Fixing bug with handling JSON unicode escape sequences when parsing utf-8.

Author: stgates

Release/include/cpprest/asyncrt_utils.h

@@ -1,12 +1,12 @@
 /***
 * ==++==
 *
-* Copyright (c) Microsoft Corporation. All rights reserved. 
+* Copyright (c) Microsoft Corporation. All rights reserved.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * http://www.apache.org/licenses/LICENSE-2.0
-* 
+*
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -30,7 +30,7 @@
 #if defined(_MSC_VER) && (_MSC_VER >= 1800)
 #include <ppltasks.h>
 namespace pplx = Concurrency;
-#else 
+#else
 #include "pplx/pplxtasks.h"
 #endif
 

Release/src/json/json_parsing.cpp

@@ -152,7 +152,8 @@ class JSON_Parser
     virtual bool CompleteComment(Token &token);
     virtual bool CompleteStringLiteral(Token &token);
     bool handle_unescape_char(Token &token);
-
+    void convert_append_unicode_code_unit(Token &token, char16_t value);
+    
 private:
 
     bool CompleteNumberLiteral(CharType first, Token &token);
@@ -750,15 +751,28 @@ inline bool JSON_Parser<CharType>::handle_unescape_char(Token &token)
             }
 
             // Construct the character based on the decoded number
-            ch = static_cast<CharType>(decoded & 0xFFFF);
-            token.string_val.push_back(ch);
+            convert_append_unicode_code_unit(token, static_cast<char16_t>(decoded));
+
             return true;
         }
         default:
             return false;
     }
 }
 
+template <typename CharType>
+inline void JSON_Parser<CharType>::convert_append_unicode_code_unit(Token &token, char16_t value)
+{
+    token.string_val.push_back(value);
+}
+
+template <>
+inline void JSON_Parser<char>::convert_append_unicode_code_unit(Token &token, char16_t value)
+{
+    utf16string utf16(reinterpret_cast<utf16char *>(&value), 1);
+    token.string_val.append(::utility::conversions::utf16_to_utf8(utf16));
+}
+
 template <typename CharType>
 bool JSON_Parser<CharType>::CompleteStringLiteral(Token &token)
 {