From 863684a584bfa5b4beeffb8d2a79e735299c1de7 Mon Sep 17 00:00:00 2001
From: Matt Broadstone <mbroadst@mongodb.com>
Date: Tue, 4 Jan 2022 16:05:44 +0000
Subject: SERVER-62333 use std::ptrdiff_t to avoid UB in MurmurHash3

---
 src/third_party/murmurhash3/MurmurHash3.cpp | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/third_party/murmurhash3/MurmurHash3.cpp b/src/third_party/murmurhash3/MurmurHash3.cpp
index 03940090b6d..62a0fbeee9b 100644
--- a/src/third_party/murmurhash3/MurmurHash3.cpp
+++ b/src/third_party/murmurhash3/MurmurHash3.cpp
@@ -82,6 +82,8 @@ FORCE_INLINE T nativeToLittle( T t )
     return t;
 }
 
+template <typename T> constexpr std::ptrdiff_t ssizeof = sizeof(T);
+
 //-----------------------------------------------------------------------------
 // Block read - if your platform needs to do endian-swapping or can only
 // handle aligned reads, do the conversion here
@@ -89,7 +91,7 @@ template <typename T>
 FORCE_INLINE T getblock( const void* p, int i )
 {
     T t;
-    std::memcpy(&t, static_cast<const char*>(p) + i * sizeof(T), sizeof(T));
+    std::memcpy(&t, static_cast<const char*>(p) + i * ssizeof<T>, sizeof(T));
     return nativeToLittle(t);
 }
 
@@ -108,7 +110,7 @@ template <typename T>
 FORCE_INLINE void putblock( void* p, int i, T t )
 {
     t = nativeToLittle(t);
-    std::memcpy(static_cast<char*>(p) + i * sizeof(T), &t, sizeof(T));
+    std::memcpy(static_cast<char*>(p) + i * ssizeof<T>, &t, sizeof(T));
 }
 
 //-----------------------------------------------------------------------------
-- 
cgit v1.2.1