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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___ALGORITHM_SHUFFLE_H
#define _LIBCPP___ALGORITHM_SHUFFLE_H
#include <__algorithm/iterator_operations.h>
#include <__config>
#include <__debug>
#include <__iterator/iterator_traits.h>
#include <__random/uniform_int_distribution.h>
#include <__utility/forward.h>
#include <__utility/move.h>
#include <cstddef>
#include <cstdint>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
#endif
_LIBCPP_PUSH_MACROS
#include <__undef_macros>
_LIBCPP_BEGIN_NAMESPACE_STD
class _LIBCPP_TYPE_VIS __libcpp_debug_randomizer {
public:
__libcpp_debug_randomizer() {
__state = __seed();
__inc = __state + 0xda3e39cb94b95bdbULL;
__inc = (__inc << 1) | 1;
}
typedef uint_fast32_t result_type;
static const result_type _Min = 0;
static const result_type _Max = 0xFFFFFFFF;
_LIBCPP_HIDE_FROM_ABI result_type operator()() {
uint_fast64_t __oldstate = __state;
__state = __oldstate * 6364136223846793005ULL + __inc;
return __oldstate >> 32;
}
static _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR result_type min() { return _Min; }
static _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR result_type max() { return _Max; }
private:
uint_fast64_t __state;
uint_fast64_t __inc;
_LIBCPP_HIDE_FROM_ABI static uint_fast64_t __seed() {
#ifdef _LIBCPP_DEBUG_RANDOMIZE_UNSPECIFIED_STABILITY_SEED
return _LIBCPP_DEBUG_RANDOMIZE_UNSPECIFIED_STABILITY_SEED;
#else
static char __x;
return reinterpret_cast<uintptr_t>(&__x);
#endif
}
};
#if _LIBCPP_STD_VER <= 14 || defined(_LIBCPP_ENABLE_CXX17_REMOVED_RANDOM_SHUFFLE) \
|| defined(_LIBCPP_BUILDING_LIBRARY)
class _LIBCPP_TYPE_VIS __rs_default;
_LIBCPP_FUNC_VIS __rs_default __rs_get();
class _LIBCPP_TYPE_VIS __rs_default
{
static unsigned __c_;
__rs_default();
public:
typedef uint_fast32_t result_type;
static const result_type _Min = 0;
static const result_type _Max = 0xFFFFFFFF;
__rs_default(const __rs_default&);
~__rs_default();
result_type operator()();
static _LIBCPP_CONSTEXPR result_type min() {return _Min;}
static _LIBCPP_CONSTEXPR result_type max() {return _Max;}
friend _LIBCPP_FUNC_VIS __rs_default __rs_get();
};
_LIBCPP_FUNC_VIS __rs_default __rs_get();
template <class _RandomAccessIterator>
_LIBCPP_DEPRECATED_IN_CXX14 void
random_shuffle(_RandomAccessIterator __first, _RandomAccessIterator __last)
{
typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
typedef uniform_int_distribution<ptrdiff_t> _Dp;
typedef typename _Dp::param_type _Pp;
difference_type __d = __last - __first;
if (__d > 1)
{
_Dp __uid;
__rs_default __g = __rs_get();
for (--__last, (void) --__d; __first < __last; ++__first, (void) --__d)
{
difference_type __i = __uid(__g, _Pp(0, __d));
if (__i != difference_type(0))
swap(*__first, *(__first + __i));
}
}
}
template <class _RandomAccessIterator, class _RandomNumberGenerator>
_LIBCPP_DEPRECATED_IN_CXX14 void
random_shuffle(_RandomAccessIterator __first, _RandomAccessIterator __last,
#ifndef _LIBCPP_CXX03_LANG
_RandomNumberGenerator&& __rand)
#else
_RandomNumberGenerator& __rand)
#endif
{
typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
difference_type __d = __last - __first;
if (__d > 1)
{
for (--__last; __first < __last; ++__first, (void) --__d)
{
difference_type __i = __rand(__d);
if (__i != difference_type(0))
swap(*__first, *(__first + __i));
}
}
}
#endif
template <class _AlgPolicy, class _RandomAccessIterator, class _Sentinel, class _UniformRandomNumberGenerator>
_RandomAccessIterator __shuffle(
_RandomAccessIterator __first, _Sentinel __last_sentinel, _UniformRandomNumberGenerator&& __g) {
typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
typedef uniform_int_distribution<ptrdiff_t> _Dp;
typedef typename _Dp::param_type _Pp;
auto __original_last = _IterOps<_AlgPolicy>::next(__first, __last_sentinel);
auto __last = __original_last;
difference_type __d = __last - __first;
if (__d > 1)
{
_Dp __uid;
for (--__last, (void) --__d; __first < __last; ++__first, (void) --__d)
{
difference_type __i = __uid(__g, _Pp(0, __d));
if (__i != difference_type(0))
_IterOps<_AlgPolicy>::iter_swap(__first, __first + __i);
}
}
return __original_last;
}
template <class _RandomAccessIterator, class _UniformRandomNumberGenerator>
void shuffle(_RandomAccessIterator __first, _RandomAccessIterator __last,
_UniformRandomNumberGenerator&& __g) {
(void)std::__shuffle<_ClassicAlgPolicy>(
std::move(__first), std::move(__last), std::forward<_UniformRandomNumberGenerator>(__g));
}
_LIBCPP_END_NAMESPACE_STD
_LIBCPP_POP_MACROS
#endif // _LIBCPP___ALGORITHM_SHUFFLE_H
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