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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
32template <uint64_t _Xp, uint64_t _Yp>
33struct __ugcd {
34 static _LIBCPP_CONSTEXPR const uint64_t value = __ugcd<_Yp, _Xp % _Yp>::value;
35};
36
37template <uint64_t _Xp>
38struct __ugcd<_Xp, 0> {
39 static _LIBCPP_CONSTEXPR const uint64_t value = _Xp;
40};
41
42template <uint64_t _Np, uint64_t _Dp>
43class __uratio {
44 static_assert(_Dp != 0, "__uratio divide by 0");
45 static _LIBCPP_CONSTEXPR const uint64_t __gcd = __ugcd<_Np, _Dp>::value;
46
47public:
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
54template <class _Engine, size_t __k>
55class shuffle_order_engine {
56 static_assert(0 < __k, "shuffle_order_engine invalid parameters");
57
58public:
59 // types
60 typedef typename _Engine::result_type result_type;
61
62private:
63 _Engine __e_;
64 result_type __v_[__k];
65 result_type __y_;
66
67public:
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
122private:
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
176template <class _Eng, size_t _Kp>
177_LIBCPP_HIDE_FROM_ABI bool
178operator==(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
182template <class _Eng, size_t _Kp>
183inline _LIBCPP_HIDE_FROM_ABI bool
184operator!=(const shuffle_order_engine<_Eng, _Kp>& __x, const shuffle_order_engine<_Eng, _Kp>& __y) {
185 return !(__x == __y);
186}
187
188template <class _CharT, class _Traits, class _Eng, size_t _Kp>
189_LIBCPP_HIDE_FROM_ABI basic_ostream<_CharT, _Traits>&
190operator<<(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
202template <class _CharT, class _Traits, class _Eng, size_t _Kp>
203_LIBCPP_HIDE_FROM_ABI basic_istream<_CharT, _Traits>&
204operator>>(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
228

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source code of libcxx/include/__random/shuffle_order_engine.h