Varun Bahl / BahlDecrypModified

Updated

Fork of BLE_API by Bluetooth Low Energy

ble/FunctionPointerWithContext.h@862:d4be8c0b9ab3, 2015-11-02 (annotated)

Committer:
rgrover1
Date:
Mon Nov 02 09:09:07 2015 +0000
Revision:
862:d4be8c0b9ab3
Parent:
852:f0de1349300c
Child:
873:2e1a7bcf6590
Synchronized with git rev 99ba55ba

Author: Rohit Grover

Merge pull request #81 from pan-/functionPointerOptimisation



Reduce the memory consumed by FunctionPointerWithContext instances

Who changed what in which revision?

UserRevisionLine numberNew contents of line
rgrover1 710:b2e1a2660ec2 1 /* mbed Microcontroller Library
rgrover1 710:b2e1a2660ec2 2 * Copyright (c) 2006-2013 ARM Limited
rgrover1 710:b2e1a2660ec2 3 *
rgrover1 710:b2e1a2660ec2 4 * Licensed under the Apache License, Version 2.0 (the "License");
rgrover1 710:b2e1a2660ec2 5 * you may not use this file except in compliance with the License.
rgrover1 710:b2e1a2660ec2 6 * You may obtain a copy of the License at
rgrover1 710:b2e1a2660ec2 7 *
rgrover1 710:b2e1a2660ec2 8 * http://www.apache.org/licenses/LICENSE-2.0
rgrover1 710:b2e1a2660ec2 9 *
rgrover1 710:b2e1a2660ec2 10 * Unless required by applicable law or agreed to in writing, software
rgrover1 710:b2e1a2660ec2 11 * distributed under the License is distributed on an "AS IS" BASIS,
rgrover1 710:b2e1a2660ec2 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
rgrover1 710:b2e1a2660ec2 13 * See the License for the specific language governing permissions and
rgrover1 710:b2e1a2660ec2 14 * limitations under the License.
rgrover1 710:b2e1a2660ec2 15 */
rgrover1 710:b2e1a2660ec2 16
rgrover1 710:b2e1a2660ec2 17 #ifndef MBED_FUNCTIONPOINTER_WITH_CONTEXT_H
rgrover1 710:b2e1a2660ec2 18 #define MBED_FUNCTIONPOINTER_WITH_CONTEXT_H
rgrover1 710:b2e1a2660ec2 19
rgrover1 710:b2e1a2660ec2 20 #include <string.h>
rgrover1 710:b2e1a2660ec2 21
rgrover1 710:b2e1a2660ec2 22
rgrover1 862:d4be8c0b9ab3 23
rgrover1 710:b2e1a2660ec2 24 /** A class for storing and calling a pointer to a static or member void function
rgrover1 710:b2e1a2660ec2 25 * which takes a context.
rgrover1 710:b2e1a2660ec2 26 */
rgrover1 710:b2e1a2660ec2 27 template <typename ContextType>
rgrover1 710:b2e1a2660ec2 28 class FunctionPointerWithContext {
rgrover1 710:b2e1a2660ec2 29 public:
rgrover1 710:b2e1a2660ec2 30 typedef FunctionPointerWithContext<ContextType> *pFunctionPointerWithContext_t;
rgrover1 710:b2e1a2660ec2 31 typedef void (*pvoidfcontext_t)(ContextType context);
rgrover1 710:b2e1a2660ec2 32
rgrover1 710:b2e1a2660ec2 33 /** Create a FunctionPointerWithContext, attaching a static function
rgrover1 710:b2e1a2660ec2 34 *
rgrover1 710:b2e1a2660ec2 35 * @param function The void static function to attach (default is none)
rgrover1 710:b2e1a2660ec2 36 */
rgrover1 710:b2e1a2660ec2 37 FunctionPointerWithContext(void (*function)(ContextType context) = NULL) :
rgrover1 862:d4be8c0b9ab3 38 _function(NULL), _caller(NULL), _next(NULL) {
rgrover1 710:b2e1a2660ec2 39 attach(function);
rgrover1 710:b2e1a2660ec2 40 }
rgrover1 710:b2e1a2660ec2 41
rgrover1 710:b2e1a2660ec2 42 /** Create a FunctionPointerWithContext, attaching a member function
rgrover1 710:b2e1a2660ec2 43 *
rgrover1 710:b2e1a2660ec2 44 * @param object The object pointer to invoke the member function on (i.e. the this pointer)
rgrover1 710:b2e1a2660ec2 45 * @param function The address of the void member function to attach
rgrover1 710:b2e1a2660ec2 46 */
rgrover1 710:b2e1a2660ec2 47 template<typename T>
rgrover1 710:b2e1a2660ec2 48 FunctionPointerWithContext(T *object, void (T::*member)(ContextType context)) :
rgrover1 862:d4be8c0b9ab3 49 _memberFunctionAndPointer(), _caller(NULL), _next(NULL) {
rgrover1 710:b2e1a2660ec2 50 attach(object, member);
rgrover1 710:b2e1a2660ec2 51 }
rgrover1 710:b2e1a2660ec2 52
rgrover1 710:b2e1a2660ec2 53 /** Attach a static function
rgrover1 710:b2e1a2660ec2 54 *
rgrover1 710:b2e1a2660ec2 55 * @param function The void static function to attach (default is none)
rgrover1 710:b2e1a2660ec2 56 */
rgrover1 710:b2e1a2660ec2 57 void attach(void (*function)(ContextType context) = NULL) {
rgrover1 710:b2e1a2660ec2 58 _function = function;
rgrover1 862:d4be8c0b9ab3 59 _caller = functioncaller;
rgrover1 710:b2e1a2660ec2 60 }
rgrover1 710:b2e1a2660ec2 61
rgrover1 710:b2e1a2660ec2 62 /** Attach a member function
rgrover1 710:b2e1a2660ec2 63 *
rgrover1 710:b2e1a2660ec2 64 * @param object The object pointer to invoke the member function on (i.e. the this pointer)
rgrover1 710:b2e1a2660ec2 65 * @param function The address of the void member function to attach
rgrover1 710:b2e1a2660ec2 66 */
rgrover1 710:b2e1a2660ec2 67 template<typename T>
rgrover1 710:b2e1a2660ec2 68 void attach(T *object, void (T::*member)(ContextType context)) {
rgrover1 862:d4be8c0b9ab3 69 _memberFunctionAndPointer._object = static_cast<void *>(object);
rgrover1 862:d4be8c0b9ab3 70 memcpy(_memberFunctionAndPointer._memberFunction, (char*) &member, sizeof(member));
rgrover1 862:d4be8c0b9ab3 71 _caller = &FunctionPointerWithContext::membercaller<T>;
rgrover1 710:b2e1a2660ec2 72 }
rgrover1 710:b2e1a2660ec2 73
rgrover1 710:b2e1a2660ec2 74 /** Call the attached static or member function; and if there are chained
rgrover1 710:b2e1a2660ec2 75 * FunctionPointers their callbacks are invoked as well.
rgrover1 710:b2e1a2660ec2 76 * @Note: all chained callbacks stack up; so hopefully there won't be too
rgrover1 710:b2e1a2660ec2 77 * many FunctionPointers in a chain. */
rgrover1 710:b2e1a2660ec2 78 void call(ContextType context) {
rgrover1 862:d4be8c0b9ab3 79 _caller(this, context);
rgrover1 710:b2e1a2660ec2 80
rgrover1 710:b2e1a2660ec2 81 /* Propagate the call to next in the chain. */
rgrover1 710:b2e1a2660ec2 82 if (_next) {
rgrover1 710:b2e1a2660ec2 83 _next->call(context);
rgrover1 710:b2e1a2660ec2 84 }
rgrover1 710:b2e1a2660ec2 85 }
rgrover1 710:b2e1a2660ec2 86
rgrover1 710:b2e1a2660ec2 87 /**
rgrover1 710:b2e1a2660ec2 88 * Setup an external FunctionPointer as a next in the chain of related
rgrover1 710:b2e1a2660ec2 89 * callbacks. Invoking call() on the head FunctionPointer will invoke all
rgrover1 710:b2e1a2660ec2 90 * chained callbacks.
rgrover1 710:b2e1a2660ec2 91 *
rgrover1 710:b2e1a2660ec2 92 * Refer to 'CallChain' as an alternative.
rgrover1 710:b2e1a2660ec2 93 */
rgrover1 710:b2e1a2660ec2 94 void chainAsNext(pFunctionPointerWithContext_t next) {
rgrover1 710:b2e1a2660ec2 95 _next = next;
rgrover1 710:b2e1a2660ec2 96 }
rgrover1 710:b2e1a2660ec2 97
rgrover1 710:b2e1a2660ec2 98 pFunctionPointerWithContext_t getNext(void) const {
rgrover1 710:b2e1a2660ec2 99 return _next;
rgrover1 710:b2e1a2660ec2 100 }
rgrover1 710:b2e1a2660ec2 101
rgrover1 710:b2e1a2660ec2 102 pvoidfcontext_t get_function() const {
rgrover1 710:b2e1a2660ec2 103 return (pvoidfcontext_t)_function;
rgrover1 710:b2e1a2660ec2 104 }
rgrover1 710:b2e1a2660ec2 105
rgrover1 710:b2e1a2660ec2 106 private:
rgrover1 710:b2e1a2660ec2 107 template<typename T>
rgrover1 862:d4be8c0b9ab3 108 static void membercaller(pFunctionPointerWithContext_t self, ContextType context) {
rgrover1 862:d4be8c0b9ab3 109 if (self->_memberFunctionAndPointer._object) {
rgrover1 862:d4be8c0b9ab3 110 T *o = static_cast<T *>(self->_memberFunctionAndPointer._object);
rgrover1 862:d4be8c0b9ab3 111 void (T::*m)(ContextType);
rgrover1 862:d4be8c0b9ab3 112 memcpy((char*) &m, self->_memberFunctionAndPointer._memberFunction, sizeof(m));
rgrover1 862:d4be8c0b9ab3 113 (o->*m)(context);
rgrover1 862:d4be8c0b9ab3 114 }
rgrover1 862:d4be8c0b9ab3 115 }
rgrover1 862:d4be8c0b9ab3 116
rgrover1 862:d4be8c0b9ab3 117 static void functioncaller(pFunctionPointerWithContext_t self, ContextType context) {
rgrover1 862:d4be8c0b9ab3 118 if (self->_function) {
rgrover1 862:d4be8c0b9ab3 119 self->_function(context);
rgrover1 862:d4be8c0b9ab3 120 }
rgrover1 710:b2e1a2660ec2 121 }
rgrover1 710:b2e1a2660ec2 122
rgrover1 862:d4be8c0b9ab3 123 struct MemberFunctionAndPtr {
rgrover1 862:d4be8c0b9ab3 124 /*
rgrover1 862:d4be8c0b9ab3 125 * forward declaration of a class and a member function to this class.
rgrover1 862:d4be8c0b9ab3 126 * Because the compiler doesn't know anything about the forwarded member
rgrover1 862:d4be8c0b9ab3 127 * function, it will always use the biggest size and the biggest alignment
rgrover1 862:d4be8c0b9ab3 128 * that a member function can take for objects of type UndefinedMemberFunction.
rgrover1 862:d4be8c0b9ab3 129 */
rgrover1 862:d4be8c0b9ab3 130 class UndefinedClass;
rgrover1 862:d4be8c0b9ab3 131 typedef void (UndefinedClass::*UndefinedMemberFunction)(ContextType);
rgrover1 862:d4be8c0b9ab3 132
rgrover1 862:d4be8c0b9ab3 133 void* _object;
rgrover1 862:d4be8c0b9ab3 134 union {
rgrover1 862:d4be8c0b9ab3 135 char _memberFunction[sizeof(UndefinedMemberFunction)];
rgrover1 862:d4be8c0b9ab3 136 UndefinedMemberFunction _alignment;
rgrover1 862:d4be8c0b9ab3 137 };
rgrover1 862:d4be8c0b9ab3 138 };
rgrover1 862:d4be8c0b9ab3 139
rgrover1 862:d4be8c0b9ab3 140 union {
rgrover1 862:d4be8c0b9ab3 141 pvoidfcontext_t _function; /**< static function pointer - NULL if none attached */
rgrover1 862:d4be8c0b9ab3 142 /**
rgrover1 862:d4be8c0b9ab3 143 * object this pointer and pointer to member -
rgrover1 862:d4be8c0b9ab3 144 * _memberFunctionAndPointer._object will be NULL if none attached
rgrover1 862:d4be8c0b9ab3 145 */
rgrover1 862:d4be8c0b9ab3 146 MemberFunctionAndPtr _memberFunctionAndPointer;
rgrover1 862:d4be8c0b9ab3 147 };
rgrover1 862:d4be8c0b9ab3 148
rgrover1 862:d4be8c0b9ab3 149 void (*_caller)(FunctionPointerWithContext*, ContextType);
rgrover1 862:d4be8c0b9ab3 150
rgrover1 710:b2e1a2660ec2 151 pFunctionPointerWithContext_t _next; /**< Optional link to make a chain out of functionPointers; this
rgrover1 710:b2e1a2660ec2 152 * allows chaining function pointers without requiring
rgrover1 710:b2e1a2660ec2 153 * external memory to manage the chain. Also refer to
rgrover1 710:b2e1a2660ec2 154 * 'CallChain' as an alternative. */
rgrover1 710:b2e1a2660ec2 155 };
rgrover1 710:b2e1a2660ec2 156
rgrover1 710:b2e1a2660ec2 157 #endif // ifndef MBED_FUNCTIONPOINTER_WITH_CONTEXT_H