Diff: FunctionPointer.h

Revision:

0:e1a608bb55e8

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/FunctionPointer.h	Thu Apr 07 18:33:58 2016 +0100
@@ -0,0 +1,202 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2006-2015 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_H
+#define MBED_FUNCTIONPOINTER_H
+
+#include <string.h>
+#include <stdint.h>
+
+namespace mbed {
+
+/* If we had variaditic templates, this wouldn't be a problem, but until C++11 is enabled, we are stuck with multiple classes... */
+
+/** A class for storing and calling a pointer to a static or member function
+ */
+template <typename R, typename A1>
+class FunctionPointerArg1{
+public:
+    /** Create a FunctionPointer, attaching a static function
+     *
+     *  @param function The static function to attach (default is none)
+     */
+    FunctionPointerArg1(R (*function)(A1) = 0) {
+        attach(function);
+    }
+
+    /** Create a FunctionPointer, 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 member function to attach
+     */
+    template<typename T>
+    FunctionPointerArg1(T *object, R (T::*member)(A1)) {
+        attach(object, member);
+    }
+
+    /** Attach a static function
+     *
+     *  @param function The static function to attach (default is none)
+     */
+    void attach(R (*function)(A1)) {
+        _p.function = function;
+        _membercaller = 0;
+    }
+
+    /** 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 member function to attach
+     */
+    template<typename T>
+    void attach(T *object, R (T::*member)(A1)) {
+        _p.object = static_cast<void*>(object);
+        *reinterpret_cast<R (T::**)(A1)>(_member) = member;
+        _membercaller = &FunctionPointerArg1::membercaller<T>;
+    }
+
+    /** Call the attached static or member function
+     */
+    R call(A1 a) {
+        if (_membercaller == 0 && _p.function) {
+           return _p.function(a);
+        } else if (_membercaller && _p.object) {
+           return _membercaller(_p.object, _member, a);
+        }
+        return (R)0;
+    }
+
+    /** Get registered static function
+     */
+    R(*get_function(A1))() {
+        return _membercaller ? (R(*)(A1))0 : (R(*)(A1))_p.function;
+    }
+
+#ifdef MBED_OPERATORS
+    R operator ()(A1 a) {
+        return call(a);
+    }
+    operator bool(void) const {
+        return (_membercaller != NULL ? _p.object : (void*)_p.function) != NULL;
+    }
+#endif
+private:
+    template<typename T>
+    static R membercaller(void *object, uintptr_t *member, A1 a) {
+        T* o = static_cast<T*>(object);
+        R (T::**m)(A1) = reinterpret_cast<R (T::**)(A1)>(member);
+        return (o->**m)(a);
+    }
+
+    union {
+        R (*function)(A1); // static function pointer
+        void *object;      // object this pointer
+    } _p;
+    uintptr_t _member[4]; // aligned raw member function pointer storage - converted back by registered _membercaller
+    R (*_membercaller)(void*, uintptr_t*, A1); // registered membercaller function to convert back and call _m.member on _object
+};
+
+/** A class for storing and calling a pointer to a static or member function (R ()(void))
+ */
+template <typename R>
+class FunctionPointerArg1<R, void>{
+public:
+    /** Create a FunctionPointer, attaching a static function
+     *
+     *  @param function The static function to attach (default is none)
+     */
+    FunctionPointerArg1(R (*function)(void) = 0) {
+        attach(function);
+    }
+
+    /** Create a FunctionPointer, 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>
+    FunctionPointerArg1(T *object, R (T::*member)(void)) {
+        attach(object, member);
+    }
+
+    /** Attach a static function
+     *
+     *  @param function The void static function to attach (default is none)
+     */
+    void attach(R (*function)(void)) {
+        _p.function = function;
+        _membercaller = 0;
+    }
+
+    /** 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, R (T::*member)(void)) {
+        _p.object = static_cast<void*>(object);
+        *reinterpret_cast<R (T::**)(void)>(_member) = member;
+        _membercaller = &FunctionPointerArg1::membercaller<T>;
+    }
+
+    /** Call the attached static or member function
+     */
+    R call(){
+        if (_membercaller == 0 && _p.function) {
+            return _p.function();
+        } else if (_membercaller && _p.object) {
+            return _membercaller(_p.object, _member);
+        }
+        return (R)0;
+    }
+
+    /** Get registered static function
+     */
+    R(*get_function())() {
+        return _membercaller ? (R(*)())0 : (R(*)())_p.function;
+    }
+
+#ifdef MBED_OPERATORS
+    R operator ()(void) {
+        return call();
+    }
+    operator bool(void) const {
+        return (_membercaller != NULL ? _p.object : (void*)_p.function) != NULL;
+    }
+#endif
+
+private:
+    template<typename T>
+    static R membercaller(void *object, uintptr_t *member) {
+        T* o = static_cast<T*>(object);
+        R (T::**m)(void) = reinterpret_cast<R (T::**)(void)>(member);
+        return (o->**m)();
+    }
+
+    union {
+        R (*function)(void); // static function pointer
+        void *object;        // object this pointer
+    } _p;
+    uintptr_t _member[4]; // aligned raw member function pointer storage - converted back by registered _membercaller
+    R (*_membercaller)(void*, uintptr_t*); // registered membercaller function to convert back and call _m.member on _object
+};
+
+typedef FunctionPointerArg1<void, void> FunctionPointer;
+typedef FunctionPointerArg1<void, int> event_callback_t;
+
+} // namespace mbed
+
+#endif