include/ratio

// -*- C++ -*-
//===---------------------------- ratio -----------------------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

#ifndef _LIBCPP_RATIO
#define _LIBCPP_RATIO

/*
    ratio synopsis

namespace std
{

template <intmax_t N, intmax_t D = 1>
class ratio
{
public:
    static const intmax_t num;
    static const intmax_t den;
};

// ratio arithmetic
template <class R1, class R2> struct ratio_add;
template <class R1, class R2> struct ratio_subtract;
template <class R1, class R2> struct ratio_multiply;
template <class R1, class R2> struct ratio_divide;

// ratio comparison
template <class R1, class R2> struct ratio_equal;
template <class R1, class R2> struct ratio_not_equal;
template <class R1, class R2> struct ratio_less;
template <class R1, class R2> struct ratio_less_equal;
template <class R1, class R2> struct ratio_greater;
template <class R1, class R2> struct ratio_greater_equal;

// convenience SI typedefs
typedef ratio<1, 1000000000000000000000000> yocto;  // not supported
typedef ratio<1,    1000000000000000000000> zepto;  // not supported
typedef ratio<1,       1000000000000000000> atto;
typedef ratio<1,          1000000000000000> femto;
typedef ratio<1,             1000000000000> pico;
typedef ratio<1,                1000000000> nano;
typedef ratio<1,                   1000000> micro;
typedef ratio<1,                      1000> milli;
typedef ratio<1,                       100> centi;
typedef ratio<1,                        10> deci;
typedef ratio<                       10, 1> deca;
typedef ratio<                      100, 1> hecto;
typedef ratio<                     1000, 1> kilo;
typedef ratio<                  1000000, 1> mega;
typedef ratio<               1000000000, 1> giga;
typedef ratio<            1000000000000, 1> tera;
typedef ratio<         1000000000000000, 1> peta;
typedef ratio<      1000000000000000000, 1> exa;
typedef ratio<   1000000000000000000000, 1> zetta;  // not supported
typedef ratio<1000000000000000000000000, 1> yotta;  // not supported

}
*/

#include <__config>
#include <cstdint>
#include <climits>
#include <type_traits>

#pragma GCC system_header

_LIBCPP_BEGIN_NAMESPACE_STD

// __static_gcd

template <intmax_t _Xp, intmax_t _Yp>
struct __static_gcd
{
    static const intmax_t value = __static_gcd<_Yp, _Xp % _Yp>::value;
};

template <intmax_t _Xp>
struct __static_gcd<_Xp, 0>
{
    static const intmax_t value = _Xp;
};

// __static_lcm

template <intmax_t _Xp, intmax_t _Yp>
struct __static_lcm
{
    static const intmax_t value = _Xp / __static_gcd<_Xp, _Yp>::value * _Yp;
};

template <intmax_t _Xp>
struct __static_abs
{
    static const intmax_t value = _Xp < 0 ? -_Xp : _Xp;
};

template <intmax_t _Xp>
struct __static_sign
{
    static const intmax_t value = _Xp == 0 ? 0 : (_Xp < 0 ? -1 : 1);
};

template <intmax_t _Xp, intmax_t _Yp, intmax_t = __static_sign<_Yp>::value>
class __ll_add;

template <intmax_t _Xp, intmax_t _Yp>
class __ll_add<_Xp, _Yp, 1>
{
    static const intmax_t min = (1LL << (sizeof(intmax_t) * CHAR_BIT - 1)) + 1;
    static const intmax_t max = -min;

    static_assert(_Xp <= max - _Yp, "overflow in __ll_add");
public:
    static const intmax_t value = _Xp + _Yp;
};

template <intmax_t _Xp, intmax_t _Yp>
class __ll_add<_Xp, _Yp, 0>
{
public:
    static const intmax_t value = _Xp;
};

template <intmax_t _Xp, intmax_t _Yp>
class __ll_add<_Xp, _Yp, -1>
{
    static const intmax_t min = (1LL << (sizeof(intmax_t) * CHAR_BIT - 1)) + 1;
    static const intmax_t max = -min;

    static_assert(min - _Yp <= _Xp, "overflow in __ll_add");
public:
    static const intmax_t value = _Xp + _Yp;
};

template <intmax_t _Xp, intmax_t _Yp, intmax_t = __static_sign<_Yp>::value>
class __ll_sub;

template <intmax_t _Xp, intmax_t _Yp>
class __ll_sub<_Xp, _Yp, 1>
{
    static const intmax_t min = (1LL << (sizeof(intmax_t) * CHAR_BIT - 1)) + 1;
    static const intmax_t max = -min;

    static_assert(min + _Yp <= _Xp, "overflow in __ll_sub");
public:
    static const intmax_t value = _Xp - _Yp;
};

template <intmax_t _Xp, intmax_t _Yp>
class __ll_sub<_Xp, _Yp, 0>
{
public:
    static const intmax_t value = _Xp;
};

template <intmax_t _Xp, intmax_t _Yp>
class __ll_sub<_Xp, _Yp, -1>
{
    static const intmax_t min = (1LL << (sizeof(intmax_t) * CHAR_BIT - 1)) + 1;
    static const intmax_t max = -min;

    static_assert(_Xp <= max + _Yp, "overflow in __ll_sub");
public:
    static const intmax_t value = _Xp - _Yp;
};

template <intmax_t _Xp, intmax_t _Yp>
class __ll_mul
{
    static const intmax_t nan = (1LL << (sizeof(intmax_t) * CHAR_BIT - 1));
    static const intmax_t min = nan + 1;
    static const intmax_t max = -min;
    static const intmax_t __a_x = __static_abs<_Xp>::value;
    static const intmax_t __a_y = __static_abs<_Yp>::value;

    static_assert(_Xp != nan && _Yp != nan && __a_x <= max / __a_y, "overflow in __ll_mul");
public:
    static const intmax_t value = _Xp * _Yp;
};

template <intmax_t _Yp>
class __ll_mul<0, _Yp>
{
public:
    static const intmax_t value = 0;
};

template <intmax_t _Xp>
class __ll_mul<_Xp, 0>
{
public:
    static const intmax_t value = 0;
};

template <>
class __ll_mul<0, 0>
{
public:
    static const intmax_t value = 0;
};

// Not actually used but left here in case needed in future maintenance
template <intmax_t _Xp, intmax_t _Yp>
class __ll_div
{
    static const intmax_t nan = (1LL << (sizeof(intmax_t) * CHAR_BIT - 1));
    static const intmax_t min = nan + 1;
    static const intmax_t max = -min;

    static_assert(_Xp != nan && _Yp != nan && _Yp != 0, "overflow in __ll_div");
public:
    static const intmax_t value = _Xp / _Yp;
};

template <intmax_t _Num, intmax_t _Den = 1>
class ratio
{
    static_assert(__static_abs<_Num>::value >= 0, "ratio numerator is out of range");
    static_assert(_Den != 0, "ratio divide by 0");
    static_assert(__static_abs<_Den>::value >  0, "ratio denominator is out of range");
    static const intmax_t __na = __static_abs<_Num>::value;
    static const intmax_t __da = __static_abs<_Den>::value;
    static const intmax_t __s = __static_sign<_Num>::value * __static_sign<_Den>::value;
    static const intmax_t __gcd = __static_gcd<__na, __da>::value;
public:
    static const intmax_t num = __s * __na / __gcd;
    static const intmax_t den = __da / __gcd;

    typedef ratio<num, den> type;
};

template <intmax_t _Num, intmax_t _Den> const intmax_t ratio<_Num, _Den>::num;
template <intmax_t _Num, intmax_t _Den> const intmax_t ratio<_Num, _Den>::den;

template <class _Tp>                    struct __is_ratio                     : false_type {};
template <intmax_t _Num, intmax_t _Den> struct __is_ratio<ratio<_Num, _Den> > : true_type  {};

typedef ratio<1LL, 1000000000000000000LL> atto;
typedef ratio<1LL,    1000000000000000LL> femto;
typedef ratio<1LL,       1000000000000LL> pico;
typedef ratio<1LL,          1000000000LL> nano;
typedef ratio<1LL,             1000000LL> micro;
typedef ratio<1LL,                1000LL> milli;
typedef ratio<1LL,                 100LL> centi;
typedef ratio<1LL,                  10LL> deci;
typedef ratio<                 10LL, 1LL> deca;
typedef ratio<                100LL, 1LL> hecto;
typedef ratio<               1000LL, 1LL> kilo;
typedef ratio<            1000000LL, 1LL> mega;
typedef ratio<         1000000000LL, 1LL> giga;
typedef ratio<      1000000000000LL, 1LL> tera;
typedef ratio<   1000000000000000LL, 1LL> peta;
typedef ratio<1000000000000000000LL, 1LL> exa;

template <class _R1, class _R2>
struct ratio_multiply
{
private:
    static const intmax_t __gcd_n1_d2 = __static_gcd<_R1::num, _R2::den>::value;
    static const intmax_t __gcd_d1_n2 = __static_gcd<_R1::den, _R2::num>::value;
public:
    typedef typename ratio
        <
            __ll_mul<_R1::num / __gcd_n1_d2, _R2::num / __gcd_d1_n2>::value,
            __ll_mul<_R2::den / __gcd_n1_d2, _R1::den / __gcd_d1_n2>::value
        >::type type;
};

template <class _R1, class _R2>
struct ratio_divide
{
private:
    static const intmax_t __gcd_n1_n2 = __static_gcd<_R1::num, _R2::num>::value;
    static const intmax_t __gcd_d1_d2 = __static_gcd<_R1::den, _R2::den>::value;
public:
    typedef typename ratio
        <
            __ll_mul<_R1::num / __gcd_n1_n2, _R2::den / __gcd_d1_d2>::value,
            __ll_mul<_R2::num / __gcd_n1_n2, _R1::den / __gcd_d1_d2>::value
        >::type type;
};

template <class _R1, class _R2>
struct ratio_add
{
private:
    static const intmax_t __gcd_n1_n2 = __static_gcd<_R1::num, _R2::num>::value;
    static const intmax_t __gcd_d1_d2 = __static_gcd<_R1::den, _R2::den>::value;
public:
    typedef typename ratio_multiply
        <
            ratio<__gcd_n1_n2, _R1::den / __gcd_d1_d2>,
            ratio
            <
                __ll_add
                <
                    __ll_mul<_R1::num / __gcd_n1_n2, _R2::den / __gcd_d1_d2>::value,
                    __ll_mul<_R2::num / __gcd_n1_n2, _R1::den / __gcd_d1_d2>::value
                >::value,
                _R2::den
            >
        >::type type;
};

template <class _R1, class _R2>
struct ratio_subtract
{
private:
    static const intmax_t __gcd_n1_n2 = __static_gcd<_R1::num, _R2::num>::value;
    static const intmax_t __gcd_d1_d2 = __static_gcd<_R1::den, _R2::den>::value;
public:
    typedef typename ratio_multiply
        <
            ratio<__gcd_n1_n2, _R1::den / __gcd_d1_d2>,
            ratio
            <
                __ll_sub
                <
                    __ll_mul<_R1::num / __gcd_n1_n2, _R2::den / __gcd_d1_d2>::value,
                    __ll_mul<_R2::num / __gcd_n1_n2, _R1::den / __gcd_d1_d2>::value
                >::value,
                _R2::den
            >
        >::type type;
};

// ratio_equal

template <class _R1, class _R2>
struct ratio_equal
    : public integral_constant<bool, _R1::num == _R2::num && _R1::den == _R2::den> {}; 

template <class _R1, class _R2>
struct ratio_not_equal
    : public integral_constant<bool, !ratio_equal<_R1, _R2>::value> {}; 

// ratio_less

template <class _R1, class _R2, bool _Odd = false,
          intmax_t _Q1 = _R1::num / _R1::den, intmax_t _M1 = _R1::num % _R1::den,
          intmax_t _Q2 = _R2::num / _R2::den, intmax_t _M2 = _R2::num % _R2::den>
struct __ratio_less1
{
    static const bool value = _Odd ? _Q2 < _Q1 : _Q1 < _Q2;
};

template <class _R1, class _R2, bool _Odd, intmax_t _Q>
struct __ratio_less1<_R1, _R2, _Odd, _Q, 0, _Q, 0>
{
    static const bool value = false;
};

template <class _R1, class _R2, bool _Odd, intmax_t _Q, intmax_t _M2>
struct __ratio_less1<_R1, _R2, _Odd, _Q, 0, _Q, _M2>
{
    static const bool value = !_Odd;
};

template <class _R1, class _R2, bool _Odd, intmax_t _Q, intmax_t _M1>
struct __ratio_less1<_R1, _R2, _Odd, _Q, _M1, _Q, 0>
{
    static const bool value = _Odd;
};

template <class _R1, class _R2, bool _Odd, intmax_t _Q, intmax_t _M1,
                                                        intmax_t _M2>
struct __ratio_less1<_R1, _R2, _Odd, _Q, _M1, _Q, _M2>
{
    static const bool value = __ratio_less1<ratio<_R1::den, _M1>,
                                            ratio<_R2::den, _M2>, !_Odd>::value;
};

template <class _R1, class _R2, intmax_t _S1 = __static_sign<_R1::num>::value,
                                intmax_t _S2 = __static_sign<_R2::num>::value>
struct __ratio_less
{
    static const bool value = _S1 < _S2;
};

template <class _R1, class _R2>
struct __ratio_less<_R1, _R2, 1LL, 1LL>
{
    static const bool value = __ratio_less1<_R1, _R2>::value;
};

template <class _R1, class _R2>
struct __ratio_less<_R1, _R2, -1LL, -1LL>
{
    static const bool value = __ratio_less1<ratio<-_R2::num, _R2::den>, ratio<-_R1::num, _R1::den> >::value;
};

template <class _R1, class _R2>
struct ratio_less
    : public integral_constant<bool, __ratio_less<_R1, _R2>::value> {};

template <class _R1, class _R2>
struct ratio_less_equal
    : public integral_constant<bool, !ratio_less<_R2, _R1>::value> {};

template <class _R1, class _R2>
struct ratio_greater
    : public integral_constant<bool, ratio_less<_R2, _R1>::value> {};

template <class _R1, class _R2>
struct ratio_greater_equal
    : public integral_constant<bool, !ratio_less<_R1, _R2>::value> {};

template <class _R1, class _R2>
struct __ratio_gcd
{
    typedef ratio<__static_gcd<_R1::num, _R2::num>::value,
                  __static_lcm<_R1::den, _R2::den>::value> type;
};

_LIBCPP_END_NAMESPACE_STD

#endif  // _LIBCPP_RATIO