+++ /dev/null
-/* -*-c-*-
- *
- * $Id: mpmul.c,v 1.5 2004/04/08 01:36:15 mdw Exp $
- *
- * Multiply many small numbers together
- *
- * (c) 2000 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.
- */
-
-/*----- Header files ------------------------------------------------------*/
-
-#include "mp.h"
-#include "mpint.h"
-#include "mpmul.h"
-
-/*----- Main code ---------------------------------------------------------*/
-
-/* --- @mpmul_init@ --- *
- *
- * Arguments: @mpmul *b@ = pointer to multiplier context to initialize
- *
- * Returns: ---
- *
- * Use: Initializes a big multiplier context for use.
- */
-
-void mpmul_init(mpmul *b)
-{
- b->i = 0;
-}
-
-/* --- @mpmul_add@ --- *
- *
- * Arguments: @mpmul *b@ = pointer to multiplier context
- * @mp *x@ = the next factor to multiply in
- *
- * Returns: ---
- *
- * Use: Contributes another factor to the mix. It's important that
- * the integer lasts at least as long as the multiplication
- * context; this sort of rules out @mp_build@ integers.
- */
-
-#define HWM (MPMUL_DEPTH - 20)
-#define LWM (MPMUL_DEPTH / 2)
-
-void mpmul_add(mpmul *b, mp *x)
-{
- size_t i = b->i;
-
- /* --- Now do the reduction step --- */
-
- x = MP_COPY(x);
-
- while (i > 0) {
- if (MP_LEN(b->v[i - 1]) > MP_LEN(x))
- break;
- i--;
- x = mp_mul(x, x, b->v[i]);
- MP_DROP(b->v[i]);
- }
-
- if (i > HWM) {
- while (i > LWM || (i > 0 && MP_LEN(b->v[i - 1]) <= MP_LEN(x))) {
- i--;
- x = mp_mul(x, x, b->v[i]);
- MP_DROP(b->v[i]);
- }
- }
-
- b->v[i++] = x;
- b->i = i;
-}
-
-/* --- @mpmul_done@ --- *
- *
- * Arguments: @mpmul *b@ = pointer to big multiplication context
- *
- * Returns: The product of all the numbers contributed.
- *
- * Use: Returns a (large) product of numbers. The context is
- * deallocated.
- */
-
-mp *mpmul_done(mpmul *b)
-{
- size_t i = b->i;
- mp *x;
-
- if (!i)
- return (MP_ONE);
- i--;
- x = b->v[i];
- while (i > 0) {
- i--;
- x = mp_mul(x, x, b->v[i]);
- MP_DROP(b->v[i]);
- }
- return (x);
-}
-
-/* --- @mp_factorial@ --- *
- *
- * Arguments: @unsigned long i@ = number whose factorial should be
- * computed.
- *
- * Returns: The requested factorial.
- */
-
-mp *mp_factorial(unsigned long i)
-{
- unsigned long j;
- mp *x = MP_NEW;
- mpmul b = MPMUL_INIT;
-
- for (j = 1; j <= i; j++) {
- x = mp_fromulong(x, j);
- mpmul_add(&b, x);
- }
- mp_drop(x);
- return (mpmul_done(&b));
-}
-
-/*----- Test rig ----------------------------------------------------------*/
-
-#ifdef TEST_RIG
-
-#include <mLib/testrig.h>
-
-static int vfact(dstr *v)
-{
- unsigned long x = *(unsigned long *)v[0].buf;
- mp *fx = *(mp **)v[1].buf;
- mp *y = mp_factorial(x);
- int ok = 1;
- if (!MP_EQ(fx, y)) {
- fprintf(stderr, "factorial failed\n");
- MP_FPRINTF(stderr, (stderr, "%lu! = ", x), fx);
- MP_EPRINT("result", y);
- ok = 0;
- }
- mp_drop(fx);
- mp_drop(y);
- assert(mparena_count(MPARENA_GLOBAL) == 0);
- return (ok);
-}
-
-static test_chunk tests[] = {
- { "factorial", vfact, { &type_ulong, &type_mp, 0 } },
- { 0, 0, { 0 } }
-};
-
-int main(int argc, char *argv[])
-{
- test_run(argc, argv, tests, SRCDIR "/tests/mp");
- return (0);
-}
-
-#endif
-
-/*----- That's all, folks -------------------------------------------------*/