libcxx/include/__random/shuffle_order_engine.h

   1 //===----------------------------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #ifndef _LIBCPP___RANDOM_SHUFFLE_ORDER_ENGINE_H
  10 #define _LIBCPP___RANDOM_SHUFFLE_ORDER_ENGINE_H
  11
  12 #include <__algorithm/equal.h>
  13 #include <__config>
  14 #include <__cstddef/size_t.h>
  15 #include <__random/is_seed_sequence.h>
  16 #include <__type_traits/enable_if.h>
  17 #include <__type_traits/integral_constant.h>
  18 #include <__type_traits/is_convertible.h>
  19 #include <__utility/move.h>
  20 #include <cstdint>
  21 #include <iosfwd>
  22
  23 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
  24 #  pragma GCC system_header
  25 #endif
  26
  27 _LIBCPP_PUSH_MACROS
  28 #include <__undef_macros>
  29
  30 _LIBCPP_BEGIN_NAMESPACE_STD
  31
  32 template <uint64_t _Xp, uint64_t _Yp>
  33 struct __ugcd {
  34   static _LIBCPP_CONSTEXPR const uint64_t value = __ugcd<_Yp, _Xp % _Yp>::value;
  35 };
  36
  37 template <uint64_t _Xp>
  38 struct __ugcd<_Xp, 0> {
  39   static _LIBCPP_CONSTEXPR const uint64_t value = _Xp;
  40 };
  41
  42 template <uint64_t _Np, uint64_t _Dp>
  43 class __uratio {
  44   static_assert(_Dp != 0, "__uratio divide by 0");
  45   static _LIBCPP_CONSTEXPR const uint64_t __gcd = __ugcd<_Np, _Dp>::value;
  46
  47 public:
  48   static _LIBCPP_CONSTEXPR const uint64_t num = _Np / __gcd;
  49   static _LIBCPP_CONSTEXPR const uint64_t den = _Dp / __gcd;
  50
  51   typedef __uratio<num, den> type;
  52 };
  53
  54 template <class _Engine, size_t __k>
  55 class _LIBCPP_TEMPLATE_VIS shuffle_order_engine {
  56   static_assert(0 < __k, "shuffle_order_engine invalid parameters");
  57
  58 public:
  59   // types
  60   typedef typename _Engine::result_type result_type;
  61
  62 private:
  63   _Engine __e_;
  64   result_type __v_[__k];
  65   result_type __y_;
  66
  67 public:
  68   // engine characteristics
  69   static inline _LIBCPP_CONSTEXPR const size_t table_size = __k;
  70
  71 #ifdef _LIBCPP_CXX03_LANG
  72   static const result_type _Min = _Engine::_Min;
  73   static const result_type _Max = _Engine::_Max;
  74 #else
  75   static _LIBCPP_CONSTEXPR const result_type _Min = _Engine::min();
  76   static _LIBCPP_CONSTEXPR const result_type _Max = _Engine::max();
  77 #endif
  78   static_assert(_Min < _Max, "shuffle_order_engine invalid parameters");
  79   _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR result_type min() { return _Min; }
  80   _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR result_type max() { return _Max; }
  81
  82   static _LIBCPP_CONSTEXPR const unsigned long long _Rp = _Max - _Min + 1ull;
  83
  84   // constructors and seeding functions
  85   _LIBCPP_HIDE_FROM_ABI shuffle_order_engine() { __init(); }
  86   _LIBCPP_HIDE_FROM_ABI explicit shuffle_order_engine(const _Engine& __e) : __e_(__e) { __init(); }
  87 #ifndef _LIBCPP_CXX03_LANG
  88   _LIBCPP_HIDE_FROM_ABI explicit shuffle_order_engine(_Engine&& __e) : __e_(std::move(__e)) { __init(); }
  89 #endif // _LIBCPP_CXX03_LANG
  90   _LIBCPP_HIDE_FROM_ABI explicit shuffle_order_engine(result_type __sd) : __e_(__sd) { __init(); }
  91   template <
  92       class _Sseq,
  93       __enable_if_t<__is_seed_sequence<_Sseq, shuffle_order_engine>::value && !is_convertible<_Sseq, _Engine>::value,
  94                     int> = 0>
  95   _LIBCPP_HIDE_FROM_ABI explicit shuffle_order_engine(_Sseq& __q) : __e_(__q) {
  96     __init();
  97   }
  98   _LIBCPP_HIDE_FROM_ABI void seed() {
  99     __e_.seed();
 100     __init();
 101   }
 102   _LIBCPP_HIDE_FROM_ABI void seed(result_type __sd) {
 103     __e_.seed(__sd);
 104     __init();
 105   }
 106   template <class _Sseq, __enable_if_t<__is_seed_sequence<_Sseq, shuffle_order_engine>::value, int> = 0>
 107   _LIBCPP_HIDE_FROM_ABI void seed(_Sseq& __q) {
 108     __e_.seed(__q);
 109     __init();
 110   }
 111
 112   // generating functions
 113   _LIBCPP_HIDE_FROM_ABI result_type operator()() { return __eval(integral_constant<bool, _Rp != 0>()); }
 114   _LIBCPP_HIDE_FROM_ABI void discard(unsigned long long __z) {
 115     for (; __z; --__z)
 116       operator()();
 117   }
 118
 119   // property functions
 120   _LIBCPP_HIDE_FROM_ABI const _Engine& base() const _NOEXCEPT { return __e_; }
 121
 122 private:
 123   template <class _Eng, size_t _Kp>
 124   friend bool operator==(const shuffle_order_engine<_Eng, _Kp>& __x, const shuffle_order_engine<_Eng, _Kp>& __y);
 125
 126   template <class _Eng, size_t _Kp>
 127   friend bool operator!=(const shuffle_order_engine<_Eng, _Kp>& __x, const shuffle_order_engine<_Eng, _Kp>& __y);
 128
 129   template <class _CharT, class _Traits, class _Eng, size_t _Kp>
 130   friend basic_ostream<_CharT, _Traits>&
 131   operator<<(basic_ostream<_CharT, _Traits>& __os, const shuffle_order_engine<_Eng, _Kp>& __x);
 132
 133   template <class _CharT, class _Traits, class _Eng, size_t _Kp>
 134   friend basic_istream<_CharT, _Traits>&
 135   operator>>(basic_istream<_CharT, _Traits>& __is, shuffle_order_engine<_Eng, _Kp>& __x);
 136
 137   _LIBCPP_HIDE_FROM_ABI void __init() {
 138     for (size_t __i = 0; __i < __k; ++__i)
 139       __v_[__i] = __e_();
 140     __y_ = __e_();
 141   }
 142
 143   _LIBCPP_HIDE_FROM_ABI result_type __eval(false_type) { return __eval2(integral_constant<bool, __k & 1>()); }
 144   _LIBCPP_HIDE_FROM_ABI result_type __eval(true_type) { return __eval(__uratio<__k, _Rp>()); }
 145
 146   _LIBCPP_HIDE_FROM_ABI result_type __eval2(false_type) { return __eval(__uratio<__k / 2, 0x8000000000000000ull>()); }
 147   _LIBCPP_HIDE_FROM_ABI result_type __eval2(true_type) { return __evalf<__k, 0>(); }
 148
 149   template <uint64_t _Np,
 150             uint64_t _Dp,
 151             __enable_if_t<(__uratio<_Np, _Dp>::num > 0xFFFFFFFFFFFFFFFFull / (_Max - _Min)), int> = 0>
 152   _LIBCPP_HIDE_FROM_ABI result_type __eval(__uratio<_Np, _Dp>) {
 153     return __evalf<__uratio<_Np, _Dp>::num, __uratio<_Np, _Dp>::den>();
 154   }
 155
 156   template <uint64_t _Np,
 157             uint64_t _Dp,
 158             __enable_if_t<__uratio<_Np, _Dp>::num <= 0xFFFFFFFFFFFFFFFFull / (_Max - _Min), int> = 0>
 159   _LIBCPP_HIDE_FROM_ABI result_type __eval(__uratio<_Np, _Dp>) {
 160     const size_t __j = static_cast<size_t>(__uratio<_Np, _Dp>::num * (__y_ - _Min) / __uratio<_Np, _Dp>::den);
 161     __y_             = __v_[__j];
 162     __v_[__j]        = __e_();
 163     return __y_;
 164   }
 165
 166   template <uint64_t __n, uint64_t __d>
 167   _LIBCPP_HIDE_FROM_ABI result_type __evalf() {
 168     const double __fp = __d == 0 ? __n / (2. * 0x8000000000000000ull) : __n / (double)__d;
 169     const size_t __j  = static_cast<size_t>(__fp * (__y_ - _Min));
 170     __y_              = __v_[__j];
 171     __v_[__j]         = __e_();
 172     return __y_;
 173   }
 174 };
 175
 176 template <class _Eng, size_t _Kp>
 177 _LIBCPP_HIDE_FROM_ABI bool
 178 operator==(const shuffle_order_engine<_Eng, _Kp>& __x, const shuffle_order_engine<_Eng, _Kp>& __y) {
 179   return __x.__y_ == __y.__y_ && std::equal(__x.__v_, __x.__v_ + _Kp, __y.__v_) && __x.__e_ == __y.__e_;
 180 }
 181
 182 template <class _Eng, size_t _Kp>
 183 inline _LIBCPP_HIDE_FROM_ABI bool
 184 operator!=(const shuffle_order_engine<_Eng, _Kp>& __x, const shuffle_order_engine<_Eng, _Kp>& __y) {
 185   return !(__x == __y);
 186 }
 187
 188 template <class _CharT, class _Traits, class _Eng, size_t _Kp>
 189 _LIBCPP_HIDE_FROM_ABI basic_ostream<_CharT, _Traits>&
 190 operator<<(basic_ostream<_CharT, _Traits>& __os, const shuffle_order_engine<_Eng, _Kp>& __x) {
 191   __save_flags<_CharT, _Traits> __lx(__os);
 192   typedef basic_ostream<_CharT, _Traits> _Ostream;
 193   __os.flags(_Ostream::dec | _Ostream::left);
 194   _CharT __sp = __os.widen(' ');
 195   __os.fill(__sp);
 196   __os << __x.__e_ << __sp << __x.__v_[0];
 197   for (size_t __i = 1; __i < _Kp; ++__i)
 198     __os << __sp << __x.__v_[__i];
 199   return __os << __sp << __x.__y_;
 200 }
 201
 202 template <class _CharT, class _Traits, class _Eng, size_t _Kp>
 203 _LIBCPP_HIDE_FROM_ABI basic_istream<_CharT, _Traits>&
 204 operator>>(basic_istream<_CharT, _Traits>& __is, shuffle_order_engine<_Eng, _Kp>& __x) {
 205   typedef typename shuffle_order_engine<_Eng, _Kp>::result_type result_type;
 206   __save_flags<_CharT, _Traits> __lx(__is);
 207   typedef basic_istream<_CharT, _Traits> _Istream;
 208   __is.flags(_Istream::dec | _Istream::skipws);
 209   _Eng __e;
 210   result_type __vp[_Kp + 1];
 211   __is >> __e;
 212   for (size_t __i = 0; __i < _Kp + 1; ++__i)
 213     __is >> __vp[__i];
 214   if (!__is.fail()) {
 215     __x.__e_ = __e;
 216     for (size_t __i = 0; __i < _Kp; ++__i)
 217       __x.__v_[__i] = __vp[__i];
 218     __x.__y_ = __vp[_Kp];
 219   }
 220   return __is;
 221 }
 222
 223 _LIBCPP_END_NAMESPACE_STD
 224
 225 _LIBCPP_POP_MACROS
 226
 227 #endif // _LIBCPP___RANDOM_SHUFFLE_ORDER_ENGINE_H