--- /dev/null
+/* -*-c-*-
+ *
+ * $Id: gf-arith.c,v 1.1.2.1 2004/03/21 22:39:46 mdw Exp $
+ *
+ * Basic arithmetic on binary polynomials
+ *
+ * (c) 2004 Straylight/Edgeware
+ */
+
+/*----- Licensing notice --------------------------------------------------*
+ *
+ * This file is part of Catacomb.
+ *
+ * Catacomb is free software; you can redistribute it and/or modify
+ * 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: gf-arith.c,v $
+ * Revision 1.1.2.1 2004/03/21 22:39:46 mdw
+ * Elliptic curves on binary fields work.
+ *
+ */
+
+/*----- Header files ------------------------------------------------------*/
+
+#include "gf.h"
+
+/*----- Macros ------------------------------------------------------------*/
+
+#define MAX(x, y) ((x) >= (y) ? (x) : (y))
+
+/*----- Main code ---------------------------------------------------------*/
+
+/* --- @gf_add@ --- *
+ *
+ * Arguments: @mp *d@ = destination
+ * @mp *a, *b@ = sources
+ *
+ * Returns: Result, @a@ added to @b@.
+ */
+
+mp *gf_add(mp *d, mp *a, mp *b)
+{
+ MP_DEST(d, MAX(MP_LEN(a), MP_LEN(b)), (a->f | b->f) & MP_BURN);
+ gfx_add(d->v, d->vl, a->v, a->vl, b->v, b->vl);
+ d->f = (a->f | b->f) & MP_BURN;
+ MP_SHRINK(d);
+ return (d);
+}
+
+/* --- @gf_mul@ --- *
+ *
+ * Arguments: @mp *d@ = destination
+ * @mp *a, *b@ = sources
+ *
+ * Returns: Result, @a@ multiplied by @b@.
+ */
+
+mp *gf_mul(mp *d, mp *a, mp *b)
+{
+ a = MP_COPY(a);
+ b = MP_COPY(b);
+
+ if (MP_LEN(a) <= MPK_THRESH || MP_LEN(b) <= GFK_THRESH) {
+ MP_DEST(d, MP_LEN(a) + MP_LEN(b), a->f | b->f | MP_UNDEF);
+ gfx_mul(d->v, d->vl, a->v, a->vl, b->v, b->vl);
+ } else {
+ size_t m = MAX(MP_LEN(a), MP_LEN(b));
+ mpw *s;
+ MP_DEST(d, 2 * m, a->f | b->f | MP_UNDEF);
+ s = mpalloc(d->a, 2 * m);
+ gfx_kmul(d->v, d->vl, a->v, a->vl, b->v, b->vl, s, s + 2 * m);
+ mpfree(d->a, s);
+ }
+
+ d->f = (a->f | b->f) & MP_BURN;
+ MP_SHRINK(d);
+ MP_DROP(a);
+ MP_DROP(b);
+ return (d);
+}
+
+/* --- @gf_sqr@ --- *
+ *
+ * Arguments: @mp *d@ = destination
+ * @mp *a@ = source
+ *
+ * Returns: Result, @a@ squared.
+ */
+
+mp *gf_sqr(mp *d, mp *a)
+{
+ MP_COPY(a);
+ MP_DEST(d, 2 * MP_LEN(a), a->f & MP_BURN);
+ gfx_sqr(d->v, d->vl, a->v, a->vl);
+ d->f = a->f & MP_BURN;
+ MP_SHRINK(d);
+ MP_DROP(a);
+ return (d);
+}
+
+/* --- @gf_div@ --- *
+ *
+ * Arguments: @mp **qq, **rr@ = destination, quotient and remainder
+ * @mp *a, *b@ = sources
+ *
+ * Use: Calculates the quotient and remainder when @a@ is divided by
+ * @b@. The destinations @*qq@ and @*rr@ must be distinct.
+ * Either of @qq@ or @rr@ may be null to indicate that the
+ * result is irrelevant. (Discarding both results is silly.)
+ * There is a performance advantage if @a == *rr@.
+ */
+
+void gf_div(mp **qq, mp **rr, mp *a, mp *b)
+ {
+ mp *r = rr ? *rr : MP_NEW;
+ mp *q = qq ? *qq : MP_NEW;
+
+ /* --- Set the remainder up right --- */
+
+ b = MP_COPY(b);
+ a = MP_COPY(a);
+ if (r)
+ MP_DROP(r);
+ r = a;
+ MP_DEST(r, MP_LEN(b) + 2, a->f | b->f);
+
+ /* --- Fix up the quotient too --- */
+
+ r = MP_COPY(r);
+ MP_DEST(q, MP_LEN(r), r->f | MP_UNDEF);
+ MP_DROP(r);
+
+ /* --- Perform the calculation --- */
+
+ gfx_div(q->v, q->vl, r->v, r->vl, b->v, b->vl);
+
+ /* --- Sort out the sign of the results --- *
+ *
+ * If the signs of the arguments differ, and the remainder is nonzero, I
+ * must add one to the absolute value of the quotient and subtract the
+ * remainder from @b@.
+ */
+
+ q->f = (r->f | b->f) & MP_BURN;
+ r->f = (r->f | b->f) & MP_BURN;
+
+ /* --- Store the return values --- */
+
+ MP_DROP(b);
+
+ if (!qq)
+ MP_DROP(q);
+ else {
+ MP_SHRINK(q);
+ *qq = q;
+ }
+
+ if (!rr)
+ MP_DROP(r);
+ else {
+ MP_SHRINK(r);
+ *rr = r;
+ }
+}
+
+/*----- Test rig ----------------------------------------------------------*/
+
+#ifdef TEST_RIG
+
+static int verify(const char *op, mp *expect, mp *result, mp *a, mp *b)
+{
+ if (!MP_EQ(expect, result)) {
+ fprintf(stderr, "\n*** %s failed", op);
+ fputs("\n*** a = ", stderr); mp_writefile(a, stderr, 16);
+ fputs("\n*** b = ", stderr); mp_writefile(b, stderr, 16);
+ fputs("\n*** result = ", stderr); mp_writefile(result, stderr, 16);
+ fputs("\n*** expect = ", stderr); mp_writefile(expect, stderr, 16);
+ fputc('\n', stderr);
+ return (0);
+ }
+ return (1);
+}
+
+#define RIG(name, op) \
+ static int t##name(dstr *v) \
+ { \
+ mp *a = *(mp **)v[0].buf; \
+ mp *b = *(mp **)v[1].buf; \
+ mp *r = *(mp **)v[2].buf; \
+ mp *c = op(MP_NEW, a, b); \
+ int ok = verify(#name, r, c, a, b); \
+ mp_drop(a); mp_drop(b); mp_drop(c); mp_drop(r); \
+ assert(mparena_count(MPARENA_GLOBAL) == 0); \
+ return (ok); \
+ }
+
+RIG(add, gf_add)
+RIG(mul, gf_mul)
+
+#undef RIG
+
+static int tsqr(dstr *v)
+{
+ mp *a = *(mp **)v[0].buf;
+ mp *r = *(mp **)v[1].buf;
+ mp *c = MP_NEW;
+ int ok = 1;
+ c = gf_sqr(MP_NEW, a);
+ ok &= verify("sqr", r, c, a, MP_ZERO);
+ mp_drop(a); mp_drop(r); mp_drop(c);
+ assert(mparena_count(MPARENA_GLOBAL) == 0);
+ return (ok);
+}
+
+static int tdiv(dstr *v)
+{
+ mp *a = *(mp **)v[0].buf;
+ mp *b = *(mp **)v[1].buf;
+ mp *q = *(mp **)v[2].buf;
+ mp *r = *(mp **)v[3].buf;
+ mp *c = MP_NEW, *d = MP_NEW;
+ int ok = 1;
+ gf_div(&c, &d, a, b);
+ ok &= verify("div(quotient)", q, c, a, b);
+ ok &= verify("div(remainder)", r, d, a, b);
+ mp_drop(a); mp_drop(b); mp_drop(c); mp_drop(d); mp_drop(r); mp_drop(q);
+ assert(mparena_count(MPARENA_GLOBAL) == 0);
+ return (ok);
+}
+
+static test_chunk tests[] = {
+ { "add", tadd, { &type_mp, &type_mp, &type_mp, 0 } },
+ { "mul", tmul, { &type_mp, &type_mp, &type_mp, 0 } },
+ { "sqr", tsqr, { &type_mp, &type_mp, 0 } },
+ { "div", tdiv, { &type_mp, &type_mp, &type_mp, &type_mp, 0 } },
+ { 0, 0, { 0 } },
+};
+
+int main(int argc, char *argv[])
+{
+ sub_init();
+ test_run(argc, argv, tests, SRCDIR "/tests/gf");
+ return (0);
+}
+
+#endif
+
+/*----- That's all, folks -------------------------------------------------*/
projects / u / mdw / catacomb / blobdiff