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- // ratio.hpp ---------------------------------------------------------------//
- // Copyright 2008 Howard Hinnant
- // Copyright 2008 Beman Dawes
- // Copyright 2009 Vicente J. Botet Escriba
- // Distributed under the Boost Software License, Version 1.0.
- // See http://www.boost.org/LICENSE_1_0.txt
- /*
- This code was derived by Beman Dawes from Howard Hinnant's time2_demo prototype.
- Many thanks to Howard for making his code available under the Boost license.
- The original code was modified to conform to Boost conventions and to section
- 20.4 Compile-time rational arithmetic [ratio], of the C++ committee working
- paper N2798.
- See http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2798.pdf.
- time2_demo contained this comment:
- Much thanks to Andrei Alexandrescu,
- Walter Brown,
- Peter Dimov,
- Jeff Garland,
- Terry Golubiewski,
- Daniel Krugler,
- Anthony Williams.
- */
- // The way overflow is managed for ratio_less is taken from llvm/libcxx/include/ratio
- #ifndef BOOST_RATIO_RATIO_HPP
- #define BOOST_RATIO_RATIO_HPP
- #include <boost/ratio/config.hpp>
- #include <boost/ratio/detail/mpl/abs.hpp>
- #include <boost/ratio/detail/mpl/sign.hpp>
- #include <boost/ratio/detail/mpl/gcd.hpp>
- #include <boost/ratio/detail/mpl/lcm.hpp>
- #include <cstdlib>
- #include <climits>
- #include <limits>
- #include <boost/cstdint.hpp>
- #include <boost/type_traits/integral_constant.hpp>
- #include <boost/core/enable_if.hpp>
- #include <boost/integer_traits.hpp>
- #include <boost/ratio/ratio_fwd.hpp>
- #include <boost/ratio/detail/overflow_helpers.hpp>
- #ifdef BOOST_RATIO_EXTENSIONS
- #include <boost/rational.hpp>
- #include <boost/ratio/mpl/rational_c_tag.hpp>
- #endif
- //
- // We simply cannot include this header on gcc without getting copious warnings of the kind:
- //
- // boost/integer.hpp:77:30: warning: use of C99 long long integer constant
- //
- // And yet there is no other reasonable implementation, so we declare this a system header
- // to suppress these warnings.
- //
- #if defined(__GNUC__) && (__GNUC__ >= 4)
- #pragma GCC system_header
- #endif
- namespace boost
- {
- //----------------------------------------------------------------------------//
- // //
- // 20.6.1 Class template ratio [ratio.ratio] //
- // //
- //----------------------------------------------------------------------------//
- template <boost::intmax_t N, boost::intmax_t D>
- class ratio
- {
- static const boost::intmax_t ABS_N = mpl::abs_c<boost::intmax_t, N>::value;
- static const boost::intmax_t ABS_D = mpl::abs_c<boost::intmax_t, D>::value;
- BOOST_RATIO_STATIC_ASSERT(ABS_N >= 0, BOOST_RATIO_NUMERATOR_IS_OUT_OF_RANGE, ());
- BOOST_RATIO_STATIC_ASSERT(ABS_D > 0, BOOST_RATIO_DENOMINATOR_IS_OUT_OF_RANGE, ());
- BOOST_RATIO_STATIC_ASSERT(D != 0, BOOST_RATIO_DIVIDE_BY_0 , ());
- static const boost::intmax_t SIGN_N = mpl::sign_c<boost::intmax_t,N>::value
- * mpl::sign_c<boost::intmax_t,D>::value;
- static const boost::intmax_t GCD = mpl::gcd_c<boost::intmax_t, ABS_N, ABS_D>::value;
- public:
- BOOST_STATIC_CONSTEXPR boost::intmax_t num = SIGN_N * ABS_N / GCD;
- BOOST_STATIC_CONSTEXPR boost::intmax_t den = ABS_D / GCD;
- #ifdef BOOST_RATIO_EXTENSIONS
- typedef mpl::rational_c_tag tag;
- typedef boost::rational<boost::intmax_t> value_type;
- typedef boost::intmax_t num_type;
- typedef boost::intmax_t den_type;
- ratio()
- {}
- template <boost::intmax_t _N2, boost::intmax_t _D2>
- ratio(const ratio<_N2, _D2>&,
- typename enable_if_c
- <
- (ratio<_N2, _D2>::num == num &&
- ratio<_N2, _D2>::den == den)
- >::type* = 0)
- {}
- template <boost::intmax_t _N2, boost::intmax_t _D2>
- typename enable_if_c
- <
- (ratio<_N2, _D2>::num == num &&
- ratio<_N2, _D2>::den == den),
- ratio&
- >::type
- operator=(const ratio<_N2, _D2>&) {return *this;}
- static value_type value() {return value_type(num,den);}
- value_type operator()() const {return value();}
- #endif
- typedef ratio<num, den> type;
- };
- #if defined(BOOST_NO_CXX11_CONSTEXPR)
- template <boost::intmax_t N, boost::intmax_t D>
- const boost::intmax_t ratio<N, D>::num;
- template <boost::intmax_t N, boost::intmax_t D>
- const boost::intmax_t ratio<N, D>::den;
- #endif
- //----------------------------------------------------------------------------//
- // //
- // 20.6.2 Arithmetic on ratio types [ratio.arithmetic] //
- // //
- //----------------------------------------------------------------------------//
- template <class R1, class R2>
- struct ratio_add
- : boost::ratio_detail::ratio_add<R1, R2>::type
- {
- };
- template <class R1, class R2>
- struct ratio_subtract
- : boost::ratio_detail::ratio_subtract<R1, R2>::type
- {
- };
- template <class R1, class R2>
- struct ratio_multiply
- : boost::ratio_detail::ratio_multiply<R1, R2>::type
- {
- };
- template <class R1, class R2>
- struct ratio_divide
- : boost::ratio_detail::ratio_divide<R1, R2>::type
- {
- };
- //----------------------------------------------------------------------------//
- // //
- // 20.6.3 Comparision of ratio types [ratio.comparison] //
- // //
- //----------------------------------------------------------------------------//
- // ratio_equal
- template <class R1, class R2>
- struct ratio_equal
- : public boost::integral_constant<bool,
- (R1::num == R2::num && R1::den == R2::den)>
- {};
- template <class R1, class R2>
- struct ratio_not_equal
- : public boost::integral_constant<bool, !ratio_equal<R1, R2>::value>
- {};
- // ratio_less
- template <class R1, class R2>
- struct ratio_less
- : boost::integral_constant<bool, boost::ratio_detail::ratio_less<R1, R2>::value>
- {};
- template <class R1, class R2>
- struct ratio_less_equal
- : boost::integral_constant<bool, !ratio_less<R2, R1>::value>
- {};
- template <class R1, class R2>
- struct ratio_greater
- : boost::integral_constant<bool, ratio_less<R2, R1>::value>
- {};
- template <class R1, class R2>
- struct ratio_greater_equal
- : boost::integral_constant<bool, !ratio_less<R1, R2>::value>
- {};
- template <class R1, class R2>
- struct ratio_gcd :
- ratio<mpl::gcd_c<boost::intmax_t, R1::num, R2::num>::value,
- mpl::lcm_c<boost::intmax_t, R1::den, R2::den>::value>::type
- {
- };
- //----------------------------------------------------------------------------//
- // //
- // More arithmetic on ratio types [ratio.arithmetic] //
- // //
- //----------------------------------------------------------------------------//
- #ifdef BOOST_RATIO_EXTENSIONS
- template <class R>
- struct ratio_negate
- : ratio<-R::num, R::den>::type
- {
- };
- template <class R>
- struct ratio_abs
- : ratio<mpl::abs_c<boost::intmax_t, R::num>::value, R::den>::type
- {
- };
- template <class R>
- struct ratio_sign
- : mpl::sign_c<boost::intmax_t, R::num>
- {
- };
- template <class R>
- struct ratio_inverse
- : ratio<R::den, R::num>::type
- {
- };
- template <class R1, class R2>
- struct ratio_lcm :
- ratio<mpl::lcm_c<boost::intmax_t, R1::num, R2::num>::value,
- mpl::gcd_c<boost::intmax_t, R1::den, R2::den>::value>::type
- {
- };
- template <class R1, class R2>
- struct ratio_modulo :
- ratio<(R1::num * R2::den) % (R2::num * R1::den), R1::den * R2::den>::type
- {
- };
- namespace detail {
- template <class R1, class R2, bool r1ltr2>
- struct ratio_min : R1 {};
- template <class R1, class R2>
- struct ratio_min<R1,R2,false> : R2 {};
- template <class R1, class R2, bool r1ltr2>
- struct ratio_max : R2 {};
- template <class R1, class R2>
- struct ratio_max<R1,R2,false> : R1 {};
- }
- template <class R1, class R2>
- struct ratio_min : detail::ratio_min<R1, R2, ratio_less<R1,R2>::value>::type
- {
- };
- template <class R1, class R2>
- struct ratio_max : detail::ratio_max<R1, R2, ratio_less<R1,R2>::value>::type
- {
- };
- template<typename R, int p>
- struct ratio_power :
- ratio_multiply<
- typename ratio_power<R, p%2>::type,
- typename ratio_power<typename ratio_multiply<R, R>::type, p/2>::type
- >::type
- {};
- template<typename R>
- struct ratio_power<R, 0> : ratio<1>::type {};
- template<typename R>
- struct ratio_power<R, 1> : R {};
- template<typename R>
- struct ratio_power<R, -1> : ratio_divide<ratio<1>, R>::type {};
- #endif
- } // namespace boost
- #endif // BOOST_RATIO_RATIO_HPP
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