1  /* Test mpz_set_d and mpz_init_set_d.
       2  
       3  Copyright 2000-2003, 2006 Free Software Foundation, Inc.
       4  
       5  This file is part of the GNU MP Library test suite.
       6  
       7  The GNU MP Library test suite is free software; you can redistribute it
       8  and/or modify it under the terms of the GNU General Public License as
       9  published by the Free Software Foundation; either version 3 of the License,
      10  or (at your option) any later version.
      11  
      12  The GNU MP Library test suite is distributed in the hope that it will be
      13  useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
      14  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General
      15  Public License for more details.
      16  
      17  You should have received a copy of the GNU General Public License along with
      18  the GNU MP Library test suite.  If not, see https://www.gnu.org/licenses/.  */
      19  
      20  #include <stdio.h>
      21  #include <stdlib.h>
      22  #include "gmp-impl.h"
      23  #include "tests.h"
      24  
      25  
      26  void
      27  check_data (void)
      28  {
      29    static const struct {
      30      double     d;
      31      mp_size_t  want_size;
      32      mp_limb_t  want_data[2];
      33    } data[] = {
      34  
      35      {  0.0,  0 },
      36      {  1.0,  1, { 1 } },
      37      { -1.0, -1, { 1 } },
      38  
      39      {  123.0,  1, { 123 } },
      40      { -123.0, -1, { 123 } },
      41  
      42      { 1e-1, 0, { 0 } },
      43      { -1e-1, 0, { 0 } },
      44      { 2.328306436538696e-10, 0, { 0 } },
      45      { -2.328306436538696e-10, 0, { 0 } },
      46      { 5.421010862427522e-20, 0, { 0 } },
      47      { -5.421010862427522e-20, 0, { 0 } },
      48      { 2.938735877055719e-39, 0, { 0 } },
      49      { -2.938735877055719e-39, 0, { 0 } },
      50    };
      51  
      52    mpz_t  z;
      53    int    i;
      54  
      55    for (i = 0; i < numberof (data); i++)
      56      {
      57        mpz_init (z);
      58        mpz_set_d (z, data[i].d);
      59        MPZ_CHECK_FORMAT (z);
      60        if (z->_mp_size != data[i].want_size
      61            || refmpn_cmp_allowzero (z->_mp_d, data[i].want_data,
      62                                     ABS (data[i].want_size)) != 0)
      63          {
      64            printf ("mpz_set_d wrong on data[%d]\n", i);
      65          bad:
      66            d_trace   ("  d  ", data[i].d);
      67            printf    ("  got  size %ld\n", (long) z->_mp_size);
      68            printf    ("  want size %ld\n", (long) data[i].want_size);
      69            mpn_trace ("  got  z", z->_mp_d, z->_mp_size);
      70            mpn_trace ("  want z", data[i].want_data, data[i].want_size);
      71            abort();
      72          }
      73        mpz_clear (z);
      74  
      75        mpz_init_set_d (z, data[i].d);
      76        MPZ_CHECK_FORMAT (z);
      77        if (z->_mp_size != data[i].want_size
      78            || refmpn_cmp_allowzero (z->_mp_d, data[i].want_data,
      79                                     ABS (data[i].want_size)) != 0)
      80          {
      81            printf ("mpz_init_set_d wrong on data[%d]\n", i);
      82            goto bad;
      83          }
      84        mpz_clear (z);
      85      }
      86  }
      87  
      88  /* Try mpz_set_d on values 2^i+1, while such a value fits a double. */
      89  void
      90  check_2n_plus_1 (void)
      91  {
      92    volatile double  p, d, diff;
      93    mpz_t  want, got;
      94    int    i;
      95  
      96    mpz_init (want);
      97    mpz_init (got);
      98  
      99    p = 1.0;
     100    mpz_set_ui (want, 2L);  /* gives 3 on first step */
     101  
     102    for (i = 1; i < 500; i++)
     103      {
     104        mpz_mul_2exp (want, want, 1L);
     105        mpz_sub_ui (want, want, 1L);   /* want = 2^i+1 */
     106  
     107        p *= 2.0;  /* p = 2^i */
     108        d = p + 1.0;
     109        diff = d - p;
     110        if (diff != 1.0)
     111          break;   /* rounding occurred, stop now */
     112  
     113        mpz_set_d (got, d);
     114        MPZ_CHECK_FORMAT (got);
     115        if (mpz_cmp (got, want) != 0)
     116          {
     117            printf ("mpz_set_d wrong on 2^%d+1\n", i);
     118            d_trace   ("  d ", d);
     119            mpz_trace ("  got  ", got);
     120            mpz_trace ("  want ", want);
     121            abort ();
     122          }
     123      }
     124  
     125    mpz_clear (want);
     126    mpz_clear (got);
     127  }
     128  
     129  int
     130  main (void)
     131  {
     132    tests_start ();
     133  
     134    check_data ();
     135    check_2n_plus_1 ();
     136  
     137    tests_end ();
     138    exit (0);
     139  }