Move popcount() to an optionally built part of wsutil for systems that

provide their own popcount().

Change-Id: Ic26f3b50cf0bd2b4af0d42e9c27488ebbac1ab33
Reviewed-on: https://code.wireshark.org/review/5998
Petri-Dish: Stephen Fisher <sfisher@sdf.org>
Reviewed-by: Stephen Fisher <sfisher@sdf.org>

1 files changed, 42 insertions, 0 deletions

diff --git a/wsutil/popcount.c b/wsutil/popcount.c
new file mode 100644
index 0000000000..04a0ade032
--- /dev/null
+++ b/wsutil/popcount.c
@@ -0,0 +1,42 @@
+/* popcount.c
+ *
+ * popcount() replacement function for systems that don't provide their own.
+ *
+ * Wireshark - Network traffic analyzer
+ * By Gerald Combs <gerald@wireshark.org>
+ * Copyright 1998 Gerald Combs
+ *
+ * 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 2
+ * 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, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "config.h"
+
+#include "wsutil/popcount.h"
+
+int
+popcount(unsigned int mask)
+{
+#if (__GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 4))
+      /* GCC 3.4 or newer */
+      return __builtin_popcount(mask);
+#else
+      /* HACKMEM 169 */
+      unsigned long y;
+
+      y = (mask >> 1) &033333333333;
+      y = mask - y - ((y >>1) & 033333333333);
+      return (((y + (y >> 3)) & 030707070707) % 077);
+#endif
+}