ext-boost/boost/last_value.hpp

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// 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