libcxx/include/__cxx03/__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___CXX03___RANDOM_GEOMETRIC_DISTRIBUTION_H
  10 #define _LIBCPP___CXX03___RANDOM_GEOMETRIC_DISTRIBUTION_H
  11
  12 #include <__cxx03/__config>
  13 #include <__cxx03/__random/is_valid.h>
  14 #include <__cxx03/__random/negative_binomial_distribution.h>
  15 #include <__cxx03/iosfwd>
  16 #include <__cxx03/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 <__cxx03/__undef_macros>
  24
  25 _LIBCPP_BEGIN_NAMESPACE_STD
  26
  27 template <class _IntType = int>
  28 class _LIBCPP_TEMPLATE_VIS geometric_distribution {
  29   static_assert(__libcpp_random_is_valid_inttype<_IntType>::value, "IntType must be a supported integer type");
  30
  31 public:
  32   // types
  33   typedef _IntType result_type;
  34
  35   class _LIBCPP_TEMPLATE_VIS param_type {
  36     double __p_;
  37
  38   public:
  39     typedef geometric_distribution distribution_type;
  40
  41     _LIBCPP_HIDE_FROM_ABI explicit param_type(double __p = 0.5) : __p_(__p) {}
  42
  43     _LIBCPP_HIDE_FROM_ABI double p() const { return __p_; }
  44
  45     friend _LIBCPP_HIDE_FROM_ABI bool operator==(const param_type& __x, const param_type& __y) {
  46       return __x.__p_ == __y.__p_;
  47     }
  48     friend _LIBCPP_HIDE_FROM_ABI bool operator!=(const param_type& __x, const param_type& __y) { return !(__x == __y); }
  49   };
  50
  51 private:
  52   param_type __p_;
  53
  54 public:
  55   // constructors and reset functions
  56 #ifndef _LIBCPP_CXX03_LANG
  57   _LIBCPP_HIDE_FROM_ABI geometric_distribution() : geometric_distribution(0.5) {}
  58   _LIBCPP_HIDE_FROM_ABI explicit geometric_distribution(double __p) : __p_(__p) {}
  59 #else
  60   _LIBCPP_HIDE_FROM_ABI explicit geometric_distribution(double __p = 0.5) : __p_(__p) {}
  61 #endif
  62   _LIBCPP_HIDE_FROM_ABI explicit geometric_distribution(const param_type& __p) : __p_(__p) {}
  63   _LIBCPP_HIDE_FROM_ABI void reset() {}
  64
  65   // generating functions
  66   template <class _URNG>
  67   _LIBCPP_HIDE_FROM_ABI result_type operator()(_URNG& __g) {
  68     return (*this)(__g, __p_);
  69   }
  70   template <class _URNG>
  71   _LIBCPP_HIDE_FROM_ABI result_type operator()(_URNG& __g, const param_type& __p) {
  72     return negative_binomial_distribution<result_type>(1, __p.p())(__g);
  73   }
  74
  75   // property functions
  76   _LIBCPP_HIDE_FROM_ABI double p() const { return __p_.p(); }
  77
  78   _LIBCPP_HIDE_FROM_ABI param_type param() const { return __p_; }
  79   _LIBCPP_HIDE_FROM_ABI void param(const param_type& __p) { __p_ = __p; }
  80
  81   _LIBCPP_HIDE_FROM_ABI result_type min() const { return 0; }
  82   _LIBCPP_HIDE_FROM_ABI result_type max() const { return numeric_limits<result_type>::max(); }
  83
  84   friend _LIBCPP_HIDE_FROM_ABI bool operator==(const geometric_distribution& __x, const geometric_distribution& __y) {
  85     return __x.__p_ == __y.__p_;
  86   }
  87   friend _LIBCPP_HIDE_FROM_ABI bool operator!=(const geometric_distribution& __x, const geometric_distribution& __y) {
  88     return !(__x == __y);
  89   }
  90 };
  91
  92 template <class _CharT, class _Traits, class _IntType>
  93 _LIBCPP_HIDE_FROM_ABI basic_ostream<_CharT, _Traits>&
  94 operator<<(basic_ostream<_CharT, _Traits>& __os, const geometric_distribution<_IntType>& __x) {
  95   __save_flags<_CharT, _Traits> __lx(__os);
  96   typedef basic_ostream<_CharT, _Traits> _OStream;
  97   __os.flags(_OStream::dec | _OStream::left | _OStream::fixed | _OStream::scientific);
  98   return __os << __x.p();
  99 }
 100
 101 template <class _CharT, class _Traits, class _IntType>
 102 _LIBCPP_HIDE_FROM_ABI basic_istream<_CharT, _Traits>&
 103 operator>>(basic_istream<_CharT, _Traits>& __is, geometric_distribution<_IntType>& __x) {
 104   typedef geometric_distribution<_IntType> _Eng;
 105   typedef typename _Eng::param_type param_type;
 106   __save_flags<_CharT, _Traits> __lx(__is);
 107   typedef basic_istream<_CharT, _Traits> _Istream;
 108   __is.flags(_Istream::dec | _Istream::skipws);
 109   double __p;
 110   __is >> __p;
 111   if (!__is.fail())
 112     __x.param(param_type(__p));
 113   return __is;
 114 }
 115
 116 _LIBCPP_END_NAMESPACE_STD
 117
 118 _LIBCPP_POP_MACROS
 119
 120 #endif // _LIBCPP___CXX03___RANDOM_GEOMETRIC_DISTRIBUTION_H