368faacac7
This commit reverts 5aaefa51 (and also partly 7f285f48e77 and b6d75682f9, which were related to the original commit). As landed, 5aaefa51 had unintended consequences on some downstream bots and didn't have proper coverage upstream due to a few subtle things. Implementing this is something we should do in libc++, however we'll first need to address a few issues listed in https://reviews.llvm.org/D106124#3349710. Differential Revision: https://reviews.llvm.org/D120683
284 lines
8.6 KiB
C++
284 lines
8.6 KiB
C++
//===----------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#ifndef _LIBCPP___RANDOM_SHUFFLE_ORDER_ENGINE_H
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#define _LIBCPP___RANDOM_SHUFFLE_ORDER_ENGINE_H
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#include <__algorithm/equal.h>
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#include <__config>
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#include <__random/is_seed_sequence.h>
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#include <__utility/move.h>
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#include <cstdint>
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#include <iosfwd>
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#include <type_traits>
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#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
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# pragma GCC system_header
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#endif
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_LIBCPP_PUSH_MACROS
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#include <__undef_macros>
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_LIBCPP_BEGIN_NAMESPACE_STD
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template <uint64_t _Xp, uint64_t _Yp>
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struct __ugcd
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{
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static _LIBCPP_CONSTEXPR const uint64_t value = __ugcd<_Yp, _Xp % _Yp>::value;
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};
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template <uint64_t _Xp>
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struct __ugcd<_Xp, 0>
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{
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static _LIBCPP_CONSTEXPR const uint64_t value = _Xp;
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};
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template <uint64_t _Np, uint64_t _Dp>
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class __uratio
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{
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static_assert(_Dp != 0, "__uratio divide by 0");
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static _LIBCPP_CONSTEXPR const uint64_t __gcd = __ugcd<_Np, _Dp>::value;
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public:
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static _LIBCPP_CONSTEXPR const uint64_t num = _Np / __gcd;
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static _LIBCPP_CONSTEXPR const uint64_t den = _Dp / __gcd;
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typedef __uratio<num, den> type;
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};
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template<class _Engine, size_t __k>
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class _LIBCPP_TEMPLATE_VIS shuffle_order_engine
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{
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static_assert(0 < __k, "shuffle_order_engine invalid parameters");
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public:
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// types
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typedef typename _Engine::result_type result_type;
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private:
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_Engine __e_;
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result_type _V_[__k];
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result_type _Y_;
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public:
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// engine characteristics
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static _LIBCPP_CONSTEXPR const size_t table_size = __k;
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#ifdef _LIBCPP_CXX03_LANG
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static const result_type _Min = _Engine::_Min;
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static const result_type _Max = _Engine::_Max;
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#else
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static _LIBCPP_CONSTEXPR const result_type _Min = _Engine::min();
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static _LIBCPP_CONSTEXPR const result_type _Max = _Engine::max();
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#endif
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static_assert(_Min < _Max, "shuffle_order_engine invalid parameters");
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_LIBCPP_INLINE_VISIBILITY
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static _LIBCPP_CONSTEXPR result_type min() { return _Min; }
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_LIBCPP_INLINE_VISIBILITY
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static _LIBCPP_CONSTEXPR result_type max() { return _Max; }
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static _LIBCPP_CONSTEXPR const unsigned long long _Rp = _Max - _Min + 1ull;
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// constructors and seeding functions
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_LIBCPP_INLINE_VISIBILITY
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shuffle_order_engine() {__init();}
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_LIBCPP_INLINE_VISIBILITY
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explicit shuffle_order_engine(const _Engine& __e)
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: __e_(__e) {__init();}
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#ifndef _LIBCPP_CXX03_LANG
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_LIBCPP_INLINE_VISIBILITY
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explicit shuffle_order_engine(_Engine&& __e)
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: __e_(_VSTD::move(__e)) {__init();}
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#endif // _LIBCPP_CXX03_LANG
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_LIBCPP_INLINE_VISIBILITY
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explicit shuffle_order_engine(result_type __sd) : __e_(__sd) {__init();}
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template<class _Sseq>
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_LIBCPP_INLINE_VISIBILITY
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explicit shuffle_order_engine(_Sseq& __q,
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typename enable_if<__is_seed_sequence<_Sseq, shuffle_order_engine>::value &&
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!is_convertible<_Sseq, _Engine>::value>::type* = 0)
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: __e_(__q) {__init();}
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_LIBCPP_INLINE_VISIBILITY
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void seed() {__e_.seed(); __init();}
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_LIBCPP_INLINE_VISIBILITY
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void seed(result_type __sd) {__e_.seed(__sd); __init();}
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template<class _Sseq>
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_LIBCPP_INLINE_VISIBILITY
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typename enable_if
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<
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__is_seed_sequence<_Sseq, shuffle_order_engine>::value,
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void
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>::type
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seed(_Sseq& __q) {__e_.seed(__q); __init();}
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// generating functions
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_LIBCPP_INLINE_VISIBILITY
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result_type operator()() {return __eval(integral_constant<bool, _Rp != 0>());}
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_LIBCPP_INLINE_VISIBILITY
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void discard(unsigned long long __z) {for (; __z; --__z) operator()();}
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// property functions
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_LIBCPP_INLINE_VISIBILITY
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const _Engine& base() const _NOEXCEPT {return __e_;}
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private:
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template<class _Eng, size_t _Kp>
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friend
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bool
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operator==(
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const shuffle_order_engine<_Eng, _Kp>& __x,
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const shuffle_order_engine<_Eng, _Kp>& __y);
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template<class _Eng, size_t _Kp>
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friend
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bool
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operator!=(
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const shuffle_order_engine<_Eng, _Kp>& __x,
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const shuffle_order_engine<_Eng, _Kp>& __y);
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template <class _CharT, class _Traits,
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class _Eng, size_t _Kp>
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friend
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basic_ostream<_CharT, _Traits>&
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operator<<(basic_ostream<_CharT, _Traits>& __os,
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const shuffle_order_engine<_Eng, _Kp>& __x);
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template <class _CharT, class _Traits,
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class _Eng, size_t _Kp>
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friend
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basic_istream<_CharT, _Traits>&
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operator>>(basic_istream<_CharT, _Traits>& __is,
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shuffle_order_engine<_Eng, _Kp>& __x);
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_LIBCPP_INLINE_VISIBILITY
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void __init()
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{
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for (size_t __i = 0; __i < __k; ++__i)
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_V_[__i] = __e_();
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_Y_ = __e_();
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}
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_LIBCPP_INLINE_VISIBILITY
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result_type __eval(false_type) {return __eval2(integral_constant<bool, __k & 1>());}
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_LIBCPP_INLINE_VISIBILITY
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result_type __eval(true_type) {return __eval(__uratio<__k, _Rp>());}
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_LIBCPP_INLINE_VISIBILITY
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result_type __eval2(false_type) {return __eval(__uratio<__k/2, 0x8000000000000000ull>());}
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_LIBCPP_INLINE_VISIBILITY
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result_type __eval2(true_type) {return __evalf<__k, 0>();}
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template <uint64_t _Np, uint64_t _Dp>
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_LIBCPP_INLINE_VISIBILITY
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typename enable_if
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<
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(__uratio<_Np, _Dp>::num > 0xFFFFFFFFFFFFFFFFull / (_Max - _Min)),
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result_type
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>::type
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__eval(__uratio<_Np, _Dp>)
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{return __evalf<__uratio<_Np, _Dp>::num, __uratio<_Np, _Dp>::den>();}
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template <uint64_t _Np, uint64_t _Dp>
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_LIBCPP_INLINE_VISIBILITY
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typename enable_if
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<
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__uratio<_Np, _Dp>::num <= 0xFFFFFFFFFFFFFFFFull / (_Max - _Min),
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result_type
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>::type
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__eval(__uratio<_Np, _Dp>)
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{
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const size_t __j = static_cast<size_t>(__uratio<_Np, _Dp>::num * (_Y_ - _Min)
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/ __uratio<_Np, _Dp>::den);
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_Y_ = _V_[__j];
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_V_[__j] = __e_();
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return _Y_;
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}
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template <uint64_t __n, uint64_t __d>
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_LIBCPP_INLINE_VISIBILITY
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result_type __evalf()
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{
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const double _Fp = __d == 0 ?
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__n / (2. * 0x8000000000000000ull) :
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__n / (double)__d;
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const size_t __j = static_cast<size_t>(_Fp * (_Y_ - _Min));
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_Y_ = _V_[__j];
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_V_[__j] = __e_();
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return _Y_;
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}
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};
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template<class _Engine, size_t __k>
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_LIBCPP_CONSTEXPR const size_t shuffle_order_engine<_Engine, __k>::table_size;
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template<class _Eng, size_t _Kp>
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bool
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operator==(
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const shuffle_order_engine<_Eng, _Kp>& __x,
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const shuffle_order_engine<_Eng, _Kp>& __y)
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{
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return __x._Y_ == __y._Y_ && _VSTD::equal(__x._V_, __x._V_ + _Kp, __y._V_) &&
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__x.__e_ == __y.__e_;
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}
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template<class _Eng, size_t _Kp>
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inline _LIBCPP_INLINE_VISIBILITY
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bool
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operator!=(
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const shuffle_order_engine<_Eng, _Kp>& __x,
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const shuffle_order_engine<_Eng, _Kp>& __y)
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{
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return !(__x == __y);
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}
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template <class _CharT, class _Traits,
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class _Eng, size_t _Kp>
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basic_ostream<_CharT, _Traits>&
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operator<<(basic_ostream<_CharT, _Traits>& __os,
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const shuffle_order_engine<_Eng, _Kp>& __x)
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{
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__save_flags<_CharT, _Traits> __lx(__os);
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typedef basic_ostream<_CharT, _Traits> _Ostream;
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__os.flags(_Ostream::dec | _Ostream::left);
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_CharT __sp = __os.widen(' ');
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__os.fill(__sp);
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__os << __x.__e_ << __sp << __x._V_[0];
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for (size_t __i = 1; __i < _Kp; ++__i)
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__os << __sp << __x._V_[__i];
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return __os << __sp << __x._Y_;
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}
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template <class _CharT, class _Traits,
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class _Eng, size_t _Kp>
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basic_istream<_CharT, _Traits>&
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operator>>(basic_istream<_CharT, _Traits>& __is,
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shuffle_order_engine<_Eng, _Kp>& __x)
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{
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typedef typename shuffle_order_engine<_Eng, _Kp>::result_type result_type;
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__save_flags<_CharT, _Traits> __lx(__is);
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typedef basic_istream<_CharT, _Traits> _Istream;
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__is.flags(_Istream::dec | _Istream::skipws);
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_Eng __e;
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result_type _Vp[_Kp+1];
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__is >> __e;
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for (size_t __i = 0; __i < _Kp+1; ++__i)
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__is >> _Vp[__i];
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if (!__is.fail())
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{
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__x.__e_ = __e;
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for (size_t __i = 0; __i < _Kp; ++__i)
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__x._V_[__i] = _Vp[__i];
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__x._Y_ = _Vp[_Kp];
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}
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return __is;
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}
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_LIBCPP_END_NAMESPACE_STD
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_LIBCPP_POP_MACROS
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#endif // _LIBCPP___RANDOM_SHUFFLE_ORDER_ENGINE_H
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