view libtommath/bn_mp_count_bits.c @ 1635:c9b5017b0a7b

drop obsolete definition for MAX_KEXHASHBUF (#65) The last code to make use of MAX_KEXHASHBUF was removed in 2005: https://github.com/mkj/dropbear/commit/736f370dce614b717193f45d084e9e009de723ce Signed-off-by: Andre McCurdy <[email protected]>
author Andre McCurdy <armccurdy@gmail.com>
date Wed, 20 Mar 2019 08:01:41 -0700
parents 8bba51a55704
children f52919ffd3b1
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line source

#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

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