view libtommath/bn_mp_count_bits.c @ 1442:517c67cbcd31

dropbear server: support -T max auth tries Add support for '-T n' for a run-time specification for maximum number of authentication attempts where 'n' is between 1 and compile time option MAX_AUTH_TRIES. A default number of tries can be specified at compile time using 'DEFAULT_AUTH_TRIES' which itself defaults to MAX_AUTH_TRIES for backwards compatibility. Signed-off-by: Kevin Darbyshire-Bryant <[email protected]>
author Kevin Darbyshire-Bryant <kevin@darbyshire-bryant.me.uk>
date Mon, 29 May 2017 10:25:09 +0100
parents 60fc6476e044
children 8bba51a55704
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#include <tommath_private.h>
#ifdef BN_MP_COUNT_BITS_C
/* LibTomMath, multiple-precision integer library -- Tom St Denis
 *
 * LibTomMath is a library that provides multiple-precision
 * integer arithmetic as well as number theoretic functionality.
 *
 * The library was designed directly after the MPI library by
 * Michael Fromberger but has been written from scratch with
 * additional optimizations in place.
 *
 * The library is free for all purposes without any express
 * guarantee it works.
 *
 * Tom St Denis, [email protected], http://libtom.org
 */

/* returns the number of bits in an int */
int
mp_count_bits (mp_int * a)
{
  int     r;
  mp_digit q;

  /* shortcut */
  if (a->used == 0) {
    return 0;
  }

  /* get number of digits and add that */
  r = (a->used - 1) * DIGIT_BIT;
  
  /* take the last digit and count the bits in it */
  q = a->dp[a->used - 1];
  while (q > ((mp_digit) 0)) {
    ++r;
    q >>= ((mp_digit) 1);
  }
  return r;
}
#endif

/* $Source$ */
/* $Revision$ */
/* $Date$ */