fp_toradix.c   [plain text]

/* TomsFastMath, a fast ISO C bignum library.
 * 
 * This project is meant to fill in where LibTomMath
 * falls short.  That is speed ;-)
 *
 * This project is public domain and free for all purposes.
 * 
 * Tom St Denis, tomstdenis@gmail.com
 */
#include <tfm.h>

int fp_toradix(fp_int *a, char *str, int radix)
{
  int     digs;
  fp_int  t;
  fp_digit d;
  char   *_s = str;

  /* check range of the radix */
  if (radix < 2 || radix > 64) {
    return FP_VAL;
  }

  /* quick out if its zero */
  if (fp_iszero(a) == 1) {
     *str++ = '0';
     *str = '\0';
     return FP_OKAY;
  }

  fp_init_copy(&t, a);

  /* if it is negative output a - */
  if (t.sign == FP_NEG) {
    ++_s;
    *str++ = '-';
    t.sign = FP_ZPOS;
  }

  digs = 0;
  while (fp_iszero (&t) == FP_NO) {
    fp_div_d (&t, (fp_digit) radix, &t, &d);
    *str++ = fp_s_rmap[d];
    ++digs;
  }

  /* reverse the digits of the string.  In this case _s points
   * to the first digit [exluding the sign] of the number]
   */
  fp_reverse ((unsigned char *)_s, digs);

  /* append a NULL so the string is properly terminated */
  *str = '\0';
  return FP_OKAY;
}

/* $Source: /cvs/libtom/tomsfastmath/src/bin/fp_toradix.c,v $ */
/* $Revision: 1.2 $ */
/* $Date: 2007/02/27 02:38:44 $ */