FunctionPointer.h

00001 /* mbed Microcontroller Library
00002  * Copyright (c) 2006-2013 ARM Limited
00003  *
00004  * Licensed under the Apache License, Version 2.0 (the "License");
00005  * you may not use this file except in compliance with the License.
00006  * You may obtain a copy of the License at
00007  *
00008  *     http://www.apache.org/licenses/LICENSE-2.0
00009  *
00010  * Unless required by applicable law or agreed to in writing, software
00011  * distributed under the License is distributed on an "AS IS" BASIS,
00012  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00013  * See the License for the specific language governing permissions and
00014  * limitations under the License.
00015  */
00016 #ifndef MBED_FUNCTIONPOINTER_H
00017 #define MBED_FUNCTIONPOINTER_H
00018 
00019 #include <string.h>
00020 
00021 namespace mbed {
00022 
00023 typedef void (*pvoidf_t)(void);
00024 
00025 /** A class for storing and calling a pointer to a static or member void function
00026  */
00027 class FunctionPointer {
00028 public:
00029 
00030     /** Create a FunctionPointer, attaching a static function
00031      *
00032      *  @param function The void static function to attach (default is none)
00033      */
00034     FunctionPointer(void (*function)(void) = 0);
00035 
00036     /** Create a FunctionPointer, attaching a member function
00037      *
00038      *  @param object The object pointer to invoke the member function on (i.e. the this pointer)
00039      *  @param function The address of the void member function to attach
00040      */
00041     template<typename T>
00042     FunctionPointer(T *object, void (T::*member)(void)) {
00043         attach(object, member);
00044     }
00045 
00046     /** Attach a static function
00047      *
00048      *  @param function The void static function to attach (default is none)
00049      */
00050     void attach(void (*function)(void) = 0);
00051 
00052     /** Attach a member function
00053      *
00054      *  @param object The object pointer to invoke the member function on (i.e. the this pointer)
00055      *  @param function The address of the void member function to attach
00056      */
00057     template<typename T>
00058     void attach(T *object, void (T::*member)(void)) {
00059         _object = static_cast<void*>(object);
00060         memcpy(_member, (char*)&member, sizeof(member));
00061         _membercaller = &FunctionPointer::membercaller<T>;
00062         _function = 0;
00063     }
00064 
00065     /** Call the attached static or member function
00066      */
00067     void call();
00068 
00069     pvoidf_t get_function() const {
00070         return (pvoidf_t)_function;
00071     }
00072 
00073 #ifdef MBED_OPERATORS
00074     void operator ()(void);
00075 #endif
00076 
00077 private:
00078     template<typename T>
00079     static void membercaller(void *object, char *member) {
00080         T* o = static_cast<T*>(object);
00081         void (T::*m)(void);
00082         memcpy((char*)&m, member, sizeof(m));
00083         (o->*m)();
00084     }
00085 
00086     void (*_function)(void);                // static function pointer - 0 if none attached
00087     void *_object;                            // object this pointer - 0 if none attached
00088     char _member[16];                        // raw member function pointer storage - converted back by registered _membercaller
00089     void (*_membercaller)(void*, char*);    // registered membercaller function to convert back and call _member on _object
00090 };
00091 
00092 } // namespace mbed
00093 
00094 #endif