Diff: public/FunctionPointerWithContext.h

Revision:

118:620d28e7a1ba

Child:

126:fdebe4d5d62f

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/public/FunctionPointerWithContext.h	Mon Sep 22 10:59:09 2014 +0100
@@ -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