1 files changed, 75 insertions, 0 deletions
diff --git a/gnulib-tests/test-count-leading-zeros.c b/gnulib-tests/test-count-leading-zeros.c
new file mode 100644
index 0000000..d85edd4
--- /dev/null
+++ b/gnulib-tests/test-count-leading-zeros.c
@@ -0,0 +1,75 @@
+/*
+ * Copyright (C) 2012-2022 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 Eric Blake.  */
+
+#include <config.h>
+
+#include "count-leading-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_LEADING_ZEROS(FUNC, TYPE, BITS, MAX, ONE)     \
+  ASSERT (FUNC (0) == BITS);                                     \
+  for (i = 0; i < BITS; i++)                                     \
+    {                                                            \
+      ASSERT (FUNC (ONE << i) == BITS - i - 1);                  \
+      for (j = 0; j < i; j++)                                    \
+        ASSERT (FUNC ((ONE << i) | (ONE << j)) == BITS - i - 1); \
+    }                                                            \
+  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 = 0; j < BITS; j++)                                 \
+        if (value & (ONE << j))                                  \
+          count = BITS - j - 1;                                  \
+      ASSERT (count == FUNC (value));                            \
+    }                                                            \
+  ASSERT (FUNC (MAX) == 0);
+
+  TEST_COUNT_LEADING_ZEROS (count_leading_zeros, unsigned int,
+                            UINT_BIT, UINT_MAX, 1U);
+  TEST_COUNT_LEADING_ZEROS (count_leading_zeros_l, unsigned long int,
+                            ULONG_BIT, ULONG_MAX, 1UL);
+  TEST_COUNT_LEADING_ZEROS (count_leading_zeros_ll, unsigned long long int,
+                            ULLONG_BIT, ULLONG_MAX, 1ULL);
+
+  return 0;
+}