X-Git-Url: https://git.distorted.org.uk/u/mdw/catacomb/blobdiff_plain/21a7c4b1cffbf33a19e4cf421e29420187ed7a89..d4bb7fded5f9a4b0db99f82e88f22effe94f2ff7:/mpbarrett.h

diff --git a/mpbarrett.h b/mpbarrett.h
index d9c02ad..71d9ba7 100644
--- a/mpbarrett.h
+++ b/mpbarrett.h
@@ -1,13 +1,13 @@
 /* -*-c-*-
  *
- * $Id: mpbarrett.h,v 1.1 1999/12/10 23:22:00 mdw Exp $
+ * $Id$
  *
  * Barrett modular reduction
  *
  * (c) 1999 Straylight/Edgeware
  */
 
-/*----- Licensing notice --------------------------------------------------* 
+/*----- Licensing notice --------------------------------------------------*
  *
  * This file is part of Catacomb.
  *
@@ -15,26 +15,18 @@
  * it under the terms of the GNU Library General Public License as
  * published by the Free Software Foundation; either version 2 of the
  * License, or (at your option) any later version.
- * 
+ *
  * Catacomb is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU Library General Public License for more details.
- * 
+ *
  * You should have received a copy of the GNU Library General Public
  * License along with Catacomb; if not, write to the Free
  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
  * MA 02111-1307, USA.
  */
 
-/*----- Revision history --------------------------------------------------* 
- *
- * $Log: mpbarrett.h,v $
- * Revision 1.1  1999/12/10 23:22:00  mdw
- * Barrett reduction support: works with even moduli.
- *
- */
-
 /*----- Notes on Barrett reduction ----------------------------------------*
  *
  * Barrett reduction is a technique for computing modular residues.  Unlike
@@ -80,13 +72,12 @@ typedef struct mpbarrett {
  * Arguments:	@mpbarrett *mb@ = pointer to Barrett reduction context
  *		@mp *m@ = modulus to work to
  *
- *
- * Returns:	---
+ * Returns:	Zero on success, nonzero on error.
  *
  * Use:		Initializes a Barrett reduction context ready for use.
  */
 
-extern void mpbarrett_create(mpbarrett */*mb*/, mp */*m*/);
+extern int mpbarrett_create(mpbarrett */*mb*/, mp */*m*/);
 
 /* --- @mpbarrett_destroy@ --- *
  *
@@ -109,8 +100,7 @@ extern void mpbarrett_destroy(mpbarrett */*mb*/);
  * Returns:	The residue of @m@ modulo the number in the reduction
  *		context.
  *
- * Use:		Performs an efficient modular reduction.  The argument is
- *		assumed to be positive.
+ * Use:		Performs an efficient modular reduction.
  */
 
 extern mp *mpbarrett_reduce(mpbarrett */*mb*/, mp */*d*/, mp */*m*/);
@@ -118,15 +108,32 @@ extern mp *mpbarrett_reduce(mpbarrett */*mb*/, mp */*d*/, mp */*m*/);
 /* --- @mpbarrett_exp@ --- *
  *
  * Arguments:	@mpbarrett *mb@ = pointer to Barrett reduction context
- *              @mp *d@ = fake destination
- *              @mp *a@ = base
- *              @mp *e@ = exponent
+ *		@mp *d@ = fake destination
+ *		@mp *a@ = base
+ *		@mp *e@ = exponent
  *
- * Returns:     Result, %$a^e \bmod m$%.
+ * Returns:	Result, %$a^e \bmod m$%.
  */
 
 extern mp *mpbarrett_exp(mpbarrett */*mb*/, mp */*d*/, mp */*a*/, mp */*e*/);
 
+/* --- @mpbarrett_mexp@ --- *
+ *
+ * Arguments:	@mpbarrett *mb@ = pointer to Barrett reduction context
+ *		@mp *d@ = fake destination
+ *		@const mp_expfactor *f@ = pointer to array of factors
+ *		@size_t n@ = number of factors supplied
+ *
+ * Returns:	If the bases are %$g_0, g_1, \ldots, g_{n-1}$% and the
+ *		exponents are %$e_0, e_1, \ldots, e_{n-1}$% then the result
+ *		is:
+ *
+ *		%$g_0^{e_0} g_1^{e_1} \ldots g_{n-1}^{e_{n-1}} \bmod m$%
+ */
+
+extern mp *mpbarrett_mexp(mpbarrett */*mb*/, mp */*d*/,
+			  const mp_expfactor */*f*/, size_t /*n*/);
+
 /*----- That's all, folks -------------------------------------------------*/
 
 #ifdef __cplusplus