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Add ratio/detail/gcd_lcm.hpp

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This commit is contained in:
Peter Dimov 2023-10-13 06:32:55 +03:00
parent 05a053c9a4
commit 00a69ca14d
3 changed files with 87 additions and 0 deletions
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53
include/boost/ratio/detail/gcd_lcm.hpp Normal file
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@ -0,0 +1,53 @@
#ifndef BOOST_RATIO_DETAIL_GCD_LCM_HPP
#define BOOST_RATIO_DETAIL_GCD_LCM_HPP
// Copyright 2023 Peter Dimov
// Distributed under the Boost Software License, Version 1.0.
// https://www.boost.org/LICENSE_1_0.txt
#include <type_traits>
#include <cstdint>
namespace boost
{
namespace ratio_detail
{
template<std::intmax_t A> struct abs_: std::integral_constant<std::intmax_t, A < 0? -A: A>
{
};
template<> struct abs_<INTMAX_MIN>: std::integral_constant<std::intmax_t, INTMAX_MIN>
{
};
template<std::intmax_t A, std::intmax_t B> struct gcd_: public gcd_<B, A % B>
{
};
template<std::intmax_t A> struct gcd_<A, 0>: std::integral_constant<std::intmax_t, A>
{
};
template<std::intmax_t A, std::intmax_t B> struct lcm_: std::integral_constant<std::intmax_t, (A / gcd_<A, B>::value) * B>
{
};
template<> struct lcm_<0, 0>: std::integral_constant<std::intmax_t, 0>
{
};
//
template<std::intmax_t A, std::intmax_t B> struct gcd: abs_< gcd_<A, B>::value >
{
};
template<std::intmax_t A, std::intmax_t B> struct lcm: abs_< lcm_<A, B>::value >
{
};
} // namespace ratio_detail
} // namespace boost
#endif // BOOST_RATIO_DETAIL_GCD_LCM_HPP

1
test/Jamfile.v2
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@ -53,6 +53,7 @@ compile ratio_comparison/ratio_greater_equal_pass.cpp ;
# test-suite "ratio_detail"
run ratio_detail/is_evenly_divisible_by.cpp ;
run ratio_detail/gcd_lcm.cpp ;
# test-suite "examples"

33
test/ratio_detail/gcd_lcm.cpp Normal file
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// Copyright 2023 Peter Dimov
// Distributed under the Boost Software License, Version 1.0.
// https://www.boost.org/LICENSE_1_0.txt
#include <boost/ratio/detail/gcd_lcm.hpp>
#include <boost/core/lightweight_test_trait.hpp>
#include <cstdint>
using boost::ratio_detail::gcd;
using boost::ratio_detail::lcm;
int main()
{
BOOST_TEST_EQ( (gcd<1, 1>::value), 1 );
BOOST_TEST_EQ( (gcd<1, -1>::value), 1 );
BOOST_TEST_EQ( (gcd<2, 2>::value), 2 );
BOOST_TEST_EQ( (gcd<-2, -2>::value), 2 );
BOOST_TEST_EQ( (gcd<INTMAX_MAX, INTMAX_MAX>::value), INTMAX_MAX );
BOOST_TEST_EQ( (gcd<INTMAX_MAX, -INTMAX_MAX>::value), INTMAX_MAX );
BOOST_TEST_EQ( (gcd<-INTMAX_MAX, -INTMAX_MAX>::value), INTMAX_MAX );
BOOST_TEST_EQ( (gcd<7*11, 11*13>::value), 11 );
BOOST_TEST_EQ( (lcm<1, 1>::value), 1 );
BOOST_TEST_EQ( (lcm<1, -1>::value), 1 );
BOOST_TEST_EQ( (lcm<2, 2>::value), 2 );
BOOST_TEST_EQ( (lcm<-2, -2>::value), 2 );
BOOST_TEST_EQ( (lcm<INTMAX_MAX, INTMAX_MAX>::value), INTMAX_MAX );
BOOST_TEST_EQ( (lcm<INTMAX_MAX, -INTMAX_MAX>::value), INTMAX_MAX );
BOOST_TEST_EQ( (lcm<-INTMAX_MAX, -INTMAX_MAX>::value), INTMAX_MAX );
BOOST_TEST_EQ( (lcm<7*11, 11*13>::value), 7*11*13 );
return boost::report_errors();
}