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llvm-project/libcxx/include/__random/shuffle_order_engine.h

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//===----------------------------------------------------------------------===//
//
// 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_SHUFFLE_ORDER_ENGINE_H
#define _LIBCPP___RANDOM_SHUFFLE_ORDER_ENGINE_H
#include <__algorithm/equal.h>
#include <__config>
#include <__random/is_seed_sequence.h>
#include <__utility/move.h>
#include <cstdint>
#include <iosfwd>
#include <type_traits>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
#pragma GCC system_header
#endif
_LIBCPP_PUSH_MACROS
#include <__undef_macros>
_LIBCPP_BEGIN_NAMESPACE_STD
template <uint64_t _Xp, uint64_t _Yp>
struct __ugcd
{
static _LIBCPP_CONSTEXPR const uint64_t value = __ugcd<_Yp, _Xp % _Yp>::value;
};
template <uint64_t _Xp>
struct __ugcd<_Xp, 0>
{
static _LIBCPP_CONSTEXPR const uint64_t value = _Xp;
};
template <uint64_t _Np, uint64_t _Dp>
class __uratio
{
static_assert(_Dp != 0, "__uratio divide by 0");
static _LIBCPP_CONSTEXPR const uint64_t __gcd = __ugcd<_Np, _Dp>::value;
public:
static _LIBCPP_CONSTEXPR const uint64_t num = _Np / __gcd;
static _LIBCPP_CONSTEXPR const uint64_t den = _Dp / __gcd;
typedef __uratio<num, den> type;
};
template<class _Engine, size_t __k>
class _LIBCPP_TEMPLATE_VIS shuffle_order_engine
{
static_assert(0 < __k, "shuffle_order_engine invalid parameters");
public:
// types
typedef typename _Engine::result_type result_type;
private:
_Engine __e_;
result_type _V_[__k];
result_type _Y_;
public:
// engine characteristics
static _LIBCPP_CONSTEXPR const size_t table_size = __k;
#ifdef _LIBCPP_CXX03_LANG
static const result_type _Min = _Engine::_Min;
static const result_type _Max = _Engine::_Max;
#else
static _LIBCPP_CONSTEXPR const result_type _Min = _Engine::min();
static _LIBCPP_CONSTEXPR const result_type _Max = _Engine::max();
#endif
static_assert(_Min < _Max, "shuffle_order_engine invalid parameters");
_LIBCPP_INLINE_VISIBILITY
static _LIBCPP_CONSTEXPR result_type min() { return _Min; }
_LIBCPP_INLINE_VISIBILITY
static _LIBCPP_CONSTEXPR result_type max() { return _Max; }
static _LIBCPP_CONSTEXPR const unsigned long long _Rp = _Max - _Min + 1ull;
// constructors and seeding functions
_LIBCPP_INLINE_VISIBILITY
shuffle_order_engine() {__init();}
_LIBCPP_INLINE_VISIBILITY
explicit shuffle_order_engine(const _Engine& __e)
: __e_(__e) {__init();}
#ifndef _LIBCPP_CXX03_LANG
_LIBCPP_INLINE_VISIBILITY
explicit shuffle_order_engine(_Engine&& __e)
: __e_(_VSTD::move(__e)) {__init();}
#endif // _LIBCPP_CXX03_LANG
_LIBCPP_INLINE_VISIBILITY
explicit shuffle_order_engine(result_type __sd) : __e_(__sd) {__init();}
template<class _Sseq>
_LIBCPP_INLINE_VISIBILITY
explicit shuffle_order_engine(_Sseq& __q,
typename enable_if<__is_seed_sequence<_Sseq, shuffle_order_engine>::value &&
!is_convertible<_Sseq, _Engine>::value>::type* = 0)
: __e_(__q) {__init();}
_LIBCPP_INLINE_VISIBILITY
void seed() {__e_.seed(); __init();}
_LIBCPP_INLINE_VISIBILITY
void seed(result_type __sd) {__e_.seed(__sd); __init();}
template<class _Sseq>
_LIBCPP_INLINE_VISIBILITY
typename enable_if
<
__is_seed_sequence<_Sseq, shuffle_order_engine>::value,
void
>::type
seed(_Sseq& __q) {__e_.seed(__q); __init();}
// generating functions
_LIBCPP_INLINE_VISIBILITY
result_type operator()() {return __eval(integral_constant<bool, _Rp != 0>());}
_LIBCPP_INLINE_VISIBILITY
void discard(unsigned long long __z) {for (; __z; --__z) operator()();}
// property functions
_LIBCPP_INLINE_VISIBILITY
const _Engine& base() const _NOEXCEPT {return __e_;}
private:
template<class _Eng, size_t _Kp>
friend
bool
operator==(
const shuffle_order_engine<_Eng, _Kp>& __x,
const shuffle_order_engine<_Eng, _Kp>& __y);
template<class _Eng, size_t _Kp>
friend
bool
operator!=(
const shuffle_order_engine<_Eng, _Kp>& __x,
const shuffle_order_engine<_Eng, _Kp>& __y);
template <class _CharT, class _Traits,
class _Eng, size_t _Kp>
friend
basic_ostream<_CharT, _Traits>&
operator<<(basic_ostream<_CharT, _Traits>& __os,
const shuffle_order_engine<_Eng, _Kp>& __x);
template <class _CharT, class _Traits,
class _Eng, size_t _Kp>
friend
basic_istream<_CharT, _Traits>&
operator>>(basic_istream<_CharT, _Traits>& __is,
shuffle_order_engine<_Eng, _Kp>& __x);
_LIBCPP_INLINE_VISIBILITY
void __init()
{
for (size_t __i = 0; __i < __k; ++__i)
_V_[__i] = __e_();
_Y_ = __e_();
}
_LIBCPP_INLINE_VISIBILITY
result_type __eval(false_type) {return __eval2(integral_constant<bool, __k & 1>());}
_LIBCPP_INLINE_VISIBILITY
result_type __eval(true_type) {return __eval(__uratio<__k, _Rp>());}
_LIBCPP_INLINE_VISIBILITY
result_type __eval2(false_type) {return __eval(__uratio<__k/2, 0x8000000000000000ull>());}
_LIBCPP_INLINE_VISIBILITY
result_type __eval2(true_type) {return __evalf<__k, 0>();}
template <uint64_t _Np, uint64_t _Dp>
_LIBCPP_INLINE_VISIBILITY
typename enable_if
<
(__uratio<_Np, _Dp>::num > 0xFFFFFFFFFFFFFFFFull / (_Max - _Min)),
result_type
>::type
__eval(__uratio<_Np, _Dp>)
{return __evalf<__uratio<_Np, _Dp>::num, __uratio<_Np, _Dp>::den>();}
template <uint64_t _Np, uint64_t _Dp>
_LIBCPP_INLINE_VISIBILITY
typename enable_if
<
__uratio<_Np, _Dp>::num <= 0xFFFFFFFFFFFFFFFFull / (_Max - _Min),
result_type
>::type
__eval(__uratio<_Np, _Dp>)
{
const size_t __j = static_cast<size_t>(__uratio<_Np, _Dp>::num * (_Y_ - _Min)
/ __uratio<_Np, _Dp>::den);
_Y_ = _V_[__j];
_V_[__j] = __e_();
return _Y_;
}
template <uint64_t __n, uint64_t __d>
_LIBCPP_INLINE_VISIBILITY
result_type __evalf()
{
const double _Fp = __d == 0 ?
__n / (2. * 0x8000000000000000ull) :
__n / (double)__d;
const size_t __j = static_cast<size_t>(_Fp * (_Y_ - _Min));
_Y_ = _V_[__j];
_V_[__j] = __e_();
return _Y_;
}
};
template<class _Engine, size_t __k>
_LIBCPP_CONSTEXPR const size_t shuffle_order_engine<_Engine, __k>::table_size;
template<class _Eng, size_t _Kp>
bool
operator==(
const shuffle_order_engine<_Eng, _Kp>& __x,
const shuffle_order_engine<_Eng, _Kp>& __y)
{
return __x._Y_ == __y._Y_ && _VSTD::equal(__x._V_, __x._V_ + _Kp, __y._V_) &&
__x.__e_ == __y.__e_;
}
template<class _Eng, size_t _Kp>
inline _LIBCPP_INLINE_VISIBILITY
bool
operator!=(
const shuffle_order_engine<_Eng, _Kp>& __x,
const shuffle_order_engine<_Eng, _Kp>& __y)
{
return !(__x == __y);
}
template <class _CharT, class _Traits,
class _Eng, size_t _Kp>
basic_ostream<_CharT, _Traits>&
operator<<(basic_ostream<_CharT, _Traits>& __os,
const shuffle_order_engine<_Eng, _Kp>& __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);
__os << __x.__e_ << __sp << __x._V_[0];
for (size_t __i = 1; __i < _Kp; ++__i)
__os << __sp << __x._V_[__i];
return __os << __sp << __x._Y_;
}
template <class _CharT, class _Traits,
class _Eng, size_t _Kp>
basic_istream<_CharT, _Traits>&
operator>>(basic_istream<_CharT, _Traits>& __is,
shuffle_order_engine<_Eng, _Kp>& __x)
{
typedef typename shuffle_order_engine<_Eng, _Kp>::result_type result_type;
__save_flags<_CharT, _Traits> __lx(__is);
typedef basic_istream<_CharT, _Traits> _Istream;
__is.flags(_Istream::dec | _Istream::skipws);
_Eng __e;
result_type _Vp[_Kp+1];
__is >> __e;
for (size_t __i = 0; __i < _Kp+1; ++__i)
__is >> _Vp[__i];
if (!__is.fail())
{
__x.__e_ = __e;
for (size_t __i = 0; __i < _Kp; ++__i)
__x._V_[__i] = _Vp[__i];
__x._Y_ = _Vp[_Kp];
}
return __is;
}
_LIBCPP_END_NAMESPACE_STD
_LIBCPP_POP_MACROS
#endif // _LIBCPP___RANDOM_SHUFFLE_ORDER_ENGINE_H
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