bn_mp_to_unsigned_bin.c 1.2 KB

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