New module 'count-trailing-zeros'.

[gnulib.git] / tests / test-count-trailing-zeros.c

diff --git a/tests/test-count-trailing-zeros.c b/tests/test-count-trailing-zeros.c
new file mode 100644 (file)
index 0000000..98a5f87
--- /dev/null
+++ b/tests/test-count-trailing-zeros.c
@@ -0,0 +1,71 @@
+/* Test counting of trailing zeros.
+   Copyright (C) 2013 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 <http://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)
+
+#ifndef ULLONG_MAX
+# define HALF (1ULL << (sizeof (unsigned long long int) * CHAR_BIT - 1))
+# define ULLONG_MAX (HALF - 1 + HALF)
+#endif
+
+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++)                                    \
+    {                                                           \
+      TYPE value = rand () ^ (rand () << 31 << 1);              \
+      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);
+#ifdef HAVE_UNSIGNED_LONG_LONG_INT
+  TEST_COUNT_TRAILING_ZEROS (count_trailing_zeros_ll, unsigned long long int,
+                             ULLONG_BIT, ULLONG_MAX, 1ULL);
+#endif
+
+  return 0;
+}