release/src/router/nettle/sexp2bignum.c

   1 /* sexp2bignum.c
   2  *
   3  */
   4
   5 /* nettle, low-level cryptographics library
   6  *
   7  * Copyright (C) 2002 Niels Möller
   8  *
   9  * The nettle library is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU Lesser General Public License as published by
  11  * the Free Software Foundation; either version 2.1 of the License, or (at your
  12  * option) any later version.
  13  *
  14  * The nettle library is distributed in the hope that it will be useful, but
  15  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  16  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
  17  * License for more details.
  18  *
  19  * You should have received a copy of the GNU Lesser General Public License
  20  * along with the nettle library; see the file COPYING.LIB.  If not, write to
  21  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
  22  * MA 02111-1301, USA.
  23  */
  24
  25 #if HAVE_CONFIG_H
  26 # include "config.h"
  27 #endif
  28
  29 #include "sexp.h"
  30 #include "bignum.h"
  31
  32 int
  33 nettle_mpz_set_sexp(mpz_t x, unsigned limit, struct sexp_iterator *i)
  34 {
  35   if (i->type == SEXP_ATOM
  36       && i->atom_length
  37       && !i->display)
  38     {
  39       /* Allow some extra here, for leading sign octets. */
  40       if (limit && (8 * i->atom_length > (16 + limit)))
  41         return 0;
  42
  43       nettle_mpz_set_str_256_s(x, i->atom_length, i->atom);
  44
  45       /* FIXME: How to interpret a limit for negative numbers? */
  46       if (limit && mpz_sizeinbase(x, 2) > limit)
  47         return 0;
  48
  49       return sexp_iterator_next(i);
  50     }
  51   else
  52     return 0;
  53 }