Tests for module 'integer_length'.

* modules/integer_length-tests: New file.
* tests/test-integer_length.c: New file.

1 files changed, 66 insertions, 0 deletions

diff --git a/tests/test-integer_length.c b/tests/test-integer_length.c
new file mode 100644
index 0000000000..b1655011fb
--- /dev/null
+++ b/tests/test-integer_length.c
@@ -0,0 +1,66 @@
+/* Test of integer_length().
+   Copyright (C) 2011 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/>.  */
+
+#include <config.h>
+
+#include "integer_length.h"
+
+#include <limits.h>
+
+#include "macros.h"
+
+#define NBITS (sizeof (unsigned int) * CHAR_BIT)
+
+static int
+naive (unsigned int x)
+{
+  int j;
+  for (j = NBITS - 1; j >= 0; j--)
+    if (x & (1U << j))
+      return j + 1;
+  return 0;
+}
+
+int
+main (int argc, char *argv[])
+{
+  unsigned int x;
+  int i;
+
+  for (x = 0; x <= 256; x++)
+    ASSERT (integer_length (x) == naive (x));
+  for (i = 0; i < NBITS; i++)
+    {
+      ASSERT (integer_length (1U << i) == naive (1U << i));
+      ASSERT (integer_length (1U << i) == i + 1);
+      ASSERT (integer_length (-1U << i) == NBITS);
+    }
+  for (i = 0; i < NBITS - 1; i++)
+    ASSERT (integer_length (3U << i) == i + 2);
+  for (i = 0; i < NBITS - 2; i++)
+    ASSERT (integer_length (-3U << i) == NBITS);
+  for (i = 0; i < NBITS - 2; i++)
+    {
+      ASSERT (integer_length (5U << i) == i + 3);
+      ASSERT (integer_length (7U << i) == i + 3);
+    }
+  for (i = 0; i < NBITS - 3; i++)
+    {
+      ASSERT (integer_length (-5U << i) == NBITS);
+      ASSERT (integer_length (-7U << i) == NBITS);
+    }
+  return 0;
+}