add pjwhash

c/include/pjwhash.h

@@ -0,0 +1,30 @@
+/* pjwhash.h - PJW hash function, extern version.
+ *
+ * Copyright (C) 2021-2022 Bruno Raoult ("br")
+ * Licensed under the GNU General Public License v3.0 or later.
+ * Some rights reserved. See COPYING.
+ *
+ * You should have received a copy of the GNU General Public License along with this
+ * program. If not, see <https://www.gnu.org/licenses/gpl-3.0-standalone.html>.
+ *
+ * SPDX-License-Identifier: GPL-3.0-or-later <https://spdx.org/licenses/GPL-3.0-or-later.html>
+ */
+
+#ifndef _PJWHASH_H
+#define _PJWHASH_H
+
+#include "bits.h"
+
+/**
+ * unsigned int pjwhash - PJW hash function
+ * @key:    the key address.
+ * @length: the length of key.
+ *
+ * This hash was created by Peter Jay Weinberger (AT&T Bell Labs):
+ * https://en.wikipedia.org/wiki/PJW_hash_function
+ *
+ * Return: the PJW hash.
+ */
+extern uint  pjwhash (const void* key, uint length);
+
+#endif  /* _PJWHASH_H */