/* Test counting of trailing zeros.
   Copyright (C) 2013-2023 Free Software Foundation, Inc.

   This program 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 3 of the License, or
   (at your option) any later version.

   This program 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 this program.  If not, see <https://www.gnu.org/licenses/>.  */

/* Written by Paul Eggert.  */

#include <config.h>

#include "count-trailing-zeros.h"

#include <limits.h>
#include <stdio.h>

#include "macros.h"

#define UINT_BIT (sizeof (unsigned int) * CHAR_BIT)
#define ULONG_BIT (sizeof (unsigned long int) * CHAR_BIT)
#define ULLONG_BIT (sizeof (unsigned long long int) * CHAR_BIT)

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

#define TEST_COUNT_TRAILING_ZEROS(FUNC, TYPE, BITS, MAX, ONE) \
  ASSERT (FUNC (0) == BITS);                                  \
  for (i = 0; i < BITS; i++)                                  \
    {                                                         \
      ASSERT (FUNC (ONE << i) == i);                          \
      for (j = 0; j < i; j++)                                 \
        ASSERT (FUNC ((ONE << i) | (ONE << j)) == j);         \
    }                                                         \
  for (i = 0; i < 1000; i++)                                  \
    {                                                         \
      /* RAND_MAX is most often 0x7fff or 0x7fffffff.  */     \
      TYPE value =                                            \
        (RAND_MAX <= 0xffff                                   \
         ? ((TYPE) rand () >> 3)                              \
           ^ (((TYPE) rand () >> 3) << 12)                    \
           ^ (((TYPE) rand () >> 3) << 24)                    \
           ^ (((TYPE) rand () >> 3) << 30 << 6)               \
           ^ (((TYPE) rand () >> 3) << 30 << 18)              \
           ^ (((TYPE) rand () >> 3) << 30 << 30)              \
         : ((TYPE) rand () >> 3)                              \
           ^ (((TYPE) rand () >> 3) << 22)                    \
           ^ (((TYPE) rand () >> 3) << 22 << 22));            \
      int count = 0;                                          \
      for (j = BITS - 1; 0 <= j; j--)                         \
        if (value & (ONE << j))                               \
          count = j;                                          \
      ASSERT (count == FUNC (value));                         \
    }                                                         \
  ASSERT (FUNC (MAX) == 0);

  TEST_COUNT_TRAILING_ZEROS (count_trailing_zeros, unsigned int,
                             UINT_BIT, UINT_MAX, 1U);
  TEST_COUNT_TRAILING_ZEROS (count_trailing_zeros_l, unsigned long int,
                             ULONG_BIT, ULONG_MAX, 1UL);
  TEST_COUNT_TRAILING_ZEROS (count_trailing_zeros_ll, unsigned long long int,
                             ULLONG_BIT, ULLONG_MAX, 1ULL);

  return 0;
}
