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_BERNOULLI_DISTRIBUTION_H
10 #define _LIBCPP___RANDOM_BERNOULLI_DISTRIBUTION_H
11 
12 #include <__config>
13 #include <__random/is_valid.h>
14 #include <__random/uniform_real_distribution.h>
15 #include <iosfwd>
16 
17 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
18 #  pragma GCC system_header
19 #endif
20 
21 _LIBCPP_PUSH_MACROS
22 #include <__undef_macros>
23 
24 _LIBCPP_BEGIN_NAMESPACE_STD
25 
26 class _LIBCPP_TEMPLATE_VIS bernoulli_distribution
27 {
28 public:
29     // types
30     typedef bool result_type;
31 
32     class _LIBCPP_TEMPLATE_VIS param_type
33     {
34         double __p_;
35     public:
36         typedef bernoulli_distribution distribution_type;
37 
38         _LIBCPP_INLINE_VISIBILITY
39         explicit param_type(double __p = 0.5) : __p_(__p) {}
40 
41         _LIBCPP_INLINE_VISIBILITY
42         double p() const {return __p_;}
43 
44         friend _LIBCPP_INLINE_VISIBILITY
45             bool operator==(const param_type& __x, const param_type& __y)
46             {return __x.__p_ == __y.__p_;}
47         friend _LIBCPP_INLINE_VISIBILITY
48             bool operator!=(const param_type& __x, const param_type& __y)
49             {return !(__x == __y);}
50     };
51 
52 private:
53     param_type __p_;
54 
55 public:
56     // constructors and reset functions
57 #ifndef _LIBCPP_CXX03_LANG
58     _LIBCPP_INLINE_VISIBILITY
59     bernoulli_distribution() : bernoulli_distribution(0.5) {}
60     _LIBCPP_INLINE_VISIBILITY
61     explicit bernoulli_distribution(double __p) : __p_(param_type(__p)) {}
62 #else
63     _LIBCPP_INLINE_VISIBILITY
64     explicit bernoulli_distribution(double __p = 0.5) : __p_(param_type(__p)) {}
65 #endif
66     _LIBCPP_INLINE_VISIBILITY
67     explicit bernoulli_distribution(const param_type& __p) : __p_(__p) {}
68     _LIBCPP_INLINE_VISIBILITY
69     void reset() {}
70 
71     // generating functions
72     template<class _URNG>
73         _LIBCPP_INLINE_VISIBILITY
74         result_type operator()(_URNG& __g)
75         {return (*this)(__g, __p_);}
76     template<class _URNG> _LIBCPP_INLINE_VISIBILITY result_type operator()(_URNG& __g, const param_type& __p);
77 
78     // property functions
79     _LIBCPP_INLINE_VISIBILITY
80     double p() const {return __p_.p();}
81 
82     _LIBCPP_INLINE_VISIBILITY
83     param_type param() const {return __p_;}
84     _LIBCPP_INLINE_VISIBILITY
85     void param(const param_type& __p) {__p_ = __p;}
86 
87     _LIBCPP_INLINE_VISIBILITY
88     result_type min() const {return false;}
89     _LIBCPP_INLINE_VISIBILITY
90     result_type max() const {return true;}
91 
92     friend _LIBCPP_INLINE_VISIBILITY
93         bool operator==(const bernoulli_distribution& __x,
94                         const bernoulli_distribution& __y)
95         {return __x.__p_ == __y.__p_;}
96     friend _LIBCPP_INLINE_VISIBILITY
97         bool operator!=(const bernoulli_distribution& __x,
98                         const bernoulli_distribution& __y)
99         {return !(__x == __y);}
100 };
101 
102 template<class _URNG>
103 inline
104 bernoulli_distribution::result_type
105 bernoulli_distribution::operator()(_URNG& __g, const param_type& __p)
106 {
107     static_assert(__libcpp_random_is_valid_urng<_URNG>::value, "");
108     uniform_real_distribution<double> __gen;
109     return __gen(__g) < __p.p();
110 }
111 
112 template <class _CharT, class _Traits>
113 basic_ostream<_CharT, _Traits>&
114 operator<<(basic_ostream<_CharT, _Traits>& __os, const bernoulli_distribution& __x)
115 {
116     __save_flags<_CharT, _Traits> __lx(__os);
117     typedef basic_ostream<_CharT, _Traits> _OStream;
118     __os.flags(_OStream::dec | _OStream::left | _OStream::fixed |
119                _OStream::scientific);
120     _CharT __sp = __os.widen(' ');
121     __os.fill(__sp);
122     return __os << __x.p();
123 }
124 
125 template <class _CharT, class _Traits>
126 basic_istream<_CharT, _Traits>&
127 operator>>(basic_istream<_CharT, _Traits>& __is, bernoulli_distribution& __x)
128 {
129     typedef bernoulli_distribution _Eng;
130     typedef typename _Eng::param_type param_type;
131     __save_flags<_CharT, _Traits> __lx(__is);
132     typedef basic_istream<_CharT, _Traits> _Istream;
133     __is.flags(_Istream::dec | _Istream::skipws);
134     double __p;
135     __is >> __p;
136     if (!__is.fail())
137         __x.param(param_type(__p));
138     return __is;
139 }
140 
141 _LIBCPP_END_NAMESPACE_STD
142 
143 _LIBCPP_POP_MACROS
144 
145 #endif // _LIBCPP___RANDOM_BERNOULLI_DISTRIBUTION_H
146