1/* test mpz_congruent_2exp_p */
2
3/*
4Copyright 2001 Free Software Foundation, Inc.
5
6This file is part of the GNU MP Library.
7
8The GNU MP Library is free software; you can redistribute it and/or modify
9it under the terms of the GNU Lesser General Public License as published by
10the Free Software Foundation; either version 3 of the License, or (at your
11option) any later version.
12
13The GNU MP Library is distributed in the hope that it will be useful, but
14WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
15or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
16License for more details.
17
18You should have received a copy of the GNU Lesser General Public License
19along with the GNU MP Library.  If not, see http://www.gnu.org/licenses/.  */
20
21#include <stdio.h>
22#include <stdlib.h>
23#include "gmp.h"
24#include "gmp-impl.h"
25#include "tests.h"
26
27
28void
29check_one (mpz_srcptr a, mpz_srcptr c, unsigned long d, int want)
30{
31  mpz_t  diff, d2exp;
32  int    got;
33  int    swap;
34
35  for (swap = 0; swap <= 1; swap++)
36    {
37      got = (mpz_congruent_2exp_p (a, c, d) != 0);
38      if (want != got)
39        {
40          mpz_init (diff);
41          mpz_init (d2exp);
42
43          mpz_sub (diff, a, c);
44          mpz_set_ui (d2exp, 1L);
45          mpz_mul_2exp (d2exp, d2exp, d);
46
47          printf ("mpz_congruent_2exp_p wrong\n");
48          printf ("   expected %d got %d\n", want, got);
49          mpz_trace ("   a", a);
50          mpz_trace ("   c", c);
51          mpz_trace (" a-c", diff);
52          mpz_trace (" 2^d", d2exp);
53          printf    ("   d=%lu\n", d);
54
55          mp_trace_base = -16;
56          mpz_trace ("   a", a);
57          mpz_trace ("   c", c);
58          mpz_trace (" a-c", diff);
59          mpz_trace (" 2^d", d2exp);
60          printf    ("   d=0x%lX\n", d);
61          abort ();
62        }
63
64      MPZ_SRCPTR_SWAP (a, c);
65    }
66}
67
68
69void
70check_data (void)
71{
72  static const struct {
73    const char     *a;
74    const char     *c;
75    unsigned long  d;
76    int            want;
77
78  } data[] = {
79
80    /* anything is congruent mod 1 */
81    { "0", "0", 0, 1 },
82    { "1", "0", 0, 1 },
83    { "0", "1", 0, 1 },
84    { "123", "456", 0, 1 },
85    { "0x123456789123456789", "0x987654321987654321", 0, 1 },
86
87  };
88
89  mpz_t   a, c;
90  int     i;
91
92  mpz_init (a);
93  mpz_init (c);
94
95  for (i = 0; i < numberof (data); i++)
96    {
97      mpz_set_str_or_abort (a, data[i].a, 0);
98      mpz_set_str_or_abort (c, data[i].c, 0);
99      check_one (a, c, data[i].d, data[i].want);
100    }
101
102  mpz_clear (a);
103  mpz_clear (c);
104}
105
106
107void
108check_random (int argc, char *argv[])
109{
110  gmp_randstate_ptr rands = RANDS;
111  unsigned long  d;
112  mpz_t  a, c, ra, rc;
113  int    i;
114  int    want;
115  int    reps = 5000;
116
117  if (argc >= 2)
118    reps = atoi (argv[1]);
119
120  mpz_init (a);
121  mpz_init (c);
122  mpz_init (ra);
123  mpz_init (rc);
124
125  for (i = 0; i < reps; i++)
126    {
127      mpz_errandomb (a, rands, 8*GMP_LIMB_BITS);
128      mpz_errandomb (c, rands, 8*GMP_LIMB_BITS);
129      d = urandom() % (8*GMP_LIMB_BITS);
130
131      mpz_mul_2exp (a, a, urandom() % (2*GMP_LIMB_BITS));
132      mpz_mul_2exp (c, c, urandom() % (2*GMP_LIMB_BITS));
133
134      mpz_negrandom (a, rands);
135      mpz_negrandom (c, rands);
136
137      mpz_fdiv_r_2exp (ra, a, d);
138      mpz_fdiv_r_2exp (rc, c, d);
139
140      want = (mpz_cmp (ra, rc) == 0);
141      check_one (a, c, d, want);
142
143      mpz_sub (ra, ra, rc);
144      mpz_sub (a, a, ra);
145      check_one (a, c, d, 1);
146    }
147
148  mpz_clear (a);
149  mpz_clear (c);
150  mpz_clear (ra);
151  mpz_clear (rc);
152}
153
154
155int
156main (int argc, char *argv[])
157{
158  tests_start ();
159
160  check_data ();
161  check_random (argc, argv);
162
163  tests_end ();
164  exit (0);
165}
166