libcxx/include/__random/bernoulli_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_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 public:
  28   // types
  29   typedef bool result_type;
  30
  31   class _LIBCPP_TEMPLATE_VIS param_type {
  32     double __p_;
  33
  34   public:
  35     typedef bernoulli_distribution distribution_type;
  36
  37     _LIBCPP_HIDE_FROM_ABI explicit param_type(double __p = 0.5) : __p_(__p) {}
  38
  39     _LIBCPP_HIDE_FROM_ABI double p() const { return __p_; }
  40
  41     friend _LIBCPP_HIDE_FROM_ABI bool operator==(const param_type& __x, const param_type& __y) {
  42       return __x.__p_ == __y.__p_;
  43     }
  44     friend _LIBCPP_HIDE_FROM_ABI bool operator!=(const param_type& __x, const param_type& __y) { return !(__x == __y); }
  45   };
  46
  47 private:
  48   param_type __p_;
  49
  50 public:
  51   // constructors and reset functions
  52 #ifndef _LIBCPP_CXX03_LANG
  53   _LIBCPP_HIDE_FROM_ABI bernoulli_distribution() : bernoulli_distribution(0.5) {}
  54   _LIBCPP_HIDE_FROM_ABI explicit bernoulli_distribution(double __p) : __p_(param_type(__p)) {}
  55 #else
  56   _LIBCPP_HIDE_FROM_ABI explicit bernoulli_distribution(double __p = 0.5) : __p_(param_type(__p)) {}
  57 #endif
  58   _LIBCPP_HIDE_FROM_ABI explicit bernoulli_distribution(const param_type& __p) : __p_(__p) {}
  59   _LIBCPP_HIDE_FROM_ABI void reset() {}
  60
  61   // generating functions
  62   template <class _URNG>
  63   _LIBCPP_HIDE_FROM_ABI result_type operator()(_URNG& __g) {
  64     return (*this)(__g, __p_);
  65   }
  66   template <class _URNG>
  67   _LIBCPP_HIDE_FROM_ABI result_type operator()(_URNG& __g, const param_type& __p);
  68
  69   // property functions
  70   _LIBCPP_HIDE_FROM_ABI double p() const { return __p_.p(); }
  71
  72   _LIBCPP_HIDE_FROM_ABI param_type param() const { return __p_; }
  73   _LIBCPP_HIDE_FROM_ABI void param(const param_type& __p) { __p_ = __p; }
  74
  75   _LIBCPP_HIDE_FROM_ABI result_type min() const { return false; }
  76   _LIBCPP_HIDE_FROM_ABI result_type max() const { return true; }
  77
  78   friend _LIBCPP_HIDE_FROM_ABI bool operator==(const bernoulli_distribution& __x, const bernoulli_distribution& __y) {
  79     return __x.__p_ == __y.__p_;
  80   }
  81   friend _LIBCPP_HIDE_FROM_ABI bool operator!=(const bernoulli_distribution& __x, const bernoulli_distribution& __y) {
  82     return !(__x == __y);
  83   }
  84 };
  85
  86 template <class _URNG>
  87 inline bernoulli_distribution::result_type bernoulli_distribution::operator()(_URNG& __g, const param_type& __p) {
  88   static_assert(__libcpp_random_is_valid_urng<_URNG>::value, "");
  89   uniform_real_distribution<double> __gen;
  90   return __gen(__g) < __p.p();
  91 }
  92
  93 template <class _CharT, class _Traits>
  94 _LIBCPP_HIDE_FROM_ABI basic_ostream<_CharT, _Traits>&
  95 operator<<(basic_ostream<_CharT, _Traits>& __os, const bernoulli_distribution& __x) {
  96   __save_flags<_CharT, _Traits> __lx(__os);
  97   typedef basic_ostream<_CharT, _Traits> _OStream;
  98   __os.flags(_OStream::dec | _OStream::left | _OStream::fixed | _OStream::scientific);
  99   _CharT __sp = __os.widen(' ');
 100   __os.fill(__sp);
 101   return __os << __x.p();
 102 }
 103
 104 template <class _CharT, class _Traits>
 105 _LIBCPP_HIDE_FROM_ABI basic_istream<_CharT, _Traits>&
 106 operator>>(basic_istream<_CharT, _Traits>& __is, bernoulli_distribution& __x) {
 107   typedef bernoulli_distribution _Eng;
 108   typedef typename _Eng::param_type param_type;
 109   __save_flags<_CharT, _Traits> __lx(__is);
 110   typedef basic_istream<_CharT, _Traits> _Istream;
 111   __is.flags(_Istream::dec | _Istream::skipws);
 112   double __p;
 113   __is >> __p;
 114   if (!__is.fail())
 115     __x.param(param_type(__p));
 116   return __is;
 117 }
 118
 119 _LIBCPP_END_NAMESPACE_STD
 120
 121 _LIBCPP_POP_MACROS
 122
 123 #endif // _LIBCPP___RANDOM_BERNOULLI_DISTRIBUTION_H