FREE(ret);

      return NULL;

    }

    num = bignum_new();

    if (num == NULL) {

      SAFE_FREE(ret);

      bignum_safe_free(ten);

      return NULL;

    }

    for (bndup = gcry_mpi_copy(bn), bignum_set_word(ten, 10), count = rsize;

        count; count--) {

      gcry_mpi_div(bndup, num, bndup, ten, 0);

      for (decnum = 0, count2 = gcry_mpi_get_nbits(num); count2;

          decnum *= 2, decnum += (gcry_mpi_test_bit(num, count2 - 1) ? 1 : 0),

          count2--)

        ;

      ret[count - 1] = decnum + '0';

    }

    for (count = 0; count < rsize && ret[count] == '0'; count++)

      ;

    for (count2 = 0; count2 < rsize - count; ++count2) {

      ret[count2] = ret[count2 + count];

    }

    ret[count2] = 0;

    bignum_safe_free(num);

    bignum_safe_free(bndup);

    bignum_safe_free(ten);

  }

  return ret;

}

/** @brief generates a random integer between 0 and max

 * @returns 1 in case of success, 0 otherwise

 */

int ssh_gcry_rand_range(bignum dest, bignum max)

{

    size_t bits;

    bignum rnd;

    int rc;

    bits = bignum_num_bits(max) + 64;

    rnd = bignum_new();

    if (rnd == NULL) {

        return 0;

    }

    rc = bignum_rand(rnd, bits);

    if (rc != 1) {

        return rc;

    }

    gcry_mpi_mod(dest, rnd, max);

    bignum_safe_free(rnd);

    return 1;

}

#endif