55 lines
1.3 KiB
C++
55 lines
1.3 KiB
C++
// last_value function object (documented as part of Boost.Signals)
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// Copyright Douglas Gregor 2001-2003. Use, modification and
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// distribution is subject to 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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// For more information, see http://www.boost.org/libs/signals
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#ifndef BOOST_LAST_VALUE_HPP
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#define BOOST_LAST_VALUE_HPP
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#include <cassert>
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#include <boost/config.hpp>
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namespace boost {
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template<typename T>
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struct last_value {
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typedef T result_type;
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template<typename InputIterator>
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T operator()(InputIterator first, InputIterator last) const
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{
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assert(first != last);
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T value = *first++;
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while (first != last)
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value = *first++;
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return value;
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}
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};
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template<>
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struct last_value<void> {
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#ifdef BOOST_NO_VOID_RETURNS
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struct unusable {};
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public:
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typedef unusable result_type;
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#else
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public:
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typedef void result_type;
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#endif // BOOST_NO_VOID_RETURNS
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template<typename InputIterator>
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result_type
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operator()(InputIterator first, InputIterator last) const
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{
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while (first != last)
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*first++;
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return result_type();
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}
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};
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}
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#endif // BOOST_SIGNALS_LAST_VALUE_HPP
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