Import uniform_int_dist.h from gcc 7.1.0/7.2.0
This commit is contained in:
375
code/uniform_int_dist.h
Normal file
375
code/uniform_int_dist.h
Normal file
@@ -0,0 +1,375 @@
|
||||
// Class template uniform_int_distribution -*- C++ -*-
|
||||
|
||||
// Copyright (C) 2009-2017 Free Software Foundation, Inc.
|
||||
//
|
||||
// This file is part of the GNU ISO C++ Library. This library is free
|
||||
// software; you can redistribute it and/or modify it under the
|
||||
// terms of the GNU General Public License as published by the
|
||||
// Free Software Foundation; either version 3, or (at your option)
|
||||
// any later version.
|
||||
|
||||
// This library is distributed in the hope that it will be useful,
|
||||
// but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||||
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
||||
// GNU General Public License for more details.
|
||||
|
||||
// Under Section 7 of GPL version 3, you are granted additional
|
||||
// permissions described in the GCC Runtime Library Exception, version
|
||||
// 3.1, as published by the Free Software Foundation.
|
||||
|
||||
// You should have received a copy of the GNU General Public License and
|
||||
// a copy of the GCC Runtime Library Exception along with this program;
|
||||
// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
|
||||
// <http://www.gnu.org/licenses/>.
|
||||
|
||||
/**
|
||||
* @file bits/uniform_int_dist.h
|
||||
* This is an internal header file, included by other library headers.
|
||||
* Do not attempt to use it directly. @headername{random}
|
||||
*/
|
||||
|
||||
#ifndef _GLIBCXX_BITS_UNIFORM_INT_DIST_H
|
||||
#define _GLIBCXX_BITS_UNIFORM_INT_DIST_H
|
||||
|
||||
#include <type_traits>
|
||||
#include <limits>
|
||||
|
||||
namespace std _GLIBCXX_VISIBILITY(default)
|
||||
{
|
||||
|
||||
namespace __detail
|
||||
{
|
||||
_GLIBCXX_BEGIN_NAMESPACE_VERSION
|
||||
/* Determine whether number is a power of 2. */
|
||||
template<typename _Tp>
|
||||
inline bool
|
||||
_Power_of_2(_Tp __x)
|
||||
{
|
||||
return ((__x - 1) & __x) == 0;
|
||||
};
|
||||
_GLIBCXX_END_NAMESPACE_VERSION
|
||||
}
|
||||
|
||||
_GLIBCXX_BEGIN_NAMESPACE_VERSION
|
||||
|
||||
/**
|
||||
* @brief Uniform discrete distribution for random numbers.
|
||||
* A discrete random distribution on the range @f$[min, max]@f$ with equal
|
||||
* probability throughout the range.
|
||||
*/
|
||||
template<typename _IntType = int>
|
||||
class uniform_int_distribution
|
||||
{
|
||||
static_assert(std::is_integral<_IntType>::value,
|
||||
"template argument must be an integral type");
|
||||
|
||||
public:
|
||||
/** The type of the range of the distribution. */
|
||||
typedef _IntType result_type;
|
||||
/** Parameter type. */
|
||||
struct param_type
|
||||
{
|
||||
typedef uniform_int_distribution<_IntType> distribution_type;
|
||||
|
||||
explicit
|
||||
param_type(_IntType __a = 0,
|
||||
_IntType __b = std::numeric_limits<_IntType>::max())
|
||||
: _M_a(__a), _M_b(__b)
|
||||
{
|
||||
__glibcxx_assert(_M_a <= _M_b);
|
||||
}
|
||||
|
||||
result_type
|
||||
a() const
|
||||
{ return _M_a; }
|
||||
|
||||
result_type
|
||||
b() const
|
||||
{ return _M_b; }
|
||||
|
||||
friend bool
|
||||
operator==(const param_type& __p1, const param_type& __p2)
|
||||
{ return __p1._M_a == __p2._M_a && __p1._M_b == __p2._M_b; }
|
||||
|
||||
friend bool
|
||||
operator!=(const param_type& __p1, const param_type& __p2)
|
||||
{ return !(__p1 == __p2); }
|
||||
|
||||
private:
|
||||
_IntType _M_a;
|
||||
_IntType _M_b;
|
||||
};
|
||||
|
||||
public:
|
||||
/**
|
||||
* @brief Constructs a uniform distribution object.
|
||||
*/
|
||||
explicit
|
||||
uniform_int_distribution(_IntType __a = 0,
|
||||
_IntType __b = std::numeric_limits<_IntType>::max())
|
||||
: _M_param(__a, __b)
|
||||
{ }
|
||||
|
||||
explicit
|
||||
uniform_int_distribution(const param_type& __p)
|
||||
: _M_param(__p)
|
||||
{ }
|
||||
|
||||
/**
|
||||
* @brief Resets the distribution state.
|
||||
*
|
||||
* Does nothing for the uniform integer distribution.
|
||||
*/
|
||||
void
|
||||
reset() { }
|
||||
|
||||
result_type
|
||||
a() const
|
||||
{ return _M_param.a(); }
|
||||
|
||||
result_type
|
||||
b() const
|
||||
{ return _M_param.b(); }
|
||||
|
||||
/**
|
||||
* @brief Returns the parameter set of the distribution.
|
||||
*/
|
||||
param_type
|
||||
param() const
|
||||
{ return _M_param; }
|
||||
|
||||
/**
|
||||
* @brief Sets the parameter set of the distribution.
|
||||
* @param __param The new parameter set of the distribution.
|
||||
*/
|
||||
void
|
||||
param(const param_type& __param)
|
||||
{ _M_param = __param; }
|
||||
|
||||
/**
|
||||
* @brief Returns the inclusive lower bound of the distribution range.
|
||||
*/
|
||||
result_type
|
||||
min() const
|
||||
{ return this->a(); }
|
||||
|
||||
/**
|
||||
* @brief Returns the inclusive upper bound of the distribution range.
|
||||
*/
|
||||
result_type
|
||||
max() const
|
||||
{ return this->b(); }
|
||||
|
||||
/**
|
||||
* @brief Generating functions.
|
||||
*/
|
||||
template<typename _UniformRandomNumberGenerator>
|
||||
result_type
|
||||
operator()(_UniformRandomNumberGenerator& __urng)
|
||||
{ return this->operator()(__urng, _M_param); }
|
||||
|
||||
template<typename _UniformRandomNumberGenerator>
|
||||
result_type
|
||||
operator()(_UniformRandomNumberGenerator& __urng,
|
||||
const param_type& __p);
|
||||
|
||||
template<typename _ForwardIterator,
|
||||
typename _UniformRandomNumberGenerator>
|
||||
void
|
||||
__generate(_ForwardIterator __f, _ForwardIterator __t,
|
||||
_UniformRandomNumberGenerator& __urng)
|
||||
{ this->__generate(__f, __t, __urng, _M_param); }
|
||||
|
||||
template<typename _ForwardIterator,
|
||||
typename _UniformRandomNumberGenerator>
|
||||
void
|
||||
__generate(_ForwardIterator __f, _ForwardIterator __t,
|
||||
_UniformRandomNumberGenerator& __urng,
|
||||
const param_type& __p)
|
||||
{ this->__generate_impl(__f, __t, __urng, __p); }
|
||||
|
||||
template<typename _UniformRandomNumberGenerator>
|
||||
void
|
||||
__generate(result_type* __f, result_type* __t,
|
||||
_UniformRandomNumberGenerator& __urng,
|
||||
const param_type& __p)
|
||||
{ this->__generate_impl(__f, __t, __urng, __p); }
|
||||
|
||||
/**
|
||||
* @brief Return true if two uniform integer distributions have
|
||||
* the same parameters.
|
||||
*/
|
||||
friend bool
|
||||
operator==(const uniform_int_distribution& __d1,
|
||||
const uniform_int_distribution& __d2)
|
||||
{ return __d1._M_param == __d2._M_param; }
|
||||
|
||||
private:
|
||||
template<typename _ForwardIterator,
|
||||
typename _UniformRandomNumberGenerator>
|
||||
void
|
||||
__generate_impl(_ForwardIterator __f, _ForwardIterator __t,
|
||||
_UniformRandomNumberGenerator& __urng,
|
||||
const param_type& __p);
|
||||
|
||||
param_type _M_param;
|
||||
};
|
||||
|
||||
template<typename _IntType>
|
||||
template<typename _UniformRandomNumberGenerator>
|
||||
typename uniform_int_distribution<_IntType>::result_type
|
||||
uniform_int_distribution<_IntType>::
|
||||
operator()(_UniformRandomNumberGenerator& __urng,
|
||||
const param_type& __param)
|
||||
{
|
||||
typedef typename _UniformRandomNumberGenerator::result_type
|
||||
_Gresult_type;
|
||||
typedef typename std::make_unsigned<result_type>::type __utype;
|
||||
typedef typename std::common_type<_Gresult_type, __utype>::type
|
||||
__uctype;
|
||||
|
||||
const __uctype __urngmin = __urng.min();
|
||||
const __uctype __urngmax = __urng.max();
|
||||
const __uctype __urngrange = __urngmax - __urngmin;
|
||||
const __uctype __urange
|
||||
= __uctype(__param.b()) - __uctype(__param.a());
|
||||
|
||||
__uctype __ret;
|
||||
|
||||
if (__urngrange > __urange)
|
||||
{
|
||||
// downscaling
|
||||
const __uctype __uerange = __urange + 1; // __urange can be zero
|
||||
const __uctype __scaling = __urngrange / __uerange;
|
||||
const __uctype __past = __uerange * __scaling;
|
||||
do
|
||||
__ret = __uctype(__urng()) - __urngmin;
|
||||
while (__ret >= __past);
|
||||
__ret /= __scaling;
|
||||
}
|
||||
else if (__urngrange < __urange)
|
||||
{
|
||||
// upscaling
|
||||
/*
|
||||
Note that every value in [0, urange]
|
||||
can be written uniquely as
|
||||
|
||||
(urngrange + 1) * high + low
|
||||
|
||||
where
|
||||
|
||||
high in [0, urange / (urngrange + 1)]
|
||||
|
||||
and
|
||||
|
||||
low in [0, urngrange].
|
||||
*/
|
||||
__uctype __tmp; // wraparound control
|
||||
do
|
||||
{
|
||||
const __uctype __uerngrange = __urngrange + 1;
|
||||
__tmp = (__uerngrange * operator()
|
||||
(__urng, param_type(0, __urange / __uerngrange)));
|
||||
__ret = __tmp + (__uctype(__urng()) - __urngmin);
|
||||
}
|
||||
while (__ret > __urange || __ret < __tmp);
|
||||
}
|
||||
else
|
||||
__ret = __uctype(__urng()) - __urngmin;
|
||||
|
||||
return __ret + __param.a();
|
||||
}
|
||||
|
||||
|
||||
template<typename _IntType>
|
||||
template<typename _ForwardIterator,
|
||||
typename _UniformRandomNumberGenerator>
|
||||
void
|
||||
uniform_int_distribution<_IntType>::
|
||||
__generate_impl(_ForwardIterator __f, _ForwardIterator __t,
|
||||
_UniformRandomNumberGenerator& __urng,
|
||||
const param_type& __param)
|
||||
{
|
||||
__glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
|
||||
typedef typename _UniformRandomNumberGenerator::result_type
|
||||
_Gresult_type;
|
||||
typedef typename std::make_unsigned<result_type>::type __utype;
|
||||
typedef typename std::common_type<_Gresult_type, __utype>::type
|
||||
__uctype;
|
||||
|
||||
const __uctype __urngmin = __urng.min();
|
||||
const __uctype __urngmax = __urng.max();
|
||||
const __uctype __urngrange = __urngmax - __urngmin;
|
||||
const __uctype __urange
|
||||
= __uctype(__param.b()) - __uctype(__param.a());
|
||||
|
||||
__uctype __ret;
|
||||
|
||||
if (__urngrange > __urange)
|
||||
{
|
||||
if (__detail::_Power_of_2(__urngrange + 1)
|
||||
&& __detail::_Power_of_2(__urange + 1))
|
||||
{
|
||||
while (__f != __t)
|
||||
{
|
||||
__ret = __uctype(__urng()) - __urngmin;
|
||||
*__f++ = (__ret & __urange) + __param.a();
|
||||
}
|
||||
}
|
||||
else
|
||||
{
|
||||
// downscaling
|
||||
const __uctype __uerange = __urange + 1; // __urange can be zero
|
||||
const __uctype __scaling = __urngrange / __uerange;
|
||||
const __uctype __past = __uerange * __scaling;
|
||||
while (__f != __t)
|
||||
{
|
||||
do
|
||||
__ret = __uctype(__urng()) - __urngmin;
|
||||
while (__ret >= __past);
|
||||
*__f++ = __ret / __scaling + __param.a();
|
||||
}
|
||||
}
|
||||
}
|
||||
else if (__urngrange < __urange)
|
||||
{
|
||||
// upscaling
|
||||
/*
|
||||
Note that every value in [0, urange]
|
||||
can be written uniquely as
|
||||
|
||||
(urngrange + 1) * high + low
|
||||
|
||||
where
|
||||
|
||||
high in [0, urange / (urngrange + 1)]
|
||||
|
||||
and
|
||||
|
||||
low in [0, urngrange].
|
||||
*/
|
||||
__uctype __tmp; // wraparound control
|
||||
while (__f != __t)
|
||||
{
|
||||
do
|
||||
{
|
||||
const __uctype __uerngrange = __urngrange + 1;
|
||||
__tmp = (__uerngrange * operator()
|
||||
(__urng, param_type(0, __urange / __uerngrange)));
|
||||
__ret = __tmp + (__uctype(__urng()) - __urngmin);
|
||||
}
|
||||
while (__ret > __urange || __ret < __tmp);
|
||||
*__f++ = __ret;
|
||||
}
|
||||
}
|
||||
else
|
||||
while (__f != __t)
|
||||
*__f++ = __uctype(__urng()) - __urngmin + __param.a();
|
||||
}
|
||||
|
||||
// operator!= and operator<< and operator>> are defined in <bits/random.h>
|
||||
|
||||
_GLIBCXX_END_NAMESPACE_VERSION
|
||||
} // namespace std
|
||||
|
||||
#endif
|
||||
Reference in New Issue
Block a user