Protect memcpy calls against undefined behaviour

[folly.git] / folly / Format.cpp

diff --git a/folly/Format.cpp b/folly/Format.cpp
index e6df11419f7dce100dc2113739da6089022c5535..177f9783e4afa4de4cf55ddac3205f30f8d15dec 100644 (file)
--- a/folly/Format.cpp
+++ b/folly/Format.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright 2016 Facebook, Inc.
+ * Copyright 2017 Facebook, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -294,7 +294,7 @@ void FormatArg::validate(Type type) const {
 
 namespace detail {
 void insertThousandsGroupingUnsafe(char* start_buffer, char** end_buffer) {
-  uint32_t remaining_digits = *end_buffer - start_buffer;
+  uint32_t remaining_digits = uint32_t(*end_buffer - start_buffer);
   uint32_t separator_size = (remaining_digits - 1) / 3;
   uint32_t result_size = remaining_digits + separator_size;
   *end_buffer = *end_buffer + separator_size;