Add commentary and licence notices.

[rhodes] / factor.c

/* -*-c-*-
 *
 * Trivial interface to PARI's integer factoring machinery
 *
 * (c) 2017 Mark Wooding
 */

/*----- Licensing notice --------------------------------------------------*
 *
 * This file is part of Rhodes, a distributed discrete-log finder.
 *
 * Rhodes is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * Rhodes 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Rhodes; if not, write to the Free Software Foundation,
 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

#include <assert.h>
#include <stdarg.h>
#include <stdlib.h>
#include <stdio.h>

#include <pari/pari.h>

static const char *prog;

__attribute__((noreturn))
static void barf(const char *msg, ...)
{
  va_list ap;

  va_start(ap, msg);
  fprintf(stderr, "%s: ", prog);
  vfprintf(stderr, msg, ap);
  fputc('\n', stderr);
  va_end(ap);
  exit(2);
}

int main(int argc, char *argv[])
{
  GEN n, ff, pp, ee;
  long nf;

  prog = argv[0];
  if (argc != 2) { fprintf(stderr, "usage: %s N\n", prog); exit(2); }
  pari_init(16ul*1024ul*1024ul, 0);
  n = gp_read_str(argv[1]);
  if (typ(n) != t_INT || signe(n) <= 0) barf("expected a positive integer");
  sd_factor_proven("1", d_SILENT);
  ff = Z_factor(n);
  assert(typ(ff) == t_MAT);
  assert(lg(ff) == 3);
  pp = gel(ff, 1); ee = gel(ff, 2);
  assert(typ(pp) == t_COL);
  assert(typ(ee) == t_COL);
  nf = lg(pp); assert(nf == lg(ee));
  nf--;
  while (nf--) {
    pp++; ee++;
    pari_printf("%Ps %Ps\n", *pp, *ee);
  }
  return (0);
}