+class TextEncodingError : public std::runtime_error
+{
+public:
+ explicit TextEncodingError (std::string s)
+ : std::runtime_error (s)
+ {}
+};
+
+class MetadataError : public std::runtime_error
+{
+public:
+ explicit MetadataError (std::string s)
+ : std::runtime_error (s)
+ {}
+};
+
+class OldFormatError : public std::runtime_error
+{
+public:
+ explicit OldFormatError (std::string s)
+ : std::runtime_error (s)
+ {}
+};
+
+class KDMAsContentError : public std::runtime_error
+{
+public:
+ KDMAsContentError ();
+};