+/**
+ * Function informs if it is safe to convert given charset to the one that is used by user.
+ *
+ * It is safe to use conversion only if user uses utf-8 encoding and when
+ * converted charset is similar to the one that is used by user.
+ *
+ * @param string $input_charset Charset of text that needs to be converted
+ * @return bool is it possible to convert to user's charset
+ */