aboutsummaryrefslogtreecommitdiffstats
path: root/contrib/libs/cxxsupp/libcxxmsvc/include/__random/independent_bits_engine.h
blob: e80d6eec49cbc89a4eab994bc1f3d941deccb923 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#ifndef _LIBCPP___RANDOM_INDEPENDENT_BITS_ENGINE_H
#define _LIBCPP___RANDOM_INDEPENDENT_BITS_ENGINE_H

#include <__config>
#include <__random/is_seed_sequence.h>
#include <__random/log2.h>
#include <__utility/move.h>
#include <iosfwd>
#include <limits>
#include <type_traits>

#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
#  pragma GCC system_header
#endif

_LIBCPP_PUSH_MACROS
#include <__undef_macros>

_LIBCPP_BEGIN_NAMESPACE_STD

template<class _Engine, size_t __w, class _UIntType>
class _LIBCPP_TEMPLATE_VIS independent_bits_engine
{
    template <class _UInt, _UInt _R0, size_t _Wp, size_t _Mp>
    class __get_n
    {
        static _LIBCPP_CONSTEXPR const size_t _Dt = numeric_limits<_UInt>::digits;
        static _LIBCPP_CONSTEXPR const size_t _Np = _Wp / _Mp + (_Wp % _Mp != 0);
        static _LIBCPP_CONSTEXPR const size_t _W0 = _Wp / _Np;
        static _LIBCPP_CONSTEXPR const _UInt _Y0 = _W0 >= _Dt ? 0 : (_R0 >> _W0) << _W0;
    public:
        static _LIBCPP_CONSTEXPR const size_t value = _R0 - _Y0 > _Y0 / _Np ? _Np + 1 : _Np;
    };
public:
    // types
    typedef _UIntType result_type;

private:
    _Engine __e_;

    static _LIBCPP_CONSTEXPR const result_type _Dt = numeric_limits<result_type>::digits;
    static_assert(  0 <  __w, "independent_bits_engine invalid parameters");
    static_assert(__w <= _Dt, "independent_bits_engine invalid parameters");

    typedef typename _Engine::result_type _Engine_result_type;
    typedef typename conditional
        <
            sizeof(_Engine_result_type) <= sizeof(result_type),
                result_type,
                _Engine_result_type
        >::type _Working_result_type;
#ifdef _LIBCPP_CXX03_LANG
    static const _Working_result_type _Rp = _Engine::_Max - _Engine::_Min
                                          + _Working_result_type(1);
#else
    static _LIBCPP_CONSTEXPR const _Working_result_type _Rp = _Engine::max() - _Engine::min()
                                                            + _Working_result_type(1);
#endif
    static _LIBCPP_CONSTEXPR const size_t __m = __log2<_Working_result_type, _Rp>::value;
    static _LIBCPP_CONSTEXPR const size_t __n = __get_n<_Working_result_type, _Rp, __w, __m>::value;
    static _LIBCPP_CONSTEXPR const size_t __w0 = __w / __n;
    static _LIBCPP_CONSTEXPR const size_t __n0 = __n - __w % __n;
    static _LIBCPP_CONSTEXPR const size_t _WDt = numeric_limits<_Working_result_type>::digits;
    static _LIBCPP_CONSTEXPR const size_t _EDt = numeric_limits<_Engine_result_type>::digits;
    static _LIBCPP_CONSTEXPR const _Working_result_type __y0 = __w0 >= _WDt ? 0 :
                                                               (_Rp >> __w0) << __w0;
    static _LIBCPP_CONSTEXPR const _Working_result_type __y1 = __w0 >= _WDt - 1 ? 0 :
                                                               (_Rp >> (__w0+1)) << (__w0+1);
    static _LIBCPP_CONSTEXPR const _Engine_result_type __mask0 = __w0 > 0 ?
                                _Engine_result_type(~0) >> (_EDt - __w0) :
                                _Engine_result_type(0);
    static _LIBCPP_CONSTEXPR const _Engine_result_type __mask1 = __w0 < _EDt - 1 ?
                                _Engine_result_type(~0) >> (_EDt - (__w0 + 1)) :
                                _Engine_result_type(~0);
public:
    static _LIBCPP_CONSTEXPR const result_type _Min = 0;
    static _LIBCPP_CONSTEXPR const result_type _Max = __w == _Dt ? result_type(~0) :
                                                      (result_type(1) << __w) - result_type(1);
    static_assert(_Min < _Max, "independent_bits_engine invalid parameters");

    // engine characteristics
    _LIBCPP_INLINE_VISIBILITY
    static _LIBCPP_CONSTEXPR result_type min() { return _Min; }
    _LIBCPP_INLINE_VISIBILITY
    static _LIBCPP_CONSTEXPR result_type max() { return _Max; }

    // constructors and seeding functions
    _LIBCPP_INLINE_VISIBILITY
    independent_bits_engine() {}
    _LIBCPP_INLINE_VISIBILITY
    explicit independent_bits_engine(const _Engine& __e)
        : __e_(__e) {}
#ifndef _LIBCPP_CXX03_LANG
    _LIBCPP_INLINE_VISIBILITY
    explicit independent_bits_engine(_Engine&& __e)
        : __e_(_VSTD::move(__e)) {}
#endif // _LIBCPP_CXX03_LANG
    _LIBCPP_INLINE_VISIBILITY
    explicit independent_bits_engine(result_type __sd) : __e_(__sd) {}
    template<class _Sseq>
        _LIBCPP_INLINE_VISIBILITY
        explicit independent_bits_engine(_Sseq& __q,
        typename enable_if<__is_seed_sequence<_Sseq, independent_bits_engine>::value &&
                           !is_convertible<_Sseq, _Engine>::value>::type* = 0)
         : __e_(__q) {}
    _LIBCPP_INLINE_VISIBILITY
    void seed() {__e_.seed();}
    _LIBCPP_INLINE_VISIBILITY
    void seed(result_type __sd) {__e_.seed(__sd);}
    template<class _Sseq>
        _LIBCPP_INLINE_VISIBILITY
        typename enable_if
        <
            __is_seed_sequence<_Sseq, independent_bits_engine>::value,
            void
        >::type
        seed(_Sseq& __q) {__e_.seed(__q);}

    // generating functions
    _LIBCPP_INLINE_VISIBILITY
    result_type operator()() {return __eval(integral_constant<bool, _Rp != 0>());}
    _LIBCPP_INLINE_VISIBILITY
    void discard(unsigned long long __z) {for (; __z; --__z) operator()();}

    // property functions
    _LIBCPP_INLINE_VISIBILITY
    const _Engine& base() const _NOEXCEPT {return __e_;}

    template<class _Eng, size_t _Wp, class _UInt>
    friend
    bool
    operator==(
        const independent_bits_engine<_Eng, _Wp, _UInt>& __x,
        const independent_bits_engine<_Eng, _Wp, _UInt>& __y);

    template<class _Eng, size_t _Wp, class _UInt>
    friend
    bool
    operator!=(
        const independent_bits_engine<_Eng, _Wp, _UInt>& __x,
        const independent_bits_engine<_Eng, _Wp, _UInt>& __y);

    template <class _CharT, class _Traits,
              class _Eng, size_t _Wp, class _UInt>
    friend
    basic_ostream<_CharT, _Traits>&
    operator<<(basic_ostream<_CharT, _Traits>& __os,
               const independent_bits_engine<_Eng, _Wp, _UInt>& __x);

    template <class _CharT, class _Traits,
              class _Eng, size_t _Wp, class _UInt>
    friend
    basic_istream<_CharT, _Traits>&
    operator>>(basic_istream<_CharT, _Traits>& __is,
               independent_bits_engine<_Eng, _Wp, _UInt>& __x);

private:
    _LIBCPP_INLINE_VISIBILITY
    result_type __eval(false_type);
    result_type __eval(true_type);

    template <size_t __count>
        _LIBCPP_INLINE_VISIBILITY
        static
        typename enable_if
        <
            __count < _Dt,
            result_type
        >::type
        __lshift(result_type __x) {return __x << __count;}

    template <size_t __count>
        _LIBCPP_INLINE_VISIBILITY
        static
        typename enable_if
        <
            (__count >= _Dt),
            result_type
        >::type
        __lshift(result_type) {return result_type(0);}
};

template<class _Engine, size_t __w, class _UIntType>
inline
_UIntType
independent_bits_engine<_Engine, __w, _UIntType>::__eval(false_type)
{
    return static_cast<result_type>(__e_() & __mask0);
}

template<class _Engine, size_t __w, class _UIntType>
_UIntType
independent_bits_engine<_Engine, __w, _UIntType>::__eval(true_type)
{
    result_type _Sp = 0;
    for (size_t __k = 0; __k < __n0; ++__k)
    {
        _Engine_result_type __u;
        do
        {
            __u = __e_() - _Engine::min();
        } while (__u >= __y0);
        _Sp = static_cast<result_type>(__lshift<__w0>(_Sp) + (__u & __mask0));
    }
    for (size_t __k = __n0; __k < __n; ++__k)
    {
        _Engine_result_type __u;
        do
        {
            __u = __e_() - _Engine::min();
        } while (__u >= __y1);
        _Sp = static_cast<result_type>(__lshift<__w0+1>(_Sp) + (__u & __mask1));
    }
    return _Sp;
}

template<class _Eng, size_t _Wp, class _UInt>
inline _LIBCPP_INLINE_VISIBILITY
bool
operator==(
    const independent_bits_engine<_Eng, _Wp, _UInt>& __x,
    const independent_bits_engine<_Eng, _Wp, _UInt>& __y)
{
    return __x.base() == __y.base();
}

template<class _Eng, size_t _Wp, class _UInt>
inline _LIBCPP_INLINE_VISIBILITY
bool
operator!=(
    const independent_bits_engine<_Eng, _Wp, _UInt>& __x,
    const independent_bits_engine<_Eng, _Wp, _UInt>& __y)
{
    return !(__x == __y);
}

template <class _CharT, class _Traits,
          class _Eng, size_t _Wp, class _UInt>
basic_ostream<_CharT, _Traits>&
operator<<(basic_ostream<_CharT, _Traits>& __os,
           const independent_bits_engine<_Eng, _Wp, _UInt>& __x)
{
    return __os << __x.base();
}

template <class _CharT, class _Traits,
          class _Eng, size_t _Wp, class _UInt>
basic_istream<_CharT, _Traits>&
operator>>(basic_istream<_CharT, _Traits>& __is,
           independent_bits_engine<_Eng, _Wp, _UInt>& __x)
{
    _Eng __e;
    __is >> __e;
    if (!__is.fail())
        __x.__e_ = __e;
    return __is;
}

_LIBCPP_END_NAMESPACE_STD

_LIBCPP_POP_MACROS

#endif // _LIBCPP___RANDOM_INDEPENDENT_BITS_ENGINE_H