From 74fdac7d77a933f6b8ef894d1f2fbd3c9052fdcb Mon Sep 17 00:00:00 2001
From: Luca Deri <deri@ntop.org>
Date: Fri, 1 Sep 2023 08:50:55 +0200
Subject: Code cleanup

---
 src/lib/ndpi_hash.c | 82 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 82 insertions(+)
 create mode 100644 src/lib/ndpi_hash.c

(limited to 'src/lib/ndpi_hash.c')

diff --git a/src/lib/ndpi_hash.c b/src/lib/ndpi_hash.c
new file mode 100644
index 000000000..4595368ef
--- /dev/null
+++ b/src/lib/ndpi_hash.c
@@ -0,0 +1,82 @@
+/*
+ * ndpi_bitmap.c
+ *
+ * Copyright (C) 2011-23 - ntop.org and contributors
+ *
+ * This file is part of nDPI, an open source deep packet inspection
+ * library based on the OpenDPI and PACE technology by ipoque GmbH
+ *
+ * nDPI is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * nDPI 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 Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with nDPI.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+
+#include "ndpi_config.h"
+#include "ndpi_api.h"
+
+/* ******************************************************************** */
+
+/* Based on djb2 hash - http://www.cse.yorku.ca/~oz/hash.html */
+u_int32_t ndpi_quick_hash(unsigned char *str, u_int str_len) {
+  u_int32_t hash = 5381, i;
+
+  for(i=0; i<str_len; i++)
+    hash = ((hash << 5) + hash) + str[i]; /* hash * 33 + str[i] */
+
+  return(hash);
+}
+
+/* ******************************************************************** */
+
+/*
+  https://en.wikipedia.org/wiki/Jenkins_hash_function
+
+  See also http://burtleburtle.net/bob/hash/spooky.html
+*/
+u_int32_t ndpi_hash_string(char *str) {
+  u_int32_t hash, i;
+
+  for(hash = i = 0; str[i] != '\0'; ++i) {
+    hash += str[i];
+    hash += (hash << 10);
+    hash ^= (hash >> 6);
+  }
+
+  hash += (hash << 3);
+  hash ^= (hash >> 11);
+  hash += (hash << 15);
+
+  return(hash);
+}
+
+/* ******************************************************************** */
+
+/* Same as above but with strings with lenght */
+u_int32_t ndpi_hash_string_len(char *str, u_int len) {
+  u_int32_t hash, i;
+
+  for(hash = i = 0; i< len; ++i) {
+    hash += str[i];
+    hash += (hash << 10);
+    hash ^= (hash >> 6);
+  }
+
+  hash += (hash << 3);
+  hash ^= (hash >> 11);
+  hash += (hash << 15);
+
+  return(hash);
+}
+
+
-- 
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