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_UNIFORM_REAL_DISTRIBUTION_H
10 #define _LIBCPP___RANDOM_UNIFORM_REAL_DISTRIBUTION_H
11 
12 #include <__config>
13 #include <__random/generate_canonical.h>
14 #include <__random/is_valid.h>
15 #include <iosfwd>
16 #include <limits>
17 #include <type_traits>
18 
19 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
20 #  pragma GCC system_header
21 #endif
22 
23 _LIBCPP_PUSH_MACROS
24 #include <__undef_macros>
25 
26 _LIBCPP_BEGIN_NAMESPACE_STD
27 
28 template<class _RealType = double>
29 class _LIBCPP_TEMPLATE_VIS uniform_real_distribution
30 {
31 public:
32     // types
33     typedef _RealType result_type;
34 
35     class _LIBCPP_TEMPLATE_VIS param_type
36     {
37         result_type __a_;
38         result_type __b_;
39     public:
40         typedef uniform_real_distribution distribution_type;
41 
42         _LIBCPP_INLINE_VISIBILITY
43         explicit param_type(result_type __a = 0,
44                             result_type __b = 1)
45             : __a_(__a), __b_(__b) {}
46 
47         _LIBCPP_INLINE_VISIBILITY
48         result_type a() const {return __a_;}
49         _LIBCPP_INLINE_VISIBILITY
50         result_type b() const {return __b_;}
51 
52         friend _LIBCPP_INLINE_VISIBILITY
53         bool operator==(const param_type& __x, const param_type& __y)
54             {return __x.__a_ == __y.__a_ && __x.__b_ == __y.__b_;}
55         friend _LIBCPP_INLINE_VISIBILITY
56         bool operator!=(const param_type& __x, const param_type& __y)
57             {return !(__x == __y);}
58     };
59 
60 private:
61     param_type __p_;
62 
63 public:
64     // constructors and reset functions
65 #ifndef _LIBCPP_CXX03_LANG
66     _LIBCPP_INLINE_VISIBILITY
67     uniform_real_distribution() : uniform_real_distribution(0) {}
68     explicit uniform_real_distribution(result_type __a, result_type __b = 1)
69         : __p_(param_type(__a, __b)) {}
70 #else
71     _LIBCPP_INLINE_VISIBILITY
72     explicit uniform_real_distribution(result_type __a = 0, result_type __b = 1)
73         : __p_(param_type(__a, __b)) {}
74 #endif
75     _LIBCPP_INLINE_VISIBILITY
76     explicit uniform_real_distribution(const param_type& __p) : __p_(__p) {}
77     _LIBCPP_INLINE_VISIBILITY
78     void reset() {}
79 
80     // generating functions
81     template<class _URNG>
82         _LIBCPP_INLINE_VISIBILITY
83         result_type operator()(_URNG& __g)
84         {return (*this)(__g, __p_);}
85     template<class _URNG> _LIBCPP_INLINE_VISIBILITY result_type operator()(_URNG& __g, const param_type& __p);
86 
87     // property functions
88     _LIBCPP_INLINE_VISIBILITY
89     result_type a() const {return __p_.a();}
90     _LIBCPP_INLINE_VISIBILITY
91     result_type b() const {return __p_.b();}
92 
93     _LIBCPP_INLINE_VISIBILITY
94     param_type param() const {return __p_;}
95     _LIBCPP_INLINE_VISIBILITY
96     void param(const param_type& __p) {__p_ = __p;}
97 
98     _LIBCPP_INLINE_VISIBILITY
99     result_type min() const {return a();}
100     _LIBCPP_INLINE_VISIBILITY
101     result_type max() const {return b();}
102 
103     friend _LIBCPP_INLINE_VISIBILITY
104         bool operator==(const uniform_real_distribution& __x,
105                         const uniform_real_distribution& __y)
106         {return __x.__p_ == __y.__p_;}
107     friend _LIBCPP_INLINE_VISIBILITY
108         bool operator!=(const uniform_real_distribution& __x,
109                         const uniform_real_distribution& __y)
110         {return !(__x == __y);}
111 };
112 
113 template<class _RealType>
114 template<class _URNG>
115 inline
116 typename uniform_real_distribution<_RealType>::result_type
117 uniform_real_distribution<_RealType>::operator()(_URNG& __g, const param_type& __p)
118 {
119     static_assert(__libcpp_random_is_valid_urng<_URNG>::value, "");
120     return (__p.b() - __p.a())
121         * _VSTD::generate_canonical<_RealType, numeric_limits<_RealType>::digits>(__g)
122         + __p.a();
123 }
124 
125 template <class _CharT, class _Traits, class _RT>
126 _LIBCPP_HIDE_FROM_ABI basic_ostream<_CharT, _Traits>&
127 operator<<(basic_ostream<_CharT, _Traits>& __os,
128            const uniform_real_distribution<_RT>& __x)
129 {
130     __save_flags<_CharT, _Traits> __lx(__os);
131     typedef basic_ostream<_CharT, _Traits> _OStream;
132     __os.flags(_OStream::dec | _OStream::left | _OStream::fixed |
133                _OStream::scientific);
134     _CharT __sp = __os.widen(' ');
135     __os.fill(__sp);
136     return __os << __x.a() << __sp << __x.b();
137 }
138 
139 template <class _CharT, class _Traits, class _RT>
140 _LIBCPP_HIDE_FROM_ABI basic_istream<_CharT, _Traits>&
141 operator>>(basic_istream<_CharT, _Traits>& __is,
142            uniform_real_distribution<_RT>& __x)
143 {
144     typedef uniform_real_distribution<_RT> _Eng;
145     typedef typename _Eng::result_type result_type;
146     typedef typename _Eng::param_type param_type;
147     __save_flags<_CharT, _Traits> __lx(__is);
148     typedef basic_istream<_CharT, _Traits> _Istream;
149     __is.flags(_Istream::dec | _Istream::skipws);
150     result_type __a;
151     result_type __b;
152     __is >> __a >> __b;
153     if (!__is.fail())
154         __x.param(param_type(__a, __b));
155     return __is;
156 }
157 
158 _LIBCPP_END_NAMESPACE_STD
159 
160 _LIBCPP_POP_MACROS
161 
162 #endif // _LIBCPP___RANDOM_UNIFORM_REAL_DISTRIBUTION_H
163