/* -*-c-*-
*
- * $Id: bbs.h,v 1.7 2004/04/08 01:36:15 mdw Exp $
+ * $Id$
*
* The Blum-Blum-Shub random bit generator
*
/*----- Large forwards and backwards jumps --------------------------------*/
-/* --- @bbs_ff@ --- *
+/* --- @bbs_{ff,rew}{,n}@ --- *
*
* Arguments: @bbs *b@ = pointer to a BBS generator state
- * @bbs_priv *bp@ = pointer to BBS modulus factors
- * @unsigned long n@ = number of steps to make
+ * @const bbs_priv *bp@ = pointer to BBS modulus factors
+ * @mp *n@, @unsigned long n@ = number of steps to make
*
* Returns: ---
*
- * Use: `Fast-forwards' a Blum-Blum-Shub generator by @n@ steps.
- * Requires the factorization of the Blum modulus to do this
- * efficiently.
+ * Use: `Fast-forwards' or rewinds a Blum-Blum-Shub generator by @n@
+ * steps. The @...n@ versions take an @unsigned long@ argument;
+ * the non-@...n@ versions a multiprecision integer. If @n@ is
+ * negative then the generator is stepped in the reverse
+ * direction.
*/
-extern void bbs_ff(bbs */*b*/, bbs_priv */*bp*/, unsigned long /*n*/);
-
-/* --- @bbs_rew@ --- *
- *
- * Arguments: @bbs *b@ = pointer to a BBS generator state
- * @bbs_priv *bp@ = pointer to BBS modulus factors
- * @unsigned long n@ = number of steps to make
- *
- * Returns: ---
- *
- * Use: `Rewinds' a Blum-Blum-Shub generator by @n@ steps.
- * Requires the factorization of the Blum modulus to do this
- * at all.
- */
-
-extern void bbs_rew(bbs */*b*/, bbs_priv */*bp*/, unsigned long /*n*/);
+extern void bbs_ff(bbs */*b*/, const bbs_priv */*bp*/, mp */*n*/);
+extern void bbs_ffn(bbs */*b*/, const bbs_priv */*bp*/, unsigned long /*n*/);
+extern void bbs_rew(bbs */*b*/, const bbs_priv */*bp*/, mp */*n*/);
+extern void bbs_rewn(bbs */*b*/, const bbs_priv */*bp*/, unsigned long /*n*/);
/*----- Parameter generation ----------------------------------------------*/
/* --- Blum-Blum-Shub-specific misc op codes --- */
enum {
- BBS_SET = GRAND_SPECIFIC('B') /* @mp *x@ */
+ BBS_SET = GRAND_SPECIFIC('B'), /* @mp *x@ */
+ BBS_STEP, /* @void@ */
+ BBS_STEPSZ, /* @void@ */
+ BBS_BITS, /* @unsigned bits, uint32 *w@ */
+ BBS_WRAP, /* @void@ */
+ BBS_FF, /* @bbs_priv *p, mp *n@ */
+ BBS_FFN, /* @bbs_priv *p, unsigned long n@ */
+ BBS_REW, /* @bbs_priv *p, mp *n@ */
+ BBS_REWN, /* @bbs_priv *p, unsigned long n@ */
+ BBS_MOD, /* @mp **n@ */
+ BBS_STATE /* @mp **x@ */
};
/*----- That's all, folks -------------------------------------------------*/