release/src/router/dropbear/libtommath/bn_mp_to_unsigned_bin.c

   1 #include <tommath.h>
   2 #ifdef BN_MP_TO_UNSIGNED_BIN_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://math.libtomcrypt.com
  16  */
  17
  18 /* store in unsigned [big endian] format */
  19 int mp_to_unsigned_bin (mp_int * a, unsigned char *b)
  20 {
  21   int     x, res;
  22   mp_int  t;
  23
  24   if ((res = mp_init_copy (&t, a)) != MP_OKAY) {
  25     return res;
  26   }
  27
  28   x = 0;
  29   while (mp_iszero (&t) == 0) {
  30 #ifndef MP_8BIT
  31       b[x++] = (unsigned char) (t.dp[0] & 255);
  32 #else
  33       b[x++] = (unsigned char) (t.dp[0] | ((t.dp[1] & 0x01) << 7));
  34 #endif
  35     if ((res = mp_div_2d (&t, 8, &t, NULL)) != MP_OKAY) {
  36       mp_clear (&t);
  37       return res;
  38     }
  39   }
  40   bn_reverse (b, x);
  41   mp_clear (&t);
  42   return MP_OKAY;
  43 }
  44 #endif
  45
  46 /* $Source: /cvs/libtom/libtommath/bn_mp_to_unsigned_bin.c,v $ */
  47 /* $Revision: 1.3 $ */
  48 /* $Date: 2006/03/31 14:18:44 $ */