150 lines
3.0 KiB
C++
150 lines
3.0 KiB
C++
// Copyright 2019 Peter Dimov
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//
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// Distributed under the Boost Software License, Version 1.0.
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//
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// 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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#if defined(ONLY_V2)
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# define NO_BV
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# define NO_SV
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#endif
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#if defined(ONLY_BV)
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# define NO_V2
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# define NO_SV
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#endif
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#if defined(ONLY_SV)
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# define NO_V2
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# define NO_BV
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#endif
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#if !defined(NO_V2)
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#include <boost/variant2/variant.hpp>
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#endif
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#if !defined(NO_BV)
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#include <boost/variant.hpp>
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#endif
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#if !defined(NO_SV)
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#include <variant>
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#endif
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#include <type_traits>
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#include <chrono>
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#include <iostream>
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#include <iomanip>
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#include <vector>
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struct prefix
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{
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int v_;
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};
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struct X1: prefix {};
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struct X2: prefix {};
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struct X3: prefix {};
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struct X4: prefix {};
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struct X5: prefix {};
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struct X6: prefix {};
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struct X7: prefix {};
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struct X8: prefix {};
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struct X9: prefix {};
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struct X10: prefix {};
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struct X11: prefix {};
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struct X12: prefix {};
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inline int get_value( prefix const& v )
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{
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return v.v_;
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}
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#if !defined(NO_V2)
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template<class... T> int get_value( boost::variant2::variant<T...> const& v )
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{
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return visit( []( prefix const& x ) { return x.v_; }, v );
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}
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#endif
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#if !defined(NO_BV)
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template<class... T> int get_value( boost::variant<T...> const& v )
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{
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return boost::apply_visitor( []( prefix const& x ) { return x.v_; }, v );
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}
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#endif
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#if !defined(NO_SV)
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template<class... T> int get_value( std::variant<T...> const& v )
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{
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return visit( []( prefix const& x ) { return x.v_; }, v );
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}
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#endif
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template<class V> void test_( int N )
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{
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std::vector<V> w;
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// lack of reserve is deliberate
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auto tp1 = std::chrono::high_resolution_clock::now();
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for( int i = 0; i < N / 12; ++i )
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{
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w.push_back( X1{ i } );
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w.push_back( X2{ i } );
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w.push_back( X3{ i } );
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w.push_back( X4{ i } );
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w.push_back( X5{ i } );
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w.push_back( X6{ i } );
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w.push_back( X7{ i } );
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w.push_back( X8{ i } );
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w.push_back( X9{ i } );
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w.push_back( X10{ i } );
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w.push_back( X11{ i } );
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w.push_back( X12{ i } );
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}
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unsigned long long s = 0;
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for( std::size_t i = 0, n = w.size(); i < n; ++i )
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{
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s = s + get_value( w[ i ] );
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}
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auto tp2 = std::chrono::high_resolution_clock::now();
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std::cout << std::setw( 6 ) << std::chrono::duration_cast<std::chrono::milliseconds>( tp2 - tp1 ).count() << " ms; S=" << s << "\n";
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}
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template<class... T> void test( int N )
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{
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std::cout << "N=" << N << ":\n";
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std::cout << " prefix: "; test_<prefix>( N );
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#if !defined(NO_V2)
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std::cout << " variant2: "; test_<boost::variant2::variant<T...>>( N );
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#endif
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#if !defined(NO_BV)
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std::cout << "boost::variant: "; test_<boost::variant<T...>>( N );
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#endif
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#if !defined(NO_SV)
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std::cout << " std::variant: "; test_<std::variant<T...>>( N );
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#endif
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std::cout << '\n';
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}
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int main()
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{
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int const N = 100'000'000;
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test<X1, X2, X3, X4, X5, X6, X7, X8, X9, X10, X11, X12>( N );
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}
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