Line data    Source code

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