bn_mp_grow.c

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Author : Daniel Mendler
Date : 2019-04-04 11:01:08
Hash : db9a47d5
Message : allocation functions: pass size to XREALLOC and XFREE This is similar to the signatures of the custom allocation functions provided by GMP. The allocation sizes are useful if the allocator has no easy way to access the allocation size.

bn_mp_grow.c

#include "tommath_private.h"
#ifdef BN_MP_GROW_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
 */

/* grow as required */
int mp_grow(mp_int *a, int size)
{
   int     i;
   mp_digit *tmp;

   /* if the alloc size is smaller alloc more ram */
   if (a->alloc < size) {
      /* ensure there are always at least MP_PREC digits extra on top */
      size += (MP_PREC * 2) - (size % MP_PREC);

      /* reallocate the array a->dp
       *
       * We store the return in a temporary variable
       * in case the operation failed we don't want
       * to overwrite the dp member of a.
       */
      tmp = (mp_digit *) XREALLOC(a->dp,
                                  (size_t)a->alloc * sizeof (mp_digit),
                                  (size_t)size * sizeof(mp_digit));
      if (tmp == NULL) {
         /* reallocation failed but "a" is still valid [can be freed] */
         return MP_MEM;
      }

      /* reallocation succeeded so set a->dp */
      a->dp = tmp;

      /* zero excess digits */
      i        = a->alloc;
      a->alloc = size;
      for (; i < a->alloc; i++) {
         a->dp[i] = 0;
      }
   }
   return MP_OKAY;
}
#endif

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kc3-lang/libtommath/bn_mp_grow.c

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