libs/libtommath/bn_mp_copy.c

   1 #include <tommath.h>
   2 #ifdef BN_MP_COPY_C
   3 /* LibTomMath, multiple-precision integer library -- Tom St Denis
   4  *
   5  * LibTomMath is a library that provides multiple-precision
   6  * integer arithmetic as well as number theoretic functionality.
   7  *
   8  * The library was designed directly after the MPI library by
   9  * Michael Fromberger but has been written from scratch with
  10  * additional optimizations in place.
  11  *
  12  * The library is free for all purposes without any express
  13  * guarantee it works.
  14  *
  15  * Tom St Denis, tomstdenis@gmail.com, http://libtom.org
  16  */
  17
  18 /* copy, b = a */
  19 int
  20 mp_copy (mp_int * a, mp_int * b)
  21 {
  22   int     res, n;
  23
  24   /* if dst == src do nothing */
  25   if (a == b) {
  26     return MP_OKAY;
  27   }
  28
  29   /* grow dest */
  30   if (b->alloc < a->used) {
  31      if ((res = mp_grow (b, a->used)) != MP_OKAY) {
  32         return res;
  33      }
  34   }
  35
  36   /* zero b and copy the parameters over */
  37   {
  38     register mp_digit *tmpa, *tmpb;
  39
  40     /* pointer aliases */
  41
  42     /* source */
  43     tmpa = a->dp;
  44
  45     /* destination */
  46     tmpb = b->dp;
  47
  48     /* copy all the digits */
  49     for (n = 0; n < a->used; n++) {
  50       *tmpb++ = *tmpa++;
  51     }
  52
  53     /* clear high digits */
  54     for (; n < b->used; n++) {
  55       *tmpb++ = 0;
  56     }
  57   }
  58
  59   /* copy used count and sign */
  60   b->used = a->used;
  61   b->sign = a->sign;
  62   return MP_OKAY;
  63 }
  64 #endif
  65
  66 /* $Source: /cvs/libtom/libtommath/bn_mp_copy.c,v $ */
  67 /* $Revision: 1.4 $ */
  68 /* $Date: 2006/12/28 01:25:13 $ */