X-Git-Url: https://git.distorted.org.uk/u/mdw/catacomb/blobdiff_plain/ab0350a65e5ac7f1f96e0e2df18c504dd8a441ce..67a452f7a9d69723741b064f08d70462bc8f00e7:/mpbarrett-mexp.c

diff --git a/mpbarrett-mexp.c b/mpbarrett-mexp.c
index e97c064..2cfda96 100644
--- a/mpbarrett-mexp.c
+++ b/mpbarrett-mexp.c
@@ -1,13 +1,13 @@
 /* -*-c-*-
  *
- * $Id: mpbarrett-mexp.c,v 1.1 2001/06/16 12:58:34 mdw Exp $
+ * $Id$
  *
  * Multiple simultaneous exponentiations
  *
  * (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-mexp.c,v $
- * Revision 1.1  2001/06/16 12:58:34  mdw
- * Added simultaneous exponentiation with Barrett reduction.
- *
- */
-
 /*----- Header files ------------------------------------------------------*/
 
 #include "mp.h"
@@ -49,7 +41,7 @@
  *
  * Arguments:	@mpbarrett *mb@ = pointer to Barrett reduction context
  *		@mp *d@ = fake destination
- *		@mp_expfactor *f@ = pointer to array of factors
+ *		@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
@@ -59,23 +51,31 @@
  *		%$g_0^{e_0} g_1^{e_1} \ldots g_{n-1}^{e_{n-1}} \bmod m$%
  */
 
-mp *mpbarrett_mexp(mpbarrett *mb, mp *d, mp_expfactor *f, size_t n)
+mp *mpbarrett_mexp(mpbarrett *mb, mp *d, const mp_expfactor *f, size_t n)
 {
+  mp_expfactor *ff = xmalloc(n * sizeof(mp_expfactor));
   mp *a = MP_ONE;
   mp *spare;
+  mp *g = MP_NEW;
   size_t i;
 
   spare = MP_NEW;
   for (i = 0; i < n; i++) {
-    if (f[i].exp->f & MP_BURN) {
+    if (f[i].exp->f & MP_BURN)
       spare = MP_NEWSEC;
-      break;
-    }
+    if (MP_NEGP(f[i].exp))
+      ff[i].base = mp_modinv(MP_NEW, f[i].base, mb->m);
+    else
+      ff[i].base = MP_COPY(f[i].base);
+    ff[i].exp = f[i].exp;
   }
-
-  EXP_SIMUL(a, f, n);
+  mp_drop(g);
+  EXP_SIMUL(a, ff, n);
   mp_drop(d);
   mp_drop(spare);
+  for (i = 0; i < n; i++)
+    mp_drop(ff[i].base);
+  xfree(ff);
   return (a);
 }
 
@@ -170,7 +170,7 @@ int main(int argc, char *argv[])
   sub_init();
   test_run(argc, argv, tests, SRCDIR "/tests/mpbarrett");
   return (0);
-}   
+}
 
 #endif