// 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>

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> {

    struct unusable {};

  public:

    typedef unusable result_type;

    template<typename InputIterator>

    result_type

    operator()(InputIterator first, InputIterator last) const

    {

      while (first != last)

        *first++;

      return result_type();

    }

  };

}

#endif // BOOST_SIGNALS_LAST_VALUE_HPP