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___ALGORITHM_SHUFFLE_H
10#define _LIBCPP___ALGORITHM_SHUFFLE_H
11
12#include <__algorithm/iterator_operations.h>
13#include <__config>
14#include <__cstddef/ptrdiff_t.h>
15#include <__iterator/iterator_traits.h>
16#include <__random/uniform_int_distribution.h>
17#include <__utility/forward.h>
18#include <__utility/move.h>
19#include <__utility/swap.h>
20#include <cstdint>
21
22#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
23# pragma GCC system_header
24#endif
25
26_LIBCPP_PUSH_MACROS
27#include <__undef_macros>
28
29_LIBCPP_BEGIN_NAMESPACE_STD
30
31class _LIBCPP_EXPORTED_FROM_ABI __libcpp_debug_randomizer {
32public:
33 _LIBCPP_HIDE_FROM_ABI __libcpp_debug_randomizer() {
34 __state_ = __seed();
35 __inc_ = __state_ + 0xda3e39cb94b95bdbULL;
36 __inc_ = (__inc_ << 1) | 1;
37 }
38 typedef uint_fast32_t result_type;
39
40 static const result_type _Min = 0;
41 static const result_type _Max = 0xFFFFFFFF;
42
43 _LIBCPP_HIDE_FROM_ABI result_type operator()() {
44 uint_fast64_t __oldstate = __state_;
45 __state_ = __oldstate * 6364136223846793005ULL + __inc_;
46 return __oldstate >> 32;
47 }
48
49 static _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR result_type min() { return _Min; }
50 static _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR result_type max() { return _Max; }
51
52private:
53 uint_fast64_t __state_;
54 uint_fast64_t __inc_;
55 _LIBCPP_HIDE_FROM_ABI static uint_fast64_t __seed() {
56#ifdef _LIBCPP_DEBUG_RANDOMIZE_UNSPECIFIED_STABILITY_SEED
57 return _LIBCPP_DEBUG_RANDOMIZE_UNSPECIFIED_STABILITY_SEED;
58#else
59 static char __x;
60 return reinterpret_cast<uintptr_t>(&__x);
61#endif
62 }
63};
64
65#if _LIBCPP_STD_VER <= 14 || defined(_LIBCPP_ENABLE_CXX17_REMOVED_RANDOM_SHUFFLE) || defined(_LIBCPP_BUILDING_LIBRARY)
66class _LIBCPP_EXPORTED_FROM_ABI __rs_default;
67
68_LIBCPP_EXPORTED_FROM_ABI __rs_default __rs_get();
69
70class _LIBCPP_EXPORTED_FROM_ABI __rs_default {
71 static unsigned __c_;
72
73 __rs_default();
74
75public:
76 typedef uint_fast32_t result_type;
77
78 static const result_type _Min = 0;
79 static const result_type _Max = 0xFFFFFFFF;
80
81 __rs_default(const __rs_default&);
82 ~__rs_default();
83
84 result_type operator()();
85
86 static _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR result_type min() { return _Min; }
87 static _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR result_type max() { return _Max; }
88
89 friend _LIBCPP_EXPORTED_FROM_ABI __rs_default __rs_get();
90};
91
92_LIBCPP_EXPORTED_FROM_ABI __rs_default __rs_get();
93
94template <class _RandomAccessIterator>
95_LIBCPP_HIDE_FROM_ABI _LIBCPP_DEPRECATED_IN_CXX14 void
96random_shuffle(_RandomAccessIterator __first, _RandomAccessIterator __last) {
97 typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
98 typedef uniform_int_distribution<ptrdiff_t> _Dp;
99 typedef typename _Dp::param_type _Pp;
100 difference_type __d = __last - __first;
101 if (__d > 1) {
102 _Dp __uid;
103 __rs_default __g = __rs_get();
104 for (--__last, (void)--__d; __first < __last; ++__first, (void)--__d) {
105 difference_type __i = __uid(__g, _Pp(0, __d));
106 if (__i != difference_type(0))
107 swap(*__first, *(__first + __i));
108 }
109 }
110}
111
112template <class _RandomAccessIterator, class _RandomNumberGenerator>
113_LIBCPP_HIDE_FROM_ABI _LIBCPP_DEPRECATED_IN_CXX14 void
114random_shuffle(_RandomAccessIterator __first,
115 _RandomAccessIterator __last,
116# ifndef _LIBCPP_CXX03_LANG
117 _RandomNumberGenerator&& __rand)
118# else
119 _RandomNumberGenerator& __rand)
120# endif
121{
122 typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
123 difference_type __d = __last - __first;
124 if (__d > 1) {
125 for (--__last; __first < __last; ++__first, (void)--__d) {
126 difference_type __i = __rand(__d);
127 if (__i != difference_type(0))
128 swap(*__first, *(__first + __i));
129 }
130 }
131}
132#endif
133
134template <class _AlgPolicy, class _RandomAccessIterator, class _Sentinel, class _UniformRandomNumberGenerator>
135_LIBCPP_HIDE_FROM_ABI _RandomAccessIterator
136__shuffle(_RandomAccessIterator __first, _Sentinel __last_sentinel, _UniformRandomNumberGenerator&& __g) {
137 typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
138 typedef uniform_int_distribution<ptrdiff_t> _Dp;
139 typedef typename _Dp::param_type _Pp;
140
141 auto __original_last = _IterOps<_AlgPolicy>::next(__first, __last_sentinel);
142 auto __last = __original_last;
143 difference_type __d = __last - __first;
144 if (__d > 1) {
145 _Dp __uid;
146 for (--__last, (void)--__d; __first < __last; ++__first, (void)--__d) {
147 difference_type __i = __uid(__g, _Pp(0, __d));
148 if (__i != difference_type(0))
149 _IterOps<_AlgPolicy>::iter_swap(__first, __first + __i);
150 }
151 }
152
153 return __original_last;
154}
155
156template <class _RandomAccessIterator, class _UniformRandomNumberGenerator>
157_LIBCPP_HIDE_FROM_ABI void
158shuffle(_RandomAccessIterator __first, _RandomAccessIterator __last, _UniformRandomNumberGenerator&& __g) {
159 (void)std::__shuffle<_ClassicAlgPolicy>(
160 std::move(__first), std::move(__last), std::forward<_UniformRandomNumberGenerator>(__g));
161}
162
163_LIBCPP_END_NAMESPACE_STD
164
165_LIBCPP_POP_MACROS
166
167#endif // _LIBCPP___ALGORITHM_SHUFFLE_H
168