For gcc>=6 JSON_USE_INT64_DOUBLE_CONVERSION

Author: cdunn2001

include/json/config.h

@@ -114,6 +114,10 @@
 #define JSONCPP_DEPRECATED(message)
 #endif // if !defined(JSONCPP_DEPRECATED)
 
+#if __GNUC__ >= 6
+#  define JSON_USE_INT64_DOUBLE_CONVERSION 1
+#endif
+
 namespace Json {
 typedef int Int;
 typedef unsigned int UInt;

src/lib_json/json_value.cpp

@@ -784,7 +784,8 @@ float Value::asFloat() const {
 #if !defined(JSON_USE_INT64_DOUBLE_CONVERSION)
     return static_cast<float>(value_.uint_);
 #else  // if !defined(JSON_USE_INT64_DOUBLE_CONVERSION)
-    return integerToDouble(value_.uint_);
+    // This can fail (silently?) if the value is bigger than MAX_FLOAT.
+    return static_cast<float>(integerToDouble(value_.uint_));
 #endif // if !defined(JSON_USE_INT64_DOUBLE_CONVERSION)
   case realValue:
     return static_cast<float>(value_.real_);