view libtommath/bn_mp_radix_size.c @ 1857:6022df862942

Use DSCP for IP QoS traffic classes The previous TOS values are deprecated and not used by modern traffic classifiers. This sets AF21 for "interactive" traffic (with a tty). Non-tty traffic sets AF11 - that indicates high throughput but is not lowest priority (which would be CS1 or LE). This differs from the CS1 used by OpenSSH, it lets interactive git over SSH have higher priority than background least effort traffic. Dropbear's settings here should be suitable with the diffservs used by CAKE qdisc.
author Matt Johnston <matt@ucc.asn.au>
date Tue, 25 Jan 2022 17:32:20 +0800
parents 1051e4eea25a
children
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#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 representation */
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) {
         goto LBL_ERR;
      }
      ++digs;
   }

   /* return digs + 1, the 1 is for the NULL byte that would be required. */
   *size = digs + 1;
   err = MP_OKAY;

LBL_ERR:
   mp_clear(&t);
   return err;
}

#endif