From 05d93790e4d2b54d043bbb61b9978ccad64f2ab3 Mon Sep 17 00:00:00 2001
From: Luca <deri@ntop.org>
Date: Mon, 5 Oct 2020 08:26:24 +0200
Subject: Added ndpi_quick_16_byte_hash Warning fix

---
 src/include/ndpi_api.h.in |  1 +
 src/lib/ndpi_utils.c      | 30 ++++++++++++++++++++++++++++++
 2 files changed, 31 insertions(+)

(limited to 'src')

diff --git a/src/include/ndpi_api.h.in b/src/include/ndpi_api.h.in
index 14658962b..39fd6bfb3 100644
--- a/src/include/ndpi_api.h.in
+++ b/src/include/ndpi_api.h.in
@@ -1087,6 +1087,7 @@ extern "C" {
 			u_int8_t num_clusters, u_int16_t *cluster_ids,
 			struct ndpi_bin *centroids);
 
+  u_int32_t ndpi_quick_16_byte_hash(u_int8_t *in_16_bytes_long);
 #ifdef __cplusplus
 }
 #endif
diff --git a/src/lib/ndpi_utils.c b/src/lib/ndpi_utils.c
index b96f52531..634b02d59 100644
--- a/src/lib/ndpi_utils.c
+++ b/src/lib/ndpi_utils.c
@@ -1765,3 +1765,33 @@ ndpi_http_method ndpi_http_str2method(const char* method, ssize_t method_len) {
 
   return(NDPI_HTTP_METHOD_UNKNOWN);
 }
+
+/* ******************************************************************** */
+
+#define ROR64(x,r) (((x)>>(r))|((x)<<(64-(r))))
+
+/*
+  'in_16_bytes_long` points to some 16 byte memory data to be hashed;
+  two independent 64-bit linear congruential generators are applied
+  results are mixed, scrambled and cast to 32-bit
+*/
+u_int32_t ndpi_quick_16_byte_hash(u_int8_t *in_16_bytes_long) {
+  u_int64_t a = *(u_int64_t*)(in_16_bytes_long + 0);
+  u_int64_t c = *(u_int64_t*)(in_16_bytes_long + 8);
+
+  // multipliers are taken from sprng.org, addends are prime
+  a = a * 0x2c6fe96ee78b6955 + 0x9af64480a3486659;
+  c = c * 0x369dea0f31a53f85 + 0xd0c6225445b76b5b;
+
+  // mix results
+  a += c;
+
+  // final scramble
+  a ^= ROR64(a, 13) ^ ROR64(a, 7);
+
+  // down-casting, also taking advantage of upper half
+  a ^= a >> 32;
+
+  return((u_int32_t)a);
+}
+
-- 
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