Support subgroups of binary fields.

[u/mdw/catacomb] / f-binpoly.c

diff --git a/f-binpoly.c b/f-binpoly.c
index 45e1449..23d9984 100644 (file)
--- a/f-binpoly.c
+++ b/f-binpoly.c
@@ -1,6 +1,6 @@
 /* -*-c-*-
  *
- * $Id: f-binpoly.c,v 1.7 2004/04/01 21:28:41 mdw Exp $
+ * $Id$
  *
  * Binary fields with polynomial basis representation
  *
@@ -27,92 +27,66 @@
  * MA 02111-1307, USA.
  */
 
-/*----- Revision history --------------------------------------------------* 
- *
- * $Log: f-binpoly.c,v $
- * Revision 1.7  2004/04/01 21:28:41  mdw
- * Normal basis support (translates to poly basis internally).  Rewrite
- * EC and prime group table generators in awk, so that they can reuse data
- * for repeated constants.
- *
- * Revision 1.6  2004/04/01 12:50:09  mdw
- * Add cyclic group abstraction, with test code.  Separate off exponentation
- * functions for better static linking.  Fix a buttload of bugs on the way.
- * Generally ensure that negative exponents do inversion correctly.  Add
- * table of standard prime-field subgroups.  (Binary field subgroups are
- * currently unimplemented but easy to add if anyone ever finds a good one.)
- *
- * Revision 1.5  2004/03/27 17:54:11  mdw
- * Standard curves and curve checking.
- *
- * Revision 1.4  2004/03/23 15:19:32  mdw
- * Test elliptic curves more thoroughly.
- *
- * Revision 1.3  2004/03/23 12:08:26  mdw
- * Random field-element selection.
- *
- * Revision 1.2  2004/03/21 22:52:06  mdw
- * Merge and close elliptic curve branch.
- *
- * Revision 1.1.2.1  2004/03/21 22:39:46  mdw
- * Elliptic curves on binary fields work.
- *
- */
-
 /*----- Header files ------------------------------------------------------*/
 
 #include <mLib/sub.h>
 
 #include "field.h"
-#include "gf.h"
-#include "gfreduce.h"
+#include "field-guts.h"
 #include "mprand.h"
-#include "gfn.h"
 
 /*----- Polynomial basis --------------------------------------------------*/
 
-typedef struct fctx {
-  field f;
-  gfreduce r;
-} fctx;
-
 /* --- Field operations --- */
 
-static void fdestroy(field *ff)
-  { fctx *f = (fctx *)ff; gfreduce_destroy(&f->r); DESTROY(f); }
+static void fdestroy(field *ff) {
+  fctx_binpoly *f = (fctx_binpoly *)ff;
+  gfreduce_destroy(&f->r);
+  DESTROY(f);
+}
 
-static mp *frand(field *f, mp *d, grand *r)
-  { return (mprand(d, f->nbits, r, 0)); }
+static mp *frand(field *f, mp *d, grand *r) {
+  return (mprand(d, f->nbits, r, 0));
+}
 
-static int fzerop(field *ff, mp *x) { return (!MP_LEN(x)); }
+static int fzerop(field *ff, mp *x) { return (MP_ZEROP(x)); }
 
 static mp *fadd(field *ff, mp *d, mp *x, mp *y) { return (gf_add(d, x, y)); }
 
 static mp *fmul(field *ff, mp *d, mp *x, mp *y) {
-  fctx *f = (fctx *)ff; d = gf_mul(d, x, y);
+  fctx_binpoly *f = (fctx_binpoly *)ff; d = gf_mul(d, x, y);
   return (gfreduce_do(&f->r, d, d));
 }
 
 static mp *fsqr(field *ff, mp *d, mp *x) {
-  fctx *f = (fctx *)ff; d = gf_sqr(d, x);
+  fctx_binpoly *f = (fctx_binpoly *)ff; d = gf_sqr(d, x);
   return (gfreduce_do(&f->r, d, d));
 }
 
-static mp *finv(field *ff, mp *d, mp *x)
-  { fctx *f = (fctx *)ff; gf_gcd(0, 0, &d, f->r.p, x); return (d); }
+static mp *finv(field *ff, mp *d, mp *x) {
+  fctx_binpoly *f = (fctx_binpoly *)ff;
+  d = gf_modinv(d, x, f->r.p);
+  return (d);
+}
 
-static mp *freduce(field *ff, mp *d, mp *x)
-  { fctx *f = (fctx *)ff; return (gfreduce_do(&f->r, d, x)); }
+static mp *freduce(field *ff, mp *d, mp *x) {
+  fctx_binpoly *f = (fctx_binpoly *)ff;
+  return (gfreduce_do(&f->r, d, x));
+}
 
-static mp *fsqrt(field *ff, mp *d, mp *x)
-  { fctx *f = (fctx *)ff; return (gfreduce_sqrt(&f->r, d, x)); }
+static mp *fsqrt(field *ff, mp *d, mp *x) {
+  fctx_binpoly *f = (fctx_binpoly *)ff;
+  return (gfreduce_sqrt(&f->r, d, x));
+}
 
-static mp *fquadsolve(field *ff, mp *d, mp *x)
-  { fctx *f = (fctx *)ff; return (gfreduce_quadsolve(&f->r, d, x)); }
+static mp *fquadsolve(field *ff, mp *d, mp *x) {
+  fctx_binpoly *f = (fctx_binpoly *)ff;
+  return (gfreduce_quadsolve(&f->r, d, x));
+}
 
 /* --- Field operations table --- */
 
-static field_ops fops = {
+static const field_ops fops = {
   FTY_BINARY, "binpoly",
   fdestroy, frand, field_stdsamep,
   freduce, field_id,
@@ -132,7 +106,7 @@ static field_ops fops = {
 
 field *field_binpoly(mp *p)
 {
-  fctx *f = CREATE(fctx);
+  fctx_binpoly *f = CREATE(fctx_binpoly);
   f->f.ops = &fops;
   f->f.zero = MP_ZERO;
   f->f.one = MP_ONE;
@@ -145,33 +119,32 @@ field *field_binpoly(mp *p)
 
 /*----- Normal basis ------------------------------------------------------*/
 
-typedef struct fnctx {
-  fctx f;
-  gfn ntop, pton;
-} fnctx;
-
 /* --- Field operations --- */
 
 static void fndestroy(field *ff) {
-  fnctx *f = (fnctx *)ff; gfreduce_destroy(&f->f.r);
+  fctx_binnorm *f = (fctx_binnorm *)ff; gfreduce_destroy(&f->f.r);
   gfn_destroy(&f->ntop); gfn_destroy(&f->pton);
   DESTROY(f);
 }
 
 static int fnsamep(field *ff, field *gg) {
-  fnctx *f = (fnctx *)ff, *g = (fnctx *)gg;
+  fctx_binnorm *f = (fctx_binnorm *)ff, *g = (fctx_binnorm *)gg;
   return (MP_EQ(f->ntop.r[0], g->ntop.r[0]) && field_stdsamep(ff, gg));
 }
 
-static mp *fnin(field *ff, mp *d, mp *x)
-  { fnctx *f = (fnctx *)ff; return (gfn_transform(&f->ntop, d, x)); }
+static mp *fnin(field *ff, mp *d, mp *x) {
+  fctx_binnorm *f = (fctx_binnorm *)ff;
+  return (gfn_transform(&f->ntop, d, x));
+}
 
-static mp *fnout(field *ff, mp *d, mp *x)
-  { fnctx *f = (fnctx *)ff; return (gfn_transform(&f->pton, d, x)); }
+static mp *fnout(field *ff, mp *d, mp *x) {
+  fctx_binnorm *f = (fctx_binnorm *)ff;
+  return (gfn_transform(&f->pton, d, x));
+}
 
 /* --- Field operations table --- */
 
-static field_ops fnops = {
+static const field_ops fnops = {
   FTY_BINARY, "binnorm",
   fndestroy, frand, fnsamep,
   fnin, fnout,
@@ -194,7 +167,7 @@ static field_ops fnops = {
 
 field *field_binnorm(mp *p, mp *beta)
 {
-  fnctx *f = CREATE(fnctx);
+  fctx_binnorm *f = CREATE(fctx_binnorm);
   f->f.f.ops = &fnops;
   f->f.f.zero = MP_ZERO;
   f->f.f.one = MP_ONE;