// last_value function object (documented as part of Boost.Signals)



// Copyright Douglas Gregor 2001-2003. Use, modification and

// distribution is subject to 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)



// For more information, see http://www.boost.org/libs/signals



#ifndef BOOST_LAST_VALUE_HPP

#define BOOST_LAST_VALUE_HPP



#include <cassert>

#include <boost/config.hpp>



namespace boost {

  template<typename T>

  struct last_value {

    typedef T result_type;



    template<typename InputIterator>

    T operator()(InputIterator first, InputIterator last) const

    {

      assert(first != last);

      T value = *first++;

      while (first != last)

        value = *first++;

      return value;

    }

  };



  template<>

  struct last_value<void> {

#ifdef BOOST_NO_VOID_RETURNS

    struct unusable {};



  public:

    typedef unusable result_type;

#else

  public:

    typedef void result_type;

#endif // BOOST_NO_VOID_RETURNS



    template<typename InputIterator>

    result_type

    operator()(InputIterator first, InputIterator last) const

    {

      while (first != last)

        *first++;

      return result_type();

    }

  };

}

#endif // BOOST_SIGNALS_LAST_VALUE_HPP

