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102 lines
2.9 KiB
C++
102 lines
2.9 KiB
C++
// Copyright 2011 Vicente J. Botet Escriba
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// Distributed under the Boost Software License, Version 1.0.
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// See http://www.boost.org/LICENSE_1_0.txt
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#include <boost/chrono/chrono.hpp>
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#include <boost/chrono/chrono_io.hpp>
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static
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const int
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is_leap_table_[400] =
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{
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1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,
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0,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,
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0,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,
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0,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0
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};
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/**
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* is_leap could be made more efficient by using a table indexed by the y % 400.
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* This table could contain true for y such as
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* y % 4 == 0 && (y % 100 != 0 || y % 400 == 0)
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*
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* is_leap = is_leap_table[y%400]
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*/
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static
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inline
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bool
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is_leap_calc(int y) BOOST_NOEXCEPT
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{
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return y % 4 == 0 && (y % 100 != 0 || y % 400 == 0);
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}
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static
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inline
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bool
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is_leap_table(int y) BOOST_NOEXCEPT
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{
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return (y % 4 == 0) && is_leap_table_[y%400];
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//return (y & 3 == 0) && is_leap_table_[y%400];
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}
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static
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inline
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bool
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is_leap(int y) BOOST_NOEXCEPT
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{
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#if defined BOOST_CHRONO_IS_LEAP_USES_TABLE
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return is_leap_table(y);
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#else
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return is_leap_calc(y);
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#endif
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}
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int main()
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{
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typedef boost::chrono::high_resolution_clock Clock;
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typedef boost::chrono::duration<double> sec;
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// for (int y = -32768; y <= 32767; ++y)
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// {
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// if (is_leap_calc(y)!=is_leap_table(y))
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// std::cout
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// << "is_leap_calc:" << is_leap_calc(y) << " "
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// << "is_leap_table:" << is_leap_table(y) << " "
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// << y << " " << y%400 <<"\n";
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//
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// }
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{
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int cnt=0;
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Clock::time_point t0 = Clock::now();
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for (int x = 0; x < 100; ++x)
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for (int y = 0; y <= 32767; ++y)
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//for (int y = -32768; y <= 32767; ++y)
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{
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cnt += is_leap_calc(y)?1:0;
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}
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Clock::time_point t1 = Clock::now();
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std::cout << "is_leap_calc: " << t1-t0 << " " << cnt <<"\n";
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}
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{
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int cnt=0;
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Clock::time_point t0 = Clock::now();
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for (int x = 0; x < 100; ++x)
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for (int y = 0; y <= 32767; ++y)
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//for (int y = -32768; y <= 32767; ++y)
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{
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cnt += is_leap_table(y)?1:0;
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}
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Clock::time_point t1 = Clock::now();
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std::cout << "is_leap_table:" << t1-t0 << " " << cnt <<"\n";
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}
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return 0;
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}
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