Sam Grove / FP

Templated function pointer class. Common utility that other classes are built on / with

Dependents:   Waldo_Embed_V2 MQTT MQTTSN MQTT ... more

Good resource about declaring templated types for the linker

Basic Use

#include "mbed.h"
#include "FP.h"
  
FP<void,bool>fp;
DigitalOut myled(LED1);
  
void handler(bool value)
{
    myled = value;
    return;
}
  
int main()
{
    fp.attach(&handler);
      
    while(1) 
    {
        fp(1);
        wait(0.2);
        fp(0);
        wait(0.2);
    }
}

Example using the FP Class with different class member functions

#include "mbed.h"
#include "FP.h"
  
FP<void,bool>fp;
DigitalOut myled(LED4);
  
class Wrapper
{
public:
    Wrapper(){}
  
    void handler(bool value)
    {
        myled = value;
        return;
    }
};
  
int main()
{
    Wrapper wrapped;
    fp.attach(&wrapped, &Wrapper::handler);
    
    while(1) 
    {
        fp(1);
        wait(0.2);
        fp(0);
        wait(0.2);
    }
}

Example using the FP Class with member FP and member function

#include "mbed.h"
#include "FP.h"
  
DigitalOut myled(LED2);
  
class Wrapper
{
public:
    Wrapper()
    {
        fp.attach(this, &Wrapper::handler);
    }
  
    void handler(bool value)
    {
        myled = value;
        return;
    }
      
    FP<void,bool>fp;
};
  
int main()
{
    Wrapper wrapped;
      
    while(1) 
    {
        wrapped.fp(1);
        wait(0.2);
        wrapped.fp(0);
        wait(0.2);
    }
}

Diff: FP.h

Revision:
0:a34f15741c5a
Child:
3:e0f19cdaa46e
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/FP.h	Fri Apr 05 22:21:33 2013 +0000
@@ -0,0 +1,183 @@
+/**
+ * @file    FP.h
+ * @brief   Core Utility - Templated Function Pointer Class
+ * @author  sam grove
+ * @version 1.0
+ * @see     
+ *
+ * Copyright (c) 2013
+ *
+ * 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 FP_H
+#define FP_H
+
+/** Example using the FP Class with global functions
+ * @code
+ *  #include "mbed.h"
+ *  #include "FP.h"
+ *  
+ *  FP<void,bool>fp;
+ *  DigitalOut myled(LED1);
+ *  
+ *  void handler(bool value)
+ *  {
+ *      myled = value;
+ *      return;
+ *  }
+ *  
+ *  int main()
+ *  {
+ *      fp.attach(&handler);
+ *      
+ *      while(1) 
+ *      {
+ *          fp(1);
+ *          wait(0.2);
+ *          fp(0);
+ *          wait(0.2);
+ *      }
+ *  }
+ * @endcode
+ */
+ 
+/** Example using the FP Class with different class member functions
+ * @code
+ *  #include "mbed.h"
+ *  #include "FP.h"
+ *  
+ *  FP<void,bool>fp;
+ *  DigitalOut myled(LED4);
+ *  
+ *  class Wrapper
+ *  {
+ *  public:
+ *      Wrapper(){}
+ *  
+ *      void handler(bool value)
+ *      {
+ *          myled = value;
+ *          return;
+ *      }
+ *  };
+ *  
+ *  int main()
+ *  {
+ *      Wrapper wrapped;
+ *      fp.attach(&wrapped, &Wrapper::handler);
+ *      
+ *      while(1) 
+ *      {
+ *          fp(1);
+ *          wait(0.2);
+ *          fp(0);
+ *          wait(0.2);
+ *      }
+ *  }
+ * @endcode
+ */
+ 
+ /** Example using the FP Class with member FP and member function
+ * @code
+ *  #include "mbed.h"
+ *  #include "FP.h"
+ *  
+ *  DigitalOut myled(LED2);
+ *  
+ *  class Wrapper
+ *  {
+ *  public:
+ *      Wrapper()
+ *      {
+ *          fp.attach(this, &Wrapper::handler);
+ *      }
+ *  
+ *      void handler(bool value)
+ *      {
+ *          myled = value;
+ *          return;
+ *      }
+ *      
+ *      FP<void,bool>fp;
+ *  };
+ *  
+ *  int main()
+ *  {
+ *      Wrapper wrapped;
+ *      
+ *      while(1) 
+ *      {
+ *          wrapped.fp(1);
+ *          wait(0.2);
+ *          wrapped.fp(0);
+ *          wait(0.2);
+ *      }
+ *  }
+ * @endcode
+ */
+
+/**
+ *  @class FP
+ *  @brief API abstraction for a Function Pointers
+ */ 
+template<class retT, class argT>
+class FP
+{
+public:
+    /** Create the FP object
+     */ 
+    FP();
+
+    /** Add a callback function to the class
+     *  @param item - Address of the initialized class
+     *  @param member - Address of the member function (dont forget the scope that the function is defined in)
+     */
+    template<class T>
+    void attach(T *item, retT (T::*method)(argT))
+    {
+        obj_callback = (FPtrDummy *)(item);
+        method_callback = (retT (FPtrDummy::*)(argT))(method);
+        return;
+    }
+
+    /** Add a callback function to the class
+     *  @param function - The address of a globally defined function
+     */
+    void attach(retT (*function)(argT));
+    
+    /** Invoke the function attached to the class
+     *  @param arg - An argument that is passed into the function handler that is called
+     *  @return The return from the function hanlder called by this class
+     */
+    retT operator()(argT arg) const;
+
+private:
+    
+    // empty type used for casting
+    class FPtrDummy;
+    
+    FPtrDummy *obj_callback;
+    
+    /**
+     *  @union Funciton
+     *  @brief Member or global callback function
+     */ 
+    union
+    {
+        retT (*c_callback)(argT);                   /*!< Footprint for a global function */
+        retT (FPtrDummy::*method_callback)(argT);   /*!< Footprint for a member function */
+    };
+};
+
+#endif