include/__random/uniform_int_distribution.h - llvm-project/libcxx - Git at Google

 //===----------------------------------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//

 #ifndef _LIBCPP___RANDOM_UNIFORM_INT_DISTRIBUTION_H
 #define _LIBCPP___RANDOM_UNIFORM_INT_DISTRIBUTION_H

 #include <__bit/countl.h>
 #include <__config>
 #include <__random/is_valid.h>
 #include <__random/log2.h>
 #include <__type_traits/conditional.h>
 #include <__type_traits/make_unsigned.h>
 #include <cstddef>
 #include <cstdint>
 #include <iosfwd>
 #include <limits>

 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif

 _LIBCPP_PUSH_MACROS
 #include <__undef_macros>

 _LIBCPP_BEGIN_NAMESPACE_STD

 template <class _Engine, class _UIntType>
 class __independent_bits_engine {
 public:
   // types
   typedef _UIntType result_type;

 private:
   typedef typename _Engine::result_type _Engine_result_type;
   typedef __conditional_t<sizeof(_Engine_result_type) <= sizeof(result_type), result_type, _Engine_result_type>
       _Working_result_type;

   _Engine& __e_;
   size_t __w_;
   size_t __w0_;
   size_t __n_;
   size_t __n0_;
   _Working_result_type __y0_;
   _Working_result_type __y1_;
   _Engine_result_type __mask0_;
   _Engine_result_type __mask1_;

 #ifdef _LIBCPP_CXX03_LANG
   static const _Working_result_type _Rp = _Engine::_Max - _Engine::_Min + _Working_result_type(1);
 #else
   static _LIBCPP_CONSTEXPR const _Working_result_type _Rp = _Engine::max() - _Engine::min() + _Working_result_type(1);
 #endif
   static _LIBCPP_CONSTEXPR const size_t __m  = __log2<_Working_result_type, _Rp>::value;
   static _LIBCPP_CONSTEXPR const size_t _WDt = numeric_limits<_Working_result_type>::digits;
   static _LIBCPP_CONSTEXPR const size_t _EDt = numeric_limits<_Engine_result_type>::digits;

 public:
   // constructors and seeding functions
   _LIBCPP_HIDE_FROM_ABI __independent_bits_engine(_Engine& __e, size_t __w);

   // generating functions
   _LIBCPP_HIDE_FROM_ABI result_type operator()() { return __eval(integral_constant<bool, _Rp != 0>()); }

 private:
   _LIBCPP_HIDE_FROM_ABI result_type __eval(false_type);
   _LIBCPP_HIDE_FROM_ABI result_type __eval(true_type);
 };

 template <class _Engine, class _UIntType>
 __independent_bits_engine<_Engine, _UIntType>::__independent_bits_engine(_Engine& __e, size_t __w)
     : __e_(__e), __w_(__w) {
   __n_  = __w_ / __m + (__w_ % __m != 0);
   __w0_ = __w_ / __n_;
   if (_Rp == 0)
     __y0_ = _Rp;
   else if (__w0_ < _WDt)
     __y0_ = (_Rp >> __w0_) << __w0_;
   else
     __y0_ = 0;
   if (_Rp - __y0_ > __y0_ / __n_) {
     ++__n_;
     __w0_ = __w_ / __n_;
     if (__w0_ < _WDt)
       __y0_ = (_Rp >> __w0_) << __w0_;
     else
       __y0_ = 0;
   }
   __n0_ = __n_ - __w_ % __n_;
   if (__w0_ < _WDt - 1)
     __y1_ = (_Rp >> (__w0_ + 1)) << (__w0_ + 1);
   else
     __y1_ = 0;
   __mask0_ = __w0_ > 0 ? _Engine_result_type(~0) >> (_EDt - __w0_) : _Engine_result_type(0);
   __mask1_ = __w0_ < _EDt - 1 ? _Engine_result_type(~0) >> (_EDt - (__w0_ + 1)) : _Engine_result_type(~0);
 }

 template <class _Engine, class _UIntType>
 inline _UIntType __independent_bits_engine<_Engine, _UIntType>::__eval(false_type) {
   return static_cast<result_type>(__e_() & __mask0_);
 }

 template <class _Engine, class _UIntType>
 _UIntType __independent_bits_engine<_Engine, _UIntType>::__eval(true_type) {
   const size_t __w_rt = numeric_limits<result_type>::digits;
   result_type __sp    = 0;
   for (size_t __k = 0; __k < __n0_; ++__k) {
     _Engine_result_type __u;
     do {
       __u = __e_() - _Engine::min();
     } while (__u >= __y0_);
     if (__w0_ < __w_rt)
       __sp <<= __w0_;
     else
       __sp = 0;
     __sp += __u & __mask0_;
   }
   for (size_t __k = __n0_; __k < __n_; ++__k) {
     _Engine_result_type __u;
     do {
       __u = __e_() - _Engine::min();
     } while (__u >= __y1_);
     if (__w0_ < __w_rt - 1)
       __sp <<= __w0_ + 1;
     else
       __sp = 0;
     __sp += __u & __mask1_;
   }
   return __sp;
 }

 template <class _IntType = int>
 class uniform_int_distribution {
   static_assert(__libcpp_random_is_valid_inttype<_IntType>::value, "IntType must be a supported integer type");

 public:
   // types
   typedef _IntType result_type;

   class param_type {
     result_type __a_;
     result_type __b_;

   public:
     typedef uniform_int_distribution distribution_type;

     _LIBCPP_HIDE_FROM_ABI explicit param_type(result_type __a = 0, result_type __b = numeric_limits<result_type>::max())
         : __a_(__a), __b_(__b) {}

     _LIBCPP_HIDE_FROM_ABI result_type a() const { return __a_; }
     _LIBCPP_HIDE_FROM_ABI result_type b() const { return __b_; }

     _LIBCPP_HIDE_FROM_ABI friend bool operator==(const param_type& __x, const param_type& __y) {
       return __x.__a_ == __y.__a_ && __x.__b_ == __y.__b_;
     }
     _LIBCPP_HIDE_FROM_ABI friend bool operator!=(const param_type& __x, const param_type& __y) { return !(__x == __y); }
   };

 private:
   param_type __p_;

 public:
   // constructors and reset functions
 #ifndef _LIBCPP_CXX03_LANG
   _LIBCPP_HIDE_FROM_ABI uniform_int_distribution() : uniform_int_distribution(0) {}
   _LIBCPP_HIDE_FROM_ABI explicit uniform_int_distribution(
       result_type __a, result_type __b = numeric_limits<result_type>::max())
       : __p_(param_type(__a, __b)) {}
 #else
   explicit uniform_int_distribution(result_type __a = 0, result_type __b = numeric_limits<result_type>::max())
       : __p_(param_type(__a, __b)) {}
 #endif
   _LIBCPP_HIDE_FROM_ABI explicit uniform_int_distribution(const param_type& __p) : __p_(__p) {}
   _LIBCPP_HIDE_FROM_ABI void reset() {}

   // generating functions
   template <class _URNG>
   _LIBCPP_HIDE_FROM_ABI result_type operator()(_URNG& __g) {
     return (*this)(__g, __p_);
   }
   template <class _URNG>
   _LIBCPP_HIDE_FROM_ABI result_type operator()(_URNG& __g, const param_type& __p);

   // property functions
   _LIBCPP_HIDE_FROM_ABI result_type a() const { return __p_.a(); }
   _LIBCPP_HIDE_FROM_ABI result_type b() const { return __p_.b(); }

   _LIBCPP_HIDE_FROM_ABI param_type param() const { return __p_; }
   _LIBCPP_HIDE_FROM_ABI void param(const param_type& __p) { __p_ = __p; }

   _LIBCPP_HIDE_FROM_ABI result_type min() const { return a(); }
   _LIBCPP_HIDE_FROM_ABI result_type max() const { return b(); }

   _LIBCPP_HIDE_FROM_ABI friend bool
   operator==(const uniform_int_distribution& __x, const uniform_int_distribution& __y) {
     return __x.__p_ == __y.__p_;
   }
   _LIBCPP_HIDE_FROM_ABI friend bool
   operator!=(const uniform_int_distribution& __x, const uniform_int_distribution& __y) {
     return !(__x == __y);
   }
 };

 template <class _IntType>
 template <class _URNG>
 typename uniform_int_distribution<_IntType>::result_type uniform_int_distribution<_IntType>::operator()(
     _URNG& __g, const param_type& __p) _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK {
   static_assert(__libcpp_random_is_valid_urng<_URNG>::value, "");
   typedef __conditional_t<sizeof(result_type) <= sizeof(uint32_t), uint32_t, __make_unsigned_t<result_type> > _UIntType;
   const _UIntType __rp = _UIntType(__p.b()) - _UIntType(__p.a()) + _UIntType(1);
   if (__rp == 1)
     return __p.a();
   const size_t __dt = numeric_limits<_UIntType>::digits;
   typedef __independent_bits_engine<_URNG, _UIntType> _Eng;
   if (__rp == 0)
     return static_cast<result_type>(_Eng(__g, __dt)());
   size_t __w = __dt - std::__countl_zero(__rp) - 1;
   if ((__rp & (numeric_limits<_UIntType>::max() >> (__dt - __w))) != 0)
     ++__w;
   _Eng __e(__g, __w);
   _UIntType __u;
   do {
     __u = __e();
   } while (__u >= __rp);
   return static_cast<result_type>(__u + __p.a());
 }

 template <class _CharT, class _Traits, class _IT>
 _LIBCPP_HIDE_FROM_ABI basic_ostream<_CharT, _Traits>&
 operator<<(basic_ostream<_CharT, _Traits>& __os, const uniform_int_distribution<_IT>& __x) {
   __save_flags<_CharT, _Traits> __lx(__os);
   typedef basic_ostream<_CharT, _Traits> _Ostream;
   __os.flags(_Ostream::dec | _Ostream::left);
   _CharT __sp = __os.widen(' ');
   __os.fill(__sp);
   return __os << __x.a() << __sp << __x.b();
 }

 template <class _CharT, class _Traits, class _IT>
 _LIBCPP_HIDE_FROM_ABI basic_istream<_CharT, _Traits>&
 operator>>(basic_istream<_CharT, _Traits>& __is, uniform_int_distribution<_IT>& __x) {
   typedef uniform_int_distribution<_IT> _Eng;
   typedef typename _Eng::result_type result_type;
   typedef typename _Eng::param_type param_type;
   __save_flags<_CharT, _Traits> __lx(__is);
   typedef basic_istream<_CharT, _Traits> _Istream;
   __is.flags(_Istream::dec | _Istream::skipws);
   result_type __a;
   result_type __b;
   __is >> __a >> __b;
   if (!__is.fail())
     __x.param(param_type(__a, __b));
   return __is;
 }

 _LIBCPP_END_NAMESPACE_STD

 _LIBCPP_POP_MACROS

 #endif // _LIBCPP___RANDOM_UNIFORM_INT_DISTRIBUTION_H
	//===----------------------------------------------------------------------===//
	//
	// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
	// See https://llvm.org/LICENSE.txt for license information.
	// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
	//
	//===----------------------------------------------------------------------===//

	#ifndef _LIBCPP___RANDOM_UNIFORM_INT_DISTRIBUTION_H
	#define _LIBCPP___RANDOM_UNIFORM_INT_DISTRIBUTION_H

	#include <__bit/countl.h>
	#include <__config>
	#include <__random/is_valid.h>
	#include <__random/log2.h>
	#include <__type_traits/conditional.h>
	#include <__type_traits/make_unsigned.h>
	#include <cstddef>
	#include <cstdint>
	#include <iosfwd>
	#include <limits>

	#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
	# pragma GCC system_header
	#endif

	_LIBCPP_PUSH_MACROS
	#include <__undef_macros>

	_LIBCPP_BEGIN_NAMESPACE_STD

	template <class _Engine, class _UIntType>
	class __independent_bits_engine {
	public:
	// types
	typedef _UIntType result_type;

	private:
	typedef typename _Engine::result_type _Engine_result_type;
	typedef __conditional_t<sizeof(_Engine_result_type) <= sizeof(result_type), result_type, _Engine_result_type>
	_Working_result_type;

	_Engine& __e_;
	size_t __w_;
	size_t __w0_;
	size_t __n_;
	size_t __n0_;
	_Working_result_type __y0_;
	_Working_result_type __y1_;
	_Engine_result_type __mask0_;
	_Engine_result_type __mask1_;

	#ifdef _LIBCPP_CXX03_LANG
	static const _Working_result_type _Rp = _Engine::_Max - _Engine::_Min + _Working_result_type(1);
	#else
	static _LIBCPP_CONSTEXPR const _Working_result_type _Rp = _Engine::max() - _Engine::min() + _Working_result_type(1);
	#endif
	static _LIBCPP_CONSTEXPR const size_t __m = __log2<_Working_result_type, _Rp>::value;
	static _LIBCPP_CONSTEXPR const size_t _WDt = numeric_limits<_Working_result_type>::digits;
	static _LIBCPP_CONSTEXPR const size_t _EDt = numeric_limits<_Engine_result_type>::digits;

	public:
	// constructors and seeding functions
	_LIBCPP_HIDE_FROM_ABI __independent_bits_engine(_Engine& __e, size_t __w);

	// generating functions
	_LIBCPP_HIDE_FROM_ABI result_type operator()() { return __eval(integral_constant<bool, _Rp != 0>()); }

	private:
	_LIBCPP_HIDE_FROM_ABI result_type __eval(false_type);
	_LIBCPP_HIDE_FROM_ABI result_type __eval(true_type);
	};

	template <class _Engine, class _UIntType>
	__independent_bits_engine<_Engine, _UIntType>::__independent_bits_engine(_Engine& __e, size_t __w)
	: __e_(__e), __w_(__w) {
	__n_ = __w_ / __m + (__w_ % __m != 0);
	__w0_ = __w_ / __n_;
	if (_Rp == 0)
	__y0_ = _Rp;
	else if (__w0_ < _WDt)
	__y0_ = (_Rp >> __w0_) << __w0_;
	else
	__y0_ = 0;
	if (_Rp - __y0_ > __y0_ / __n_) {
	++__n_;
	__w0_ = __w_ / __n_;
	if (__w0_ < _WDt)
	__y0_ = (_Rp >> __w0_) << __w0_;
	else
	__y0_ = 0;
	}
	__n0_ = __n_ - __w_ % __n_;
	if (__w0_ < _WDt - 1)
	__y1_ = (_Rp >> (__w0_ + 1)) << (__w0_ + 1);
	else
	__y1_ = 0;
	__mask0_ = __w0_ > 0 ? _Engine_result_type(~0) >> (_EDt - __w0_) : _Engine_result_type(0);
	__mask1_ = __w0_ < _EDt - 1 ? _Engine_result_type(~0) >> (_EDt - (__w0_ + 1)) : _Engine_result_type(~0);
	}

	template <class _Engine, class _UIntType>
	inline _UIntType __independent_bits_engine<_Engine, _UIntType>::__eval(false_type) {
	return static_cast<result_type>(__e_() & __mask0_);
	}

	template <class _Engine, class _UIntType>
	_UIntType __independent_bits_engine<_Engine, _UIntType>::__eval(true_type) {
	const size_t __w_rt = numeric_limits<result_type>::digits;
	result_type __sp = 0;
	for (size_t __k = 0; __k < __n0_; ++__k) {
	_Engine_result_type __u;
	do {
	__u = __e_() - _Engine::min();
	} while (__u >= __y0_);
	if (__w0_ < __w_rt)
	__sp <<= __w0_;
	else
	__sp = 0;
	__sp += __u & __mask0_;
	}
	for (size_t __k = __n0_; __k < __n_; ++__k) {
	_Engine_result_type __u;
	do {
	__u = __e_() - _Engine::min();
	} while (__u >= __y1_);
	if (__w0_ < __w_rt - 1)
	__sp <<= __w0_ + 1;
	else
	__sp = 0;
	__sp += __u & __mask1_;
	}
	return __sp;
	}

	template <class _IntType = int>
	class uniform_int_distribution {
	static_assert(__libcpp_random_is_valid_inttype<_IntType>::value, "IntType must be a supported integer type");

	public:
	// types
	typedef _IntType result_type;

	class param_type {
	result_type __a_;
	result_type __b_;

	public:
	typedef uniform_int_distribution distribution_type;

	_LIBCPP_HIDE_FROM_ABI explicit param_type(result_type __a = 0, result_type __b = numeric_limits<result_type>::max())
	: __a_(__a), __b_(__b) {}

	_LIBCPP_HIDE_FROM_ABI result_type a() const { return __a_; }
	_LIBCPP_HIDE_FROM_ABI result_type b() const { return __b_; }

	_LIBCPP_HIDE_FROM_ABI friend bool operator==(const param_type& __x, const param_type& __y) {
	return __x.__a_ == __y.__a_ && __x.__b_ == __y.__b_;
	}
	_LIBCPP_HIDE_FROM_ABI friend bool operator!=(const param_type& __x, const param_type& __y) { return !(__x == __y); }
	};

	private:
	param_type __p_;

	public:
	// constructors and reset functions
	#ifndef _LIBCPP_CXX03_LANG
	_LIBCPP_HIDE_FROM_ABI uniform_int_distribution() : uniform_int_distribution(0) {}
	_LIBCPP_HIDE_FROM_ABI explicit uniform_int_distribution(
	result_type __a, result_type __b = numeric_limits<result_type>::max())
	: __p_(param_type(__a, __b)) {}
	#else
	explicit uniform_int_distribution(result_type __a = 0, result_type __b = numeric_limits<result_type>::max())
	: __p_(param_type(__a, __b)) {}
	#endif
	_LIBCPP_HIDE_FROM_ABI explicit uniform_int_distribution(const param_type& __p) : __p_(__p) {}
	_LIBCPP_HIDE_FROM_ABI void reset() {}

	// generating functions
	template <class _URNG>
	_LIBCPP_HIDE_FROM_ABI result_type operator()(_URNG& __g) {
	return (*this)(__g, __p_);
	}
	template <class _URNG>
	_LIBCPP_HIDE_FROM_ABI result_type operator()(_URNG& __g, const param_type& __p);

	// property functions
	_LIBCPP_HIDE_FROM_ABI result_type a() const { return __p_.a(); }
	_LIBCPP_HIDE_FROM_ABI result_type b() const { return __p_.b(); }

	_LIBCPP_HIDE_FROM_ABI param_type param() const { return __p_; }
	_LIBCPP_HIDE_FROM_ABI void param(const param_type& __p) { __p_ = __p; }

	_LIBCPP_HIDE_FROM_ABI result_type min() const { return a(); }
	_LIBCPP_HIDE_FROM_ABI result_type max() const { return b(); }

	_LIBCPP_HIDE_FROM_ABI friend bool
	operator==(const uniform_int_distribution& __x, const uniform_int_distribution& __y) {
	return __x.__p_ == __y.__p_;
	}
	_LIBCPP_HIDE_FROM_ABI friend bool
	operator!=(const uniform_int_distribution& __x, const uniform_int_distribution& __y) {
	return !(__x == __y);
	}
	};

	template <class _IntType>
	template <class _URNG>
	typename uniform_int_distribution<_IntType>::result_type uniform_int_distribution<_IntType>::operator()(
	_URNG& __g, const param_type& __p) _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK {
	static_assert(__libcpp_random_is_valid_urng<_URNG>::value, "");
	typedef __conditional_t<sizeof(result_type) <= sizeof(uint32_t), uint32_t, __make_unsigned_t<result_type> > _UIntType;
	const _UIntType __rp = _UIntType(__p.b()) - _UIntType(__p.a()) + _UIntType(1);
	if (__rp == 1)
	return __p.a();
	const size_t __dt = numeric_limits<_UIntType>::digits;
	typedef __independent_bits_engine<_URNG, _UIntType> _Eng;
	if (__rp == 0)
	return static_cast<result_type>(_Eng(__g, __dt)());
	size_t __w = __dt - std::__countl_zero(__rp) - 1;
	if ((__rp & (numeric_limits<_UIntType>::max() >> (__dt - __w))) != 0)
	++__w;
	_Eng __e(__g, __w);
	_UIntType __u;
	do {
	__u = __e();
	} while (__u >= __rp);
	return static_cast<result_type>(__u + __p.a());
	}

	template <class _CharT, class _Traits, class _IT>
	_LIBCPP_HIDE_FROM_ABI basic_ostream<_CharT, _Traits>&
	operator<<(basic_ostream<_CharT, _Traits>& __os, const uniform_int_distribution<_IT>& __x) {
	__save_flags<_CharT, _Traits> __lx(__os);
	typedef basic_ostream<_CharT, _Traits> _Ostream;
	__os.flags(_Ostream::dec \| _Ostream::left);
	_CharT __sp = __os.widen(' ');
	__os.fill(__sp);
	return __os << __x.a() << __sp << __x.b();
	}

	template <class _CharT, class _Traits, class _IT>
	_LIBCPP_HIDE_FROM_ABI basic_istream<_CharT, _Traits>&
	operator>>(basic_istream<_CharT, _Traits>& __is, uniform_int_distribution<_IT>& __x) {
	typedef uniform_int_distribution<_IT> _Eng;
	typedef typename _Eng::result_type result_type;
	typedef typename _Eng::param_type param_type;
	__save_flags<_CharT, _Traits> __lx(__is);
	typedef basic_istream<_CharT, _Traits> _Istream;
	__is.flags(_Istream::dec \| _Istream::skipws);
	result_type __a;
	result_type __b;
	__is >> __a >> __b;
	if (!__is.fail())
	__x.param(param_type(__a, __b));
	return __is;
	}

	_LIBCPP_END_NAMESPACE_STD

	_LIBCPP_POP_MACROS

	#endif // _LIBCPP___RANDOM_UNIFORM_INT_DISTRIBUTION_H