diff --git a/include/color.hpp b/include/color.hpp
index caa6778..d426daf 100644
--- a/include/color.hpp
+++ b/include/color.hpp
@@ -114,7 +114,9 @@ namespace ztd
   };
 
   //! Insert color code to stream
-  inline std::ostream& operator<<(std::ostream& st, const color& c) { return st << c.code(); }
+  inline std::ostream& operator<<(std::ostream& st, const ztd::color& c) { return st << c.code(); }
+  //! Insert color code to stream
+  inline std::ostream& operator<<(std::ostream& st, const ztd::color::color_name& c) { return st << ztd::color::color_index[c]; }
 }
 
 #endif //COLOR_HPP
diff --git a/include/filedat.hpp b/include/filedat.hpp
index 3ce9a46..74e1ddb 100644
--- a/include/filedat.hpp
+++ b/include/filedat.hpp
@@ -342,10 +342,10 @@ namespace ztd
 
     //! @brief Reference to subchunk
     //! @see chunkdat::operator[](std::string const &a) const
-    inline chunkdat& operator[](const std::string& index) { return m_dataChunk->subChunkRef(index); }
+    inline chunkdat& operator[](const std::string& index) const { return m_dataChunk->subChunkRef(index); }
     //! @brief Reference to subchunk
     //! @see chunkdat::operator[](const unsigned int a) const
-    inline chunkdat& operator[](const unsigned int index) { return m_dataChunk->subChunkRef(index); }
+    inline chunkdat& operator[](const unsigned int index) const { return m_dataChunk->subChunkRef(index); }
 
     //! @brief add data and return *this
     //! @see chunkdat::operator+=(std::pair<std::string, chunkdat> const& a)