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      1 // -*- C++ -*-
      2 //===---------------------------- ratio -----------------------------------===//
      3 //
      4 //                     The LLVM Compiler Infrastructure
      5 //
      6 // This file is dual licensed under the MIT and the University of Illinois Open
      7 // Source Licenses. See LICENSE.TXT for details.
      8 //
      9 //===----------------------------------------------------------------------===//
     10 
     11 #ifndef _LIBCPP_RATIO
     12 #define _LIBCPP_RATIO
     13 
     14 /*
     15     ratio synopsis
     16 
     17 namespace std
     18 {
     19 
     20 template <intmax_t N, intmax_t D = 1>
     21 class ratio
     22 {
     23 public:
     24     static constexpr intmax_t num;
     25     static constexpr intmax_t den;
     26     typedef ratio<num, den> type;
     27 };
     28 
     29 // ratio arithmetic
     30 template <class R1, class R2> using ratio_add = ...;
     31 template <class R1, class R2> using ratio_subtract = ...;
     32 template <class R1, class R2> using ratio_multiply = ...;
     33 template <class R1, class R2> using ratio_divide = ...;
     34 
     35 // ratio comparison
     36 template <class R1, class R2> struct ratio_equal;
     37 template <class R1, class R2> struct ratio_not_equal;
     38 template <class R1, class R2> struct ratio_less;
     39 template <class R1, class R2> struct ratio_less_equal;
     40 template <class R1, class R2> struct ratio_greater;
     41 template <class R1, class R2> struct ratio_greater_equal;
     42 
     43 // convenience SI typedefs
     44 typedef ratio<1, 1000000000000000000000000> yocto;  // not supported
     45 typedef ratio<1,    1000000000000000000000> zepto;  // not supported
     46 typedef ratio<1,       1000000000000000000> atto;
     47 typedef ratio<1,          1000000000000000> femto;
     48 typedef ratio<1,             1000000000000> pico;
     49 typedef ratio<1,                1000000000> nano;
     50 typedef ratio<1,                   1000000> micro;
     51 typedef ratio<1,                      1000> milli;
     52 typedef ratio<1,                       100> centi;
     53 typedef ratio<1,                        10> deci;
     54 typedef ratio<                       10, 1> deca;
     55 typedef ratio<                      100, 1> hecto;
     56 typedef ratio<                     1000, 1> kilo;
     57 typedef ratio<                  1000000, 1> mega;
     58 typedef ratio<               1000000000, 1> giga;
     59 typedef ratio<            1000000000000, 1> tera;
     60 typedef ratio<         1000000000000000, 1> peta;
     61 typedef ratio<      1000000000000000000, 1> exa;
     62 typedef ratio<   1000000000000000000000, 1> zetta;  // not supported
     63 typedef ratio<1000000000000000000000000, 1> yotta;  // not supported
     64 
     65   // 20.11.5, ratio comparison
     66   template <class R1, class R2> constexpr bool ratio_equal_v
     67     = ratio_equal<R1, R2>::value;                                       // C++17
     68   template <class R1, class R2> constexpr bool ratio_not_equal_v
     69     = ratio_not_equal<R1, R2>::value;                                   // C++17
     70   template <class R1, class R2> constexpr bool ratio_less_v
     71     = ratio_less<R1, R2>::value;                                        // C++17
     72   template <class R1, class R2> constexpr bool ratio_less_equal_v
     73     = ratio_less_equal<R1, R2>::value;                                  // C++17
     74   template <class R1, class R2> constexpr bool ratio_greater_v
     75     = ratio_greater<R1, R2>::value;                                     // C++17
     76   template <class R1, class R2> constexpr bool ratio_greater_equal_v
     77     = ratio_greater_equal<R1, R2>::value;                               // C++17
     78 }
     79 */
     80 
     81 #include <__config>
     82 #include <cstdint>
     83 #include <climits>
     84 #include <type_traits>
     85 
     86 #include <__undef_min_max>
     87 
     88 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
     89 #pragma GCC system_header
     90 #endif
     91 
     92 _LIBCPP_BEGIN_NAMESPACE_STD
     93 
     94 // __static_gcd
     95 
     96 template <intmax_t _Xp, intmax_t _Yp>
     97 struct __static_gcd
     98 {
     99     static const intmax_t value = __static_gcd<_Yp, _Xp % _Yp>::value;
    100 };
    101 
    102 template <intmax_t _Xp>
    103 struct __static_gcd<_Xp, 0>
    104 {
    105     static const intmax_t value = _Xp;
    106 };
    107 
    108 template <>
    109 struct __static_gcd<0, 0>
    110 {
    111     static const intmax_t value = 1;
    112 };
    113 
    114 // __static_lcm
    115 
    116 template <intmax_t _Xp, intmax_t _Yp>
    117 struct __static_lcm
    118 {
    119     static const intmax_t value = _Xp / __static_gcd<_Xp, _Yp>::value * _Yp;
    120 };
    121 
    122 template <intmax_t _Xp>
    123 struct __static_abs
    124 {
    125     static const intmax_t value = _Xp < 0 ? -_Xp : _Xp;
    126 };
    127 
    128 template <intmax_t _Xp>
    129 struct __static_sign
    130 {
    131     static const intmax_t value = _Xp == 0 ? 0 : (_Xp < 0 ? -1 : 1);
    132 };
    133 
    134 template <intmax_t _Xp, intmax_t _Yp, intmax_t = __static_sign<_Yp>::value>
    135 class __ll_add;
    136 
    137 template <intmax_t _Xp, intmax_t _Yp>
    138 class __ll_add<_Xp, _Yp, 1>
    139 {
    140     static const intmax_t min = (1LL << (sizeof(intmax_t) * CHAR_BIT - 1)) + 1;
    141     static const intmax_t max = -min;
    142 
    143     static_assert(_Xp <= max - _Yp, "overflow in __ll_add");
    144 public:
    145     static const intmax_t value = _Xp + _Yp;
    146 };
    147 
    148 template <intmax_t _Xp, intmax_t _Yp>
    149 class __ll_add<_Xp, _Yp, 0>
    150 {
    151 public:
    152     static const intmax_t value = _Xp;
    153 };
    154 
    155 template <intmax_t _Xp, intmax_t _Yp>
    156 class __ll_add<_Xp, _Yp, -1>
    157 {
    158     static const intmax_t min = (1LL << (sizeof(intmax_t) * CHAR_BIT - 1)) + 1;
    159     static const intmax_t max = -min;
    160 
    161     static_assert(min - _Yp <= _Xp, "overflow in __ll_add");
    162 public:
    163     static const intmax_t value = _Xp + _Yp;
    164 };
    165 
    166 template <intmax_t _Xp, intmax_t _Yp, intmax_t = __static_sign<_Yp>::value>
    167 class __ll_sub;
    168 
    169 template <intmax_t _Xp, intmax_t _Yp>
    170 class __ll_sub<_Xp, _Yp, 1>
    171 {
    172     static const intmax_t min = (1LL << (sizeof(intmax_t) * CHAR_BIT - 1)) + 1;
    173     static const intmax_t max = -min;
    174 
    175     static_assert(min + _Yp <= _Xp, "overflow in __ll_sub");
    176 public:
    177     static const intmax_t value = _Xp - _Yp;
    178 };
    179 
    180 template <intmax_t _Xp, intmax_t _Yp>
    181 class __ll_sub<_Xp, _Yp, 0>
    182 {
    183 public:
    184     static const intmax_t value = _Xp;
    185 };
    186 
    187 template <intmax_t _Xp, intmax_t _Yp>
    188 class __ll_sub<_Xp, _Yp, -1>
    189 {
    190     static const intmax_t min = (1LL << (sizeof(intmax_t) * CHAR_BIT - 1)) + 1;
    191     static const intmax_t max = -min;
    192 
    193     static_assert(_Xp <= max + _Yp, "overflow in __ll_sub");
    194 public:
    195     static const intmax_t value = _Xp - _Yp;
    196 };
    197 
    198 template <intmax_t _Xp, intmax_t _Yp>
    199 class __ll_mul
    200 {
    201     static const intmax_t nan = (1LL << (sizeof(intmax_t) * CHAR_BIT - 1));
    202     static const intmax_t min = nan + 1;
    203     static const intmax_t max = -min;
    204     static const intmax_t __a_x = __static_abs<_Xp>::value;
    205     static const intmax_t __a_y = __static_abs<_Yp>::value;
    206 
    207     static_assert(_Xp != nan && _Yp != nan && __a_x <= max / __a_y, "overflow in __ll_mul");
    208 public:
    209     static const intmax_t value = _Xp * _Yp;
    210 };
    211 
    212 template <intmax_t _Yp>
    213 class __ll_mul<0, _Yp>
    214 {
    215 public:
    216     static const intmax_t value = 0;
    217 };
    218 
    219 template <intmax_t _Xp>
    220 class __ll_mul<_Xp, 0>
    221 {
    222 public:
    223     static const intmax_t value = 0;
    224 };
    225 
    226 template <>
    227 class __ll_mul<0, 0>
    228 {
    229 public:
    230     static const intmax_t value = 0;
    231 };
    232 
    233 // Not actually used but left here in case needed in future maintenance
    234 template <intmax_t _Xp, intmax_t _Yp>
    235 class __ll_div
    236 {
    237     static const intmax_t nan = (1LL << (sizeof(intmax_t) * CHAR_BIT - 1));
    238     static const intmax_t min = nan + 1;
    239     static const intmax_t max = -min;
    240 
    241     static_assert(_Xp != nan && _Yp != nan && _Yp != 0, "overflow in __ll_div");
    242 public:
    243     static const intmax_t value = _Xp / _Yp;
    244 };
    245 
    246 template <intmax_t _Num, intmax_t _Den = 1>
    247 class _LIBCPP_TEMPLATE_VIS ratio
    248 {
    249     static_assert(__static_abs<_Num>::value >= 0, "ratio numerator is out of range");
    250     static_assert(_Den != 0, "ratio divide by 0");
    251     static_assert(__static_abs<_Den>::value >  0, "ratio denominator is out of range");
    252     static _LIBCPP_CONSTEXPR const intmax_t __na = __static_abs<_Num>::value;
    253     static _LIBCPP_CONSTEXPR const intmax_t __da = __static_abs<_Den>::value;
    254     static _LIBCPP_CONSTEXPR const intmax_t __s = __static_sign<_Num>::value * __static_sign<_Den>::value;
    255     static _LIBCPP_CONSTEXPR const intmax_t __gcd = __static_gcd<__na, __da>::value;
    256 public:
    257     static _LIBCPP_CONSTEXPR const intmax_t num = __s * __na / __gcd;
    258     static _LIBCPP_CONSTEXPR const intmax_t den = __da / __gcd;
    259 
    260     typedef ratio<num, den> type;
    261 };
    262 
    263 template <intmax_t _Num, intmax_t _Den>
    264 _LIBCPP_CONSTEXPR const intmax_t ratio<_Num, _Den>::num;
    265 
    266 template <intmax_t _Num, intmax_t _Den>
    267 _LIBCPP_CONSTEXPR const intmax_t ratio<_Num, _Den>::den;
    268 
    269 template <class _Tp>                    struct __is_ratio                     : false_type {};
    270 template <intmax_t _Num, intmax_t _Den> struct __is_ratio<ratio<_Num, _Den> > : true_type  {};
    271 
    272 typedef ratio<1LL, 1000000000000000000LL> atto;
    273 typedef ratio<1LL,    1000000000000000LL> femto;
    274 typedef ratio<1LL,       1000000000000LL> pico;
    275 typedef ratio<1LL,          1000000000LL> nano;
    276 typedef ratio<1LL,             1000000LL> micro;
    277 typedef ratio<1LL,                1000LL> milli;
    278 typedef ratio<1LL,                 100LL> centi;
    279 typedef ratio<1LL,                  10LL> deci;
    280 typedef ratio<                 10LL, 1LL> deca;
    281 typedef ratio<                100LL, 1LL> hecto;
    282 typedef ratio<               1000LL, 1LL> kilo;
    283 typedef ratio<            1000000LL, 1LL> mega;
    284 typedef ratio<         1000000000LL, 1LL> giga;
    285 typedef ratio<      1000000000000LL, 1LL> tera;
    286 typedef ratio<   1000000000000000LL, 1LL> peta;
    287 typedef ratio<1000000000000000000LL, 1LL> exa;
    288 
    289 template <class _R1, class _R2>
    290 struct __ratio_multiply
    291 {
    292 private:
    293     static const intmax_t __gcd_n1_d2 = __static_gcd<_R1::num, _R2::den>::value;
    294     static const intmax_t __gcd_d1_n2 = __static_gcd<_R1::den, _R2::num>::value;
    295 public:
    296     typedef typename ratio
    297         <
    298             __ll_mul<_R1::num / __gcd_n1_d2, _R2::num / __gcd_d1_n2>::value,
    299             __ll_mul<_R2::den / __gcd_n1_d2, _R1::den / __gcd_d1_n2>::value
    300         >::type type;
    301 };
    302 
    303 #ifndef _LIBCPP_CXX03_LANG
    304 
    305 template <class _R1, class _R2> using ratio_multiply
    306                                     = typename __ratio_multiply<_R1, _R2>::type;
    307 
    308 #else  // _LIBCPP_CXX03_LANG
    309 
    310 template <class _R1, class _R2>
    311 struct _LIBCPP_TEMPLATE_VIS ratio_multiply
    312     : public __ratio_multiply<_R1, _R2>::type {};
    313 
    314 #endif  // _LIBCPP_CXX03_LANG
    315 
    316 template <class _R1, class _R2>
    317 struct __ratio_divide
    318 {
    319 private:
    320     static const intmax_t __gcd_n1_n2 = __static_gcd<_R1::num, _R2::num>::value;
    321     static const intmax_t __gcd_d1_d2 = __static_gcd<_R1::den, _R2::den>::value;
    322 public:
    323     typedef typename ratio
    324         <
    325             __ll_mul<_R1::num / __gcd_n1_n2, _R2::den / __gcd_d1_d2>::value,
    326             __ll_mul<_R2::num / __gcd_n1_n2, _R1::den / __gcd_d1_d2>::value
    327         >::type type;
    328 };
    329 
    330 #ifndef _LIBCPP_CXX03_LANG
    331 
    332 template <class _R1, class _R2> using ratio_divide
    333                                       = typename __ratio_divide<_R1, _R2>::type;
    334 
    335 #else  // _LIBCPP_CXX03_LANG
    336 
    337 template <class _R1, class _R2>
    338 struct _LIBCPP_TEMPLATE_VIS ratio_divide
    339     : public __ratio_divide<_R1, _R2>::type {};
    340 
    341 #endif  // _LIBCPP_CXX03_LANG
    342 
    343 template <class _R1, class _R2>
    344 struct __ratio_add
    345 {
    346 private:
    347     static const intmax_t __gcd_n1_n2 = __static_gcd<_R1::num, _R2::num>::value;
    348     static const intmax_t __gcd_d1_d2 = __static_gcd<_R1::den, _R2::den>::value;
    349 public:
    350     typedef typename ratio_multiply
    351         <
    352             ratio<__gcd_n1_n2, _R1::den / __gcd_d1_d2>,
    353             ratio
    354             <
    355                 __ll_add
    356                 <
    357                     __ll_mul<_R1::num / __gcd_n1_n2, _R2::den / __gcd_d1_d2>::value,
    358                     __ll_mul<_R2::num / __gcd_n1_n2, _R1::den / __gcd_d1_d2>::value
    359                 >::value,
    360                 _R2::den
    361             >
    362         >::type type;
    363 };
    364 
    365 #ifndef _LIBCPP_CXX03_LANG
    366 
    367 template <class _R1, class _R2> using ratio_add
    368                                          = typename __ratio_add<_R1, _R2>::type;
    369 
    370 #else  // _LIBCPP_CXX03_LANG
    371 
    372 template <class _R1, class _R2>
    373 struct _LIBCPP_TEMPLATE_VIS ratio_add
    374     : public __ratio_add<_R1, _R2>::type {};
    375 
    376 #endif  // _LIBCPP_CXX03_LANG
    377 
    378 template <class _R1, class _R2>
    379 struct __ratio_subtract
    380 {
    381 private:
    382     static const intmax_t __gcd_n1_n2 = __static_gcd<_R1::num, _R2::num>::value;
    383     static const intmax_t __gcd_d1_d2 = __static_gcd<_R1::den, _R2::den>::value;
    384 public:
    385     typedef typename ratio_multiply
    386         <
    387             ratio<__gcd_n1_n2, _R1::den / __gcd_d1_d2>,
    388             ratio
    389             <
    390                 __ll_sub
    391                 <
    392                     __ll_mul<_R1::num / __gcd_n1_n2, _R2::den / __gcd_d1_d2>::value,
    393                     __ll_mul<_R2::num / __gcd_n1_n2, _R1::den / __gcd_d1_d2>::value
    394                 >::value,
    395                 _R2::den
    396             >
    397         >::type type;
    398 };
    399 
    400 #ifndef _LIBCPP_CXX03_LANG
    401 
    402 template <class _R1, class _R2> using ratio_subtract
    403                                     = typename __ratio_subtract<_R1, _R2>::type;
    404 
    405 #else  // _LIBCPP_CXX03_LANG
    406 
    407 template <class _R1, class _R2>
    408 struct _LIBCPP_TEMPLATE_VIS ratio_subtract
    409     : public __ratio_subtract<_R1, _R2>::type {};
    410 
    411 #endif  // _LIBCPP_CXX03_LANG
    412 
    413 // ratio_equal
    414 
    415 template <class _R1, class _R2>
    416 struct _LIBCPP_TEMPLATE_VIS ratio_equal
    417     : public _LIBCPP_BOOL_CONSTANT((_R1::num == _R2::num && _R1::den == _R2::den)) {};
    418 
    419 template <class _R1, class _R2>
    420 struct _LIBCPP_TEMPLATE_VIS ratio_not_equal
    421     : public _LIBCPP_BOOL_CONSTANT((!ratio_equal<_R1, _R2>::value)) {};
    422 
    423 // ratio_less
    424 
    425 template <class _R1, class _R2, bool _Odd = false,
    426           intmax_t _Q1 = _R1::num / _R1::den, intmax_t _M1 = _R1::num % _R1::den,
    427           intmax_t _Q2 = _R2::num / _R2::den, intmax_t _M2 = _R2::num % _R2::den>
    428 struct __ratio_less1
    429 {
    430     static const bool value = _Odd ? _Q2 < _Q1 : _Q1 < _Q2;
    431 };
    432 
    433 template <class _R1, class _R2, bool _Odd, intmax_t _Qp>
    434 struct __ratio_less1<_R1, _R2, _Odd, _Qp, 0, _Qp, 0>
    435 {
    436     static const bool value = false;
    437 };
    438 
    439 template <class _R1, class _R2, bool _Odd, intmax_t _Qp, intmax_t _M2>
    440 struct __ratio_less1<_R1, _R2, _Odd, _Qp, 0, _Qp, _M2>
    441 {
    442     static const bool value = !_Odd;
    443 };
    444 
    445 template <class _R1, class _R2, bool _Odd, intmax_t _Qp, intmax_t _M1>
    446 struct __ratio_less1<_R1, _R2, _Odd, _Qp, _M1, _Qp, 0>
    447 {
    448     static const bool value = _Odd;
    449 };
    450 
    451 template <class _R1, class _R2, bool _Odd, intmax_t _Qp, intmax_t _M1,
    452                                                         intmax_t _M2>
    453 struct __ratio_less1<_R1, _R2, _Odd, _Qp, _M1, _Qp, _M2>
    454 {
    455     static const bool value = __ratio_less1<ratio<_R1::den, _M1>,
    456                                             ratio<_R2::den, _M2>, !_Odd>::value;
    457 };
    458 
    459 template <class _R1, class _R2, intmax_t _S1 = __static_sign<_R1::num>::value,
    460                                 intmax_t _S2 = __static_sign<_R2::num>::value>
    461 struct __ratio_less
    462 {
    463     static const bool value = _S1 < _S2;
    464 };
    465 
    466 template <class _R1, class _R2>
    467 struct __ratio_less<_R1, _R2, 1LL, 1LL>
    468 {
    469     static const bool value = __ratio_less1<_R1, _R2>::value;
    470 };
    471 
    472 template <class _R1, class _R2>
    473 struct __ratio_less<_R1, _R2, -1LL, -1LL>
    474 {
    475     static const bool value = __ratio_less1<ratio<-_R2::num, _R2::den>, ratio<-_R1::num, _R1::den> >::value;
    476 };
    477 
    478 template <class _R1, class _R2>
    479 struct _LIBCPP_TEMPLATE_VIS ratio_less
    480     : public _LIBCPP_BOOL_CONSTANT((__ratio_less<_R1, _R2>::value)) {};
    481 
    482 template <class _R1, class _R2>
    483 struct _LIBCPP_TEMPLATE_VIS ratio_less_equal
    484     : public _LIBCPP_BOOL_CONSTANT((!ratio_less<_R2, _R1>::value)) {};
    485 
    486 template <class _R1, class _R2>
    487 struct _LIBCPP_TEMPLATE_VIS ratio_greater
    488     : public _LIBCPP_BOOL_CONSTANT((ratio_less<_R2, _R1>::value)) {};
    489 
    490 template <class _R1, class _R2>
    491 struct _LIBCPP_TEMPLATE_VIS ratio_greater_equal
    492     : public _LIBCPP_BOOL_CONSTANT((!ratio_less<_R1, _R2>::value)) {};
    493 
    494 template <class _R1, class _R2>
    495 struct __ratio_gcd
    496 {
    497     typedef ratio<__static_gcd<_R1::num, _R2::num>::value,
    498                   __static_lcm<_R1::den, _R2::den>::value> type;
    499 };
    500 
    501 #if _LIBCPP_STD_VER > 14 && !defined(_LIBCPP_HAS_NO_VARIABLE_TEMPLATES)
    502 template <class _R1, class _R2> _LIBCPP_CONSTEXPR bool ratio_equal_v
    503     = ratio_equal<_R1, _R2>::value;
    504 
    505 template <class _R1, class _R2> _LIBCPP_CONSTEXPR bool ratio_not_equal_v
    506     = ratio_not_equal<_R1, _R2>::value;
    507 
    508 template <class _R1, class _R2> _LIBCPP_CONSTEXPR bool ratio_less_v
    509     = ratio_less<_R1, _R2>::value;
    510 
    511 template <class _R1, class _R2> _LIBCPP_CONSTEXPR bool ratio_less_equal_v
    512     = ratio_less_equal<_R1, _R2>::value;
    513 
    514 template <class _R1, class _R2> _LIBCPP_CONSTEXPR bool ratio_greater_v
    515     = ratio_greater<_R1, _R2>::value;
    516 
    517 template <class _R1, class _R2> _LIBCPP_CONSTEXPR bool ratio_greater_equal_v
    518     = ratio_greater_equal<_R1, _R2>::value;
    519 #endif
    520 
    521 _LIBCPP_END_NAMESPACE_STD
    522 
    523 #endif  // _LIBCPP_RATIO
    524