Peng's delegate

gistfile1.cpp

/*******************************************************************************
 *
 *      @name   : DELEGATE_H
 *
 *      @author : BigBird (peng@nextopsoftware.com)
 *      @date   : 2012-10-16 21:58:04
 *
 *      @brief  :
 *
 *******************************************************************************/


#ifndef  dpDelegate_h
#define  dpDelegate_h

#include <vector>

template< class T >

struct DelegateFuncBase {
    T* obj;
    
    DelegateFuncBase() : obj (NULL) {}
    
    virtual void evaluate() = 0;
    virtual ~DelegateFuncBase() {}
};


template< class T, typename P0 = void,
    typename P1 = void >
    class DelegateFunc;

template< class T, typename P0, typename P1 >
    class DelegateFunc
    : public DelegateFuncBase<T> {
    
        typedef DelegateFuncBase<T> Base;
        typedef void (T::*Function) (P0,P1);
        Function func;
        P0 p0; P1 p1;
public:
DelegateFunc(Function f, P0 s0, P1 s1)
    :func(f),
            p0(s0), p1(s1),
            Base() {}
        void evaluate() { (Base::obj->*func)(p0, p1); }
};

template< class T, typename P0 >
    class DelegateFunc< T, P0 >

    : public DelegateFuncBase<T> {
        typedef DelegateFuncBase<T> Base;
        typedef void (T::*Function) (P0);
        Function func;
        P0 p0;

public:
DelegateFunc(Function f, P0 s0)
    :func(f), p0(s0),
     Base() {}
    void evaluate() { (Base::obj->*func)(p0); }
};

template< class T >

class DelegateFunc< T >
: public DelegateFuncBase<T> {

    typedef DelegateFuncBase<T> Base;
    typedef void (T::*Function) ();
    Function func;

public:
DelegateFunc(Function f)
    :func(f), Base() {}

    void evaluate() { (Base::obj->*func)(); }

};


template< class T >
class Delegate {
    typedef DelegateFuncBase<T> DelegateFuncBaseType;
    std::vector< DelegateFuncBaseType* > delegates;

public:

    void operator += (DelegateFuncBaseType* o) {
        delegates.push_back(o);
    }

    void evaluation(T* obj) {
        for(int i = 0; i < delegates.size(); ++i) {
            DelegateFuncBaseType* df = delegates[i];
            df->obj = obj;
            df->evaluate();
        }
    }

    ~Delegate() {
        for(int i = 0; i < delegates.size(); ++i) {
            delete delegates[i];
        }
    }
};



template< typename T >
DelegateFuncBase<T>* delegate(void (T::*func)()) {
    return new DelegateFunc<T>(func);

}

template< typename T, typename P0 >
    DelegateFuncBase<T>* delegate(void (T::*func)(P0), P0 p0) {
    return new DelegateFunc<T,P0>(func,p0);

}

template< typename T, typename P0, typename P1 >
    DelegateFuncBase<T>* delegate(void (T::*func)(P0,P1), P0 p0, P1 p1) {
    return new DelegateFunc<T,P0,P1>(func,p0,p1);

}

#endif /*dpDelegate_h*/



/*******************************************************************************
 *
 *      main.cpp
 *
 *      @brief
 *
 *      @author   BigBird (peng@nextopsoftware.com)
 *
 *      COPYRIGHT (C) 2011, Nextop INC., ALL RIGHTS RESERVED.
 *
 *******************************************************************************/
// main.cc

#include <iostream>
#include "delegate.h"

using namespace std;

class B {
    int v;
public:

    B() : v(0) {}

    void print() {
        cout << "Hello World!" << endl;
    }

    void assign(int d) {
        v = d;
    }

    void print_value() {
        cout << v << endl;
    }
};

int main () {
    Delegate<B> db;
    db += (delegate(&B::assign, 2));
    db += (delegate(&B::print_value));
    db += (delegate(&B::print));

    B b;

    db.evaluation(&b);

    return 0;

}