crypto/external/bsd/heimdal/dist/lib/hcrypto/libtommath/bn_mp_grow.c

   1 /*      $NetBSD: bn_mp_grow.c,v 1.1.1.2 2014/04/24 12:45:31 pettai Exp $        */
   2
   3 #include <tommath.h>
   4 #ifdef BN_MP_GROW_C
   5 /* LibTomMath, multiple-precision integer library -- Tom St Denis
   6  *
   7  * LibTomMath is a library that provides multiple-precision
   8  * integer arithmetic as well as number theoretic functionality.
   9  *
  10  * The library was designed directly after the MPI library by
  11  * Michael Fromberger but has been written from scratch with
  12  * additional optimizations in place.
  13  *
  14  * The library is free for all purposes without any express
  15  * guarantee it works.
  16  *
  17  * Tom St Denis, tomstdenis@gmail.com, http://libtom.org
  18  */
  19
  20 /* grow as required */
  21 int mp_grow (mp_int * a, int size)
  22 {
  23   int     i;
  24   mp_digit *tmp;
  25
  26   /* if the alloc size is smaller alloc more ram */
  27   if (a->alloc < size) {
  28     /* ensure there are always at least MP_PREC digits extra on top */
  29     size += (MP_PREC * 2) - (size % MP_PREC);
  30
  31     /* reallocate the array a->dp
  32      *
  33      * We store the return in a temporary variable
  34      * in case the operation failed we don't want
  35      * to overwrite the dp member of a.
  36      */
  37     tmp = OPT_CAST(mp_digit) XREALLOC (a->dp, sizeof (mp_digit) * size);
  38     if (tmp == NULL) {
  39       /* reallocation failed but "a" is still valid [can be freed] */
  40       return MP_MEM;
  41     }
  42
  43     /* reallocation succeeded so set a->dp */
  44     a->dp = tmp;
  45
  46     /* zero excess digits */
  47     i        = a->alloc;
  48     a->alloc = size;
  49     for (; i < a->alloc; i++) {
  50       a->dp[i] = 0;
  51     }
  52   }
  53   return MP_OKAY;
  54 }
  55 #endif
  56
  57 /* Source: /cvs/libtom/libtommath/bn_mp_grow.c,v  */
  58 /* Revision: 1.4  */
  59 /* Date: 2006/12/28 01:25:13  */