Line data    Source code

       1              : /** \file changeable.hpp
       2              :  * \brief A simple class to track member data changes
       3              :  *
       4              :  * \author Jared R. Males (jaredmales@gmail.com)
       5              :  *
       6              :  * \ingroup utils_files
       7              :  *
       8              :  */
       9              : 
      10              : #ifndef mx_base_changeable_hpp
      11              : #define mx_base_changeable_hpp
      12              : 
      13              : #include <cstdint>
      14              : #include <limits>
      15              : 
      16              : namespace mx
      17              : {
      18              : namespace base
      19              : {
      20              : 
      21              : /// A simple class to track member data changes.
      22              : /** Maintains a monotonic counter that derived classes increment anytime a member
      23              :  * datum is changed.  This allows for, say, re-initializing automatically on a subsequent
      24              :  * call to a function.
      25              :  *
      26              :  * \ingroup base
      27              :  */
      28              : template <class _derivedT>
      29              : class changeable
      30              : {
      31              : 
      32              :   public:
      33              :     typedef _derivedT derivedT;
      34              : 
      35              :     /// The integer type of the counter.
      36              :     typedef uint64_t changeT;
      37              : 
      38              :   private:
      39              :     /// The counter itself.
      40              :     changeT m_change{ 0 };
      41              : 
      42              :     /// A marker for last change, set by \ref setChangePoint
      43              :     changeT m_changePoint{ std::numeric_limits<changeT>::max() };
      44              : 
      45              :   public:
      46              :     /// Increment the counter
      47              :     /** Call this function anytime the derived class changes something important.
      48              :      *
      49              :      */
      50           18 :     void changed()
      51              :     {
      52           18 :         ++m_change;
      53           18 :     }
      54              : 
      55              :     /// Get the value of the counter
      56              :     /** Get this at a checkpoint and compare it later to decide if any
      57              :      * action should be taken.
      58              :      */
      59            0 :     changeT change()
      60              :     {
      61            0 :         return m_change;
      62              :     }
      63              : 
      64            5 :     void setChangePoint()
      65              :     {
      66            5 :         m_changePoint = m_change;
      67            5 :     }
      68              : 
      69           11 :     bool isChanged()
      70              :     {
      71           11 :         return ( m_change != m_changePoint );
      72              :     }
      73              : };
      74              : 
      75              : } // namespace base
      76              : } // namespace mx
      77              : 
      78              : #endif // mx_base_changeable_hpp