message: fix bug
  fix a bug
diff: @@ -94,7 +94,7 @@ private:
  public:
  VList();
  VList(std::string& _filepath, std::string& _mode, unsigned long long _buffer_size);//create a fixed-size file or open an existence
  - bool readValue(unsigned _block_num, char*& _str, unsigned& _len);
  + bool readValue(unsigned _block_num, char*& _str, unsigned& _len, unsigned _key);
  unsigned writeValue(char* _str, unsigned _len);
  bool removeValue(unsigned _block_num);
  ~VList();
  