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Diff: public/FunctionPointerWithContext.h
- Revision:
- 0:289fd2dae405
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/public/FunctionPointerWithContext.h Fri Dec 19 18:54:46 2014 +0000 @@ -0,0 +1,131 @@ +/* mbed Microcontroller Library + * Copyright (c) 2006-2013 ARM Limited + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +#ifndef MBED_FUNCTIONPOINTER_WITH_CONTEXT_H +#define MBED_FUNCTIONPOINTER_WITH_CONTEXT_H + +#include <string.h> + +namespace mbed { + +/** A class for storing and calling a pointer to a static or member void function + * which takes a context. + */ +template <typename ContextType> +class FunctionPointerWithContext { +public: + typedef FunctionPointerWithContext<ContextType> *pFunctionPointerWithContext_t; + typedef void (*pvoidfcontext_t)(ContextType context); + + /** Create a FunctionPointerWithContext, attaching a static function + * + * @param function The void static function to attach (default is none) + */ + FunctionPointerWithContext(void (*function)(ContextType context) = NULL) : + _function(NULL), _object(NULL), _member(), _membercaller(NULL), _next(NULL) { + attach(function); + } + + /** Create a FunctionPointerWithContext, attaching a member function + * + * @param object The object pointer to invoke the member function on (i.e. the this pointer) + * @param function The address of the void member function to attach + */ + template<typename T> + FunctionPointerWithContext(T *object, void (T::*member)(ContextType context)) : + _function(NULL), _object(NULL), _member(), _membercaller(NULL), _next(NULL) { + attach(object, member); + } + + /** Attach a static function + * + * @param function The void static function to attach (default is none) + */ + void attach(void (*function)(ContextType context) = NULL) { + _function = function; + } + + /** Attach a member function + * + * @param object The object pointer to invoke the member function on (i.e. the this pointer) + * @param function The address of the void member function to attach + */ + template<typename T> + void attach(T *object, void (T::*member)(ContextType context)) { + _object = static_cast<void *>(object); + memcpy(_member, (char *)&member, sizeof(member)); + _membercaller = &FunctionPointerWithContext::membercaller<T>; + } + + /** Call the attached static or member function; and if there are chained + * FunctionPointers their callbacks are invoked as well. + * @Note: all chained callbacks stack up; so hopefully there won't be too + * many FunctionPointers in a chain. */ + void call(ContextType context) { + if (_function) { + _function(context); + } else if (_object && _membercaller) { + _membercaller(_object, _member, context); + } + + /* Propagate the call to next in the chain. */ + if (_next) { + _next->call(context); + } + } + + /** + * Setup an external FunctionPointer as a next in the chain of related + * callbacks. Invoking call() on the head FunctionPointer will invoke all + * chained callbacks. + * + * Refer to 'CallChain' as an alternative. + */ + void chainAsNext(pFunctionPointerWithContext_t next) { + _next = next; + } + + pFunctionPointerWithContext_t getNext(void) const { + return _next; + } + + pvoidfcontext_t get_function() const { + return (pvoidfcontext_t)_function; + } + +private: + template<typename T> + static void membercaller(void *object, char *member, ContextType context) { + T *o = static_cast<T *>(object); + void (T::*m)(ContextType); + memcpy((char *)&m, member, sizeof(m)); + (o->*m)(context); + } + + void (*_function)(ContextType context); /**< static function pointer - NULL if none attached */ + void *_object; /**< object this pointer - NULL if none attached */ + char _member[16]; /**< raw member function pointer storage - converted back by + * registered _membercaller */ + void (*_membercaller)(void *, char *, ContextType); /**< registered membercaller function to convert back and call + * _member on _object passing the context. */ + pFunctionPointerWithContext_t _next; /**< Optional link to make a chain out of functionPointers; this + * allows chaining function pointers without requiring + * external memory to manage the chain. Also refer to + * 'CallChain' as an alternative. */ +}; +} // namespace mbed + +#endif // ifndef MBED_FUNCTIONPOINTER_WITH_CONTEXT_H