t-cmp_d.c

a very popular packet of cryptography tools,it encloses the most common used algorithm and protocols

/* Test mpz_cmp_d and mpz_cmpabs_d.

Copyright 2001, 2002 Free Software Foundation, Inc.

This file is part of the GNU MP Library.

The GNU MP Library is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or (at your
option) any later version.

The GNU MP Library 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 Lesser General Public
License for more details.

You should have received a copy of the GNU Lesser General Public License
along with the GNU MP Library; see the file COPYING.LIB.  If not, write to
the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
MA 02111-1307, USA. */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "gmp.h"
#include "gmp-impl.h"
#include "tests.h"


/* FIXME: Not sure if the tests here are exhaustive.  Ought to try to get
   each possible exit from mpz_cmp_d (and mpz_cmpabs_d) exercised.  */


#define SGN(n)  ((n) > 0 ? 1 : (n) < 0 ? -1 : 0)


void
check_one (const char *name, mpz_srcptr x, double y, int cmp, int cmpabs)
{
  int   got;

  got = mpz_cmp_d (x, y);
  if (SGN(got) != cmp)
    {
      int i;
      printf    ("mpz_cmp_d wrong (from %s)\n", name);
      printf    ("  got  %d\n", got);
      printf    ("  want %d\n", cmp);
    fail:
      mpz_trace ("  x", x);
      printf    ("  y %g\n", y);
      mp_trace_base=-16;
      mpz_trace ("  x", x);
      printf    ("  y %A\n", y);
      printf    ("  y");
      for (i = 0; i < sizeof(y); i++)
        printf (" %02X", (unsigned) ((unsigned char *) &y)[i]);
      printf ("\n");
      abort ();
    }

  got = mpz_cmpabs_d (x, y);
  if (SGN(got) != cmpabs)
    {
      printf    ("mpz_cmpabs_d wrong\n");
      printf    ("  got  %d\n", got);
      printf    ("  want %d\n", cmpabs);
      goto fail;
    }
}


void
check_data (void)
{
  static const struct {
    const char  *x;
    double      y;
    int         cmp, cmpabs;

  } data[] = {

    {  "0",  0.0,  0,  0 },

    {  "1",  0.0,  1,  1 },
    { "-1",  0.0, -1,  1 },

    {  "0",  1.0, -1, -1 },
    {  "0", -1.0,  1, -1 },

    {  "0x1000000000000000000000000000000000000000000000000", 0.0,  1, 1 },
    { "-0x1000000000000000000000000000000000000000000000000", 0.0, -1, 1 },

    {  "0",  1e100, -1, -1 },
    {  "0", -1e100,  1, -1 },

    {  "2",  1.5,   1,  1 },
    {  "2", -1.5,   1,  1 },
    { "-2",  1.5,  -1,  1 },
    { "-2", -1.5,  -1,  1 },
  };

  mpz_t  x;
  int    i;

  mpz_init (x);

  for (i = 0; i < numberof (data); i++)
    {
      mpz_set_str_or_abort (x, data[i].x, 0);
      check_one ("check_data", x, data[i].y, data[i].cmp, data[i].cmpabs);
    }

  mpz_clear (x);
}


/* Equality of integers with up to 53 bits */
void
check_onebits (void)
{
  mpz_t   x, x2;
  double  y;
  int     i;

  mpz_init_set_ui (x, 0L);
  mpz_init (x2);

  for (i = 0; i < 512; i++)
    {
      mpz_mul_2exp (x, x, 1);
      mpz_add_ui (x, x, 1L);

      y = mpz_get_d (x);
      mpz_set_d (x2, y);

      /* stop if any truncation is occurring */
      if (mpz_cmp (x, x2) != 0)
        break;

      check_one ("check_onebits", x, y, 0, 0);
      check_one ("check_onebits", x, -y, 1, 0);
      mpz_neg (x, x);
      check_one ("check_onebits", x, y, -1, 0);
      check_one ("check_onebits", x, -y, 0, 0);
      mpz_neg (x, x);
    }

  mpz_clear (x);
  mpz_clear (x2);
}


/* With the mpz differing by 1, in a limb position possibly below the double */
void
check_low_z_one (void)
{
  mpz_t          x;
  double         y;
  unsigned long  i;

  mpz_init (x);

  /* FIXME: It'd be better to base this on the float format. */
#ifdef __vax
#define LIM 127			/* vax fp numbers have limited range */
#else
#define LIM 512
#endif

  for (i = 1; i < LIM; i++)
    {
      mpz_set_ui (x, 1L);
      mpz_mul_2exp (x, x, i);
      y = mpz_get_d (x);

      check_one ("check_low_z_one", x, y,   0, 0);
      check_one ("check_low_z_one", x, -y,  1, 0);
      mpz_neg (x, x);
      check_one ("check_low_z_one", x, y,  -1, 0);
      check_one ("check_low_z_one", x, -y,  0, 0);
      mpz_neg (x, x);

      mpz_sub_ui (x, x, 1);

      check_one ("check_low_z_one", x, y,  -1, -1);
      check_one ("check_low_z_one", x, -y,  1, -1);
      mpz_neg (x, x);
      check_one ("check_low_z_one", x, y,  -1, -1);
      check_one ("check_low_z_one", x, -y,  1, -1);
      mpz_neg (x, x);

      mpz_add_ui (x, x, 2);

      check_one ("check_low_z_one", x, y,   1, 1);
      check_one ("check_low_z_one", x, -y,  1, 1);
      mpz_neg (x, x);
      check_one ("check_low_z_one", x, y,  -1, 1);
      check_one ("check_low_z_one", x, -y, -1, 1);
      mpz_neg (x, x);
    }

  mpz_clear (x);
}

/* Comparing 1 and 1+2^-n.  "y" is volatile to make gcc store and fetch it,
   which forces it to a 64-bit double, whereas on x86 it would otherwise
   remain on the float stack as an 80-bit long double.  */
void
check_one_2exp (void)
{
  double           e;
  mpz_t            x;
  volatile double  y;
  int              i;

  mpz_init (x);

  e = 1.0;
  for (i = 0; i < 128; i++)
    {
      e /= 2.0;
      y = 1.0 + e;
      if (y == 1.0)
        break;

      mpz_set_ui (x, 1L);
      check_one ("check_one_2exp", x,  y, -1, -1);
      check_one ("check_one_2exp", x, -y,  1, -1);

      mpz_set_si (x, -1L);
      check_one ("check_one_2exp", x,  y, -1, -1);
      check_one ("check_one_2exp", x, -y,  1, -1);
    }

  mpz_clear (x);
}


int
main (int argc, char *argv[])
{
  tests_start ();

  check_data ();
  check_onebits ();
  check_low_z_one ();
  check_one_2exp ();

  tests_end ();
  exit (0);
}