Home | History | Annotate | Line # | Download | only in std
      1 // ratio -*- C++ -*-
      2 
      3 // Copyright (C) 2008-2024 Free Software Foundation, Inc.
      4 //
      5 // This file is part of the GNU ISO C++ Library.  This library is free
      6 // software; you can redistribute it and/or modify it under the
      7 // terms of the GNU General Public License as published by the
      8 // Free Software Foundation; either version 3, or (at your option)
      9 // any later version.
     10 
     11 // This library is distributed in the hope that it will be useful,
     12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
     13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     14 // GNU General Public License for more details.
     15 
     16 // Under Section 7 of GPL version 3, you are granted additional
     17 // permissions described in the GCC Runtime Library Exception, version
     18 // 3.1, as published by the Free Software Foundation.
     19 
     20 // You should have received a copy of the GNU General Public License and
     21 // a copy of the GCC Runtime Library Exception along with this program;
     22 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
     23 // <http://www.gnu.org/licenses/>.
     24 
     25 /** @file include/ratio
     26  *  This is a Standard C++ Library header.
     27  *  @ingroup ratio
     28  */
     29 
     30 #ifndef _GLIBCXX_RATIO
     31 #define _GLIBCXX_RATIO 1
     32 
     33 #pragma GCC system_header
     34 
     35 #if __cplusplus < 201103L
     36 # include <bits/c++0x_warning.h>
     37 #else
     38 
     39 #include <type_traits>
     40 #include <cstdint>		// intmax_t, uintmax_t
     41 
     42 #define __glibcxx_want_ratio
     43 #include <bits/version.h>
     44 
     45 namespace std _GLIBCXX_VISIBILITY(default)
     46 {
     47 _GLIBCXX_BEGIN_NAMESPACE_VERSION
     48 
     49   /**
     50    * @defgroup ratio Rational Arithmetic
     51    * @ingroup utilities
     52    *
     53    * Compile time representation of finite rational numbers.
     54    * @{
     55    */
     56 
     57   /// @cond undocumented
     58 
     59   template<intmax_t _Pn>
     60     struct __static_sign
     61     : integral_constant<intmax_t, (_Pn < 0) ? -1 : 1>
     62     { };
     63 
     64   template<intmax_t _Pn>
     65     struct __static_abs
     66     : integral_constant<intmax_t, _Pn * __static_sign<_Pn>::value>
     67     { };
     68 
     69   template<intmax_t _Pn, intmax_t _Qn>
     70     struct __static_gcd
     71     : __static_gcd<_Qn, (_Pn % _Qn)>
     72     { };
     73 
     74   template<intmax_t _Pn>
     75     struct __static_gcd<_Pn, 0>
     76     : integral_constant<intmax_t, __static_abs<_Pn>::value>
     77     { };
     78 
     79   template<intmax_t _Qn>
     80     struct __static_gcd<0, _Qn>
     81     : integral_constant<intmax_t, __static_abs<_Qn>::value>
     82     { };
     83 
     84   // Let c = 2^(half # of bits in an intmax_t)
     85   // then we find a1, a0, b1, b0 s.t. N = a1*c + a0, M = b1*c + b0
     86   // The multiplication of N and M becomes,
     87   // N * M = (a1 * b1)c^2 + (a0 * b1 + b0 * a1)c + a0 * b0
     88   // Multiplication is safe if each term and the sum of the terms
     89   // is representable by intmax_t.
     90   template<intmax_t _Pn, intmax_t _Qn>
     91     struct __safe_multiply
     92     {
     93     private:
     94       static const uintmax_t __c = uintmax_t(1) << (sizeof(intmax_t) * 4);
     95 
     96       static const uintmax_t __a0 = __static_abs<_Pn>::value % __c;
     97       static const uintmax_t __a1 = __static_abs<_Pn>::value / __c;
     98       static const uintmax_t __b0 = __static_abs<_Qn>::value % __c;
     99       static const uintmax_t __b1 = __static_abs<_Qn>::value / __c;
    100 
    101       static_assert(__a1 == 0 || __b1 == 0,
    102 		    "overflow in multiplication");
    103       static_assert(__a0 * __b1 + __b0 * __a1 < (__c >> 1),
    104 		    "overflow in multiplication");
    105       static_assert(__b0 * __a0 <= __INTMAX_MAX__,
    106 		    "overflow in multiplication");
    107       static_assert((__a0 * __b1 + __b0 * __a1) * __c
    108 		    <= __INTMAX_MAX__ -  __b0 * __a0,
    109 		    "overflow in multiplication");
    110 
    111     public:
    112       static const intmax_t value = _Pn * _Qn;
    113     };
    114 
    115   // Some double-precision utilities, where numbers are represented as
    116   // __hi*2^(8*sizeof(uintmax_t)) + __lo.
    117   template<uintmax_t __hi1, uintmax_t __lo1, uintmax_t __hi2, uintmax_t __lo2>
    118     struct __big_less
    119     : integral_constant<bool, (__hi1 < __hi2
    120 			       || (__hi1 == __hi2 && __lo1 < __lo2))>
    121     { };
    122 
    123   template<uintmax_t __hi1, uintmax_t __lo1, uintmax_t __hi2, uintmax_t __lo2>
    124     struct __big_add
    125     {
    126       static constexpr uintmax_t __lo = __lo1 + __lo2;
    127       static constexpr uintmax_t __hi = (__hi1 + __hi2 +
    128 					 (__lo1 + __lo2 < __lo1)); // carry
    129     };
    130 
    131   // Subtract a number from a bigger one.
    132   template<uintmax_t __hi1, uintmax_t __lo1, uintmax_t __hi2, uintmax_t __lo2>
    133     struct __big_sub
    134     {
    135       static_assert(!__big_less<__hi1, __lo1, __hi2, __lo2>::value,
    136 		    "Internal library error");
    137       static constexpr uintmax_t __lo = __lo1 - __lo2;
    138       static constexpr uintmax_t __hi = (__hi1 - __hi2 -
    139 					 (__lo1 < __lo2)); // carry
    140     };
    141 
    142   // Same principle as __safe_multiply.
    143   template<uintmax_t __x, uintmax_t __y>
    144     struct __big_mul
    145     {
    146     private:
    147       static constexpr uintmax_t __c = uintmax_t(1) << (sizeof(intmax_t) * 4);
    148       static constexpr uintmax_t __x0 = __x % __c;
    149       static constexpr uintmax_t __x1 = __x / __c;
    150       static constexpr uintmax_t __y0 = __y % __c;
    151       static constexpr uintmax_t __y1 = __y / __c;
    152       static constexpr uintmax_t __x0y0 = __x0 * __y0;
    153       static constexpr uintmax_t __x0y1 = __x0 * __y1;
    154       static constexpr uintmax_t __x1y0 = __x1 * __y0;
    155       static constexpr uintmax_t __x1y1 = __x1 * __y1;
    156       static constexpr uintmax_t __mix = __x0y1 + __x1y0; // possible carry...
    157       static constexpr uintmax_t __mix_lo = __mix * __c;
    158       static constexpr uintmax_t __mix_hi
    159       = __mix / __c + ((__mix < __x0y1) ? __c : 0); // ... added here
    160       typedef __big_add<__mix_hi, __mix_lo, __x1y1, __x0y0> _Res;
    161     public:
    162       static constexpr uintmax_t __hi = _Res::__hi;
    163       static constexpr uintmax_t __lo = _Res::__lo;
    164     };
    165 
    166   // Adapted from __udiv_qrnnd_c in longlong.h
    167   // This version assumes that the high bit of __d is 1.
    168   template<uintmax_t __n1, uintmax_t __n0, uintmax_t __d>
    169     struct __big_div_impl
    170     {
    171     private:
    172       static_assert(__d >= (uintmax_t(1) << (sizeof(intmax_t) * 8 - 1)),
    173 		    "Internal library error");
    174       static_assert(__n1 < __d, "Internal library error");
    175       static constexpr uintmax_t __c = uintmax_t(1) << (sizeof(intmax_t) * 4);
    176       static constexpr uintmax_t __d1 = __d / __c;
    177       static constexpr uintmax_t __d0 = __d % __c;
    178 
    179       static constexpr uintmax_t __q1x = __n1 / __d1;
    180       static constexpr uintmax_t __r1x = __n1 % __d1;
    181       static constexpr uintmax_t __m = __q1x * __d0;
    182       static constexpr uintmax_t __r1y = __r1x * __c + __n0 / __c;
    183       static constexpr uintmax_t __r1z = __r1y + __d;
    184       static constexpr uintmax_t __r1
    185       = ((__r1y < __m) ? ((__r1z >= __d) && (__r1z < __m))
    186 	 ? (__r1z + __d) : __r1z : __r1y) - __m;
    187       static constexpr uintmax_t __q1
    188       = __q1x - ((__r1y < __m)
    189 		 ? ((__r1z >= __d) && (__r1z < __m)) ? 2 : 1 : 0);
    190       static constexpr uintmax_t __q0x = __r1 / __d1;
    191       static constexpr uintmax_t __r0x = __r1 % __d1;
    192       static constexpr uintmax_t __n = __q0x * __d0;
    193       static constexpr uintmax_t __r0y = __r0x * __c + __n0 % __c;
    194       static constexpr uintmax_t __r0z = __r0y + __d;
    195       static constexpr uintmax_t __r0
    196       = ((__r0y < __n) ? ((__r0z >= __d) && (__r0z < __n))
    197 	 ? (__r0z + __d) : __r0z : __r0y) - __n;
    198       static constexpr uintmax_t __q0
    199       = __q0x - ((__r0y < __n) ? ((__r0z >= __d)
    200 				  && (__r0z < __n)) ? 2 : 1 : 0);
    201 
    202     public:
    203       static constexpr uintmax_t __quot = __q1 * __c + __q0;
    204       static constexpr uintmax_t __rem = __r0;
    205 
    206     private:
    207       typedef __big_mul<__quot, __d> _Prod;
    208       typedef __big_add<_Prod::__hi, _Prod::__lo, 0, __rem> _Sum;
    209       static_assert(_Sum::__hi == __n1 && _Sum::__lo == __n0,
    210 		    "Internal library error");
    211   };
    212 
    213   template<uintmax_t __n1, uintmax_t __n0, uintmax_t __d>
    214     struct __big_div
    215     {
    216     private:
    217       static_assert(__d != 0, "Internal library error");
    218       static_assert(sizeof (uintmax_t) == sizeof (unsigned long long),
    219 		    "This library calls __builtin_clzll on uintmax_t, which "
    220 		    "is unsafe on your platform. Please complain to "
    221 		    "http://gcc.gnu.org/bugzilla/");
    222       static constexpr int __shift = __builtin_clzll(__d);
    223       static constexpr int __coshift_ = sizeof(uintmax_t) * 8 - __shift;
    224       static constexpr int __coshift = (__shift != 0) ? __coshift_ : 0;
    225       static constexpr uintmax_t __c1 = uintmax_t(1) << __shift;
    226       static constexpr uintmax_t __c2 = uintmax_t(1) << __coshift;
    227       static constexpr uintmax_t __new_d = __d * __c1;
    228       static constexpr uintmax_t __new_n0 = __n0 * __c1;
    229       static constexpr uintmax_t __n1_shifted = (__n1 % __d) * __c1;
    230       static constexpr uintmax_t __n0_top = (__shift != 0) ? (__n0 / __c2) : 0;
    231       static constexpr uintmax_t __new_n1 = __n1_shifted + __n0_top;
    232       typedef __big_div_impl<__new_n1, __new_n0, __new_d> _Res;
    233 
    234     public:
    235       static constexpr uintmax_t __quot_hi = __n1 / __d;
    236       static constexpr uintmax_t __quot_lo = _Res::__quot;
    237       static constexpr uintmax_t __rem = _Res::__rem / __c1;
    238 
    239     private:
    240       typedef __big_mul<__quot_lo, __d> _P0;
    241       typedef __big_mul<__quot_hi, __d> _P1;
    242       typedef __big_add<_P0::__hi, _P0::__lo, _P1::__lo, __rem> _Sum;
    243       // No overflow.
    244       static_assert(_P1::__hi == 0, "Internal library error");
    245       static_assert(_Sum::__hi >= _P0::__hi, "Internal library error");
    246       // Matches the input data.
    247       static_assert(_Sum::__hi == __n1 && _Sum::__lo == __n0,
    248 		    "Internal library error");
    249       static_assert(__rem < __d, "Internal library error");
    250     };
    251 
    252   /// @endcond
    253 
    254   /**
    255    *  @brief Provides compile-time rational arithmetic.
    256    *
    257    *  This class template represents any finite rational number with a
    258    *  numerator and denominator representable by compile-time constants of
    259    *  type intmax_t. The ratio is simplified when instantiated.
    260    *
    261    *  For example:
    262    *  @code
    263    *    std::ratio<7,-21>::num == -1;
    264    *    std::ratio<7,-21>::den == 3;
    265    *  @endcode
    266    *
    267   */
    268   template<intmax_t _Num, intmax_t _Den = 1>
    269     struct ratio
    270     {
    271       static_assert(_Den != 0, "denominator cannot be zero");
    272       static_assert(_Num >= -__INTMAX_MAX__ && _Den >= -__INTMAX_MAX__,
    273 		    "out of range");
    274 
    275       // Note: sign(N) * abs(N) == N
    276       static constexpr intmax_t num =
    277         _Num * __static_sign<_Den>::value / __static_gcd<_Num, _Den>::value;
    278 
    279       static constexpr intmax_t den =
    280         __static_abs<_Den>::value / __static_gcd<_Num, _Den>::value;
    281 
    282       typedef ratio<num, den> type;
    283     };
    284 
    285 #if ! __cpp_inline_variables
    286   template<intmax_t _Num, intmax_t _Den>
    287     constexpr intmax_t ratio<_Num, _Den>::num;
    288 
    289   template<intmax_t _Num, intmax_t _Den>
    290     constexpr intmax_t ratio<_Num, _Den>::den;
    291 #endif
    292 
    293   /// @cond undocumented
    294 
    295   template<typename _Tp>
    296     struct __is_ratio
    297     : std::false_type
    298     { };
    299 
    300   template<intmax_t _Num, intmax_t _Den>
    301     struct __is_ratio<ratio<_Num, _Den>>
    302     : std::true_type
    303     { };
    304 
    305 #if __cpp_variable_templates
    306   template<typename _Tp>
    307     constexpr bool __is_ratio_v = false;
    308   template<intmax_t _Num, intmax_t _Den>
    309     constexpr bool __is_ratio_v<ratio<_Num, _Den>> = true;
    310 #endif
    311 
    312   template<typename _R1, typename _R2>
    313     constexpr bool
    314     __are_both_ratios() noexcept
    315     {
    316 #if __cpp_variable_templates && __cpp_if_constexpr
    317       if constexpr (__is_ratio_v<_R1>)
    318 	if constexpr (__is_ratio_v<_R2>)
    319 	  return true;
    320       return false;
    321 #else
    322       return __and_<__is_ratio<_R1>, __is_ratio<_R2>>::value;
    323 #endif
    324     }
    325 
    326   template<typename _R1, typename _R2>
    327     struct __ratio_multiply
    328     {
    329       static_assert(std::__are_both_ratios<_R1, _R2>(),
    330 		    "both template arguments must be a std::ratio");
    331 
    332     private:
    333       static const intmax_t __gcd1 =
    334         __static_gcd<_R1::num, _R2::den>::value;
    335       static const intmax_t __gcd2 =
    336         __static_gcd<_R2::num, _R1::den>::value;
    337 
    338     public:
    339       typedef ratio<
    340         __safe_multiply<(_R1::num / __gcd1),
    341                         (_R2::num / __gcd2)>::value,
    342         __safe_multiply<(_R1::den / __gcd2),
    343                         (_R2::den / __gcd1)>::value> type;
    344 
    345       static constexpr intmax_t num = type::num;
    346       static constexpr intmax_t den = type::den;
    347     };
    348 
    349 #if ! __cpp_inline_variables
    350   template<typename _R1, typename _R2>
    351     constexpr intmax_t __ratio_multiply<_R1, _R2>::num;
    352 
    353   template<typename _R1, typename _R2>
    354     constexpr intmax_t __ratio_multiply<_R1, _R2>::den;
    355 #endif
    356 
    357   /// @endcond
    358 
    359   /// ratio_multiply
    360   template<typename _R1, typename _R2>
    361     using ratio_multiply = typename __ratio_multiply<_R1, _R2>::type;
    362 
    363   /// @cond undocumented
    364 
    365   template<typename _R1, typename _R2>
    366     struct __ratio_divide
    367     {
    368       static_assert(_R2::num != 0, "division by 0");
    369 
    370       typedef typename __ratio_multiply<
    371         _R1,
    372         ratio<_R2::den, _R2::num>>::type type;
    373 
    374       static constexpr intmax_t num = type::num;
    375       static constexpr intmax_t den = type::den;
    376     };
    377 
    378 #if ! __cpp_inline_variables
    379   template<typename _R1, typename _R2>
    380     constexpr intmax_t __ratio_divide<_R1, _R2>::num;
    381 
    382   template<typename _R1, typename _R2>
    383     constexpr intmax_t __ratio_divide<_R1, _R2>::den;
    384 #endif
    385 
    386   /// @endcond
    387 
    388   /// ratio_divide
    389   template<typename _R1, typename _R2>
    390     using ratio_divide = typename __ratio_divide<_R1, _R2>::type;
    391 
    392   /// ratio_equal
    393   template<typename _R1, typename _R2>
    394     struct ratio_equal
    395     : integral_constant<bool, _R1::num == _R2::num && _R1::den == _R2::den>
    396     {
    397       static_assert(std::__are_both_ratios<_R1, _R2>(),
    398 		    "both template arguments must be a std::ratio");
    399     };
    400 
    401   /// ratio_not_equal
    402   template<typename _R1, typename _R2>
    403     struct ratio_not_equal
    404     : integral_constant<bool, !ratio_equal<_R1, _R2>::value>
    405     { };
    406 
    407   /// @cond undocumented
    408 
    409   // Both numbers are positive.
    410   template<typename _R1, typename _R2,
    411            typename _Left = __big_mul<_R1::num,_R2::den>,
    412            typename _Right = __big_mul<_R2::num,_R1::den> >
    413     struct __ratio_less_impl_1
    414     : integral_constant<bool, __big_less<_Left::__hi, _Left::__lo,
    415            _Right::__hi, _Right::__lo>::value>
    416     { };
    417 
    418   template<typename _R1, typename _R2,
    419 	   bool = (_R1::num == 0 || _R2::num == 0
    420 		   || (__static_sign<_R1::num>::value
    421 		       != __static_sign<_R2::num>::value)),
    422 	   bool = (__static_sign<_R1::num>::value == -1
    423 		   && __static_sign<_R2::num>::value == -1)>
    424     struct __ratio_less_impl
    425     : __ratio_less_impl_1<_R1, _R2>::type
    426     { };
    427 
    428   template<typename _R1, typename _R2>
    429     struct __ratio_less_impl<_R1, _R2, true, false>
    430     : integral_constant<bool, _R1::num < _R2::num>
    431     { };
    432 
    433   template<typename _R1, typename _R2>
    434     struct __ratio_less_impl<_R1, _R2, false, true>
    435     : __ratio_less_impl_1<ratio<-_R2::num, _R2::den>,
    436            ratio<-_R1::num, _R1::den> >::type
    437     { };
    438 
    439   /// @endcond
    440 
    441   /// ratio_less
    442   template<typename _R1, typename _R2>
    443     struct ratio_less
    444     : __ratio_less_impl<_R1, _R2>::type
    445     {
    446       static_assert(std::__are_both_ratios<_R1, _R2>(),
    447 		    "both template arguments must be a std::ratio");
    448     };
    449 
    450   /// ratio_less_equal
    451   template<typename _R1, typename _R2>
    452     struct ratio_less_equal
    453     : integral_constant<bool, !ratio_less<_R2, _R1>::value>
    454     { };
    455 
    456   /// ratio_greater
    457   template<typename _R1, typename _R2>
    458     struct ratio_greater
    459     : integral_constant<bool, ratio_less<_R2, _R1>::value>
    460     { };
    461 
    462   /// ratio_greater_equal
    463   template<typename _R1, typename _R2>
    464     struct ratio_greater_equal
    465     : integral_constant<bool, !ratio_less<_R1, _R2>::value>
    466     { };
    467 
    468 #if __cplusplus > 201402L
    469   template <typename _R1, typename _R2>
    470     inline constexpr bool ratio_equal_v = ratio_equal<_R1, _R2>::value;
    471   template <typename _R1, typename _R2>
    472     inline constexpr bool ratio_not_equal_v = ratio_not_equal<_R1, _R2>::value;
    473   template <typename _R1, typename _R2>
    474     inline constexpr bool ratio_less_v = ratio_less<_R1, _R2>::value;
    475   template <typename _R1, typename _R2>
    476     inline constexpr bool ratio_less_equal_v
    477       = ratio_less_equal<_R1, _R2>::value;
    478   template <typename _R1, typename _R2>
    479     inline constexpr bool ratio_greater_v = ratio_greater<_R1, _R2>::value;
    480   template <typename _R1, typename _R2>
    481     inline constexpr bool ratio_greater_equal_v
    482       = ratio_greater_equal<_R1, _R2>::value;
    483 #endif // C++17
    484 
    485   /// @cond undocumented
    486 
    487   template<typename _R1, typename _R2,
    488       bool = (_R1::num >= 0),
    489       bool = (_R2::num >= 0),
    490       bool = ratio_less<ratio<__static_abs<_R1::num>::value, _R1::den>,
    491         ratio<__static_abs<_R2::num>::value, _R2::den> >::value>
    492     struct __ratio_add_impl
    493     {
    494     private:
    495       typedef typename __ratio_add_impl<
    496         ratio<-_R1::num, _R1::den>,
    497         ratio<-_R2::num, _R2::den> >::type __t;
    498     public:
    499       typedef ratio<-__t::num, __t::den> type;
    500     };
    501 
    502   // True addition of nonnegative numbers.
    503   template<typename _R1, typename _R2, bool __b>
    504     struct __ratio_add_impl<_R1, _R2, true, true, __b>
    505     {
    506     private:
    507       static constexpr uintmax_t __g = __static_gcd<_R1::den, _R2::den>::value;
    508       static constexpr uintmax_t __d2 = _R2::den / __g;
    509       typedef __big_mul<_R1::den, __d2> __d;
    510       typedef __big_mul<_R1::num, _R2::den / __g> __x;
    511       typedef __big_mul<_R2::num, _R1::den / __g> __y;
    512       typedef __big_add<__x::__hi, __x::__lo, __y::__hi, __y::__lo> __n;
    513       static_assert(__n::__hi >= __x::__hi, "Internal library error");
    514       typedef __big_div<__n::__hi, __n::__lo, __g> __ng;
    515       static constexpr uintmax_t __g2 = __static_gcd<__ng::__rem, __g>::value;
    516       typedef __big_div<__n::__hi, __n::__lo, __g2> __n_final;
    517       static_assert(__n_final::__rem == 0, "Internal library error");
    518       static_assert(__n_final::__quot_hi == 0 &&
    519         __n_final::__quot_lo <= __INTMAX_MAX__, "overflow in addition");
    520       typedef __big_mul<_R1::den / __g2, __d2> __d_final;
    521       static_assert(__d_final::__hi == 0 &&
    522         __d_final::__lo <= __INTMAX_MAX__, "overflow in addition");
    523     public:
    524       typedef ratio<__n_final::__quot_lo, __d_final::__lo> type;
    525     };
    526 
    527   template<typename _R1, typename _R2>
    528     struct __ratio_add_impl<_R1, _R2, false, true, true>
    529     : __ratio_add_impl<_R2, _R1>
    530     { };
    531 
    532   // True subtraction of nonnegative numbers yielding a nonnegative result.
    533   template<typename _R1, typename _R2>
    534     struct __ratio_add_impl<_R1, _R2, true, false, false>
    535     {
    536     private:
    537       static constexpr uintmax_t __g = __static_gcd<_R1::den, _R2::den>::value;
    538       static constexpr uintmax_t __d2 = _R2::den / __g;
    539       typedef __big_mul<_R1::den, __d2> __d;
    540       typedef __big_mul<_R1::num, _R2::den / __g> __x;
    541       typedef __big_mul<-_R2::num, _R1::den / __g> __y;
    542       typedef __big_sub<__x::__hi, __x::__lo, __y::__hi, __y::__lo> __n;
    543       typedef __big_div<__n::__hi, __n::__lo, __g> __ng;
    544       static constexpr uintmax_t __g2 = __static_gcd<__ng::__rem, __g>::value;
    545       typedef __big_div<__n::__hi, __n::__lo, __g2> __n_final;
    546       static_assert(__n_final::__rem == 0, "Internal library error");
    547       static_assert(__n_final::__quot_hi == 0 &&
    548         __n_final::__quot_lo <= __INTMAX_MAX__, "overflow in addition");
    549       typedef __big_mul<_R1::den / __g2, __d2> __d_final;
    550       static_assert(__d_final::__hi == 0 &&
    551         __d_final::__lo <= __INTMAX_MAX__, "overflow in addition");
    552     public:
    553       typedef ratio<__n_final::__quot_lo, __d_final::__lo> type;
    554     };
    555 
    556   template<typename _R1, typename _R2>
    557     struct __ratio_add
    558     {
    559       static_assert(std::__are_both_ratios<_R1, _R2>(),
    560 		    "both template arguments must be a std::ratio");
    561 
    562       typedef typename __ratio_add_impl<_R1, _R2>::type type;
    563       static constexpr intmax_t num = type::num;
    564       static constexpr intmax_t den = type::den;
    565     };
    566 
    567 #if ! __cpp_inline_variables
    568   template<typename _R1, typename _R2>
    569     constexpr intmax_t __ratio_add<_R1, _R2>::num;
    570 
    571   template<typename _R1, typename _R2>
    572     constexpr intmax_t __ratio_add<_R1, _R2>::den;
    573 #endif
    574 
    575   /// @endcond
    576 
    577   /// ratio_add
    578   template<typename _R1, typename _R2>
    579     using ratio_add = typename __ratio_add<_R1, _R2>::type;
    580 
    581   /// @cond undocumented
    582 
    583   template<typename _R1, typename _R2>
    584     struct __ratio_subtract
    585     {
    586       typedef typename __ratio_add<
    587         _R1,
    588         ratio<-_R2::num, _R2::den>>::type type;
    589 
    590       static constexpr intmax_t num = type::num;
    591       static constexpr intmax_t den = type::den;
    592     };
    593 
    594 #if ! __cpp_inline_variables
    595   template<typename _R1, typename _R2>
    596     constexpr intmax_t __ratio_subtract<_R1, _R2>::num;
    597 
    598   template<typename _R1, typename _R2>
    599     constexpr intmax_t __ratio_subtract<_R1, _R2>::den;
    600 #endif
    601 
    602   /// @endcond
    603 
    604   /// ratio_subtract
    605   template<typename _R1, typename _R2>
    606     using ratio_subtract = typename __ratio_subtract<_R1, _R2>::type;
    607 
    608 #if __INTMAX_WIDTH__ >= 96
    609 # if __cpp_lib_ratio >= 202306L
    610 #  if __INTMAX_WIDTH__ >= 128
    611   using quecto = ratio<                  1, 1000000000000000000000000000000>;
    612 #  endif
    613   using ronto  = ratio<                     1, 1000000000000000000000000000>;
    614 # endif
    615   using yocto  = ratio<                        1, 1000000000000000000000000>;
    616   using zepto  = ratio<                        1,    1000000000000000000000>;
    617 #endif
    618   using atto   = ratio<                        1,       1000000000000000000>;
    619   using femto  = ratio<                        1,          1000000000000000>;
    620   using pico   = ratio<                        1,             1000000000000>;
    621   using nano   = ratio<                        1,                1000000000>;
    622   using micro  = ratio<                        1,                   1000000>;
    623   using milli  = ratio<                        1,                      1000>;
    624   using centi  = ratio<                        1,                       100>;
    625   using deci   = ratio<                        1,                        10>;
    626   using deca   = ratio<                       10,                         1>;
    627   using hecto  = ratio<                      100,                         1>;
    628   using kilo   = ratio<                     1000,                         1>;
    629   using mega   = ratio<                  1000000,                         1>;
    630   using giga   = ratio<               1000000000,                         1>;
    631   using tera   = ratio<            1000000000000,                         1>;
    632   using peta   = ratio<         1000000000000000,                         1>;
    633   using exa    = ratio<      1000000000000000000,                         1>;
    634 #if __INTMAX_WIDTH__ >= 96
    635   using zetta  = ratio<   1000000000000000000000,                         1>;
    636   using yotta  = ratio<1000000000000000000000000,                         1>;
    637 # if __cpp_lib_ratio >= 202306L
    638   using ronna  = ratio<1000000000000000000000000000,                      1>;
    639 #  if __INTMAX_WIDTH__ >= 128
    640   using quetta = ratio<1000000000000000000000000000000,                   1>;
    641 #  endif
    642 # endif
    643 #endif
    644 
    645   /// @} group ratio
    646 _GLIBCXX_END_NAMESPACE_VERSION
    647 } // namespace
    648 
    649 #endif // C++11
    650 
    651 #endif //_GLIBCXX_RATIO
    652