kc3-lang/libtommath/bn_mp_radix_size.c

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• Hash : 8b2daf78
  Author :
  Date : 2019-05-19T17:16:13
  

  always use varname err with mp_err

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• bn_mp_radix_size.c

• #include "tommath_private.h"
  #ifdef BN_MP_RADIX_SIZE_C
  /* LibTomMath, multiple-precision integer library -- Tom St Denis */
  /* SPDX-License-Identifier: Unlicense */
  
  /* returns size of ASCII reprensentation */
  mp_err mp_radix_size(const mp_int *a, int radix, int *size)
  {
     mp_err  err;
     int     digs;
     mp_int   t;
     mp_digit d;
  
     *size = 0;
  
     /* make sure the radix is in range */
     if ((radix < 2) || (radix > 64)) {
        return MP_VAL;
     }
  
     if (MP_IS_ZERO(a)) {
        *size = 2;
        return MP_OKAY;
     }
  
     /* special case for binary */
     if (radix == 2) {
        *size = mp_count_bits(a) + ((a->sign == MP_NEG) ? 1 : 0) + 1;
        return MP_OKAY;
     }
  
     /* digs is the digit count */
     digs = 0;
  
     /* if it's negative add one for the sign */
     if (a->sign == MP_NEG) {
        ++digs;
     }
  
     /* init a copy of the input */
     if ((err = mp_init_copy(&t, a)) != MP_OKAY) {
        return err;
     }
  
     /* force temp to positive */
     t.sign = MP_ZPOS;
  
     /* fetch out all of the digits */
     while (!MP_IS_ZERO(&t)) {
        if ((err = mp_div_d(&t, (mp_digit)radix, &t, &d)) != MP_OKAY) {
           mp_clear(&t);
           return err;
        }
        ++digs;
     }
     mp_clear(&t);
  
     /* return digs + 1, the 1 is for the NULL byte that would be required. */
     *size = digs + 1;
     return MP_OKAY;
  }
  
  #endif
  

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