Chris@16: // last_value function object (documented as part of Boost.Signals)
Chris@16: 
Chris@16: // Copyright Douglas Gregor 2001-2003. Use, modification and
Chris@16: // distribution is subject to the Boost Software License, Version
Chris@16: // 1.0. (See accompanying file LICENSE_1_0.txt or copy at
Chris@16: // http://www.boost.org/LICENSE_1_0.txt)
Chris@16: 
Chris@16: // For more information, see http://www.boost.org/libs/signals
Chris@16: 
Chris@16: #ifndef BOOST_LAST_VALUE_HPP
Chris@16: #define BOOST_LAST_VALUE_HPP
Chris@16: 
Chris@16: #include <cassert>
Chris@16: #include <boost/config.hpp>
Chris@16: 
Chris@16: namespace boost {
Chris@16:   template<typename T>
Chris@16:   struct last_value {
Chris@16:     typedef T result_type;
Chris@16: 
Chris@16:     template<typename InputIterator>
Chris@16:     T operator()(InputIterator first, InputIterator last) const
Chris@16:     {
Chris@16:       assert(first != last);
Chris@16:       T value = *first++;
Chris@16:       while (first != last)
Chris@16:         value = *first++;
Chris@16:       return value;
Chris@16:     }
Chris@16:   };
Chris@16: 
Chris@16:   template<>
Chris@16:   struct last_value<void> {
Chris@16: #ifdef BOOST_NO_VOID_RETURNS
Chris@16:     struct unusable {};
Chris@16: 
Chris@16:   public:
Chris@16:     typedef unusable result_type;
Chris@16: #else
Chris@16:   public:
Chris@16:     typedef void result_type;
Chris@16: #endif // BOOST_NO_VOID_RETURNS
Chris@16: 
Chris@16:     template<typename InputIterator>
Chris@16:     result_type
Chris@16:     operator()(InputIterator first, InputIterator last) const
Chris@16:     {
Chris@16:       while (first != last)
Chris@16:         *first++;
Chris@16:       return result_type();
Chris@16:     }
Chris@16:   };
Chris@16: }
Chris@16: #endif // BOOST_SIGNALS_LAST_VALUE_HPP