libcxx/include/__random/geometric_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_GEOMETRIC_DISTRIBUTION_H
  10 #define _LIBCPP___RANDOM_GEOMETRIC_DISTRIBUTION_H
  11
  12 #include <__config>
  13 #include <__random/is_valid.h>
  14 #include <__random/negative_binomial_distribution.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 _IntType = int>
  28 class _LIBCPP_TEMPLATE_VIS geometric_distribution
  29 {
  30     static_assert(__libcpp_random_is_valid_inttype<_IntType>::value, "IntType must be a supported integer type");
  31 public:
  32     // types
  33     typedef _IntType result_type;
  34
  35     class _LIBCPP_TEMPLATE_VIS param_type
  36     {
  37         double __p_;
  38     public:
  39         typedef geometric_distribution distribution_type;
  40
  41         _LIBCPP_INLINE_VISIBILITY
  42         explicit param_type(double __p = 0.5) : __p_(__p) {}
  43
  44         _LIBCPP_INLINE_VISIBILITY
  45         double p() const {return __p_;}
  46
  47         friend _LIBCPP_INLINE_VISIBILITY
  48             bool operator==(const param_type& __x, const param_type& __y)
  49             {return __x.__p_ == __y.__p_;}
  50         friend _LIBCPP_INLINE_VISIBILITY
  51             bool operator!=(const param_type& __x, const param_type& __y)
  52             {return !(__x == __y);}
  53     };
  54
  55 private:
  56     param_type __p_;
  57
  58 public:
  59     // constructors and reset functions
  60 #ifndef _LIBCPP_CXX03_LANG
  61     _LIBCPP_INLINE_VISIBILITY
  62     geometric_distribution() : geometric_distribution(0.5) {}
  63     _LIBCPP_INLINE_VISIBILITY
  64     explicit geometric_distribution(double __p)
  65         : __p_(__p) {}
  66 #else
  67     _LIBCPP_INLINE_VISIBILITY
  68     explicit geometric_distribution(double __p = 0.5)
  69         : __p_(__p) {}
  70 #endif
  71     _LIBCPP_INLINE_VISIBILITY
  72     explicit geometric_distribution(const param_type& __p) : __p_(__p) {}
  73     _LIBCPP_INLINE_VISIBILITY
  74     void reset() {}
  75
  76     // generating functions
  77     template<class _URNG>
  78         _LIBCPP_INLINE_VISIBILITY
  79         result_type operator()(_URNG& __g)
  80         {return (*this)(__g, __p_);}
  81     template<class _URNG>
  82         _LIBCPP_INLINE_VISIBILITY
  83         result_type operator()(_URNG& __g, const param_type& __p)
  84         {return negative_binomial_distribution<result_type>(1, __p.p())(__g);}
  85
  86     // property functions
  87     _LIBCPP_INLINE_VISIBILITY
  88     double p() const {return __p_.p();}
  89
  90     _LIBCPP_INLINE_VISIBILITY
  91     param_type param() const {return __p_;}
  92     _LIBCPP_INLINE_VISIBILITY
  93     void param(const param_type& __p) {__p_ = __p;}
  94
  95     _LIBCPP_INLINE_VISIBILITY
  96     result_type min() const {return 0;}
  97     _LIBCPP_INLINE_VISIBILITY
  98     result_type max() const {return numeric_limits<result_type>::max();}
  99
 100     friend _LIBCPP_INLINE_VISIBILITY
 101         bool operator==(const geometric_distribution& __x,
 102                         const geometric_distribution& __y)
 103         {return __x.__p_ == __y.__p_;}
 104     friend _LIBCPP_INLINE_VISIBILITY
 105         bool operator!=(const geometric_distribution& __x,
 106                         const geometric_distribution& __y)
 107         {return !(__x == __y);}
 108 };
 109
 110 template <class _CharT, class _Traits, class _IntType>
 111 _LIBCPP_HIDE_FROM_ABI basic_ostream<_CharT, _Traits>&
 112 operator<<(basic_ostream<_CharT, _Traits>& __os,
 113            const geometric_distribution<_IntType>& __x)
 114 {
 115     __save_flags<_CharT, _Traits> __lx(__os);
 116     typedef basic_ostream<_CharT, _Traits> _OStream;
 117     __os.flags(_OStream::dec | _OStream::left | _OStream::fixed |
 118                _OStream::scientific);
 119     return __os << __x.p();
 120 }
 121
 122 template <class _CharT, class _Traits, class _IntType>
 123 _LIBCPP_HIDE_FROM_ABI basic_istream<_CharT, _Traits>&
 124 operator>>(basic_istream<_CharT, _Traits>& __is,
 125            geometric_distribution<_IntType>& __x)
 126 {
 127     typedef geometric_distribution<_IntType> _Eng;
 128     typedef typename _Eng::param_type param_type;
 129     __save_flags<_CharT, _Traits> __lx(__is);
 130     typedef basic_istream<_CharT, _Traits> _Istream;
 131     __is.flags(_Istream::dec | _Istream::skipws);
 132     double __p;
 133     __is >> __p;
 134     if (!__is.fail())
 135         __x.param(param_type(__p));
 136     return __is;
 137 }
 138
 139 _LIBCPP_END_NAMESPACE_STD
 140
 141 _LIBCPP_POP_MACROS
 142
 143 #endif // _LIBCPP___RANDOM_GEOMETRIC_DISTRIBUTION_H