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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 const intmax_t num;
     25     static const 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 }
     66 */
     67 
     68 #include <__config>
     69 #include <cstdint>
     70 #include <climits>
     71 #include <type_traits>
     72 
     73 #include <__undef_min_max>
     74 
     75 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
     76 #pragma GCC system_header
     77 #endif
     78 
     79 _LIBCPP_BEGIN_NAMESPACE_STD
     80 
     81 // __static_gcd
     82 
     83 template <intmax_t _Xp, intmax_t _Yp>
     84 struct __static_gcd
     85 {
     86     static const intmax_t value = __static_gcd<_Yp, _Xp % _Yp>::value;
     87 };
     88 
     89 template <intmax_t _Xp>
     90 struct __static_gcd<_Xp, 0>
     91 {
     92     static const intmax_t value = _Xp;
     93 };
     94 
     95 template <>
     96 struct __static_gcd<0, 0>
     97 {
     98     static const intmax_t value = 1;
     99 };
    100 
    101 // __static_lcm
    102 
    103 template <intmax_t _Xp, intmax_t _Yp>
    104 struct __static_lcm
    105 {
    106     static const intmax_t value = _Xp / __static_gcd<_Xp, _Yp>::value * _Yp;
    107 };
    108 
    109 template <intmax_t _Xp>
    110 struct __static_abs
    111 {
    112     static const intmax_t value = _Xp < 0 ? -_Xp : _Xp;
    113 };
    114 
    115 template <intmax_t _Xp>
    116 struct __static_sign
    117 {
    118     static const intmax_t value = _Xp == 0 ? 0 : (_Xp < 0 ? -1 : 1);
    119 };
    120 
    121 template <intmax_t _Xp, intmax_t _Yp, intmax_t = __static_sign<_Yp>::value>
    122 class __ll_add;
    123 
    124 template <intmax_t _Xp, intmax_t _Yp>
    125 class __ll_add<_Xp, _Yp, 1>
    126 {
    127     static const intmax_t min = (1LL << (sizeof(intmax_t) * CHAR_BIT - 1)) + 1;
    128     static const intmax_t max = -min;
    129 
    130     static_assert(_Xp <= max - _Yp, "overflow in __ll_add");
    131 public:
    132     static const intmax_t value = _Xp + _Yp;
    133 };
    134 
    135 template <intmax_t _Xp, intmax_t _Yp>
    136 class __ll_add<_Xp, _Yp, 0>
    137 {
    138 public:
    139     static const intmax_t value = _Xp;
    140 };
    141 
    142 template <intmax_t _Xp, intmax_t _Yp>
    143 class __ll_add<_Xp, _Yp, -1>
    144 {
    145     static const intmax_t min = (1LL << (sizeof(intmax_t) * CHAR_BIT - 1)) + 1;
    146     static const intmax_t max = -min;
    147 
    148     static_assert(min - _Yp <= _Xp, "overflow in __ll_add");
    149 public:
    150     static const intmax_t value = _Xp + _Yp;
    151 };
    152 
    153 template <intmax_t _Xp, intmax_t _Yp, intmax_t = __static_sign<_Yp>::value>
    154 class __ll_sub;
    155 
    156 template <intmax_t _Xp, intmax_t _Yp>
    157 class __ll_sub<_Xp, _Yp, 1>
    158 {
    159     static const intmax_t min = (1LL << (sizeof(intmax_t) * CHAR_BIT - 1)) + 1;
    160     static const intmax_t max = -min;
    161 
    162     static_assert(min + _Yp <= _Xp, "overflow in __ll_sub");
    163 public:
    164     static const intmax_t value = _Xp - _Yp;
    165 };
    166 
    167 template <intmax_t _Xp, intmax_t _Yp>
    168 class __ll_sub<_Xp, _Yp, 0>
    169 {
    170 public:
    171     static const intmax_t value = _Xp;
    172 };
    173 
    174 template <intmax_t _Xp, intmax_t _Yp>
    175 class __ll_sub<_Xp, _Yp, -1>
    176 {
    177     static const intmax_t min = (1LL << (sizeof(intmax_t) * CHAR_BIT - 1)) + 1;
    178     static const intmax_t max = -min;
    179 
    180     static_assert(_Xp <= max + _Yp, "overflow in __ll_sub");
    181 public:
    182     static const intmax_t value = _Xp - _Yp;
    183 };
    184 
    185 template <intmax_t _Xp, intmax_t _Yp>
    186 class __ll_mul
    187 {
    188     static const intmax_t nan = (1LL << (sizeof(intmax_t) * CHAR_BIT - 1));
    189     static const intmax_t min = nan + 1;
    190     static const intmax_t max = -min;
    191     static const intmax_t __a_x = __static_abs<_Xp>::value;
    192     static const intmax_t __a_y = __static_abs<_Yp>::value;
    193 
    194     static_assert(_Xp != nan && _Yp != nan && __a_x <= max / __a_y, "overflow in __ll_mul");
    195 public:
    196     static const intmax_t value = _Xp * _Yp;
    197 };
    198 
    199 template <intmax_t _Yp>
    200 class __ll_mul<0, _Yp>
    201 {
    202 public:
    203     static const intmax_t value = 0;
    204 };
    205 
    206 template <intmax_t _Xp>
    207 class __ll_mul<_Xp, 0>
    208 {
    209 public:
    210     static const intmax_t value = 0;
    211 };
    212 
    213 template <>
    214 class __ll_mul<0, 0>
    215 {
    216 public:
    217     static const intmax_t value = 0;
    218 };
    219 
    220 // Not actually used but left here in case needed in future maintenance
    221 template <intmax_t _Xp, intmax_t _Yp>
    222 class __ll_div
    223 {
    224     static const intmax_t nan = (1LL << (sizeof(intmax_t) * CHAR_BIT - 1));
    225     static const intmax_t min = nan + 1;
    226     static const intmax_t max = -min;
    227 
    228     static_assert(_Xp != nan && _Yp != nan && _Yp != 0, "overflow in __ll_div");
    229 public:
    230     static const intmax_t value = _Xp / _Yp;
    231 };
    232 
    233 template <intmax_t _Num, intmax_t _Den = 1>
    234 class _LIBCPP_TYPE_VIS ratio
    235 {
    236     static_assert(__static_abs<_Num>::value >= 0, "ratio numerator is out of range");
    237     static_assert(_Den != 0, "ratio divide by 0");
    238     static_assert(__static_abs<_Den>::value >  0, "ratio denominator is out of range");
    239     static const intmax_t __na = __static_abs<_Num>::value;
    240     static const intmax_t __da = __static_abs<_Den>::value;
    241     static const intmax_t __s = __static_sign<_Num>::value * __static_sign<_Den>::value;
    242     static const intmax_t __gcd = __static_gcd<__na, __da>::value;
    243 public:
    244     static const intmax_t num = __s * __na / __gcd;
    245     static const intmax_t den = __da / __gcd;
    246 
    247     typedef ratio<num, den> type;
    248 };
    249 
    250 template <intmax_t _Num, intmax_t _Den> const intmax_t ratio<_Num, _Den>::num;
    251 template <intmax_t _Num, intmax_t _Den> const intmax_t ratio<_Num, _Den>::den;
    252 
    253 template <class _Tp>                    struct __is_ratio                     : false_type {};
    254 template <intmax_t _Num, intmax_t _Den> struct __is_ratio<ratio<_Num, _Den> > : true_type  {};
    255 
    256 typedef ratio<1LL, 1000000000000000000LL> atto;
    257 typedef ratio<1LL,    1000000000000000LL> femto;
    258 typedef ratio<1LL,       1000000000000LL> pico;
    259 typedef ratio<1LL,          1000000000LL> nano;
    260 typedef ratio<1LL,             1000000LL> micro;
    261 typedef ratio<1LL,                1000LL> milli;
    262 typedef ratio<1LL,                 100LL> centi;
    263 typedef ratio<1LL,                  10LL> deci;
    264 typedef ratio<                 10LL, 1LL> deca;
    265 typedef ratio<                100LL, 1LL> hecto;
    266 typedef ratio<               1000LL, 1LL> kilo;
    267 typedef ratio<            1000000LL, 1LL> mega;
    268 typedef ratio<         1000000000LL, 1LL> giga;
    269 typedef ratio<      1000000000000LL, 1LL> tera;
    270 typedef ratio<   1000000000000000LL, 1LL> peta;
    271 typedef ratio<1000000000000000000LL, 1LL> exa;
    272 
    273 template <class _R1, class _R2>
    274 struct __ratio_multiply
    275 {
    276 private:
    277     static const intmax_t __gcd_n1_d2 = __static_gcd<_R1::num, _R2::den>::value;
    278     static const intmax_t __gcd_d1_n2 = __static_gcd<_R1::den, _R2::num>::value;
    279 public:
    280     typedef typename ratio
    281         <
    282             __ll_mul<_R1::num / __gcd_n1_d2, _R2::num / __gcd_d1_n2>::value,
    283             __ll_mul<_R2::den / __gcd_n1_d2, _R1::den / __gcd_d1_n2>::value
    284         >::type type;
    285 };
    286 
    287 #ifndef _LIBCPP_HAS_NO_TEMPLATE_ALIASES
    288 
    289 template <class _R1, class _R2> using ratio_multiply
    290                                     = typename __ratio_multiply<_R1, _R2>::type;
    291 
    292 #else  // _LIBCPP_HAS_NO_TEMPLATE_ALIASES
    293 
    294 template <class _R1, class _R2>
    295 struct _LIBCPP_TYPE_VIS ratio_multiply
    296     : public __ratio_multiply<_R1, _R2>::type {};
    297 
    298 #endif  // _LIBCPP_HAS_NO_TEMPLATE_ALIASES
    299 
    300 template <class _R1, class _R2>
    301 struct __ratio_divide
    302 {
    303 private:
    304     static const intmax_t __gcd_n1_n2 = __static_gcd<_R1::num, _R2::num>::value;
    305     static const intmax_t __gcd_d1_d2 = __static_gcd<_R1::den, _R2::den>::value;
    306 public:
    307     typedef typename ratio
    308         <
    309             __ll_mul<_R1::num / __gcd_n1_n2, _R2::den / __gcd_d1_d2>::value,
    310             __ll_mul<_R2::num / __gcd_n1_n2, _R1::den / __gcd_d1_d2>::value
    311         >::type type;
    312 };
    313 
    314 #ifndef _LIBCPP_HAS_NO_TEMPLATE_ALIASES
    315 
    316 template <class _R1, class _R2> using ratio_divide
    317                                       = typename __ratio_divide<_R1, _R2>::type;
    318 
    319 #else  // _LIBCPP_HAS_NO_TEMPLATE_ALIASES
    320 
    321 template <class _R1, class _R2>
    322 struct _LIBCPP_TYPE_VIS ratio_divide
    323     : public __ratio_divide<_R1, _R2>::type {};
    324 
    325 #endif  // _LIBCPP_HAS_NO_TEMPLATE_ALIASES
    326 
    327 template <class _R1, class _R2>
    328 struct __ratio_add
    329 {
    330 private:
    331     static const intmax_t __gcd_n1_n2 = __static_gcd<_R1::num, _R2::num>::value;
    332     static const intmax_t __gcd_d1_d2 = __static_gcd<_R1::den, _R2::den>::value;
    333 public:
    334     typedef typename ratio_multiply
    335         <
    336             ratio<__gcd_n1_n2, _R1::den / __gcd_d1_d2>,
    337             ratio
    338             <
    339                 __ll_add
    340                 <
    341                     __ll_mul<_R1::num / __gcd_n1_n2, _R2::den / __gcd_d1_d2>::value,
    342                     __ll_mul<_R2::num / __gcd_n1_n2, _R1::den / __gcd_d1_d2>::value
    343                 >::value,
    344                 _R2::den
    345             >
    346         >::type type;
    347 };
    348 
    349 #ifndef _LIBCPP_HAS_NO_TEMPLATE_ALIASES
    350 
    351 template <class _R1, class _R2> using ratio_add
    352                                          = typename __ratio_add<_R1, _R2>::type;
    353 
    354 #else  // _LIBCPP_HAS_NO_TEMPLATE_ALIASES
    355 
    356 template <class _R1, class _R2>
    357 struct _LIBCPP_TYPE_VIS ratio_add
    358     : public __ratio_add<_R1, _R2>::type {};
    359 
    360 #endif  // _LIBCPP_HAS_NO_TEMPLATE_ALIASES
    361 
    362 template <class _R1, class _R2>
    363 struct __ratio_subtract
    364 {
    365 private:
    366     static const intmax_t __gcd_n1_n2 = __static_gcd<_R1::num, _R2::num>::value;
    367     static const intmax_t __gcd_d1_d2 = __static_gcd<_R1::den, _R2::den>::value;
    368 public:
    369     typedef typename ratio_multiply
    370         <
    371             ratio<__gcd_n1_n2, _R1::den / __gcd_d1_d2>,
    372             ratio
    373             <
    374                 __ll_sub
    375                 <
    376                     __ll_mul<_R1::num / __gcd_n1_n2, _R2::den / __gcd_d1_d2>::value,
    377                     __ll_mul<_R2::num / __gcd_n1_n2, _R1::den / __gcd_d1_d2>::value
    378                 >::value,
    379                 _R2::den
    380             >
    381         >::type type;
    382 };
    383 
    384 #ifndef _LIBCPP_HAS_NO_TEMPLATE_ALIASES
    385 
    386 template <class _R1, class _R2> using ratio_subtract
    387                                     = typename __ratio_subtract<_R1, _R2>::type;
    388 
    389 #else  // _LIBCPP_HAS_NO_TEMPLATE_ALIASES
    390 
    391 template <class _R1, class _R2>
    392 struct _LIBCPP_TYPE_VIS ratio_subtract
    393     : public __ratio_subtract<_R1, _R2>::type {};
    394 
    395 #endif  // _LIBCPP_HAS_NO_TEMPLATE_ALIASES
    396 
    397 // ratio_equal
    398 
    399 template <class _R1, class _R2>
    400 struct _LIBCPP_TYPE_VIS ratio_equal
    401     : public integral_constant<bool, _R1::num == _R2::num && _R1::den == _R2::den> {};
    402 
    403 template <class _R1, class _R2>
    404 struct _LIBCPP_TYPE_VIS ratio_not_equal
    405     : public integral_constant<bool, !ratio_equal<_R1, _R2>::value> {};
    406 
    407 // ratio_less
    408 
    409 template <class _R1, class _R2, bool _Odd = false,
    410           intmax_t _Q1 = _R1::num / _R1::den, intmax_t _M1 = _R1::num % _R1::den,
    411           intmax_t _Q2 = _R2::num / _R2::den, intmax_t _M2 = _R2::num % _R2::den>
    412 struct __ratio_less1
    413 {
    414     static const bool value = _Odd ? _Q2 < _Q1 : _Q1 < _Q2;
    415 };
    416 
    417 template <class _R1, class _R2, bool _Odd, intmax_t _Qp>
    418 struct __ratio_less1<_R1, _R2, _Odd, _Qp, 0, _Qp, 0>
    419 {
    420     static const bool value = false;
    421 };
    422 
    423 template <class _R1, class _R2, bool _Odd, intmax_t _Qp, intmax_t _M2>
    424 struct __ratio_less1<_R1, _R2, _Odd, _Qp, 0, _Qp, _M2>
    425 {
    426     static const bool value = !_Odd;
    427 };
    428 
    429 template <class _R1, class _R2, bool _Odd, intmax_t _Qp, intmax_t _M1>
    430 struct __ratio_less1<_R1, _R2, _Odd, _Qp, _M1, _Qp, 0>
    431 {
    432     static const bool value = _Odd;
    433 };
    434 
    435 template <class _R1, class _R2, bool _Odd, intmax_t _Qp, intmax_t _M1,
    436                                                         intmax_t _M2>
    437 struct __ratio_less1<_R1, _R2, _Odd, _Qp, _M1, _Qp, _M2>
    438 {
    439     static const bool value = __ratio_less1<ratio<_R1::den, _M1>,
    440                                             ratio<_R2::den, _M2>, !_Odd>::value;
    441 };
    442 
    443 template <class _R1, class _R2, intmax_t _S1 = __static_sign<_R1::num>::value,
    444                                 intmax_t _S2 = __static_sign<_R2::num>::value>
    445 struct __ratio_less
    446 {
    447     static const bool value = _S1 < _S2;
    448 };
    449 
    450 template <class _R1, class _R2>
    451 struct __ratio_less<_R1, _R2, 1LL, 1LL>
    452 {
    453     static const bool value = __ratio_less1<_R1, _R2>::value;
    454 };
    455 
    456 template <class _R1, class _R2>
    457 struct __ratio_less<_R1, _R2, -1LL, -1LL>
    458 {
    459     static const bool value = __ratio_less1<ratio<-_R2::num, _R2::den>, ratio<-_R1::num, _R1::den> >::value;
    460 };
    461 
    462 template <class _R1, class _R2>
    463 struct _LIBCPP_TYPE_VIS ratio_less
    464     : public integral_constant<bool, __ratio_less<_R1, _R2>::value> {};
    465 
    466 template <class _R1, class _R2>
    467 struct _LIBCPP_TYPE_VIS ratio_less_equal
    468     : public integral_constant<bool, !ratio_less<_R2, _R1>::value> {};
    469 
    470 template <class _R1, class _R2>
    471 struct _LIBCPP_TYPE_VIS ratio_greater
    472     : public integral_constant<bool, ratio_less<_R2, _R1>::value> {};
    473 
    474 template <class _R1, class _R2>
    475 struct _LIBCPP_TYPE_VIS ratio_greater_equal
    476     : public integral_constant<bool, !ratio_less<_R1, _R2>::value> {};
    477 
    478 template <class _R1, class _R2>
    479 struct __ratio_gcd
    480 {
    481     typedef ratio<__static_gcd<_R1::num, _R2::num>::value,
    482                   __static_lcm<_R1::den, _R2::den>::value> type;
    483 };
    484 
    485 _LIBCPP_END_NAMESPACE_STD
    486 
    487 #endif  // _LIBCPP_RATIO
    488