libcxx/include/__random/uniform_real_distribution.h

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