69 lines
1.7 KiB
C++
69 lines
1.7 KiB
C++
// optional_last_value function object (documented as part of Boost.Signals2)
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// Copyright Frank Mori Hess 2007-2008.
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// Copyright Douglas Gregor 2001-2003.
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// Distributed under the Boost Software License, Version
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// 1.0. (See accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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// See http://www.boost.org/libs/signals2 for library home page.
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#ifndef BOOST_SIGNALS2_OPTIONAL_LAST_VALUE_HPP
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#define BOOST_SIGNALS2_OPTIONAL_LAST_VALUE_HPP
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#include <boost/core/no_exceptions_support.hpp>
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#include <boost/optional.hpp>
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#include <boost/signals2/expired_slot.hpp>
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namespace boost {
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namespace signals2 {
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template<typename T>
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class optional_last_value
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{
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public:
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typedef optional<T> result_type;
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template<typename InputIterator>
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optional<T> operator()(InputIterator first, InputIterator last) const
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{
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optional<T> value;
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while (first != last)
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{
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BOOST_TRY
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{
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value = *first;
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}
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BOOST_CATCH(const expired_slot &) {}
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BOOST_CATCH_END
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++first;
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}
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return value;
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}
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};
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template<>
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class optional_last_value<void>
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{
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public:
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typedef void result_type;
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template<typename InputIterator>
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result_type operator()(InputIterator first, InputIterator last) const
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{
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while (first != last)
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{
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BOOST_TRY
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{
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*first;
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}
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BOOST_CATCH(const expired_slot &) {}
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BOOST_CATCH_END
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++first;
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}
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return;
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}
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};
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} // namespace signals2
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} // namespace boost
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#endif // BOOST_SIGNALS2_OPTIONAL_LAST_VALUE_HPP
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