From f212fc8de784519da02e14cd8a3810eab0082b3b Mon Sep 17 00:00:00 2001
From: Martchus <martchus@gmx.net>
Date: Sat, 4 Nov 2017 15:15:12 +0100
Subject: [PATCH] Prevent overflow on size type conversion

---
 lib/json/reflector-chronoutilities.h |  4 ++--
 lib/json/reflector.h                 | 10 ++++++++++
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/lib/json/reflector-chronoutilities.h b/lib/json/reflector-chronoutilities.h
index 08f0867..ee24ace 100644
--- a/lib/json/reflector-chronoutilities.h
+++ b/lib/json/reflector-chronoutilities.h
@@ -24,7 +24,7 @@ inline void push<ChronoUtilities::DateTime>(
     const ChronoUtilities::DateTime &reflectable, RAPIDJSON_NAMESPACE::Value &value, RAPIDJSON_NAMESPACE::Document::AllocatorType &allocator)
 {
     const std::string str(reflectable.toIsoString());
-    value.SetString(str.data(), str.size(), allocator);
+    value.SetString(str.data(), rapidJsonSize(str.size()), allocator);
 }
 
 template <>
@@ -32,7 +32,7 @@ inline void push<ChronoUtilities::TimeSpan>(
     const ChronoUtilities::TimeSpan &reflectable, RAPIDJSON_NAMESPACE::Value &value, RAPIDJSON_NAMESPACE::Document::AllocatorType &allocator)
 {
     const std::string str(reflectable.toString());
-    value.SetString(str.data(), str.size(), allocator);
+    value.SetString(str.data(), rapidJsonSize(str.size()), allocator);
 }
 
 // define functions to "pull" values from a RapidJSON array or object
diff --git a/lib/json/reflector.h b/lib/json/reflector.h
index b31b424..25219f7 100644
--- a/lib/json/reflector.h
+++ b/lib/json/reflector.h
@@ -15,6 +15,7 @@
 #include <rapidjson/stringbuffer.h>
 #include <rapidjson/writer.h>
 
+#include <limits>
 #include <string>
 #include <tuple>
 
@@ -26,6 +27,15 @@ template <typename Type> struct JsonSerializable;
 
 namespace JsonReflector {
 
+/*!
+ * \brief Casts the specified \a size to the size type used by RapidJSON ensuring no overflow happens.
+ */
+constexpr RAPIDJSON_NAMESPACE::SizeType rapidJsonSize(std::size_t size)
+{
+    return size > std::numeric_limits<RAPIDJSON_NAMESPACE::SizeType>::max() ? std::numeric_limits<RAPIDJSON_NAMESPACE::SizeType>::max()
+                                                                            : static_cast<RAPIDJSON_NAMESPACE::SizeType>(size);
+}
+
 /*!
  * \brief Serializes the specified JSON \a document.
  */