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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___CXX03___RANDOM_SHUFFLE_ORDER_ENGINE_H
10#define _LIBCPP___CXX03___RANDOM_SHUFFLE_ORDER_ENGINE_H
11
12#include <__cxx03/__algorithm/equal.h>
13#include <__cxx03/__config>
14#include <__cxx03/__random/is_seed_sequence.h>
15#include <__cxx03/__type_traits/enable_if.h>
16#include <__cxx03/__type_traits/integral_constant.h>
17#include <__cxx03/__type_traits/is_convertible.h>
18#include <__cxx03/__utility/move.h>
19#include <__cxx03/cstddef>
20#include <__cxx03/cstdint>
21#include <__cxx03/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 <__cxx03/__undef_macros>
29
30_LIBCPP_BEGIN_NAMESPACE_STD
31
32template <uint64_t _Xp, uint64_t _Yp>
33struct __ugcd {
34 static const uint64_t value = __ugcd<_Yp, _Xp % _Yp>::value;
35};
36
37template <uint64_t _Xp>
38struct __ugcd<_Xp, 0> {
39 static 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 const uint64_t __gcd = __ugcd<_Np, _Dp>::value;
46
47public:
48 static const uint64_t num = _Np / __gcd;
49 static const uint64_t den = _Dp / __gcd;
50
51 typedef __uratio<num, den> type;
52};
53
54template <class _Engine, size_t __k>
55class _LIBCPP_TEMPLATE_VIS 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 const size_t table_size = __k;
70
71 static const result_type _Min = _Engine::_Min;
72 static const result_type _Max = _Engine::_Max;
73 static_assert(_Min < _Max, "shuffle_order_engine invalid parameters");
74 _LIBCPP_HIDE_FROM_ABI static result_type min() { return _Min; }
75 _LIBCPP_HIDE_FROM_ABI static result_type max() { return _Max; }
76
77 static const unsigned long long _Rp = _Max - _Min + 1ull;
78
79 // constructors and seeding functions
80 _LIBCPP_HIDE_FROM_ABI shuffle_order_engine() { __init(); }
81 _LIBCPP_HIDE_FROM_ABI explicit shuffle_order_engine(const _Engine& __e) : __e_(__e) { __init(); }
82 _LIBCPP_HIDE_FROM_ABI explicit shuffle_order_engine(result_type __sd) : __e_(__sd) { __init(); }
83 template <
84 class _Sseq,
85 __enable_if_t<__is_seed_sequence<_Sseq, shuffle_order_engine>::value && !is_convertible<_Sseq, _Engine>::value,
86 int> = 0>
87 _LIBCPP_HIDE_FROM_ABI explicit shuffle_order_engine(_Sseq& __q) : __e_(__q) {
88 __init();
89 }
90 _LIBCPP_HIDE_FROM_ABI void seed() {
91 __e_.seed();
92 __init();
93 }
94 _LIBCPP_HIDE_FROM_ABI void seed(result_type __sd) {
95 __e_.seed(__sd);
96 __init();
97 }
98 template <class _Sseq, __enable_if_t<__is_seed_sequence<_Sseq, shuffle_order_engine>::value, int> = 0>
99 _LIBCPP_HIDE_FROM_ABI void seed(_Sseq& __q) {
100 __e_.seed(__q);
101 __init();
102 }
103
104 // generating functions
105 _LIBCPP_HIDE_FROM_ABI result_type operator()() { return __eval(integral_constant<bool, _Rp != 0>()); }
106 _LIBCPP_HIDE_FROM_ABI void discard(unsigned long long __z) {
107 for (; __z; --__z)
108 operator()();
109 }
110
111 // property functions
112 _LIBCPP_HIDE_FROM_ABI const _Engine& base() const _NOEXCEPT { return __e_; }
113
114private:
115 template <class _Eng, size_t _Kp>
116 friend bool operator==(const shuffle_order_engine<_Eng, _Kp>& __x, const shuffle_order_engine<_Eng, _Kp>& __y);
117
118 template <class _Eng, size_t _Kp>
119 friend bool operator!=(const shuffle_order_engine<_Eng, _Kp>& __x, const shuffle_order_engine<_Eng, _Kp>& __y);
120
121 template <class _CharT, class _Traits, class _Eng, size_t _Kp>
122 friend basic_ostream<_CharT, _Traits>&
123 operator<<(basic_ostream<_CharT, _Traits>& __os, const shuffle_order_engine<_Eng, _Kp>& __x);
124
125 template <class _CharT, class _Traits, class _Eng, size_t _Kp>
126 friend basic_istream<_CharT, _Traits>&
127 operator>>(basic_istream<_CharT, _Traits>& __is, shuffle_order_engine<_Eng, _Kp>& __x);
128
129 _LIBCPP_HIDE_FROM_ABI void __init() {
130 for (size_t __i = 0; __i < __k; ++__i)
131 __v_[__i] = __e_();
132 __y_ = __e_();
133 }
134
135 _LIBCPP_HIDE_FROM_ABI result_type __eval(false_type) { return __eval2(integral_constant<bool, __k & 1>()); }
136 _LIBCPP_HIDE_FROM_ABI result_type __eval(true_type) { return __eval(__uratio<__k, _Rp>()); }
137
138 _LIBCPP_HIDE_FROM_ABI result_type __eval2(false_type) { return __eval(__uratio<__k / 2, 0x8000000000000000ull>()); }
139 _LIBCPP_HIDE_FROM_ABI result_type __eval2(true_type) { return __evalf<__k, 0>(); }
140
141 template <uint64_t _Np,
142 uint64_t _Dp,
143 __enable_if_t<(__uratio<_Np, _Dp>::num > 0xFFFFFFFFFFFFFFFFull / (_Max - _Min)), int> = 0>
144 _LIBCPP_HIDE_FROM_ABI result_type __eval(__uratio<_Np, _Dp>) {
145 return __evalf<__uratio<_Np, _Dp>::num, __uratio<_Np, _Dp>::den>();
146 }
147
148 template <uint64_t _Np,
149 uint64_t _Dp,
150 __enable_if_t<__uratio<_Np, _Dp>::num <= 0xFFFFFFFFFFFFFFFFull / (_Max - _Min), int> = 0>
151 _LIBCPP_HIDE_FROM_ABI result_type __eval(__uratio<_Np, _Dp>) {
152 const size_t __j = static_cast<size_t>(__uratio<_Np, _Dp>::num * (__y_ - _Min) / __uratio<_Np, _Dp>::den);
153 __y_ = __v_[__j];
154 __v_[__j] = __e_();
155 return __y_;
156 }
157
158 template <uint64_t __n, uint64_t __d>
159 _LIBCPP_HIDE_FROM_ABI result_type __evalf() {
160 const double __fp = __d == 0 ? __n / (2. * 0x8000000000000000ull) : __n / (double)__d;
161 const size_t __j = static_cast<size_t>(__fp * (__y_ - _Min));
162 __y_ = __v_[__j];
163 __v_[__j] = __e_();
164 return __y_;
165 }
166};
167
168template <class _Engine, size_t __k>
169const size_t shuffle_order_engine<_Engine, __k>::table_size;
170
171template <class _Eng, size_t _Kp>
172_LIBCPP_HIDE_FROM_ABI bool
173operator==(const shuffle_order_engine<_Eng, _Kp>& __x, const shuffle_order_engine<_Eng, _Kp>& __y) {
174 return __x.__y_ == __y.__y_ && std::equal(__x.__v_, __x.__v_ + _Kp, __y.__v_) && __x.__e_ == __y.__e_;
175}
176
177template <class _Eng, size_t _Kp>
178inline _LIBCPP_HIDE_FROM_ABI bool
179operator!=(const shuffle_order_engine<_Eng, _Kp>& __x, const shuffle_order_engine<_Eng, _Kp>& __y) {
180 return !(__x == __y);
181}
182
183template <class _CharT, class _Traits, class _Eng, size_t _Kp>
184_LIBCPP_HIDE_FROM_ABI basic_ostream<_CharT, _Traits>&
185operator<<(basic_ostream<_CharT, _Traits>& __os, const shuffle_order_engine<_Eng, _Kp>& __x) {
186 __save_flags<_CharT, _Traits> __lx(__os);
187 typedef basic_ostream<_CharT, _Traits> _Ostream;
188 __os.flags(_Ostream::dec | _Ostream::left);
189 _CharT __sp = __os.widen(' ');
190 __os.fill(__sp);
191 __os << __x.__e_ << __sp << __x.__v_[0];
192 for (size_t __i = 1; __i < _Kp; ++__i)
193 __os << __sp << __x.__v_[__i];
194 return __os << __sp << __x.__y_;
195}
196
197template <class _CharT, class _Traits, class _Eng, size_t _Kp>
198_LIBCPP_HIDE_FROM_ABI basic_istream<_CharT, _Traits>&
199operator>>(basic_istream<_CharT, _Traits>& __is, shuffle_order_engine<_Eng, _Kp>& __x) {
200 typedef typename shuffle_order_engine<_Eng, _Kp>::result_type result_type;
201 __save_flags<_CharT, _Traits> __lx(__is);
202 typedef basic_istream<_CharT, _Traits> _Istream;
203 __is.flags(_Istream::dec | _Istream::skipws);
204 _Eng __e;
205 result_type __vp[_Kp + 1];
206 __is >> __e;
207 for (size_t __i = 0; __i < _Kp + 1; ++__i)
208 __is >> __vp[__i];
209 if (!__is.fail()) {
210 __x.__e_ = __e;
211 for (size_t __i = 0; __i < _Kp; ++__i)
212 __x.__v_[__i] = __vp[__i];
213 __x.__y_ = __vp[_Kp];
214 }
215 return __is;
216}
217
218_LIBCPP_END_NAMESPACE_STD
219
220_LIBCPP_POP_MACROS
221
222#endif // _LIBCPP___CXX03___RANDOM_SHUFFLE_ORDER_ENGINE_H
223

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source code of libcxx/include/__cxx03/__random/shuffle_order_engine.h