.. _program_listing_file_src_knx_callback_property.h:

Program Listing for File callback_property.h
============================================

|exhale_lsh| :ref:`Return to documentation for file <file_src_knx_callback_property.h>` (``src/knx/callback_property.h``)

.. |exhale_lsh| unicode:: U+021B0 .. UPWARDS ARROW WITH TIP LEFTWARDS

.. code-block:: cpp

   #pragma once
   
   #include "property.h"
   
   class InterfaceObject;
   
   template <class T> class CallbackProperty : public Property
   {
       public:
           CallbackProperty(T* io, PropertyID id, bool writeEnable, PropertyDataType type, uint16_t maxElements,
                            uint8_t access, uint8_t (*readCallback)(T*, uint16_t, uint8_t, uint8_t*),
                            uint8_t (*writeCallback)(T*, uint16_t, uint8_t, const uint8_t*))
               : Property(id, writeEnable, type, maxElements, access),
                 _interfaceObject(io), _readCallback(readCallback), _writeCallback(writeCallback)
           {}
           CallbackProperty(T* io, PropertyID id, bool writeEnable, PropertyDataType type, uint16_t maxElements,
                            uint8_t access, uint8_t (*readCallback)(T*, uint16_t, uint8_t, uint8_t*))
               : Property(id, writeEnable, type, maxElements, access), _interfaceObject(io), _readCallback(readCallback)
           {}
   
           uint8_t read(uint16_t start, uint8_t count, uint8_t* data) const override
           {
               if (count == 0 || _readCallback == nullptr || start > _maxElements || start + count > _maxElements + 1)
                   return 0;
   
               return _readCallback(_interfaceObject, start, count, data);
           }
           uint8_t write(uint16_t start, uint8_t count, const uint8_t* data) override
           {
               if (count == 0 || start > _maxElements || start + count > _maxElements + 1 || _writeCallback == nullptr)
                   return 0;
   
               return _writeCallback(_interfaceObject, start, count, data);
           }
       private:
           T* _interfaceObject = nullptr;
           uint8_t (*_readCallback)(T*, uint16_t, uint8_t, uint8_t*) = nullptr;
           uint8_t (*_writeCallback)(T*, uint16_t, uint8_t, const uint8_t*) = nullptr;
   };