234 lines
7.2 KiB
C++
234 lines
7.2 KiB
C++
// ratio.hpp ---------------------------------------------------------------//
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// Copyright 2008 Howard Hinnant
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// Copyright 2008 Beman Dawes
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// Copyright 2009 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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/*
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This code was derived by Beman Dawes from Howard Hinnant's time2_demo prototype.
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Many thanks to Howard for making his code available under the Boost license.
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The original code was modified to conform to Boost conventions and to section
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20.4 Compile-time rational arithmetic [ratio], of the C++ committee working
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paper N2798.
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See http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2798.pdf.
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time2_demo contained this comment:
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Much thanks to Andrei Alexandrescu,
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Walter Brown,
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Peter Dimov,
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Jeff Garland,
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Terry Golubiewski,
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Daniel Krugler,
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Anthony Williams.
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*/
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// The way overflow is managed for ratio_less is taken from llvm/libcxx/include/ratio
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#ifndef BOOST_RATIO_RATIO_HPP
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#define BOOST_RATIO_RATIO_HPP
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#include <boost/config.hpp>
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#include <boost/ratio/detail/mpl/abs.hpp>
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#include <boost/ratio/detail/mpl/sign.hpp>
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#include <boost/ratio/detail/mpl/gcd.hpp>
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#include <boost/ratio/detail/mpl/lcm.hpp>
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#include <cstdlib>
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#include <climits>
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#include <limits>
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#include <boost/cstdint.hpp>
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#include <boost/type_traits/integral_constant.hpp>
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#include <boost/utility/enable_if.hpp>
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#include <boost/integer_traits.hpp>
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#include <boost/ratio/ratio_fwd.hpp>
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#include <boost/ratio/detail/overflow_helpers.hpp>
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#ifdef BOOST_RATIO_EXTENSIONS
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#include <boost/rational.hpp>
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#include <boost/ratio/mpl/rational_c_tag.hpp>
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#endif
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//
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// We simply cannot include this header on gcc without getting copious warnings of the kind:
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//
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// boost/integer.hpp:77:30: warning: use of C99 long long integer constant
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//
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// And yet there is no other reasonable implementation, so we declare this a system header
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// to suppress these warnings.
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//
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#if defined(__GNUC__) && (__GNUC__ >= 4)
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#pragma GCC system_header
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#endif
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namespace boost
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{
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//----------------------------------------------------------------------------//
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// //
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// 20.6.1 Class template ratio [ratio.ratio] //
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// //
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//----------------------------------------------------------------------------//
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template <boost::intmax_t N, boost::intmax_t D>
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class ratio
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{
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static const boost::intmax_t ABS_N = mpl::abs_c<boost::intmax_t, N>::value;
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static const boost::intmax_t ABS_D = mpl::abs_c<boost::intmax_t, D>::value;
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BOOST_RATIO_STATIC_ASSERT(ABS_N >= 0, BOOST_RATIO_NUMERATOR_IS_OUT_OF_RANGE, ());
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BOOST_RATIO_STATIC_ASSERT(ABS_D > 0, BOOST_RATIO_DENOMINATOR_IS_OUT_OF_RANGE, ());
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BOOST_RATIO_STATIC_ASSERT(D != 0, BOOST_RATIO_DIVIDE_BY_0 , ());
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static const boost::intmax_t SIGN_N = mpl::sign_c<boost::intmax_t,N>::value
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* mpl::sign_c<boost::intmax_t,D>::value;
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static const boost::intmax_t GCD = mpl::gcd_c<boost::intmax_t, ABS_N, ABS_D>::value;
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public:
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BOOST_STATIC_CONSTEXPR boost::intmax_t num = SIGN_N * ABS_N / GCD;
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BOOST_STATIC_CONSTEXPR boost::intmax_t den = ABS_D / GCD;
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#ifdef BOOST_RATIO_EXTENSIONS
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typedef mpl::rational_c_tag tag;
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typedef boost::rational<boost::intmax_t> value_type;
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typedef boost::intmax_t num_type;
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typedef boost::intmax_t den_type;
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ratio()
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{}
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template <boost::intmax_t _N2, boost::intmax_t _D2>
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ratio(const ratio<_N2, _D2>&,
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typename enable_if_c
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<
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(ratio<_N2, _D2>::num == num &&
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ratio<_N2, _D2>::den == den)
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>::type* = 0)
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{}
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template <boost::intmax_t _N2, boost::intmax_t _D2>
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typename enable_if_c
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<
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(ratio<_N2, _D2>::num == num &&
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ratio<_N2, _D2>::den == den),
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ratio&
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>::type
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operator=(const ratio<_N2, _D2>&) {return *this;}
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static value_type value() {return value_type(num,den);}
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value_type operator()() const {return value();}
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#endif
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typedef ratio<num, den> type;
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};
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#if defined(BOOST_NO_CONSTEXPR)
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template <boost::intmax_t N, boost::intmax_t D>
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const boost::intmax_t ratio<N, D>::num;
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template <boost::intmax_t N, boost::intmax_t D>
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const boost::intmax_t ratio<N, D>::den;
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#endif
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//----------------------------------------------------------------------------//
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// //
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// 20.6.2 Arithmetic on ratio types [ratio.arithmetic] //
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// //
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//----------------------------------------------------------------------------//
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template <class R1, class R2>
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struct ratio_add
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: boost::ratio_detail::ratio_add<R1, R2>::type
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{
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};
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template <class R1, class R2>
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struct ratio_subtract
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: boost::ratio_detail::ratio_subtract<R1, R2>::type
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{
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};
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template <class R1, class R2>
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struct ratio_multiply
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: boost::ratio_detail::ratio_multiply<R1, R2>::type
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{
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};
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template <class R1, class R2>
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struct ratio_divide
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: boost::ratio_detail::ratio_divide<R1, R2>::type
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{
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};
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//----------------------------------------------------------------------------//
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// //
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// 20.6.3 Comparasion of ratio types [ratio.comparison] //
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// //
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//----------------------------------------------------------------------------//
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// ratio_equal
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template <class R1, class R2>
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struct ratio_equal
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: public boost::integral_constant<bool,
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(R1::num == R2::num && R1::den == R2::den)>
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{};
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template <class R1, class R2>
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struct ratio_not_equal
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: public boost::integral_constant<bool, !ratio_equal<R1, R2>::value>
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{};
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// ratio_less
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template <class R1, class R2>
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struct ratio_less
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: boost::integral_constant<bool, boost::ratio_detail::ratio_less<R1, R2>::value>
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{};
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template <class R1, class R2>
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struct ratio_less_equal
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: boost::integral_constant<bool, !ratio_less<R2, R1>::value>
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{};
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template <class R1, class R2>
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struct ratio_greater
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: boost::integral_constant<bool, ratio_less<R2, R1>::value>
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{};
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template <class R1, class R2>
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struct ratio_greater_equal
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: boost::integral_constant<bool, !ratio_less<R1, R2>::value>
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{};
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template <class R1, class R2>
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struct ratio_gcd :
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ratio<mpl::gcd_c<boost::intmax_t, R1::num, R2::num>::value,
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mpl::lcm_c<boost::intmax_t, R1::den, R2::den>::value>::type
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{
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};
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#ifdef BOOST_RATIO_EXTENSIONS
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template <class R>
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struct ratio_negate
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: ratio<-R::num, R::den>::type
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{
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};
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template <class R>
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struct ratio_abs
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: ratio<mpl::abs_c<boost::intmax_t, R::num>::value, R::den>::type
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{
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};
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template <class R>
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struct ratio_sign
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: mpl::sign_c<boost::intmax_t, R::num>
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{
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};
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template <class R1, class R2>
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struct ratio_lcm :
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ratio<mpl::lcm_c<boost::intmax_t, R1::num, R2::num>::value,
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mpl::gcd_c<boost::intmax_t, R1::den, R2::den>::value>::type
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{
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};
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#endif
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} // namespace boost
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#endif // BOOST_RATIO_RATIO_HPP
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