Fast C++ Delegate: Boost.Function 'drop-in' replacement and multicast

// FD.Delegate library

//  Copyright (c) 2007 JaeWook Choi
//
// Distributed under the Boost Software License, Version 1.0. (See
// accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)

#include <boost/test/minimal.hpp>
#include <cassert>
#include <iostream>
#include <fd/delegate/delegate0.hpp>
#include <fd/delegate/delegate1.hpp>
#include <boost/last_value.hpp>

int inc_1(int & n) { std::cout<< "inc_1(" << n << ")" << std::endl; return ++n; };
int inc_2(int & n) { std::cout<< "inc_2(" << n << ")" << std::endl; return ++n; };
int inc_3(int & n) { std::cout<< "inc_3(" << n << ")" << std::endl; return ++n; };
int inc_4(int & n) { std::cout<< "inc_4(" << n << ")" << std::endl; return ++n; };
int inc_5(int & n) { std::cout<< "inc_5(" << n << ")" << std::endl; return ++n; };

void inc_v1() { std::cout<< "inc_v1()" << std::endl; };
void inc_v2() { std::cout<< "inc_v2()" << std::endl; };
void inc_v3() { std::cout<< "inc_v3()" << std::endl; };
void inc_v4() { std::cout<< "inc_v4()" << std::endl; };
void inc_v5() { std::cout<< "inc_v5()" << std::endl; };

struct abort_if_greater_than_3
{
  typedef bool result_type;

  template<typename InputIterator>
  bool operator ()(InputIterator first, InputIterator last) const
  {
    if(first == last)
      return false;

    for( ; first != last; ++first )
    {
      if( *first > 3 )
        return true;
    }
    return false;
  }
};

struct abort_after_3_call
{
  typedef void result_type;

  int num_;

  abort_after_3_call() : num_( 0 ) { }

  template<typename InputIterator>
  void operator ()(InputIterator first, InputIterator last)
  {
    for( ; first != last && num_ < 3; ++first, ++num_)
    {
      *first; // Dereferencing the iterator causes the delegate invocation at the specific position.
    }
  }
};

int
test_main(int, char*[])
{
  fd::delegate1<int, int &> dg1;

  dg1 += &inc_1;
  dg1 += &inc_2;
  dg1 += &inc_3;
  dg1 += &inc_4;
  dg1 += &inc_5;

  int n = 0;

  std::cout << "dg1( n );" << std::endl;
  dg1( n );
  BOOST_CHECK( n == 5 );

  n = 0;
  std::cout << "dg1( n, abort_if_greater_than_3() );" << std::endl;
  dg1( n, abort_if_greater_than_3() );
  BOOST_CHECK( n == 4 );

  int n1 = 0, n2 = 0;
  std::cout << "dg1( n1 ) == dg1( n2, boost::last_value<int>() )" << std::endl;
  BOOST_CHECK( dg1( n1 ) == dg1( n2, boost::last_value<int>() ) );

  fd::delegate0<void> dg2;

  dg2 += &inc_v1;
  dg2 += &inc_v2;
  dg2 += &inc_v3;
  dg2 += &inc_v4;
  dg2 += &inc_v5;

  std::cout << "dg2();" << std::endl;
  dg2();

  std::cout << "dg2( boost::last_value<void>() );" << std::endl;
  dg2( boost::last_value<void>() );

  std::cout << "dg2( abort_after_3_call() );" << std::endl;
  dg2( abort_after_3_call() );

  return 0;
}