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      1 /*	$NetBSD: bn_mp_toradix.c,v 1.2 2017/01/28 21:31:47 christos Exp $	*/
      2 
      3 #include <tommath.h>
      4 #ifdef BN_MP_TORADIX_C
      5 /* LibTomMath, multiple-precision integer library -- Tom St Denis
      6  *
      7  * LibTomMath is a library that provides multiple-precision
      8  * integer arithmetic as well as number theoretic functionality.
      9  *
     10  * The library was designed directly after the MPI library by
     11  * Michael Fromberger but has been written from scratch with
     12  * additional optimizations in place.
     13  *
     14  * The library is free for all purposes without any express
     15  * guarantee it works.
     16  *
     17  * Tom St Denis, tomstdenis (at) gmail.com, http://libtom.org
     18  */
     19 
     20 /* stores a bignum as a ASCII string in a given radix (2..64) */
     21 int mp_toradix (mp_int * a, char *str, int radix)
     22 {
     23   int     res, digs;
     24   mp_int  t;
     25   mp_digit d;
     26   char   *_s = str;
     27 
     28   /* check range of the radix */
     29   if (radix < 2 || radix > 64) {
     30     return MP_VAL;
     31   }
     32 
     33   /* quick out if its zero */
     34   if (mp_iszero(a) == 1) {
     35      *str++ = '0';
     36      *str = '\0';
     37      return MP_OKAY;
     38   }
     39 
     40   if ((res = mp_init_copy (&t, a)) != MP_OKAY) {
     41     return res;
     42   }
     43 
     44   /* if it is negative output a - */
     45   if (t.sign == MP_NEG) {
     46     ++_s;
     47     *str++ = '-';
     48     t.sign = MP_ZPOS;
     49   }
     50 
     51   digs = 0;
     52   while (mp_iszero (&t) == 0) {
     53     if ((res = mp_div_d (&t, (mp_digit) radix, &t, &d)) != MP_OKAY) {
     54       mp_clear (&t);
     55       return res;
     56     }
     57     *str++ = mp_s_rmap[d];
     58     ++digs;
     59   }
     60 
     61   /* reverse the digits of the string.  In this case _s points
     62    * to the first digit [exluding the sign] of the number]
     63    */
     64   bn_reverse ((unsigned char *)_s, digs);
     65 
     66   /* append a NULL so the string is properly terminated */
     67   *str = '\0';
     68 
     69   mp_clear (&t);
     70   return MP_OKAY;
     71 }
     72 
     73 #endif
     74 
     75 /* Source: /cvs/libtom/libtommath/bn_mp_toradix.c,v  */
     76 /* Revision: 1.4  */
     77 /* Date: 2006/12/28 01:25:13  */
     78