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// optional_last_value function object (documented as part of Boost.Signals2)
// Copyright Frank Mori Hess 2007-2008.
// Copyright Douglas Gregor 2001-2003.
// 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)
// See http://www.boost.org/libs/signals2 for library home page.
#ifndef BOOST_SIGNALS2_OPTIONAL_LAST_VALUE_HPP
#define BOOST_SIGNALS2_OPTIONAL_LAST_VALUE_HPP
#include <boost/optional.hpp>
#include <boost/signals2/expired_slot.hpp>
namespace boost {
namespace signals2 {
template<typename T>
class optional_last_value
{
public:
typedef optional<T> result_type;
template<typename InputIterator>
optional<T> operator()(InputIterator first, InputIterator last) const
{
optional<T> value;
while (first != last)
{
try
{
value = *first;
}
catch(const expired_slot &) {}
++first;
}
return value;
}
};
template<>
class optional_last_value<void>
{
public:
typedef void result_type;
template<typename InputIterator>
result_type operator()(InputIterator first, InputIterator last) const
{
while (first != last)
{
try
{
*first;
}
catch(const expired_slot &) {}
++first;
}
return;
}
};
} // namespace signals2
} // namespace boost
#endif // BOOST_SIGNALS2_OPTIONAL_LAST_VALUE_HPP
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