From 16f952abb866c452a2249fbee24b515c139fb8ff Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ren=C3=A9=20Canna=C3=B2?= <rene.cannao@gmail.com>
Date: Thu, 22 Dec 2022 02:13:33 +0000
Subject: [PATCH] Fixed a harmless "Source and destination overlap in memcpy"

Fixed a harmess overlap in memcpy() in queue_zero() when the queue
itself is empty. If the queue is empty memcpy can be skipped.
---
 lib/mysql_data_stream.cpp | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/lib/mysql_data_stream.cpp b/lib/mysql_data_stream.cpp
index 28d21c216..35f878688 100644
--- a/lib/mysql_data_stream.cpp
+++ b/lib/mysql_data_stream.cpp
@@ -118,7 +118,9 @@ static void __dump_pkt(const char *func, unsigned char *_ptr, unsigned int len)
 }
 
 #define queue_zero(_q) { \
-  memcpy(_q.buffer, (unsigned char *)_q.buffer + _q.tail, _q.head - _q.tail); \
+  if (_q.tail != 0) { \
+    memcpy(_q.buffer, (unsigned char *)_q.buffer + _q.tail, _q.head - _q.tail); \
+  } \
   _q.head-=_q.tail; \
   _q.tail=0; \
 }