Added StyledStreamWriter, which has no reason to derive from Writer, since its write() method does cannot return a string and must take a stream.

include/json/writer.h

@@ -30,6 +30,7 @@ namespace Json {
    {
    public:
       FastWriter();
+      virtual ~FastWriter(){}
 
       void enableYAMLCompatibility();
 
@@ -61,7 +62,7 @@ namespace Json {
     *
     * \sa Reader, Value, Value::setComment()
     */
-   class JSON_API StyledWriter
+   class JSON_API StyledWriter: public Writer
    {
    public:
       StyledWriter();
@@ -98,13 +99,71 @@ namespace Json {
       bool addChildValues_;
    };
 
+   /** \brief Writes a Value in <a HREF="http://www.json.org">JSON</a> format in a human friendly way,
+        to a stream rather than to a string.
+    *
+    * The rules for line break and indent are as follow:
+    * - Object value:
+    *     - if empty then print {} without indent and line break
+    *     - if not empty the print '{', line break & indent, print one value per line
+    *       and then unindent and line break and print '}'.
+    * - Array value:
+    *     - if empty then print [] without indent and line break
+    *     - if the array contains no object value, empty array or some other value types,
+    *       and all the values fit on one lines, then print the array on a single line.
+    *     - otherwise, it the values do not fit on one line, or the array contains
+    *       object or non empty array, then print one value per line.
+    *
+    * If the Value have comments then they are outputed according to their #CommentPlacement.
+    *
+    * \param indentation Each level will be indented by this amount extra.
+    * \sa Reader, Value, Value::setComment()
+    */
+   class JSON_API StyledStreamWriter
+   {
+   public:
+      StyledStreamWriter( std::string indentation="\t" );
+      ~StyledStreamWriter(){}
+
+   public:
+      /** \brief Serialize a Value in <a HREF="http://www.json.org">JSON</a> format.
+       * \param out Stream to write to. (Can be ostringstream, e.g.)
+       * \param root Value to serialize.
+       * \note There is no point in deriving from Writer, since write() should not return a value.
+       */
+      void write( std::ostream &out, const Value &root );
+
+   private:
+      void writeValue( const Value &value );
+      void writeArrayValue( const Value &value );
+      bool isMultineArray( const Value &value );
+      void pushValue( const std::string &value );
+      void writeIndent();
+      void writeWithIndent( const std::string &value );
+      void indent();
+      void unindent();
+      void writeCommentBeforeValue( const Value &root );
+      void writeCommentAfterValueOnSameLine( const Value &root );
+      bool hasCommentForValue( const Value &value );
+      static std::string normalizeEOL( const std::string &text );
+
+      typedef std::vector<std::string> ChildValues;
+
+      ChildValues childValues_;
+      std::ostream* document_;
+      std::string indentString_;
+      int rightMargin_;
+      std::string indentation_;
+      bool addChildValues_;
+   };
+
    std::string JSON_API valueToString( Value::Int value );
    std::string JSON_API valueToString( Value::UInt value );
    std::string JSON_API valueToString( double value );
    std::string JSON_API valueToString( bool value );
    std::string JSON_API valueToQuotedString( const char *value );
 
-   /// \brief Output using the StyledWriter.
+   /// \brief Output using the StyledStreamWriter.
    /// \see Json::operator>>()
    std::ostream& operator<<( std::ostream&, const Value &root );