view libtommath/bn_mp_read_unsigned_bin.c @ 1656:a36e545fb43d

Prime-related bugfixes (#81) * Merge pull request #180 from czurnieden/isprimeerror Fixed bug in mp_prime_isprime (cherry picked from commit f3ff7064f3301a2fc11b84d389fd67769862d437) * do 2 MR rounds for numbers >=2048bits * back-port modified mp_prime_next_prime()
author Steffen Jaeckel <s@jaeckel.eu>
date Tue, 17 Sep 2019 16:11:09 +0200
parents f52919ffd3b1
children
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#include "tommath_private.h"
#ifdef BN_MP_READ_UNSIGNED_BIN_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.
 *
 * SPDX-License-Identifier: Unlicense
 */

/* reads a unsigned char array, assumes the msb is stored first [big endian] */
int mp_read_unsigned_bin(mp_int *a, const unsigned char *b, int c)
{
   int     res;

   /* make sure there are at least two digits */
   if (a->alloc < 2) {
      if ((res = mp_grow(a, 2)) != MP_OKAY) {
         return res;
      }
   }

   /* zero the int */
   mp_zero(a);

   /* read the bytes in */
   while (c-- > 0) {
      if ((res = mp_mul_2d(a, 8, a)) != MP_OKAY) {
         return res;
      }

#ifndef MP_8BIT
      a->dp[0] |= *b++;
      a->used += 1;
#else
      a->dp[0] = (*b & MP_MASK);
      a->dp[1] |= ((*b++ >> 7) & 1u);
      a->used += 2;
#endif
   }
   mp_clamp(a);
   return MP_OKAY;
}
#endif

/* ref:         HEAD -> master, tag: v1.1.0 */
/* git commit:  08549ad6bc8b0cede0b357a9c341c5c6473a9c55 */
/* commit time: 2019-01-28 20:32:32 +0100 */