mbed/src/cpp/FunctionPointer.h

   1 /* mbed Microcontroller Library
   2  * Copyright (c) 2006-2013 ARM Limited
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  *     http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16 #ifndef MBED_FUNCTIONPOINTER_H
  17 #define MBED_FUNCTIONPOINTER_H
  18
  19 #include <string.h>
  20
  21 namespace mbed {
  22
  23 /** A class for storing and calling a pointer to a static or member void function
  24  */
  25 class FunctionPointer {
  26 public:
  27
  28     /** Create a FunctionPointer, attaching a static function
  29      *
  30      *  @param function The void static function to attach (default is none)
  31      */
  32     FunctionPointer(void (*function)(void) = 0);
  33
  34     /** Create a FunctionPointer, attaching a member function
  35      *
  36      *  @param object The object pointer to invoke the member function on (i.e. the this pointer)
  37      *  @param function The address of the void member function to attach
  38      */
  39     template<typename T>
  40     FunctionPointer(T *object, void (T::*member)(void)) {
  41         attach(object, member);
  42     }
  43
  44     /** Attach a static function
  45      *
  46      *  @param function The void static function to attach (default is none)
  47      */
  48     void attach(void (*function)(void) = 0);
  49
  50     /** Attach a member function
  51      *
  52      *  @param object The object pointer to invoke the member function on (i.e. the this pointer)
  53      *  @param function The address of the void member function to attach
  54      */
  55     template<typename T>
  56     void attach(T *object, void (T::*member)(void)) {
  57         _object = static_cast<void*>(object);
  58         memcpy(_member, (char*)&member, sizeof(member));
  59         _membercaller = &FunctionPointer::membercaller<T>;
  60         _function = 0;
  61     }
  62
  63     /** Call the attached static or member function
  64      */
  65     void call();
  66
  67 private:
  68     template<typename T>
  69     static void membercaller(void *object, char *member) {
  70         T* o = static_cast<T*>(object);
  71         void (T::*m)(void);
  72         memcpy((char*)&m, member, sizeof(m));
  73         (o->*m)();
  74     }
  75
  76     void (*_function)(void);                // static function pointer - 0 if none attached
  77     void *_object;                            // object this pointer - 0 if none attached
  78     char _member[16];                        // raw member function pointer storage - converted back by registered _membercaller
  79     void (*_membercaller)(void*, char*);    // registered membercaller function to convert back and call _member on _object
  80 };
  81
  82 } // namespace mbed
  83
  84 #endif