mirror of https://gitee.com/bigwinds/arangodb
49 lines
1.2 KiB
C++
49 lines
1.2 KiB
C++
// Boost.Signals library
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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
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#include <boost/signals/signal2.hpp>
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#include <iostream>
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template<typename T>
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struct first_positive {
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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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while (first != last && !(*first > 0)) { ++first; }
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return (first == last) ? 0
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: *first;
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}
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};
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template<typename T>
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struct noisy_divide {
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typedef T result_type;
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T operator()(const T& x, const T& y) const
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{
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std::cout << "Dividing " << x << " and " << y << std::endl;
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return x/y;
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}
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};
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int main()
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{
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boost::signal2<int, int, int, first_positive<int> > sig_positive;
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sig_positive.connect(std::plus<int>());
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sig_positive.connect(std::multiplies<int>());
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sig_positive.connect(std::minus<int>());
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sig_positive.connect(noisy_divide<int>());
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assert(sig_positive(3, -5) == 8); // returns 8, but prints nothing
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return 0;
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}
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