X-Git-Url: https://git.distorted.org.uk/u/mdw/catacomb/blobdiff_plain/b817bfc642225b8c3c0b6a7e42d1fb949b61a606..f4535c6454395e6d56ce0091a07b6d4f7d54a47f:/f-niceprime.c

diff --git a/f-niceprime.c b/f-niceprime.c
index 8645cb6..ce96977 100644
--- a/f-niceprime.c
+++ b/f-niceprime.c
@@ -1,6 +1,6 @@
 /* -*-c-*-
  *
- * $Id: f-niceprime.c,v 1.6 2004/04/08 01:36:15 mdw Exp $
+ * $Id$
  *
  * Prime fields with efficient reduction for special-form primes
  *
@@ -32,84 +32,93 @@
 #include <mLib/sub.h>
 
 #include "field.h"
-#include "mpreduce.h"
+#include "field-guts.h"
 #include "mprand.h"
 
 /*----- Main code ---------------------------------------------------------*/
 
-typedef struct fctx {
-  field f;
-  mpreduce r;
-} fctx;
-
 /* --- Field operations --- */
 
-static void fdestroy(field *ff)
-  { fctx *f = (fctx *)ff; mpreduce_destroy(&f->r); DESTROY(f); }
+static void fdestroy(field *ff) {
+  fctx_niceprime *f = (fctx_niceprime *)ff;
+  mpreduce_destroy(&f->r);
+  DESTROY(f);
+}
 
-static mp *frand(field *ff, mp *d, grand *r)
-  { fctx *f = (fctx *)ff; return (mprand_range(d, f->r.p, r, 0)); }
+static mp *frand(field *ff, mp *d, grand *r) {
+  fctx_niceprime *f = (fctx_niceprime *)ff;
+  return (mprand_range(d, f->r.p, 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 *fneg(field *ff, mp *d, mp *x)
-  { fctx *f = (fctx *)ff; return (mp_sub(d, f->r.p, x)); }
+static mp *fneg(field *ff, mp *d, mp *x) {
+  fctx_niceprime *f = (fctx_niceprime *)ff;
+  return (mp_sub(d, f->r.p, x));
+}
 
 static mp *fadd(field *ff, mp *d, mp *x, mp *y) {
-  fctx *f = (fctx *)ff; d = mp_add(d, x, y);
-  if (d->f & MP_NEG) d = mp_add(d, d, f->r.p);
+  fctx_niceprime *f = (fctx_niceprime *)ff; d = mp_add(d, x, y);
+  if (MP_NEGP(d)) d = mp_add(d, d, f->r.p);
   else if (MP_CMP(d, >, f->r.p)) d = mp_sub(d, d, f->r.p);
   return (d);
 }
 
 static mp *fsub(field *ff, mp *d, mp *x, mp *y) {
-  fctx *f = (fctx *)ff; d = mp_sub(d, x, y);
-  if (d->f & MP_NEG) d = mp_add(d, d, f->r.p);
+  fctx_niceprime *f = (fctx_niceprime *)ff; d = mp_sub(d, x, y);
+  if (MP_NEGP(d)) d = mp_add(d, d, f->r.p);
   else if (MP_CMP(d, >, f->r.p)) d = mp_sub(d, d, f->r.p);
   return (d);
 }
 
 static mp *fmul(field *ff, mp *d, mp *x, mp *y) {
-  fctx *f = (fctx *)ff; d = mp_mul(d, x, y);
+  fctx_niceprime *f = (fctx_niceprime *)ff; d = mp_mul(d, x, y);
   return (mpreduce_do(&f->r, d, d));
 }
 
 static mp *fsqr(field *ff, mp *d, mp *x) {
-  fctx *f = (fctx *)ff; d = mp_sqr(d, x);
+  fctx_niceprime *f = (fctx_niceprime *)ff; d = mp_sqr(d, x);
   return (mpreduce_do(&f->r, d, d));
 }
 
-static mp *finv(field *ff, mp *d, mp *x)
-  { fctx *f = (fctx *)ff; d = mp_modinv(d, x, f->r.p); return (d); }
+static mp *finv(field *ff, mp *d, mp *x) {
+  fctx_niceprime *f = (fctx_niceprime *)ff;
+  d = mp_modinv(d, x, f->r.p);
+  return (d);
+}
 
-static mp *freduce(field *ff, mp *d, mp *x)
-  { fctx *f = (fctx *)ff; return (mpreduce_do(&f->r, d, x)); }
+static mp *freduce(field *ff, mp *d, mp *x) {
+  fctx_niceprime *f = (fctx_niceprime *)ff;
+  return (mpreduce_do(&f->r, d, x));
+}
 
-static mp *fsqrt(field *ff, mp *d, mp *x)
-  { fctx *f = (fctx *)ff; return (mp_modsqrt(d, x, f->r.p)); }
+static mp *fsqrt(field *ff, mp *d, mp *x) {
+  fctx_niceprime *f = (fctx_niceprime *)ff;
+  return (mp_modsqrt(d, x, f->r.p));
+}
 
 static mp *fdbl(field *ff, mp *d, mp *x) {
-  fctx *f = (fctx *)ff; d = mp_lsl(d, x, 1);
+  fctx_niceprime *f = (fctx_niceprime *)ff; d = mp_lsl(d, x, 1);
   if (MP_CMP(d, >, f->r.p)) d = mp_sub(d, d, f->r.p);
   return (d);
 }
 
 static mp *ftpl(field *ff, mp *d, mp *x) {
-  fctx *f = (fctx *)ff; MP_DEST(d, MP_LEN(x) + 1, x->f);
+  fctx_niceprime *f = (fctx_niceprime *)ff; MP_DEST(d, MP_LEN(x) + 1, x->f);
   MPX_UMULN(d->v, d->vl, x->v, x->vl, 3);
   while (MP_CMP(d, >, f->r.p)) d = mp_sub(d, d, f->r.p);
   return (d);
 }
 
 static mp *fqdl(field *ff, mp *d, mp *x) {
-  fctx *f = (fctx *)ff; d = mp_lsl(d, x, 2);
+  fctx_niceprime *f = (fctx_niceprime *)ff; d = mp_lsl(d, x, 2);
   while (MP_CMP(d, >, f->r.p)) d = mp_sub(d, d, f->r.p);
   return (d);
 }
 
 static mp *fhlv(field *ff, mp *d, mp *x) {
-  fctx *f = (fctx *)ff;
-  if (!MP_LEN(x)) { MP_COPY(x); MP_DROP(d); return (x); }
+  fctx_niceprime *f = (fctx_niceprime *)ff;
+  if (MP_ZEROP(x)) { MP_COPY(x); MP_DROP(d); return (x); }
   if (x->v[0] & 1) { d = mp_add(d, x, f->r.p); x = d; }
   return (mp_lsr(d, x, 1));
 }
@@ -129,7 +138,7 @@ static const field_ops fops = {
  *
  * Arguments:	@mp *p@ = the characteristic of the field
  *
- * Returns:	A pointer to the field.
+ * Returns:	A pointer to the field, or null.
  *
  * Use:		Creates a field structure for a prime field of size %$p$%,
  *		using efficient reduction for nice primes.
@@ -137,13 +146,16 @@ static const field_ops fops = {
 
 field *field_niceprime(mp *p)
 {
-  fctx *f = CREATE(fctx);
+  fctx_niceprime *f = CREATE(fctx_niceprime);
   f->f.ops = &fops;
   f->f.zero = MP_ZERO;
   f->f.one = MP_ONE;
   f->f.nbits = mp_bits(p);
   f->f.noctets = (f->f.nbits + 7) >> 3;
-  mpreduce_create(&f->r, p);
+  if (mpreduce_create(&f->r, p)) {
+    DESTROY(f);
+    return (0);
+  }
   f->f.m = f->r.p;
   return (&f->f);
 }