/home/ntakagi/work/tcl8.5.1/libtommath/bn_mp_copy.c Source File

00001 #include <tommath.h>
00002 #ifdef BN_MP_COPY_C
00003 /* LibTomMath, multiple-precision integer library -- Tom St Denis
00004  *
00005  * LibTomMath is a library that provides multiple-precision
00006  * integer arithmetic as well as number theoretic functionality.
00007  *
00008  * The library was designed directly after the MPI library by
00009  * Michael Fromberger but has been written from scratch with
00010  * additional optimizations in place.
00011  *
00012  * The library is free for all purposes without any express
00013  * guarantee it works.
00014  *
00015  * Tom St Denis, tomstdenis@gmail.com, http://math.libtomcrypt.com
00016  */
00017 
00018 /* copy, b = a */
00019 int
00020 mp_copy (mp_int * a, mp_int * b)
00021 {
00022   int     res, n;
00023 
00024   /* if dst == src do nothing */
00025   if (a == b) {
00026     return MP_OKAY;
00027   }
00028 
00029   /* grow dest */
00030   if (b->alloc < a->used) {
00031      if ((res = mp_grow (b, a->used)) != MP_OKAY) {
00032         return res;
00033      }
00034   }
00035 
00036   /* zero b and copy the parameters over */
00037   {
00038     register mp_digit *tmpa, *tmpb;
00039 
00040     /* pointer aliases */
00041 
00042     /* source */
00043     tmpa = a->dp;
00044 
00045     /* destination */
00046     tmpb = b->dp;
00047 
00048     /* copy all the digits */
00049     for (n = 0; n < a->used; n++) {
00050       *tmpb++ = *tmpa++;
00051     }
00052 
00053     /* clear high digits */
00054     for (; n < b->used; n++) {
00055       *tmpb++ = 0;
00056     }
00057   }
00058 
00059   /* copy used count and sign */
00060   b->used = a->used;
00061   b->sign = a->sign;
00062   return MP_OKAY;
00063 }
00064 #endif
00065 
00066 /* $Source: /cvsroot/tcl/libtommath/bn_mp_copy.c,v $ */
00067 /* $Revision: 1.1.1.3 $ */
00068 /* $Date: 2006/12/01 00:08:11 $ */