Protect memcpy calls against undefined behaviour

[folly.git] / folly / Format.cpp

diff --git a/folly/Format.cpp b/folly/Format.cpp
index 0d1d61b126d19e7ad99be135922aef04575a4f68..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.
@@ -214,11 +214,11 @@ void FormatArg::initSlow() {
     }
 
     auto readInt = [&] {
-      auto const b = p;
+      auto const c = p;
       do {
         ++p;
       } while (p != end && *p >= '0' && *p <= '9');
-      return to<int>(StringPiece(b, p));
+      return to<int>(StringPiece(c, p));
     };
 
     if (*p == '*') {
@@ -242,12 +242,12 @@ void FormatArg::initSlow() {
     }
 
     if (*p == '.') {
-      auto b = ++p;
+      auto d = ++p;
       while (p != end && *p >= '0' && *p <= '9') {
         ++p;
       }
-      if (p != b) {
-        precision = to<int>(StringPiece(b, p));
+      if (p != d) {
+        precision = to<int>(StringPiece(d, p));
         if (p != end && *p == '.') {
           trailingDot = true;
           ++p;
@@ -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;