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gcc/libstdc++-v3/include/bits/ranges_algo.h
Patrick Palka 8661f4faa8 libstdc++: Fix ranges::search_n for random access iterators [PR97828] 
My ranges transcription of the std::search_n implementation for random
access iterators missed a crucial part of the algorithm which the
existing tests didn't exercise.  When __remainder is less than __count
at the start of an iteration of the outer while loop, it means we're
continuing a partial match of __count - __remainder elements from the
previous iteration.  If at the end of the iteration we don't complete
this partial match, we need to reset __remainder so that it's only
offset by the size of the most recent partial match before starting the
next iteration.

This patch fixes this appropriately, mirroring how it's done in the
corresponding std::search_n implementation.

libstdc++-v3/ChangeLog:

	PR libstdc++/97828
	* include/bits/ranges_algo.h (__search_n_fn::operator()): Check
	random_access_iterator before using the backtracking
	implementation.  When the backwards scan fails prematurely,
	reset __remainder appropriately.
	* testsuite/25_algorithms/search_n/97828.cc: New test.
2020-11-17 10:28:20 -05:00

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// Core algorithmic facilities -*- C++ -*-
// Copyright (C) 2020 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/ranges_algo.h
* This is an internal header file, included by other library headers.
* Do not attempt to use it directly. @headername{algorithm}
*/
#ifndef _RANGES_ALGO_H
#define _RANGES_ALGO_H 1
#if __cplusplus > 201703L
#include <bits/ranges_algobase.h>
#include <bits/ranges_util.h>
#include <bits/uniform_int_dist.h> // concept uniform_random_bit_generator
#if __cpp_lib_concepts
namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
namespace ranges
{
namespace __detail
{
template<typename _Comp, typename _Proj>
constexpr auto
__make_comp_proj(_Comp& __comp, _Proj& __proj)
{
return [&] (auto&& __lhs, auto&& __rhs) -> bool {
using _TL = decltype(__lhs);
using _TR = decltype(__rhs);
return std::__invoke(__comp,
std::__invoke(__proj, std::forward<_TL>(__lhs)),
std::__invoke(__proj, std::forward<_TR>(__rhs)));
};
}
template<typename _Pred, typename _Proj>
constexpr auto
__make_pred_proj(_Pred& __pred, _Proj& __proj)
{
return [&] <typename _Tp> (_Tp&& __arg) -> bool {
return std::__invoke(__pred,
std::__invoke(__proj, std::forward<_Tp>(__arg)));
};
}
} // namespace __detail
struct __all_of_fn
{
template<input_iterator _Iter, sentinel_for<_Iter> _Sent,
typename _Proj = identity,
indirect_unary_predicate<projected<_Iter, _Proj>> _Pred>
constexpr bool
operator()(_Iter __first, _Sent __last,
_Pred __pred, _Proj __proj = {}) const
{
for (; __first != __last; ++__first)
if (!(bool)std::__invoke(__pred, std::__invoke(__proj, *__first)))
return false;
return true;
}
template<input_range _Range, typename _Proj = identity,
indirect_unary_predicate<projected<iterator_t<_Range>, _Proj>>
_Pred>
constexpr bool
operator()(_Range&& __r, _Pred __pred, _Proj __proj = {}) const
{
return (*this)(ranges::begin(__r), ranges::end(__r),
std::move(__pred), std::move(__proj));
}
};
inline constexpr __all_of_fn all_of{};
struct __any_of_fn
{
template<input_iterator _Iter, sentinel_for<_Iter> _Sent,
typename _Proj = identity,
indirect_unary_predicate<projected<_Iter, _Proj>> _Pred>
constexpr bool
operator()(_Iter __first, _Sent __last,
_Pred __pred, _Proj __proj = {}) const
{
for (; __first != __last; ++__first)
if (std::__invoke(__pred, std::__invoke(__proj, *__first)))
return true;
return false;
}
template<input_range _Range, typename _Proj = identity,
indirect_unary_predicate<projected<iterator_t<_Range>, _Proj>>
_Pred>
constexpr bool
operator()(_Range&& __r, _Pred __pred, _Proj __proj = {}) const
{
return (*this)(ranges::begin(__r), ranges::end(__r),
std::move(__pred), std::move(__proj));
}
};
inline constexpr __any_of_fn any_of{};
struct __none_of_fn
{
template<input_iterator _Iter, sentinel_for<_Iter> _Sent,
typename _Proj = identity,
indirect_unary_predicate<projected<_Iter, _Proj>> _Pred>
constexpr bool
operator()(_Iter __first, _Sent __last,
_Pred __pred, _Proj __proj = {}) const
{
for (; __first != __last; ++__first)
if (std::__invoke(__pred, std::__invoke(__proj, *__first)))
return false;
return true;
}
template<input_range _Range, typename _Proj = identity,
indirect_unary_predicate<projected<iterator_t<_Range>, _Proj>>
_Pred>
constexpr bool
operator()(_Range&& __r, _Pred __pred, _Proj __proj = {}) const
{
return (*this)(ranges::begin(__r), ranges::end(__r),
std::move(__pred), std::move(__proj));
}
};
inline constexpr __none_of_fn none_of{};
template<typename _Iter, typename _Fp>
struct in_fun_result
{
[[no_unique_address]] _Iter in;
[[no_unique_address]] _Fp fun;
template<typename _Iter2, typename _F2p>
requires convertible_to<const _Iter&, _Iter2>
&& convertible_to<const _Fp&, _F2p>
constexpr
operator in_fun_result<_Iter2, _F2p>() const &
{ return {in, fun}; }
template<typename _Iter2, typename _F2p>
requires convertible_to<_Iter, _Iter2> && convertible_to<_Fp, _F2p>
constexpr
operator in_fun_result<_Iter2, _F2p>() &&
{ return {std::move(in), std::move(fun)}; }
};
template<typename _Iter, typename _Fp>
using for_each_result = in_fun_result<_Iter, _Fp>;
struct __for_each_fn
{
template<input_iterator _Iter, sentinel_for<_Iter> _Sent,
typename _Proj = identity,
indirectly_unary_invocable<projected<_Iter, _Proj>> _Fun>
constexpr for_each_result<_Iter, _Fun>
operator()(_Iter __first, _Sent __last, _Fun __f, _Proj __proj = {}) const
{
for (; __first != __last; ++__first)
std::__invoke(__f, std::__invoke(__proj, *__first));
return { std::move(__first), std::move(__f) };
}
template<input_range _Range, typename _Proj = identity,
indirectly_unary_invocable<projected<iterator_t<_Range>, _Proj>>
_Fun>
constexpr for_each_result<borrowed_iterator_t<_Range>, _Fun>
operator()(_Range&& __r, _Fun __f, _Proj __proj = {}) const
{
return (*this)(ranges::begin(__r), ranges::end(__r),
std::move(__f), std::move(__proj));
}
};
inline constexpr __for_each_fn for_each{};
template<typename _Iter, typename _Fp>
using for_each_n_result = in_fun_result<_Iter, _Fp>;
struct __for_each_n_fn
{
template<input_iterator _Iter, typename _Proj = identity,
indirectly_unary_invocable<projected<_Iter, _Proj>> _Fun>
constexpr for_each_n_result<_Iter, _Fun>
operator()(_Iter __first, iter_difference_t<_Iter> __n,
_Fun __f, _Proj __proj = {}) const
{
if constexpr (random_access_iterator<_Iter>)
{
if (__n <= 0)
return {std::move(__first), std::move(__f)};
auto __last = __first + __n;
return ranges::for_each(std::move(__first), std::move(__last),
std::move(__f), std::move(__proj));
}
else
{
while (__n-- > 0)
{
std::__invoke(__f, std::__invoke(__proj, *__first));
++__first;
}
return {std::move(__first), std::move(__f)};
}
}
};
inline constexpr __for_each_n_fn for_each_n{};
struct __find_fn
{
template<input_iterator _Iter, sentinel_for<_Iter> _Sent, typename _Tp,
typename _Proj = identity>
requires indirect_binary_predicate<ranges::equal_to,
projected<_Iter, _Proj>, const _Tp*>
constexpr _Iter
operator()(_Iter __first, _Sent __last,
const _Tp& __value, _Proj __proj = {}) const
{
while (__first != __last
&& !(std::__invoke(__proj, *__first) == __value))
++__first;
return __first;
}
template<input_range _Range, typename _Tp, typename _Proj = identity>
requires indirect_binary_predicate<ranges::equal_to,
projected<iterator_t<_Range>, _Proj>,
const _Tp*>
constexpr borrowed_iterator_t<_Range>
operator()(_Range&& __r, const _Tp& __value, _Proj __proj = {}) const
{
return (*this)(ranges::begin(__r), ranges::end(__r),
__value, std::move(__proj));
}
};
inline constexpr __find_fn find{};
struct __find_if_fn
{
template<input_iterator _Iter, sentinel_for<_Iter> _Sent,
typename _Proj = identity,
indirect_unary_predicate<projected<_Iter, _Proj>> _Pred>
constexpr _Iter
operator()(_Iter __first, _Sent __last,
_Pred __pred, _Proj __proj = {}) const
{
while (__first != __last
&& !(bool)std::__invoke(__pred, std::__invoke(__proj, *__first)))
++__first;
return __first;
}
template<input_range _Range, typename _Proj = identity,
indirect_unary_predicate<projected<iterator_t<_Range>, _Proj>>
_Pred>
constexpr borrowed_iterator_t<_Range>
operator()(_Range&& __r, _Pred __pred, _Proj __proj = {}) const
{
return (*this)(ranges::begin(__r), ranges::end(__r),
std::move(__pred), std::move(__proj));
}
};
inline constexpr __find_if_fn find_if{};
struct __find_if_not_fn
{
template<input_iterator _Iter, sentinel_for<_Iter> _Sent,
typename _Proj = identity,
indirect_unary_predicate<projected<_Iter, _Proj>> _Pred>
constexpr _Iter
operator()(_Iter __first, _Sent __last,
_Pred __pred, _Proj __proj = {}) const
{
while (__first != __last
&& (bool)std::__invoke(__pred, std::__invoke(__proj, *__first)))
++__first;
return __first;
}
template<input_range _Range, typename _Proj = identity,
indirect_unary_predicate<projected<iterator_t<_Range>, _Proj>>
_Pred>
constexpr borrowed_iterator_t<_Range>
operator()(_Range&& __r, _Pred __pred, _Proj __proj = {}) const
{
return (*this)(ranges::begin(__r), ranges::end(__r),
std::move(__pred), std::move(__proj));
}
};
inline constexpr __find_if_not_fn find_if_not{};
struct __find_first_of_fn
{
template<input_iterator _Iter1, sentinel_for<_Iter1> _Sent1,
forward_iterator _Iter2, sentinel_for<_Iter2> _Sent2,
typename _Pred = ranges::equal_to,
typename _Proj1 = identity, typename _Proj2 = identity>
requires indirectly_comparable<_Iter1, _Iter2, _Pred, _Proj1, _Proj2>
constexpr _Iter1
operator()(_Iter1 __first1, _Sent1 __last1,
_Iter2 __first2, _Sent2 __last2, _Pred __pred = {},
_Proj1 __proj1 = {}, _Proj2 __proj2 = {}) const
{
for (; __first1 != __last1; ++__first1)
for (auto __iter = __first2; __iter != __last2; ++__iter)
if (std::__invoke(__pred,
std::__invoke(__proj1, *__first1),
std::__invoke(__proj2, *__iter)))
return __first1;
return __first1;
}
template<input_range _Range1, forward_range _Range2,
typename _Pred = ranges::equal_to,
typename _Proj1 = identity, typename _Proj2 = identity>
requires indirectly_comparable<iterator_t<_Range1>, iterator_t<_Range2>,
_Pred, _Proj1, _Proj2>
constexpr borrowed_iterator_t<_Range1>
operator()(_Range1&& __r1, _Range2&& __r2, _Pred __pred = {},
_Proj1 __proj1 = {}, _Proj2 __proj2 = {}) const
{
return (*this)(ranges::begin(__r1), ranges::end(__r1),
ranges::begin(__r2), ranges::end(__r2),
std::move(__pred),
std::move(__proj1), std::move(__proj2));
}
};
inline constexpr __find_first_of_fn find_first_of{};
struct __count_fn
{
template<input_iterator _Iter, sentinel_for<_Iter> _Sent,
typename _Tp, typename _Proj = identity>
requires indirect_binary_predicate<ranges::equal_to,
projected<_Iter, _Proj>,
const _Tp*>
constexpr iter_difference_t<_Iter>
operator()(_Iter __first, _Sent __last,
const _Tp& __value, _Proj __proj = {}) const
{
iter_difference_t<_Iter> __n = 0;
for (; __first != __last; ++__first)
if (std::__invoke(__proj, *__first) == __value)
++__n;
return __n;
}
template<input_range _Range, typename _Tp, typename _Proj = identity>
requires indirect_binary_predicate<ranges::equal_to,
projected<iterator_t<_Range>, _Proj>,
const _Tp*>
constexpr range_difference_t<_Range>
operator()(_Range&& __r, const _Tp& __value, _Proj __proj = {}) const
{
return (*this)(ranges::begin(__r), ranges::end(__r),
__value, std::move(__proj));
}
};
inline constexpr __count_fn count{};
struct __count_if_fn
{
template<input_iterator _Iter, sentinel_for<_Iter> _Sent,
typename _Proj = identity,
indirect_unary_predicate<projected<_Iter, _Proj>> _Pred>
constexpr iter_difference_t<_Iter>
operator()(_Iter __first, _Sent __last,
_Pred __pred, _Proj __proj = {}) const
{
iter_difference_t<_Iter> __n = 0;
for (; __first != __last; ++__first)
if (std::__invoke(__pred, std::__invoke(__proj, *__first)))
++__n;
return __n;
}
template<input_range _Range,
typename _Proj = identity,
indirect_unary_predicate<projected<iterator_t<_Range>, _Proj>>
_Pred>
constexpr range_difference_t<_Range>
operator()(_Range&& __r, _Pred __pred, _Proj __proj = {}) const
{
return (*this)(ranges::begin(__r), ranges::end(__r),
std::move(__pred), std::move(__proj));
}
};
inline constexpr __count_if_fn count_if{};
template<typename _Iter1, typename _Iter2>
struct in_in_result
{
[[no_unique_address]] _Iter1 in1;
[[no_unique_address]] _Iter2 in2;
template<typename _IIter1, typename _IIter2>
requires convertible_to<const _Iter1&, _IIter1>
&& convertible_to<const _Iter2&, _IIter2>
constexpr
operator in_in_result<_IIter1, _IIter2>() const &
{ return {in1, in2}; }
template<typename _IIter1, typename _IIter2>
requires convertible_to<_Iter1, _IIter1>
&& convertible_to<_Iter2, _IIter2>
constexpr
operator in_in_result<_IIter1, _IIter2>() &&
{ return {std::move(in1), std::move(in2)}; }
};
template<typename _Iter1, typename _Iter2>
using mismatch_result = in_in_result<_Iter1, _Iter2>;
struct __mismatch_fn
{
template<input_iterator _Iter1, sentinel_for<_Iter1> _Sent1,
input_iterator _Iter2, sentinel_for<_Iter2> _Sent2,
typename _Pred = ranges::equal_to,
typename _Proj1 = identity, typename _Proj2 = identity>
requires indirectly_comparable<_Iter1, _Iter2, _Pred, _Proj1, _Proj2>
constexpr mismatch_result<_Iter1, _Iter2>
operator()(_Iter1 __first1, _Sent1 __last1,
_Iter2 __first2, _Sent2 __last2, _Pred __pred = {},
_Proj1 __proj1 = {}, _Proj2 __proj2 = {}) const
{
while (__first1 != __last1 && __first2 != __last2
&& (bool)std::__invoke(__pred,
std::__invoke(__proj1, *__first1),
std::__invoke(__proj2, *__first2)))
{
++__first1;
++__first2;
}
return { std::move(__first1), std::move(__first2) };
}
template<input_range _Range1, input_range _Range2,
typename _Pred = ranges::equal_to,
typename _Proj1 = identity, typename _Proj2 = identity>
requires indirectly_comparable<iterator_t<_Range1>, iterator_t<_Range2>,
_Pred, _Proj1, _Proj2>
constexpr mismatch_result<iterator_t<_Range1>, iterator_t<_Range2>>
operator()(_Range1&& __r1, _Range2&& __r2, _Pred __pred = {},
_Proj1 __proj1 = {}, _Proj2 __proj2 = {}) const
{
return (*this)(ranges::begin(__r1), ranges::end(__r1),
ranges::begin(__r2), ranges::end(__r2),
std::move(__pred),
std::move(__proj1), std::move(__proj2));
}
};
inline constexpr __mismatch_fn mismatch{};
struct __search_fn
{
template<forward_iterator _Iter1, sentinel_for<_Iter1> _Sent1,
forward_iterator _Iter2, sentinel_for<_Iter2> _Sent2,
typename _Pred = ranges::equal_to,
typename _Proj1 = identity, typename _Proj2 = identity>
requires indirectly_comparable<_Iter1, _Iter2, _Pred, _Proj1, _Proj2>
constexpr subrange<_Iter1>
operator()(_Iter1 __first1, _Sent1 __last1,
_Iter2 __first2, _Sent2 __last2, _Pred __pred = {},
_Proj1 __proj1 = {}, _Proj2 __proj2 = {}) const
{
if (__first1 == __last1 || __first2 == __last2)
return {__first1, __first1};
for (;;)
{
for (;;)
{
if (__first1 == __last1)
return {__first1, __first1};
if (std::__invoke(__pred,
std::__invoke(__proj1, *__first1),
std::__invoke(__proj2, *__first2)))
break;
++__first1;
}
auto __cur1 = __first1;
auto __cur2 = __first2;
for (;;)
{
if (++__cur2 == __last2)
return {__first1, ++__cur1};
if (++__cur1 == __last1)
return {__cur1, __cur1};
if (!(bool)std::__invoke(__pred,
std::__invoke(__proj1, *__cur1),
std::__invoke(__proj2, *__cur2)))
{
++__first1;
break;
}
}
}
}
template<forward_range _Range1, forward_range _Range2,
typename _Pred = ranges::equal_to,
typename _Proj1 = identity, typename _Proj2 = identity>
requires indirectly_comparable<iterator_t<_Range1>, iterator_t<_Range2>,
_Pred, _Proj1, _Proj2>
constexpr borrowed_subrange_t<_Range1>
operator()(_Range1&& __r1, _Range2&& __r2, _Pred __pred = {},
_Proj1 __proj1 = {}, _Proj2 __proj2 = {}) const
{
return (*this)(ranges::begin(__r1), ranges::end(__r1),
ranges::begin(__r2), ranges::end(__r2),
std::move(__pred),
std::move(__proj1), std::move(__proj2));
}
};
inline constexpr __search_fn search{};
struct __search_n_fn
{
template<forward_iterator _Iter, sentinel_for<_Iter> _Sent, typename _Tp,
typename _Pred = ranges::equal_to, typename _Proj = identity>
requires indirectly_comparable<_Iter, const _Tp*, _Pred, _Proj>
constexpr subrange<_Iter>
operator()(_Iter __first, _Sent __last, iter_difference_t<_Iter> __count,
const _Tp& __value, _Pred __pred = {}, _Proj __proj = {}) const
{
if (__count <= 0)
return {__first, __first};
auto __value_comp = [&] <typename _Rp> (_Rp&& __arg) {
return std::__invoke(__pred, std::forward<_Rp>(__arg), __value);
};
if (__count == 1)
{
__first = ranges::find_if(std::move(__first), __last,
std::move(__value_comp),
std::move(__proj));
if (__first == __last)
return {__first, __first};
else
{
auto __end = __first;
return {__first, ++__end};
}
}
if constexpr (sized_sentinel_for<_Sent, _Iter>
&& random_access_iterator<_Iter>)
{
auto __tail_size = __last - __first;
auto __remainder = __count;
while (__remainder <= __tail_size)
{
__first += __remainder;
__tail_size -= __remainder;
auto __backtrack = __first;
while (__value_comp(std::__invoke(__proj, *--__backtrack)))
{
if (--__remainder == 0)
return {__first - __count, __first};
}
__remainder = __count + 1 - (__first - __backtrack);
}
auto __i = __first + __tail_size;
return {__i, __i};
}
else
{
__first = ranges::find_if(__first, __last, __value_comp, __proj);
while (__first != __last)
{
auto __n = __count;
auto __i = __first;
++__i;
while (__i != __last && __n != 1
&& __value_comp(std::__invoke(__proj, *__i)))
{
++__i;
--__n;
}
if (__n == 1)
return {__first, __i};
if (__i == __last)
return {__i, __i};
__first = ranges::find_if(++__i, __last, __value_comp, __proj);
}
return {__first, __first};
}
}
template<forward_range _Range, typename _Tp,
typename _Pred = ranges::equal_to, typename _Proj = identity>
requires indirectly_comparable<iterator_t<_Range>, const _Tp*,
_Pred, _Proj>
constexpr borrowed_subrange_t<_Range>
operator()(_Range&& __r, range_difference_t<_Range> __count,
const _Tp& __value, _Pred __pred = {}, _Proj __proj = {}) const
{
return (*this)(ranges::begin(__r), ranges::end(__r),
std::move(__count), __value,
std::move(__pred), std::move(__proj));
}
};
inline constexpr __search_n_fn search_n{};
struct __find_end_fn
{
template<forward_iterator _Iter1, sentinel_for<_Iter1> _Sent1,
forward_iterator _Iter2, sentinel_for<_Iter2> _Sent2,
typename _Pred = ranges::equal_to,
typename _Proj1 = identity, typename _Proj2 = identity>
requires indirectly_comparable<_Iter1, _Iter2, _Pred, _Proj1, _Proj2>
constexpr subrange<_Iter1>
operator()(_Iter1 __first1, _Sent1 __last1,
_Iter2 __first2, _Sent2 __last2, _Pred __pred = {},
_Proj1 __proj1 = {}, _Proj2 __proj2 = {}) const
{
if constexpr (bidirectional_iterator<_Iter1>
&& bidirectional_iterator<_Iter2>)
{
auto __i1 = ranges::next(__first1, __last1);
auto __i2 = ranges::next(__first2, __last2);
auto __rresult
= ranges::search(reverse_iterator<_Iter1>{__i1},
reverse_iterator<_Iter1>{__first1},
reverse_iterator<_Iter2>{__i2},
reverse_iterator<_Iter2>{__first2},
std::move(__pred),
std::move(__proj1), std::move(__proj2));
auto __result_first = ranges::end(__rresult).base();
auto __result_last = ranges::begin(__rresult).base();
if (__result_last == __first1)
return {__i1, __i1};
else
return {__result_first, __result_last};
}
else
{
auto __i = ranges::next(__first1, __last1);
if (__first2 == __last2)
return {__i, __i};
auto __result_begin = __i;
auto __result_end = __i;
for (;;)
{
auto __new_range = ranges::search(__first1, __last1,
__first2, __last2,
__pred, __proj1, __proj2);
auto __new_result_begin = ranges::begin(__new_range);
auto __new_result_end = ranges::end(__new_range);
if (__new_result_begin == __last1)
return {__result_begin, __result_end};
else
{
__result_begin = __new_result_begin;
__result_end = __new_result_end;
__first1 = __result_begin;
++__first1;
}
}
}
}
template<forward_range _Range1, forward_range _Range2,
typename _Pred = ranges::equal_to,
typename _Proj1 = identity, typename _Proj2 = identity>
requires indirectly_comparable<iterator_t<_Range1>, iterator_t<_Range2>,
_Pred, _Proj1, _Proj2>
constexpr borrowed_subrange_t<_Range1>
operator()(_Range1&& __r1, _Range2&& __r2, _Pred __pred = {},
_Proj1 __proj1 = {}, _Proj2 __proj2 = {}) const
{
return (*this)(ranges::begin(__r1), ranges::end(__r1),
ranges::begin(__r2), ranges::end(__r2),
std::move(__pred),
std::move(__proj1), std::move(__proj2));
}
};
inline constexpr __find_end_fn find_end{};
struct __adjacent_find_fn
{
template<forward_iterator _Iter, sentinel_for<_Iter> _Sent,
typename _Proj = identity,
indirect_binary_predicate<projected<_Iter, _Proj>,
projected<_Iter, _Proj>> _Pred
= ranges::equal_to>
constexpr _Iter
operator()(_Iter __first, _Sent __last,
_Pred __pred = {}, _Proj __proj = {}) const
{
if (__first == __last)
return __first;
auto __next = __first;
for (; ++__next != __last; __first = __next)
{
if (std::__invoke(__pred,
std::__invoke(__proj, *__first),
std::__invoke(__proj, *__next)))
return __first;
}
return __next;
}
template<forward_range _Range, typename _Proj = identity,
indirect_binary_predicate<
projected<iterator_t<_Range>, _Proj>,
projected<iterator_t<_Range>, _Proj>> _Pred = ranges::equal_to>
constexpr borrowed_iterator_t<_Range>
operator()(_Range&& __r, _Pred __pred = {}, _Proj __proj = {}) const
{
return (*this)(ranges::begin(__r), ranges::end(__r),
std::move(__pred), std::move(__proj));
}
};
inline constexpr __adjacent_find_fn adjacent_find{};
struct __is_permutation_fn
{
template<forward_iterator _Iter1, sentinel_for<_Iter1> _Sent1,
forward_iterator _Iter2, sentinel_for<_Iter2> _Sent2,
typename _Proj1 = identity, typename _Proj2 = identity,
indirect_equivalence_relation<projected<_Iter1, _Proj1>,
projected<_Iter2, _Proj2>> _Pred
= ranges::equal_to>
constexpr bool
operator()(_Iter1 __first1, _Sent1 __last1,
_Iter2 __first2, _Sent2 __last2, _Pred __pred = {},
_Proj1 __proj1 = {}, _Proj2 __proj2 = {}) const
{
constexpr bool __sized_iters
= (sized_sentinel_for<_Sent1, _Iter1>
&& sized_sentinel_for<_Sent2, _Iter2>);
if constexpr (__sized_iters)
{
auto __d1 = ranges::distance(__first1, __last1);
auto __d2 = ranges::distance(__first2, __last2);
if (__d1 != __d2)
return false;
}
// Efficiently compare identical prefixes: O(N) if sequences
// have the same elements in the same order.
for (; __first1 != __last1 && __first2 != __last2;
++__first1, (void)++__first2)
if (!(bool)std::__invoke(__pred,
std::__invoke(__proj1, *__first1),
std::__invoke(__proj2, *__first2)))
break;
if constexpr (__sized_iters)
{
if (__first1 == __last1)
return true;
}
else
{
auto __d1 = ranges::distance(__first1, __last1);
auto __d2 = ranges::distance(__first2, __last2);
if (__d1 == 0 && __d2 == 0)
return true;
if (__d1 != __d2)
return false;
}
for (auto __scan = __first1; __scan != __last1; ++__scan)
{
auto __proj_scan = std::__invoke(__proj1, *__scan);
auto __comp_scan = [&] <typename _Tp> (_Tp&& __arg) {
return std::__invoke(__pred, __proj_scan,
std::forward<_Tp>(__arg));
};
if (__scan != ranges::find_if(__first1, __scan,
__comp_scan, __proj1))
continue; // We've seen this one before.
auto __matches = ranges::count_if(__first2, __last2,
__comp_scan, __proj2);
if (__matches == 0
|| ranges::count_if(__scan, __last1,
__comp_scan, __proj1) != __matches)
return false;
}
return true;
}
template<forward_range _Range1, forward_range _Range2,
typename _Proj1 = identity, typename _Proj2 = identity,
indirect_equivalence_relation<
projected<iterator_t<_Range1>, _Proj1>,
projected<iterator_t<_Range2>, _Proj2>> _Pred = ranges::equal_to>
constexpr bool
operator()(_Range1&& __r1, _Range2&& __r2, _Pred __pred = {},
_Proj1 __proj1 = {}, _Proj2 __proj2 = {}) const
{
return (*this)(ranges::begin(__r1), ranges::end(__r1),
ranges::begin(__r2), ranges::end(__r2),
std::move(__pred),
std::move(__proj1), std::move(__proj2));
}
};
inline constexpr __is_permutation_fn is_permutation{};
template<typename _Iter, typename _Out>
using copy_if_result = in_out_result<_Iter, _Out>;
struct __copy_if_fn
{
template<input_iterator _Iter, sentinel_for<_Iter> _Sent,
weakly_incrementable _Out, typename _Proj = identity,
indirect_unary_predicate<projected<_Iter, _Proj>> _Pred>
requires indirectly_copyable<_Iter, _Out>
constexpr copy_if_result<_Iter, _Out>
operator()(_Iter __first, _Sent __last, _Out __result,
_Pred __pred, _Proj __proj = {}) const
{
for (; __first != __last; ++__first)
if (std::__invoke(__pred, std::__invoke(__proj, *__first)))
{
*__result = *__first;
++__result;
}
return {std::move(__first), std::move(__result)};
}
template<input_range _Range, weakly_incrementable _Out,
typename _Proj = identity,
indirect_unary_predicate<projected<iterator_t<_Range>, _Proj>>
_Pred>
requires indirectly_copyable<iterator_t<_Range>, _Out>
constexpr copy_if_result<borrowed_iterator_t<_Range>, _Out>
operator()(_Range&& __r, _Out __result,
_Pred __pred, _Proj __proj = {}) const
{
return (*this)(ranges::begin(__r), ranges::end(__r),
std::move(__result),
std::move(__pred), std::move(__proj));
}
};
inline constexpr __copy_if_fn copy_if{};
template<typename _Iter1, typename _Iter2>
using swap_ranges_result = in_in_result<_Iter1, _Iter2>;
struct __swap_ranges_fn
{
template<input_iterator _Iter1, sentinel_for<_Iter1> _Sent1,
input_iterator _Iter2, sentinel_for<_Iter2> _Sent2>
requires indirectly_swappable<_Iter1, _Iter2>
constexpr swap_ranges_result<_Iter1, _Iter2>
operator()(_Iter1 __first1, _Sent1 __last1,
_Iter2 __first2, _Sent2 __last2) const
{
for (; __first1 != __last1 && __first2 != __last2;
++__first1, (void)++__first2)
ranges::iter_swap(__first1, __first2);
return {std::move(__first1), std::move(__first2)};
}
template<input_range _Range1, input_range _Range2>
requires indirectly_swappable<iterator_t<_Range1>, iterator_t<_Range2>>
constexpr swap_ranges_result<borrowed_iterator_t<_Range1>,
borrowed_iterator_t<_Range2>>
operator()(_Range1&& __r1, _Range2&& __r2) const
{
return (*this)(ranges::begin(__r1), ranges::end(__r1),
ranges::begin(__r2), ranges::end(__r2));
}
};
inline constexpr __swap_ranges_fn swap_ranges{};
template<typename _Iter, typename _Out>
using unary_transform_result = in_out_result<_Iter, _Out>;
template<typename _Iter1, typename _Iter2, typename _Out>
struct in_in_out_result
{
[[no_unique_address]] _Iter1 in1;
[[no_unique_address]] _Iter2 in2;
[[no_unique_address]] _Out out;
template<typename _IIter1, typename _IIter2, typename _OOut>
requires convertible_to<const _Iter1&, _IIter1>
&& convertible_to<const _Iter2&, _IIter2>
&& convertible_to<const _Out&, _OOut>
constexpr
operator in_in_out_result<_IIter1, _IIter2, _OOut>() const &
{ return {in1, in2, out}; }
template<typename _IIter1, typename _IIter2, typename _OOut>
requires convertible_to<_Iter1, _IIter1>
&& convertible_to<_Iter2, _IIter2>
&& convertible_to<_Out, _OOut>
constexpr
operator in_in_out_result<_IIter1, _IIter2, _OOut>() &&
{ return {std::move(in1), std::move(in2), std::move(out)}; }
};
template<typename _Iter1, typename _Iter2, typename _Out>
using binary_transform_result = in_in_out_result<_Iter1, _Iter2, _Out>;
struct __transform_fn
{
template<input_iterator _Iter, sentinel_for<_Iter> _Sent,
weakly_incrementable _Out,
copy_constructible _Fp, typename _Proj = identity>
requires indirectly_writable<_Out,
indirect_result_t<_Fp&,
projected<_Iter, _Proj>>>
constexpr unary_transform_result<_Iter, _Out>
operator()(_Iter __first1, _Sent __last1, _Out __result,
_Fp __op, _Proj __proj = {}) const
{
for (; __first1 != __last1; ++__first1, (void)++__result)
*__result = std::__invoke(__op, std::__invoke(__proj, *__first1));
return {std::move(__first1), std::move(__result)};
}
template<input_range _Range, weakly_incrementable _Out,
copy_constructible _Fp, typename _Proj = identity>
requires indirectly_writable<_Out,
indirect_result_t<_Fp&,
projected<iterator_t<_Range>, _Proj>>>
constexpr unary_transform_result<borrowed_iterator_t<_Range>, _Out>
operator()(_Range&& __r, _Out __result, _Fp __op, _Proj __proj = {}) const
{
return (*this)(ranges::begin(__r), ranges::end(__r),
std::move(__result),
std::move(__op), std::move(__proj));
}
template<input_iterator _Iter1, sentinel_for<_Iter1> _Sent1,
input_iterator _Iter2, sentinel_for<_Iter2> _Sent2,
weakly_incrementable _Out, copy_constructible _Fp,
typename _Proj1 = identity, typename _Proj2 = identity>
requires indirectly_writable<_Out,
indirect_result_t<_Fp&,
projected<_Iter1, _Proj1>,
projected<_Iter2, _Proj2>>>
constexpr binary_transform_result<_Iter1, _Iter2, _Out>
operator()(_Iter1 __first1, _Sent1 __last1,
_Iter2 __first2, _Sent2 __last2,
_Out __result, _Fp __binary_op,
_Proj1 __proj1 = {}, _Proj2 __proj2 = {}) const
{
for (; __first1 != __last1 && __first2 != __last2;
++__first1, (void)++__first2, ++__result)
*__result = std::__invoke(__binary_op,
std::__invoke(__proj1, *__first1),
std::__invoke(__proj2, *__first2));
return {std::move(__first1), std::move(__first2), std::move(__result)};
}
template<input_range _Range1, input_range _Range2,
weakly_incrementable _Out, copy_constructible _Fp,
typename _Proj1 = identity, typename _Proj2 = identity>
requires indirectly_writable<_Out,
indirect_result_t<_Fp&,
projected<iterator_t<_Range1>, _Proj1>,
projected<iterator_t<_Range2>, _Proj2>>>
constexpr binary_transform_result<borrowed_iterator_t<_Range1>,
borrowed_iterator_t<_Range2>, _Out>
operator()(_Range1&& __r1, _Range2&& __r2, _Out __result, _Fp __binary_op,
_Proj1 __proj1 = {}, _Proj2 __proj2 = {}) const
{
return (*this)(ranges::begin(__r1), ranges::end(__r1),
ranges::begin(__r2), ranges::end(__r2),
std::move(__result), std::move(__binary_op),
std::move(__proj1), std::move(__proj2));
}
};
inline constexpr __transform_fn transform{};
struct __replace_fn
{
template<input_iterator _Iter, sentinel_for<_Iter> _Sent,
typename _Tp1, typename _Tp2, typename _Proj = identity>
requires indirectly_writable<_Iter, const _Tp2&>
&& indirect_binary_predicate<ranges::equal_to, projected<_Iter, _Proj>,
const _Tp1*>
constexpr _Iter
operator()(_Iter __first, _Sent __last,
const _Tp1& __old_value, const _Tp2& __new_value,
_Proj __proj = {}) const
{
for (; __first != __last; ++__first)
if (std::__invoke(__proj, *__first) == __old_value)
*__first = __new_value;
return __first;
}
template<input_range _Range,
typename _Tp1, typename _Tp2, typename _Proj = identity>
requires indirectly_writable<iterator_t<_Range>, const _Tp2&>
&& indirect_binary_predicate<ranges::equal_to,
projected<iterator_t<_Range>, _Proj>,
const _Tp1*>
constexpr borrowed_iterator_t<_Range>
operator()(_Range&& __r,
const _Tp1& __old_value, const _Tp2& __new_value,
_Proj __proj = {}) const
{
return (*this)(ranges::begin(__r), ranges::end(__r),
__old_value, __new_value, std::move(__proj));
}
};
inline constexpr __replace_fn replace{};
struct __replace_if_fn
{
template<input_iterator _Iter, sentinel_for<_Iter> _Sent,
typename _Tp, typename _Proj = identity,
indirect_unary_predicate<projected<_Iter, _Proj>> _Pred>
requires indirectly_writable<_Iter, const _Tp&>
constexpr _Iter
operator()(_Iter __first, _Sent __last,
_Pred __pred, const _Tp& __new_value, _Proj __proj = {}) const
{
for (; __first != __last; ++__first)
if (std::__invoke(__pred, std::__invoke(__proj, *__first)))
*__first = __new_value;
return std::move(__first);
}
template<input_range _Range, typename _Tp, typename _Proj = identity,
indirect_unary_predicate<projected<iterator_t<_Range>, _Proj>>
_Pred>
requires indirectly_writable<iterator_t<_Range>, const _Tp&>
constexpr borrowed_iterator_t<_Range>
operator()(_Range&& __r,
_Pred __pred, const _Tp& __new_value, _Proj __proj = {}) const
{
return (*this)(ranges::begin(__r), ranges::end(__r),
std::move(__pred), __new_value, std::move(__proj));
}
};
inline constexpr __replace_if_fn replace_if{};
template<typename _Iter, typename _Out>
using replace_copy_result = in_out_result<_Iter, _Out>;
struct __replace_copy_fn
{
template<input_iterator _Iter, sentinel_for<_Iter> _Sent,
typename _Tp1, typename _Tp2, output_iterator<const _Tp2&> _Out,
typename _Proj = identity>
requires indirectly_copyable<_Iter, _Out>
&& indirect_binary_predicate<ranges::equal_to,
projected<_Iter, _Proj>, const _Tp1*>
constexpr replace_copy_result<_Iter, _Out>
operator()(_Iter __first, _Sent __last, _Out __result,
const _Tp1& __old_value, const _Tp2& __new_value,
_Proj __proj = {}) const
{
for (; __first != __last; ++__first, (void)++__result)
if (std::__invoke(__proj, *__first) == __old_value)
*__result = __new_value;
else
*__result = *__first;
return {std::move(__first), std::move(__result)};
}
template<input_range _Range, typename _Tp1, typename _Tp2,
output_iterator<const _Tp2&> _Out, typename _Proj = identity>
requires indirectly_copyable<iterator_t<_Range>, _Out>
&& indirect_binary_predicate<ranges::equal_to,
projected<iterator_t<_Range>, _Proj>,
const _Tp1*>
constexpr replace_copy_result<borrowed_iterator_t<_Range>, _Out>
operator()(_Range&& __r, _Out __result,
const _Tp1& __old_value, const _Tp2& __new_value,
_Proj __proj = {}) const
{
return (*this)(ranges::begin(__r), ranges::end(__r),
std::move(__result), __old_value,
__new_value, std::move(__proj));
}
};
inline constexpr __replace_copy_fn replace_copy{};
template<typename _Iter, typename _Out>
using replace_copy_if_result = in_out_result<_Iter, _Out>;
struct __replace_copy_if_fn
{
template<input_iterator _Iter, sentinel_for<_Iter> _Sent,
typename _Tp, output_iterator<const _Tp&> _Out,
typename _Proj = identity,
indirect_unary_predicate<projected<_Iter, _Proj>> _Pred>
requires indirectly_copyable<_Iter, _Out>
constexpr replace_copy_if_result<_Iter, _Out>
operator()(_Iter __first, _Sent __last, _Out __result,
_Pred __pred, const _Tp& __new_value, _Proj __proj = {}) const
{
for (; __first != __last; ++__first, (void)++__result)
if (std::__invoke(__pred, std::__invoke(__proj, *__first)))
*__result = __new_value;
else
*__result = *__first;
return {std::move(__first), std::move(__result)};
}
template<input_range _Range,
typename _Tp, output_iterator<const _Tp&> _Out,
typename _Proj = identity,
indirect_unary_predicate<projected<iterator_t<_Range>, _Proj>>
_Pred>
requires indirectly_copyable<iterator_t<_Range>, _Out>
constexpr replace_copy_if_result<borrowed_iterator_t<_Range>, _Out>
operator()(_Range&& __r, _Out __result,
_Pred __pred, const _Tp& __new_value, _Proj __proj = {}) const
{
return (*this)(ranges::begin(__r), ranges::end(__r),
std::move(__result), std::move(__pred),
__new_value, std::move(__proj));
}
};
inline constexpr __replace_copy_if_fn replace_copy_if{};
struct __generate_n_fn
{
template<input_or_output_iterator _Out, copy_constructible _Fp>
requires invocable<_Fp&>
&& indirectly_writable<_Out, invoke_result_t<_Fp&>>
constexpr _Out
operator()(_Out __first, iter_difference_t<_Out> __n, _Fp __gen) const
{
for (; __n > 0; --__n, (void)++__first)
*__first = std::__invoke(__gen);
return __first;
}
};
inline constexpr __generate_n_fn generate_n{};
struct __generate_fn
{
template<input_or_output_iterator _Out, sentinel_for<_Out> _Sent,
copy_constructible _Fp>
requires invocable<_Fp&>
&& indirectly_writable<_Out, invoke_result_t<_Fp&>>
constexpr _Out
operator()(_Out __first, _Sent __last, _Fp __gen) const
{
for (; __first != __last; ++__first)
*__first = std::__invoke(__gen);
return __first;
}
template<typename _Range, copy_constructible _Fp>
requires invocable<_Fp&> && output_range<_Range, invoke_result_t<_Fp&>>
constexpr borrowed_iterator_t<_Range>
operator()(_Range&& __r, _Fp __gen) const
{
return (*this)(ranges::begin(__r), ranges::end(__r), std::move(__gen));
}
};
inline constexpr __generate_fn generate{};
struct __remove_if_fn
{
template<permutable _Iter, sentinel_for<_Iter> _Sent,
typename _Proj = identity,
indirect_unary_predicate<projected<_Iter, _Proj>> _Pred>
constexpr subrange<_Iter>
operator()(_Iter __first, _Sent __last,
_Pred __pred, _Proj __proj = {}) const
{
__first = ranges::find_if(__first, __last, __pred, __proj);
if (__first == __last)
return {__first, __first};
auto __result = __first;
++__first;
for (; __first != __last; ++__first)
if (!std::__invoke(__pred, std::__invoke(__proj, *__first)))
{
*__result = std::move(*__first);
++__result;
}
return {__result, __first};
}
template<forward_range _Range, typename _Proj = identity,
indirect_unary_predicate<projected<iterator_t<_Range>, _Proj>>
_Pred>
requires permutable<iterator_t<_Range>>
constexpr borrowed_subrange_t<_Range>
operator()(_Range&& __r, _Pred __pred, _Proj __proj = {}) const
{
return (*this)(ranges::begin(__r), ranges::end(__r),
std::move(__pred), std::move(__proj));
}
};
inline constexpr __remove_if_fn remove_if{};
struct __remove_fn
{
template<permutable _Iter, sentinel_for<_Iter> _Sent,
typename _Tp, typename _Proj = identity>
requires indirect_binary_predicate<ranges::equal_to,
projected<_Iter, _Proj>,
const _Tp*>
constexpr subrange<_Iter>
operator()(_Iter __first, _Sent __last,
const _Tp& __value, _Proj __proj = {}) const
{
auto __pred = [&] (auto&& __arg) {
return std::forward<decltype(__arg)>(__arg) == __value;
};
return ranges::remove_if(__first, __last,
std::move(__pred), std::move(__proj));
}
template<forward_range _Range, typename _Tp, typename _Proj = identity>
requires permutable<iterator_t<_Range>>
&& indirect_binary_predicate<ranges::equal_to,
projected<iterator_t<_Range>, _Proj>,
const _Tp*>
constexpr borrowed_subrange_t<_Range>
operator()(_Range&& __r, const _Tp& __value, _Proj __proj = {}) const
{
return (*this)(ranges::begin(__r), ranges::end(__r),
__value, std::move(__proj));
}
};
inline constexpr __remove_fn remove{};
template<typename _Iter, typename _Out>
using remove_copy_if_result = in_out_result<_Iter, _Out>;
struct __remove_copy_if_fn
{
template<input_iterator _Iter, sentinel_for<_Iter> _Sent,
weakly_incrementable _Out, typename _Proj = identity,
indirect_unary_predicate<projected<_Iter, _Proj>> _Pred>
requires indirectly_copyable<_Iter, _Out>
constexpr remove_copy_if_result<_Iter, _Out>
operator()(_Iter __first, _Sent __last, _Out __result,
_Pred __pred, _Proj __proj = {}) const
{
for (; __first != __last; ++__first)
if (!std::__invoke(__pred, std::__invoke(__proj, *__first)))
{
*__result = *__first;
++__result;
}
return {std::move(__first), std::move(__result)};
}
template<input_range _Range, weakly_incrementable _Out,
typename _Proj = identity,
indirect_unary_predicate<projected<iterator_t<_Range>, _Proj>>
_Pred>
requires indirectly_copyable<iterator_t<_Range>, _Out>
constexpr remove_copy_if_result<borrowed_iterator_t<_Range>, _Out>
operator()(_Range&& __r, _Out __result,
_Pred __pred, _Proj __proj = {}) const
{
return (*this)(ranges::begin(__r), ranges::end(__r),
std::move(__result),
std::move(__pred), std::move(__proj));
}
};
inline constexpr __remove_copy_if_fn remove_copy_if{};
template<typename _Iter, typename _Out>
using remove_copy_result = in_out_result<_Iter, _Out>;
struct __remove_copy_fn
{
template<input_iterator _Iter, sentinel_for<_Iter> _Sent,
weakly_incrementable _Out, typename _Tp, typename _Proj = identity>
requires indirectly_copyable<_Iter, _Out>
&& indirect_binary_predicate<ranges::equal_to,
projected<_Iter, _Proj>,
const _Tp*>
constexpr remove_copy_result<_Iter, _Out>
operator()(_Iter __first, _Sent __last, _Out __result,
const _Tp& __value, _Proj __proj = {}) const
{
for (; __first != __last; ++__first)
if (!(std::__invoke(__proj, *__first) == __value))
{
*__result = *__first;
++__result;
}
return {std::move(__first), std::move(__result)};
}
template<input_range _Range, weakly_incrementable _Out,
typename _Tp, typename _Proj = identity>
requires indirectly_copyable<iterator_t<_Range>, _Out>
&& indirect_binary_predicate<ranges::equal_to,
projected<iterator_t<_Range>, _Proj>,
const _Tp*>
constexpr remove_copy_result<borrowed_iterator_t<_Range>, _Out>
operator()(_Range&& __r, _Out __result,
const _Tp& __value, _Proj __proj = {}) const
{
return (*this)(ranges::begin(__r), ranges::end(__r),
std::move(__result), __value, std::move(__proj));
}
};
inline constexpr __remove_copy_fn remove_copy{};
struct __unique_fn
{
template<permutable _Iter, sentinel_for<_Iter> _Sent,
typename _Proj = identity,
indirect_equivalence_relation<
projected<_Iter, _Proj>> _Comp = ranges::equal_to>
constexpr subrange<_Iter>
operator()(_Iter __first, _Sent __last,
_Comp __comp = {}, _Proj __proj = {}) const
{
__first = ranges::adjacent_find(__first, __last, __comp, __proj);
if (__first == __last)
return {__first, __first};
auto __dest = __first;
++__first;
while (++__first != __last)
if (!std::__invoke(__comp,
std::__invoke(__proj, *__dest),
std::__invoke(__proj, *__first)))
*++__dest = std::move(*__first);
return {++__dest, __first};
}
template<forward_range _Range, typename _Proj = identity,
indirect_equivalence_relation<
projected<iterator_t<_Range>, _Proj>> _Comp = ranges::equal_to>
requires permutable<iterator_t<_Range>>
constexpr borrowed_subrange_t<_Range>
operator()(_Range&& __r, _Comp __comp = {}, _Proj __proj = {}) const
{
return (*this)(ranges::begin(__r), ranges::end(__r),
std::move(__comp), std::move(__proj));
}
};
inline constexpr __unique_fn unique{};
template<typename _Iter, typename _Out>
using unique_copy_result = in_out_result<_Iter, _Out>;
struct __unique_copy_fn
{
template<input_iterator _Iter, sentinel_for<_Iter> _Sent,
weakly_incrementable _Out, typename _Proj = identity,
indirect_equivalence_relation<
projected<_Iter, _Proj>> _Comp = ranges::equal_to>
requires indirectly_copyable<_Iter, _Out>
&& (forward_iterator<_Iter>
|| (input_iterator<_Out>
&& same_as<iter_value_t<_Iter>, iter_value_t<_Out>>)
|| indirectly_copyable_storable<_Iter, _Out>)
constexpr unique_copy_result<_Iter, _Out>
operator()(_Iter __first, _Sent __last, _Out __result,
_Comp __comp = {}, _Proj __proj = {}) const
{
if (__first == __last)
return {std::move(__first), std::move(__result)};
// TODO: perform a closer comparison with reference implementations
if constexpr (forward_iterator<_Iter>)
{
auto __next = __first;
*__result = *__next;
while (++__next != __last)
if (!std::__invoke(__comp,
std::__invoke(__proj, *__first),
std::__invoke(__proj, *__next)))
{
__first = __next;
*++__result = *__first;
}
return {__next, std::move(++__result)};
}
else if constexpr (input_iterator<_Out>
&& same_as<iter_value_t<_Iter>, iter_value_t<_Out>>)
{
*__result = *__first;
while (++__first != __last)
if (!std::__invoke(__comp,
std::__invoke(__proj, *__result),
std::__invoke(__proj, *__first)))
*++__result = *__first;
return {std::move(__first), std::move(++__result)};
}
else // indirectly_copyable_storable<_Iter, _Out>
{
auto __value = *__first;
*__result = __value;
while (++__first != __last)
{
if (!(bool)std::__invoke(__comp,
std::__invoke(__proj, *__first),
std::__invoke(__proj, __value)))
{
__value = *__first;
*++__result = __value;
}
}
return {std::move(__first), std::move(++__result)};
}
}
template<input_range _Range,
weakly_incrementable _Out, typename _Proj = identity,
indirect_equivalence_relation<
projected<iterator_t<_Range>, _Proj>> _Comp = ranges::equal_to>
requires indirectly_copyable<iterator_t<_Range>, _Out>
&& (forward_iterator<iterator_t<_Range>>
|| (input_iterator<_Out>
&& same_as<range_value_t<_Range>, iter_value_t<_Out>>)
|| indirectly_copyable_storable<iterator_t<_Range>, _Out>)
constexpr unique_copy_result<borrowed_iterator_t<_Range>, _Out>
operator()(_Range&& __r, _Out __result,
_Comp __comp = {}, _Proj __proj = {}) const
{
return (*this)(ranges::begin(__r), ranges::end(__r),
std::move(__result),
std::move(__comp), std::move(__proj));
}
};
inline constexpr __unique_copy_fn unique_copy{};
struct __reverse_fn
{
template<bidirectional_iterator _Iter, sentinel_for<_Iter> _Sent>
requires permutable<_Iter>
constexpr _Iter
operator()(_Iter __first, _Sent __last) const
{
auto __i = ranges::next(__first, __last);
auto __tail = __i;
if constexpr (random_access_iterator<_Iter>)
{
if (__first != __last)
{
--__tail;
while (__first < __tail)
{
ranges::iter_swap(__first, __tail);
++__first;
--__tail;
}
}
return __i;
}
else
{
for (;;)
if (__first == __tail || __first == --__tail)
break;
else
{
ranges::iter_swap(__first, __tail);
++__first;
}
return __i;
}
}
template<bidirectional_range _Range>
requires permutable<iterator_t<_Range>>
constexpr borrowed_iterator_t<_Range>
operator()(_Range&& __r) const
{
return (*this)(ranges::begin(__r), ranges::end(__r));
}
};
inline constexpr __reverse_fn reverse{};
template<typename _Iter, typename _Out>
using reverse_copy_result = in_out_result<_Iter, _Out>;
struct __reverse_copy_fn
{
template<bidirectional_iterator _Iter, sentinel_for<_Iter> _Sent,
weakly_incrementable _Out>
requires indirectly_copyable<_Iter, _Out>
constexpr reverse_copy_result<_Iter, _Out>
operator()(_Iter __first, _Sent __last, _Out __result) const
{
auto __i = ranges::next(__first, __last);
auto __tail = __i;
while (__first != __tail)
{
--__tail;
*__result = *__tail;
++__result;
}
return {__i, __result};
}
template<bidirectional_range _Range, weakly_incrementable _Out>
requires indirectly_copyable<iterator_t<_Range>, _Out>
constexpr reverse_copy_result<borrowed_iterator_t<_Range>, _Out>
operator()(_Range&& __r, _Out __result) const
{
return (*this)(ranges::begin(__r), ranges::end(__r),
std::move(__result));
}
};
inline constexpr __reverse_copy_fn reverse_copy{};
struct __rotate_fn
{
template<permutable _Iter, sentinel_for<_Iter> _Sent>
constexpr subrange<_Iter>
operator()(_Iter __first, _Iter __middle, _Sent __last) const
{
auto __lasti = ranges::next(__first, __last);
if (__first == __middle)
return {__lasti, __lasti};
if (__last == __middle)
return {std::move(__first), std::move(__lasti)};
if constexpr (random_access_iterator<_Iter>)
{
auto __n = __lasti - __first;
auto __k = __middle - __first;
if (__k == __n - __k)
{
ranges::swap_ranges(__first, __middle, __middle, __middle + __k);
return {std::move(__middle), std::move(__lasti)};
}
auto __p = __first;
auto __ret = __first + (__lasti - __middle);
for (;;)
{
if (__k < __n - __k)
{
// TODO: is_pod is deprecated, but this condition is
// consistent with the STL implementation.
if constexpr (__is_pod(iter_value_t<_Iter>))
if (__k == 1)
{
auto __t = std::move(*__p);
ranges::move(__p + 1, __p + __n, __p);
*(__p + __n - 1) = std::move(__t);
return {std::move(__ret), std::move(__lasti)};
}
auto __q = __p + __k;
for (decltype(__n) __i = 0; __i < __n - __k; ++ __i)
{
ranges::iter_swap(__p, __q);
++__p;
++__q;
}
__n %= __k;
if (__n == 0)
return {std::move(__ret), std::move(__lasti)};
ranges::swap(__n, __k);
__k = __n - __k;
}
else
{
__k = __n - __k;
// TODO: is_pod is deprecated, but this condition is
// consistent with the STL implementation.
if constexpr (__is_pod(iter_value_t<_Iter>))
if (__k == 1)
{
auto __t = std::move(*(__p + __n - 1));
ranges::move_backward(__p, __p + __n - 1, __p + __n);
*__p = std::move(__t);
return {std::move(__ret), std::move(__lasti)};
}
auto __q = __p + __n;
__p = __q - __k;
for (decltype(__n) __i = 0; __i < __n - __k; ++ __i)
{
--__p;
--__q;
ranges::iter_swap(__p, __q);
}
__n %= __k;
if (__n == 0)
return {std::move(__ret), std::move(__lasti)};
std::swap(__n, __k);
}
}
}
else if constexpr (bidirectional_iterator<_Iter>)
{
auto __tail = __lasti;
ranges::reverse(__first, __middle);
ranges::reverse(__middle, __tail);
while (__first != __middle && __middle != __tail)
{
ranges::iter_swap(__first, --__tail);
++__first;
}
if (__first == __middle)
{
ranges::reverse(__middle, __tail);
return {std::move(__tail), std::move(__lasti)};
}
else
{
ranges::reverse(__first, __middle);
return {std::move(__first), std::move(__lasti)};
}
}
else
{
auto __first2 = __middle;
do
{
ranges::iter_swap(__first, __first2);
++__first;
++__first2;
if (__first == __middle)
__middle = __first2;
} while (__first2 != __last);
auto __ret = __first;
__first2 = __middle;
while (__first2 != __last)
{
ranges::iter_swap(__first, __first2);
++__first;
++__first2;
if (__first == __middle)
__middle = __first2;
else if (__first2 == __last)
__first2 = __middle;
}
return {std::move(__ret), std::move(__lasti)};
}
}
template<forward_range _Range>
requires permutable<iterator_t<_Range>>
constexpr borrowed_subrange_t<_Range>
operator()(_Range&& __r, iterator_t<_Range> __middle) const
{
return (*this)(ranges::begin(__r), std::move(__middle),
ranges::end(__r));
}
};
inline constexpr __rotate_fn rotate{};
template<typename _Iter, typename _Out>
using rotate_copy_result = in_out_result<_Iter, _Out>;
struct __rotate_copy_fn
{
template<forward_iterator _Iter, sentinel_for<_Iter> _Sent,
weakly_incrementable _Out>
requires indirectly_copyable<_Iter, _Out>
constexpr rotate_copy_result<_Iter, _Out>
operator()(_Iter __first, _Iter __middle, _Sent __last,
_Out __result) const
{
auto __copy1 = ranges::copy(__middle,
std::move(__last),
std::move(__result));
auto __copy2 = ranges::copy(std::move(__first),
std::move(__middle),
std::move(__copy1.out));
return { std::move(__copy1.in), std::move(__copy2.out) };
}
template<forward_range _Range, weakly_incrementable _Out>
requires indirectly_copyable<iterator_t<_Range>, _Out>
constexpr rotate_copy_result<borrowed_iterator_t<_Range>, _Out>
operator()(_Range&& __r, iterator_t<_Range> __middle, _Out __result) const
{
return (*this)(ranges::begin(__r), std::move(__middle),
ranges::end(__r), std::move(__result));
}
};
inline constexpr __rotate_copy_fn rotate_copy{};
struct __sample_fn
{
template<input_iterator _Iter, sentinel_for<_Iter> _Sent,
weakly_incrementable _Out, typename _Gen>
requires (forward_iterator<_Iter> || random_access_iterator<_Out>)
&& indirectly_copyable<_Iter, _Out>
&& uniform_random_bit_generator<remove_reference_t<_Gen>>
_Out
operator()(_Iter __first, _Sent __last, _Out __out,
iter_difference_t<_Iter> __n, _Gen&& __g) const
{
if constexpr (forward_iterator<_Iter>)
{
// FIXME: Forwarding to std::sample here requires computing __lasti
// which may take linear time.
auto __lasti = ranges::next(__first, __last);
return _GLIBCXX_STD_A::
sample(std::move(__first), std::move(__lasti), std::move(__out),
__n, std::forward<_Gen>(__g));
}
else
{
using __distrib_type
= uniform_int_distribution<iter_difference_t<_Iter>>;
using __param_type = typename __distrib_type::param_type;
__distrib_type __d{};
iter_difference_t<_Iter> __sample_sz = 0;
while (__first != __last && __sample_sz != __n)
{
__out[__sample_sz++] = *__first;
++__first;
}
for (auto __pop_sz = __sample_sz; __first != __last;
++__first, (void) ++__pop_sz)
{
const auto __k = __d(__g, __param_type{0, __pop_sz});
if (__k < __n)
__out[__k] = *__first;
}
return __out + __sample_sz;
}
}
template<input_range _Range, weakly_incrementable _Out, typename _Gen>
requires (forward_range<_Range> || random_access_iterator<_Out>)
&& indirectly_copyable<iterator_t<_Range>, _Out>
&& uniform_random_bit_generator<remove_reference_t<_Gen>>
_Out
operator()(_Range&& __r, _Out __out,
range_difference_t<_Range> __n, _Gen&& __g) const
{
return (*this)(ranges::begin(__r), ranges::end(__r),
std::move(__out), __n,
std::forward<_Gen>(__g));
}
};
inline constexpr __sample_fn sample{};
#ifdef _GLIBCXX_USE_C99_STDINT_TR1
struct __shuffle_fn
{
template<random_access_iterator _Iter, sentinel_for<_Iter> _Sent,
typename _Gen>
requires permutable<_Iter>
&& uniform_random_bit_generator<remove_reference_t<_Gen>>
_Iter
operator()(_Iter __first, _Sent __last, _Gen&& __g) const
{
auto __lasti = ranges::next(__first, __last);
std::shuffle(std::move(__first), __lasti, std::forward<_Gen>(__g));
return __lasti;
}
template<random_access_range _Range, typename _Gen>
requires permutable<iterator_t<_Range>>
&& uniform_random_bit_generator<remove_reference_t<_Gen>>
borrowed_iterator_t<_Range>
operator()(_Range&& __r, _Gen&& __g) const
{
return (*this)(ranges::begin(__r), ranges::end(__r),
std::forward<_Gen>(__g));
}
};
inline constexpr __shuffle_fn shuffle{};
#endif
struct __push_heap_fn
{
template<random_access_iterator _Iter, sentinel_for<_Iter> _Sent,
typename _Comp = ranges::less, typename _Proj = identity>
requires sortable<_Iter, _Comp, _Proj>
constexpr _Iter
operator()(_Iter __first, _Sent __last,
_Comp __comp = {}, _Proj __proj = {}) const
{
auto __lasti = ranges::next(__first, __last);
std::push_heap(__first, __lasti,
__detail::__make_comp_proj(__comp, __proj));
return __lasti;
}
template<random_access_range _Range,
typename _Comp = ranges::less, typename _Proj = identity>
requires sortable<iterator_t<_Range>, _Comp, _Proj>
constexpr borrowed_iterator_t<_Range>
operator()(_Range&& __r, _Comp __comp = {}, _Proj __proj = {}) const
{
return (*this)(ranges::begin(__r), ranges::end(__r),
std::move(__comp), std::move(__proj));
}
};
inline constexpr __push_heap_fn push_heap{};
struct __pop_heap_fn
{
template<random_access_iterator _Iter, sentinel_for<_Iter> _Sent,
typename _Comp = ranges::less, typename _Proj = identity>
requires sortable<_Iter, _Comp, _Proj>
constexpr _Iter
operator()(_Iter __first, _Sent __last,
_Comp __comp = {}, _Proj __proj = {}) const
{
auto __lasti = ranges::next(__first, __last);
std::pop_heap(__first, __lasti,
__detail::__make_comp_proj(__comp, __proj));
return __lasti;
}
template<random_access_range _Range,
typename _Comp = ranges::less, typename _Proj = identity>
requires sortable<iterator_t<_Range>, _Comp, _Proj>
constexpr borrowed_iterator_t<_Range>
operator()(_Range&& __r, _Comp __comp = {}, _Proj __proj = {}) const
{
return (*this)(ranges::begin(__r), ranges::end(__r),
std::move(__comp), std::move(__proj));
}
};
inline constexpr __pop_heap_fn pop_heap{};
struct __make_heap_fn
{
template<random_access_iterator _Iter, sentinel_for<_Iter> _Sent,
typename _Comp = ranges::less, typename _Proj = identity>
requires sortable<_Iter, _Comp, _Proj>
constexpr _Iter
operator()(_Iter __first, _Sent __last,
_Comp __comp = {}, _Proj __proj = {}) const
{
auto __lasti = ranges::next(__first, __last);
std::make_heap(__first, __lasti,
__detail::__make_comp_proj(__comp, __proj));
return __lasti;
}
template<random_access_range _Range,
typename _Comp = ranges::less, typename _Proj = identity>
requires sortable<iterator_t<_Range>, _Comp, _Proj>
constexpr borrowed_iterator_t<_Range>
operator()(_Range&& __r, _Comp __comp = {}, _Proj __proj = {}) const
{
return (*this)(ranges::begin(__r), ranges::end(__r),
std::move(__comp), std::move(__proj));
}
};
inline constexpr __make_heap_fn make_heap{};
struct __sort_heap_fn
{
template<random_access_iterator _Iter, sentinel_for<_Iter> _Sent,
typename _Comp = ranges::less, typename _Proj = identity>
requires sortable<_Iter, _Comp, _Proj>
constexpr _Iter
operator()(_Iter __first, _Sent __last,
_Comp __comp = {}, _Proj __proj = {}) const
{
auto __lasti = ranges::next(__first, __last);
std::sort_heap(__first, __lasti,
__detail::__make_comp_proj(__comp, __proj));
return __lasti;
}
template<random_access_range _Range,
typename _Comp = ranges::less, typename _Proj = identity>
requires sortable<iterator_t<_Range>, _Comp, _Proj>
constexpr borrowed_iterator_t<_Range>
operator()(_Range&& __r, _Comp __comp = {}, _Proj __proj = {}) const
{
return (*this)(ranges::begin(__r), ranges::end(__r),
std::move(__comp), std::move(__proj));
}
};
inline constexpr __sort_heap_fn sort_heap{};
struct __is_heap_until_fn
{
template<random_access_iterator _Iter, sentinel_for<_Iter> _Sent,
typename _Proj = identity,
indirect_strict_weak_order<projected<_Iter, _Proj>>
_Comp = ranges::less>
constexpr _Iter
operator()(_Iter __first, _Sent __last,
_Comp __comp = {}, _Proj __proj = {}) const
{
iter_difference_t<_Iter> __n = ranges::distance(__first, __last);
iter_difference_t<_Iter> __parent = 0, __child = 1;
for (; __child < __n; ++__child)
if (std::__invoke(__comp,
std::__invoke(__proj, *(__first + __parent)),
std::__invoke(__proj, *(__first + __child))))
return __first + __child;
else if ((__child & 1) == 0)
++__parent;
return __first + __n;
}
template<random_access_range _Range,
typename _Proj = identity,
indirect_strict_weak_order<projected<iterator_t<_Range>, _Proj>>
_Comp = ranges::less>
constexpr borrowed_iterator_t<_Range>
operator()(_Range&& __r, _Comp __comp = {}, _Proj __proj = {}) const
{
return (*this)(ranges::begin(__r), ranges::end(__r),
std::move(__comp), std::move(__proj));
}
};
inline constexpr __is_heap_until_fn is_heap_until{};
struct __is_heap_fn
{
template<random_access_iterator _Iter, sentinel_for<_Iter> _Sent,
typename _Proj = identity,
indirect_strict_weak_order<projected<_Iter, _Proj>>
_Comp = ranges::less>
constexpr bool
operator()(_Iter __first, _Sent __last,
_Comp __comp = {}, _Proj __proj = {}) const
{
return (__last
== ranges::is_heap_until(__first, __last,
std::move(__comp),
std::move(__proj)));
}
template<random_access_range _Range,
typename _Proj = identity,
indirect_strict_weak_order<projected<iterator_t<_Range>, _Proj>>
_Comp = ranges::less>
constexpr bool
operator()(_Range&& __r, _Comp __comp = {}, _Proj __proj = {}) const
{
return (*this)(ranges::begin(__r), ranges::end(__r),
std::move(__comp), std::move(__proj));
}
};
inline constexpr __is_heap_fn is_heap{};
struct __sort_fn
{
template<random_access_iterator _Iter, sentinel_for<_Iter> _Sent,
typename _Comp = ranges::less, typename _Proj = identity>
requires sortable<_Iter, _Comp, _Proj>
constexpr _Iter
operator()(_Iter __first, _Sent __last,
_Comp __comp = {}, _Proj __proj = {}) const
{
auto __lasti = ranges::next(__first, __last);
_GLIBCXX_STD_A::sort(std::move(__first), __lasti,
__detail::__make_comp_proj(__comp, __proj));
return __lasti;
}
template<random_access_range _Range,
typename _Comp = ranges::less, typename _Proj = identity>
requires sortable<iterator_t<_Range>, _Comp, _Proj>
constexpr borrowed_iterator_t<_Range>
operator()(_Range&& __r, _Comp __comp = {}, _Proj __proj = {}) const
{
return (*this)(ranges::begin(__r), ranges::end(__r),
std::move(__comp), std::move(__proj));
}
};
inline constexpr __sort_fn sort{};
struct __stable_sort_fn
{
template<random_access_iterator _Iter, sentinel_for<_Iter> _Sent,
typename _Comp = ranges::less, typename _Proj = identity>
requires sortable<_Iter, _Comp, _Proj>
_Iter
operator()(_Iter __first, _Sent __last,
_Comp __comp = {}, _Proj __proj = {}) const
{
auto __lasti = ranges::next(__first, __last);
std::stable_sort(std::move(__first), __lasti,
__detail::__make_comp_proj(__comp, __proj));
return __lasti;
}
template<random_access_range _Range,
typename _Comp = ranges::less, typename _Proj = identity>
requires sortable<iterator_t<_Range>, _Comp, _Proj>
borrowed_iterator_t<_Range>
operator()(_Range&& __r, _Comp __comp = {}, _Proj __proj = {}) const
{
return (*this)(ranges::begin(__r), ranges::end(__r),
std::move(__comp), std::move(__proj));
}
};
inline constexpr __stable_sort_fn stable_sort{};
struct __partial_sort_fn
{
template<random_access_iterator _Iter, sentinel_for<_Iter> _Sent,
typename _Comp = ranges::less, typename _Proj = identity>
requires sortable<_Iter, _Comp, _Proj>
constexpr _Iter
operator()(_Iter __first, _Iter __middle, _Sent __last,
_Comp __comp = {}, _Proj __proj = {}) const
{
if (__first == __middle)
return ranges::next(__first, __last);
ranges::make_heap(__first, __middle, __comp, __proj);
auto __i = __middle;
for (; __i != __last; ++__i)
if (std::__invoke(__comp,
std::__invoke(__proj, *__i),
std::__invoke(__proj, *__first)))
{
ranges::pop_heap(__first, __middle, __comp, __proj);
ranges::iter_swap(__middle-1, __i);
ranges::push_heap(__first, __middle, __comp, __proj);
}
ranges::sort_heap(__first, __middle, __comp, __proj);
return __i;
}
template<random_access_range _Range,
typename _Comp = ranges::less, typename _Proj = identity>
requires sortable<iterator_t<_Range>, _Comp, _Proj>
constexpr borrowed_iterator_t<_Range>
operator()(_Range&& __r, iterator_t<_Range> __middle,
_Comp __comp = {}, _Proj __proj = {}) const
{
return (*this)(ranges::begin(__r), std::move(__middle),
ranges::end(__r),
std::move(__comp), std::move(__proj));
}
};
inline constexpr __partial_sort_fn partial_sort{};
template<typename _Iter, typename _Out>
using partial_sort_copy_result = in_out_result<_Iter, _Out>;
struct __partial_sort_copy_fn
{
template<input_iterator _Iter1, sentinel_for<_Iter1> _Sent1,
random_access_iterator _Iter2, sentinel_for<_Iter2> _Sent2,
typename _Comp = ranges::less,
typename _Proj1 = identity, typename _Proj2 = identity>
requires indirectly_copyable<_Iter1, _Iter2>
&& sortable<_Iter2, _Comp, _Proj2>
&& indirect_strict_weak_order<_Comp,
projected<_Iter1, _Proj1>,
projected<_Iter2, _Proj2>>
constexpr partial_sort_copy_result<_Iter1, _Iter2>
operator()(_Iter1 __first, _Sent1 __last,
_Iter2 __result_first, _Sent2 __result_last,
_Comp __comp = {},
_Proj1 __proj1 = {}, _Proj2 __proj2 = {}) const
{
if (__result_first == __result_last)
{
// TODO: Eliminating the variable __lasti triggers an ICE.
auto __lasti = ranges::next(std::move(__first),
std::move(__last));
return {std::move(__lasti), std::move(__result_first)};
}
auto __result_real_last = __result_first;
while (__first != __last && __result_real_last != __result_last)
{
*__result_real_last = *__first;
++__result_real_last;
++__first;
}
ranges::make_heap(__result_first, __result_real_last, __comp, __proj2);
for (; __first != __last; ++__first)
if (std::__invoke(__comp,
std::__invoke(__proj1, *__first),
std::__invoke(__proj2, *__result_first)))
{
ranges::pop_heap(__result_first, __result_real_last,
__comp, __proj2);
*(__result_real_last-1) = *__first;
ranges::push_heap(__result_first, __result_real_last,
__comp, __proj2);
}
ranges::sort_heap(__result_first, __result_real_last, __comp, __proj2);
return {std::move(__first), std::move(__result_real_last)};
}
template<input_range _Range1, random_access_range _Range2,
typename _Comp = ranges::less,
typename _Proj1 = identity, typename _Proj2 = identity>
requires indirectly_copyable<iterator_t<_Range1>, iterator_t<_Range2>>
&& sortable<iterator_t<_Range2>, _Comp, _Proj2>
&& indirect_strict_weak_order<_Comp,
projected<iterator_t<_Range1>, _Proj1>,
projected<iterator_t<_Range2>, _Proj2>>
constexpr partial_sort_copy_result<borrowed_iterator_t<_Range1>,
borrowed_iterator_t<_Range2>>
operator()(_Range1&& __r, _Range2&& __out, _Comp __comp = {},
_Proj1 __proj1 = {}, _Proj2 __proj2 = {}) const
{
return (*this)(ranges::begin(__r), ranges::end(__r),
ranges::begin(__out), ranges::end(__out),
std::move(__comp),
std::move(__proj1), std::move(__proj2));
}
};
inline constexpr __partial_sort_copy_fn partial_sort_copy{};
struct __is_sorted_until_fn
{
template<forward_iterator _Iter, sentinel_for<_Iter> _Sent,
typename _Proj = identity,
indirect_strict_weak_order<projected<_Iter, _Proj>>
_Comp = ranges::less>
constexpr _Iter
operator()(_Iter __first, _Sent __last,
_Comp __comp = {}, _Proj __proj = {}) const
{
if (__first == __last)
return __first;
auto __next = __first;
for (++__next; __next != __last; __first = __next, (void)++__next)
if (std::__invoke(__comp,
std::__invoke(__proj, *__next),
std::__invoke(__proj, *__first)))
return __next;
return __next;
}
template<forward_range _Range, typename _Proj = identity,
indirect_strict_weak_order<projected<iterator_t<_Range>, _Proj>>
_Comp = ranges::less>
constexpr borrowed_iterator_t<_Range>
operator()(_Range&& __r, _Comp __comp = {}, _Proj __proj = {}) const
{
return (*this)(ranges::begin(__r), ranges::end(__r),
std::move(__comp), std::move(__proj));
}
};
inline constexpr __is_sorted_until_fn is_sorted_until{};
struct __is_sorted_fn
{
template<forward_iterator _Iter, sentinel_for<_Iter> _Sent,
typename _Proj = identity,
indirect_strict_weak_order<projected<_Iter, _Proj>>
_Comp = ranges::less>
constexpr bool
operator()(_Iter __first, _Sent __last,
_Comp __comp = {}, _Proj __proj = {}) const
{
if (__first == __last)
return true;
auto __next = __first;
for (++__next; __next != __last; __first = __next, (void)++__next)
if (std::__invoke(__comp,
std::__invoke(__proj, *__next),
std::__invoke(__proj, *__first)))
return false;
return true;
}
template<forward_range _Range, typename _Proj = identity,
indirect_strict_weak_order<projected<iterator_t<_Range>, _Proj>>
_Comp = ranges::less>
constexpr bool
operator()(_Range&& __r, _Comp __comp = {}, _Proj __proj = {}) const
{
return (*this)(ranges::begin(__r), ranges::end(__r),
std::move(__comp), std::move(__proj));
}
};
inline constexpr __is_sorted_fn is_sorted{};
struct __nth_element_fn
{
template<random_access_iterator _Iter, sentinel_for<_Iter> _Sent,
typename _Comp = ranges::less, typename _Proj = identity>
requires sortable<_Iter, _Comp, _Proj>
constexpr _Iter
operator()(_Iter __first, _Iter __nth, _Sent __last,
_Comp __comp = {}, _Proj __proj = {}) const
{
auto __lasti = ranges::next(__first, __last);
_GLIBCXX_STD_A::nth_element(std::move(__first), std::move(__nth),
__lasti,
__detail::__make_comp_proj(__comp, __proj));
return __lasti;
}
template<random_access_range _Range,
typename _Comp = ranges::less, typename _Proj = identity>
requires sortable<iterator_t<_Range>, _Comp, _Proj>
constexpr borrowed_iterator_t<_Range>
operator()(_Range&& __r, iterator_t<_Range> __nth,
_Comp __comp = {}, _Proj __proj = {}) const
{
return (*this)(ranges::begin(__r), std::move(__nth),
ranges::end(__r), std::move(__comp), std::move(__proj));
}
};
inline constexpr __nth_element_fn nth_element{};
struct __lower_bound_fn
{
template<forward_iterator _Iter, sentinel_for<_Iter> _Sent,
typename _Tp, typename _Proj = identity,
indirect_strict_weak_order<const _Tp*, projected<_Iter, _Proj>>
_Comp = ranges::less>
constexpr _Iter
operator()(_Iter __first, _Sent __last,
const _Tp& __value, _Comp __comp = {}, _Proj __proj = {}) const
{
auto __len = ranges::distance(__first, __last);
while (__len > 0)
{
auto __half = __len / 2;
auto __middle = __first;
ranges::advance(__middle, __half);
if (std::__invoke(__comp, std::__invoke(__proj, *__middle), __value))
{
__first = __middle;
++__first;
__len = __len - __half - 1;
}
else
__len = __half;
}
return __first;
}
template<forward_range _Range, typename _Tp, typename _Proj = identity,
indirect_strict_weak_order<const _Tp*,
projected<iterator_t<_Range>, _Proj>>
_Comp = ranges::less>
constexpr borrowed_iterator_t<_Range>
operator()(_Range&& __r,
const _Tp& __value, _Comp __comp = {}, _Proj __proj = {}) const
{
return (*this)(ranges::begin(__r), ranges::end(__r),
__value, std::move(__comp), std::move(__proj));
}
};
inline constexpr __lower_bound_fn lower_bound{};
struct __upper_bound_fn
{
template<forward_iterator _Iter, sentinel_for<_Iter> _Sent,
typename _Tp, typename _Proj = identity,
indirect_strict_weak_order<const _Tp*, projected<_Iter, _Proj>>
_Comp = ranges::less>
constexpr _Iter
operator()(_Iter __first, _Sent __last,
const _Tp& __value, _Comp __comp = {}, _Proj __proj = {}) const
{
auto __len = ranges::distance(__first, __last);
while (__len > 0)
{
auto __half = __len / 2;
auto __middle = __first;
ranges::advance(__middle, __half);
if (std::__invoke(__comp, __value, std::__invoke(__proj, *__middle)))
__len = __half;
else
{
__first = __middle;
++__first;
__len = __len - __half - 1;
}
}
return __first;
}
template<forward_range _Range, typename _Tp, typename _Proj = identity,
indirect_strict_weak_order<const _Tp*,
projected<iterator_t<_Range>, _Proj>>
_Comp = ranges::less>
constexpr borrowed_iterator_t<_Range>
operator()(_Range&& __r,
const _Tp& __value, _Comp __comp = {}, _Proj __proj = {}) const
{
return (*this)(ranges::begin(__r), ranges::end(__r),
__value, std::move(__comp), std::move(__proj));
}
};
inline constexpr __upper_bound_fn upper_bound{};
struct __equal_range_fn
{
template<forward_iterator _Iter, sentinel_for<_Iter> _Sent,
typename _Tp, typename _Proj = identity,
indirect_strict_weak_order<const _Tp*, projected<_Iter, _Proj>>
_Comp = ranges::less>
constexpr subrange<_Iter>
operator()(_Iter __first, _Sent __last,
const _Tp& __value, _Comp __comp = {}, _Proj __proj = {}) const
{
auto __len = ranges::distance(__first, __last);
while (__len > 0)
{
auto __half = __len / 2;
auto __middle = __first;
ranges::advance(__middle, __half);
if (std::__invoke(__comp,
std::__invoke(__proj, *__middle),
__value))
{
__first = __middle;
++__first;
__len = __len - __half - 1;
}
else if (std::__invoke(__comp,
__value,
std::__invoke(__proj, *__middle)))
__len = __half;
else
{
auto __left
= ranges::lower_bound(__first, __middle,
__value, __comp, __proj);
ranges::advance(__first, __len);
auto __right
= ranges::upper_bound(++__middle, __first,
__value, __comp, __proj);
return {__left, __right};
}
}
return {__first, __first};
}
template<forward_range _Range,
typename _Tp, typename _Proj = identity,
indirect_strict_weak_order<const _Tp*,
projected<iterator_t<_Range>, _Proj>>
_Comp = ranges::less>
constexpr borrowed_subrange_t<_Range>
operator()(_Range&& __r, const _Tp& __value,
_Comp __comp = {}, _Proj __proj = {}) const
{
return (*this)(ranges::begin(__r), ranges::end(__r),
__value, std::move(__comp), std::move(__proj));
}
};
inline constexpr __equal_range_fn equal_range{};
struct __binary_search_fn
{
template<forward_iterator _Iter, sentinel_for<_Iter> _Sent,
typename _Tp, typename _Proj = identity,
indirect_strict_weak_order<const _Tp*, projected<_Iter, _Proj>>
_Comp = ranges::less>
constexpr bool
operator()(_Iter __first, _Sent __last,
const _Tp& __value, _Comp __comp = {}, _Proj __proj = {}) const
{
auto __i = ranges::lower_bound(__first, __last, __value, __comp, __proj);
if (__i == __last)
return false;
return !(bool)std::__invoke(__comp, __value,
std::__invoke(__proj, *__i));
}
template<forward_range _Range,
typename _Tp, typename _Proj = identity,
indirect_strict_weak_order<const _Tp*,
projected<iterator_t<_Range>, _Proj>>
_Comp = ranges::less>
constexpr bool
operator()(_Range&& __r, const _Tp& __value, _Comp __comp = {},
_Proj __proj = {}) const
{
return (*this)(ranges::begin(__r), ranges::end(__r),
__value, std::move(__comp), std::move(__proj));
}
};
inline constexpr __binary_search_fn binary_search{};
struct __is_partitioned_fn
{
template<input_iterator _Iter, sentinel_for<_Iter> _Sent,
typename _Proj = identity,
indirect_unary_predicate<projected<_Iter, _Proj>> _Pred>
constexpr bool
operator()(_Iter __first, _Sent __last,
_Pred __pred, _Proj __proj = {}) const
{
__first = ranges::find_if_not(std::move(__first), __last,
__pred, __proj);
if (__first == __last)
return true;
++__first;
return ranges::none_of(std::move(__first), std::move(__last),
std::move(__pred), std::move(__proj));
}
template<input_range _Range, typename _Proj = identity,
indirect_unary_predicate<projected<iterator_t<_Range>, _Proj>>
_Pred>
constexpr bool
operator()(_Range&& __r, _Pred __pred, _Proj __proj = {}) const
{
return (*this)(ranges::begin(__r), ranges::end(__r),
std::move(__pred), std::move(__proj));
}
};
inline constexpr __is_partitioned_fn is_partitioned{};
struct __partition_fn
{
template<permutable _Iter, sentinel_for<_Iter> _Sent,
typename _Proj = identity,
indirect_unary_predicate<projected<_Iter, _Proj>> _Pred>
constexpr subrange<_Iter>
operator()(_Iter __first, _Sent __last,
_Pred __pred, _Proj __proj = {}) const
{
if constexpr (bidirectional_iterator<_Iter>)
{
auto __lasti = ranges::next(__first, __last);
auto __tail = __lasti;
for (;;)
{
for (;;)
if (__first == __tail)
return {std::move(__first), std::move(__lasti)};
else if (std::__invoke(__pred,
std::__invoke(__proj, *__first)))
++__first;
else
break;
--__tail;
for (;;)
if (__first == __tail)
return {std::move(__first), std::move(__lasti)};
else if (!(bool)std::__invoke(__pred,
std::__invoke(__proj, *__tail)))
--__tail;
else
break;
ranges::iter_swap(__first, __tail);
++__first;
}
}
else
{
if (__first == __last)
return {std::move(__first), std::move(__first)};
while (std::__invoke(__pred, std::__invoke(__proj, *__first)))
if (++__first == __last)
return {std::move(__first), std::move(__first)};
auto __next = __first;
while (++__next != __last)
if (std::__invoke(__pred, std::__invoke(__proj, *__next)))
{
ranges::iter_swap(__first, __next);
++__first;
}
return {std::move(__first), std::move(__next)};
}
}
template<forward_range _Range, typename _Proj = identity,
indirect_unary_predicate<projected<iterator_t<_Range>, _Proj>>
_Pred>
requires permutable<iterator_t<_Range>>
constexpr borrowed_subrange_t<_Range>
operator()(_Range&& __r, _Pred __pred, _Proj __proj = {}) const
{
return (*this)(ranges::begin(__r), ranges::end(__r),
std::move(__pred), std::move(__proj));
}
};
inline constexpr __partition_fn partition{};
struct __stable_partition_fn
{
template<bidirectional_iterator _Iter, sentinel_for<_Iter> _Sent,
typename _Proj = identity,
indirect_unary_predicate<projected<_Iter, _Proj>> _Pred>
requires permutable<_Iter>
subrange<_Iter>
operator()(_Iter __first, _Sent __last,
_Pred __pred, _Proj __proj = {}) const
{
auto __lasti = ranges::next(__first, __last);
auto __middle
= std::stable_partition(std::move(__first), __lasti,
__detail::__make_pred_proj(__pred, __proj));
return {std::move(__middle), std::move(__lasti)};
}
template<bidirectional_range _Range, typename _Proj = identity,
indirect_unary_predicate<projected<iterator_t<_Range>, _Proj>>
_Pred>
requires permutable<iterator_t<_Range>>
borrowed_subrange_t<_Range>
operator()(_Range&& __r, _Pred __pred, _Proj __proj = {}) const
{
return (*this)(ranges::begin(__r), ranges::end(__r),
std::move(__pred), std::move(__proj));
}
};
inline constexpr __stable_partition_fn stable_partition{};
template<typename _Iter, typename _Out1, typename _Out2>
struct in_out_out_result
{
[[no_unique_address]] _Iter in;
[[no_unique_address]] _Out1 out1;
[[no_unique_address]] _Out2 out2;
template<typename _IIter, typename _OOut1, typename _OOut2>
requires convertible_to<const _Iter&, _IIter>
&& convertible_to<const _Out1&, _OOut1>
&& convertible_to<const _Out2&, _OOut2>
constexpr
operator in_out_out_result<_IIter, _OOut1, _OOut2>() const &
{ return {in, out1, out2}; }
template<typename _IIter, typename _OOut1, typename _OOut2>
requires convertible_to<_Iter, _IIter>
&& convertible_to<_Out1, _OOut1>
&& convertible_to<_Out2, _OOut2>
constexpr
operator in_out_out_result<_IIter, _OOut1, _OOut2>() &&
{ return {std::move(in), std::move(out1), std::move(out2)}; }
};
template<typename _Iter, typename _Out1, typename _Out2>
using partition_copy_result = in_out_out_result<_Iter, _Out1, _Out2>;
struct __partition_copy_fn
{
template<input_iterator _Iter, sentinel_for<_Iter> _Sent,
weakly_incrementable _Out1, weakly_incrementable _O2,
typename _Proj = identity,
indirect_unary_predicate<projected<_Iter, _Proj>> _Pred>
requires indirectly_copyable<_Iter, _Out1>
&& indirectly_copyable<_Iter, _O2>
constexpr partition_copy_result<_Iter, _Out1, _O2>
operator()(_Iter __first, _Sent __last,
_Out1 __out_true, _O2 __out_false,
_Pred __pred, _Proj __proj = {}) const
{
for (; __first != __last; ++__first)
if (std::__invoke(__pred, std::__invoke(__proj, *__first)))
{
*__out_true = *__first;
++__out_true;
}
else
{
*__out_false = *__first;
++__out_false;
}
return {std::move(__first),
std::move(__out_true), std::move(__out_false)};
}
template<input_range _Range, weakly_incrementable _Out1,
weakly_incrementable _O2,
typename _Proj = identity,
indirect_unary_predicate<projected<iterator_t<_Range>, _Proj>>
_Pred>
requires indirectly_copyable<iterator_t<_Range>, _Out1>
&& indirectly_copyable<iterator_t<_Range>, _O2>
constexpr partition_copy_result<borrowed_iterator_t<_Range>, _Out1, _O2>
operator()(_Range&& __r, _Out1 out_true, _O2 out_false,
_Pred __pred, _Proj __proj = {}) const
{
return (*this)(ranges::begin(__r), ranges::end(__r),
std::move(out_true), std::move(out_false),
std::move(__pred), std::move(__proj));
}
};
inline constexpr __partition_copy_fn partition_copy{};
struct __partition_point_fn
{
template<forward_iterator _Iter, sentinel_for<_Iter> _Sent,
typename _Proj = identity,
indirect_unary_predicate<projected<_Iter, _Proj>> _Pred>
constexpr _Iter
operator()(_Iter __first, _Sent __last,
_Pred __pred, _Proj __proj = {}) const
{
auto __len = ranges::distance(__first, __last);
while (__len > 0)
{
auto __half = __len / 2;
auto __middle = __first;
ranges::advance(__middle, __half);
if (std::__invoke(__pred, std::__invoke(__proj, *__middle)))
{
__first = __middle;
++__first;
__len = __len - __half - 1;
}
else
__len = __half;
}
return __first;
}
template<forward_range _Range, typename _Proj = identity,
indirect_unary_predicate<projected<iterator_t<_Range>, _Proj>>
_Pred>
constexpr borrowed_iterator_t<_Range>
operator()(_Range&& __r, _Pred __pred, _Proj __proj = {}) const
{
return (*this)(ranges::begin(__r), ranges::end(__r),
std::move(__pred), std::move(__proj));
}
};
inline constexpr __partition_point_fn partition_point{};
template<typename _Iter1, typename _Iter2, typename _Out>
using merge_result = in_in_out_result<_Iter1, _Iter2, _Out>;
struct __merge_fn
{
template<input_iterator _Iter1, sentinel_for<_Iter1> _Sent1,
input_iterator _Iter2, sentinel_for<_Iter2> _Sent2,
weakly_incrementable _Out, typename _Comp = ranges::less,
typename _Proj1 = identity, typename _Proj2 = identity>
requires mergeable<_Iter1, _Iter2, _Out, _Comp, _Proj1, _Proj2>
constexpr merge_result<_Iter1, _Iter2, _Out>
operator()(_Iter1 __first1, _Sent1 __last1,
_Iter2 __first2, _Sent2 __last2, _Out __result,
_Comp __comp = {},
_Proj1 __proj1 = {}, _Proj2 __proj2 = {}) const
{
while (__first1 != __last1 && __first2 != __last2)
{
if (std::__invoke(__comp,
std::__invoke(__proj2, *__first2),
std::__invoke(__proj1, *__first1)))
{
*__result = *__first2;
++__first2;
}
else
{
*__result = *__first1;
++__first1;
}
++__result;
}
auto __copy1 = ranges::copy(std::move(__first1), std::move(__last1),
std::move(__result));
auto __copy2 = ranges::copy(std::move(__first2), std::move(__last2),
std::move(__copy1.out));
return { std::move(__copy1.in), std::move(__copy2.in),
std::move(__copy2.out) };
}
template<input_range _Range1, input_range _Range2, weakly_incrementable _Out,
typename _Comp = ranges::less,
typename _Proj1 = identity, typename _Proj2 = identity>
requires mergeable<iterator_t<_Range1>, iterator_t<_Range2>, _Out,
_Comp, _Proj1, _Proj2>
constexpr merge_result<borrowed_iterator_t<_Range1>,
borrowed_iterator_t<_Range2>,
_Out>
operator()(_Range1&& __r1, _Range2&& __r2, _Out __result,
_Comp __comp = {},
_Proj1 __proj1 = {}, _Proj2 __proj2 = {}) const
{
return (*this)(ranges::begin(__r1), ranges::end(__r1),
ranges::begin(__r2), ranges::end(__r2),
std::move(__result), std::move(__comp),
std::move(__proj1), std::move(__proj2));
}
};
inline constexpr __merge_fn merge{};
struct __inplace_merge_fn
{
template<bidirectional_iterator _Iter, sentinel_for<_Iter> _Sent,
typename _Comp = ranges::less,
typename _Proj = identity>
requires sortable<_Iter, _Comp, _Proj>
_Iter
operator()(_Iter __first, _Iter __middle, _Sent __last,
_Comp __comp = {}, _Proj __proj = {}) const
{
auto __lasti = ranges::next(__first, __last);
std::inplace_merge(std::move(__first), std::move(__middle), __lasti,
__detail::__make_comp_proj(__comp, __proj));
return __lasti;
}
template<bidirectional_range _Range,
typename _Comp = ranges::less, typename _Proj = identity>
requires sortable<iterator_t<_Range>, _Comp, _Proj>
borrowed_iterator_t<_Range>
operator()(_Range&& __r, iterator_t<_Range> __middle,
_Comp __comp = {}, _Proj __proj = {}) const
{
return (*this)(ranges::begin(__r), std::move(__middle),
ranges::end(__r),
std::move(__comp), std::move(__proj));
}
};
inline constexpr __inplace_merge_fn inplace_merge{};
struct __includes_fn
{
template<input_iterator _Iter1, sentinel_for<_Iter1> _Sent1,
input_iterator _Iter2, sentinel_for<_Iter2> _Sent2,
typename _Proj1 = identity, typename _Proj2 = identity,
indirect_strict_weak_order<projected<_Iter1, _Proj1>,
projected<_Iter2, _Proj2>>
_Comp = ranges::less>
constexpr bool
operator()(_Iter1 __first1, _Sent1 __last1,
_Iter2 __first2, _Sent2 __last2,
_Comp __comp = {},
_Proj1 __proj1 = {}, _Proj2 __proj2 = {}) const
{
while (__first1 != __last1 && __first2 != __last2)
if (std::__invoke(__comp,
std::__invoke(__proj2, *__first2),
std::__invoke(__proj1, *__first1)))
return false;
else if (std::__invoke(__comp,
std::__invoke(__proj1, *__first1),
std::__invoke(__proj2, *__first2)))
++__first1;
else
{
++__first1;
++__first2;
}
return __first2 == __last2;
}
template<input_range _Range1, input_range _Range2,
typename _Proj1 = identity, typename _Proj2 = identity,
indirect_strict_weak_order<projected<iterator_t<_Range1>, _Proj1>,
projected<iterator_t<_Range2>, _Proj2>>
_Comp = ranges::less>
constexpr bool
operator()(_Range1&& __r1, _Range2&& __r2, _Comp __comp = {},
_Proj1 __proj1 = {}, _Proj2 __proj2 = {}) const
{
return (*this)(ranges::begin(__r1), ranges::end(__r1),
ranges::begin(__r2), ranges::end(__r2),
std::move(__comp),
std::move(__proj1), std::move(__proj2));
}
};
inline constexpr __includes_fn includes{};
template<typename _Iter1, typename _Iter2, typename _Out>
using set_union_result = in_in_out_result<_Iter1, _Iter2, _Out>;
struct __set_union_fn
{
template<input_iterator _Iter1, sentinel_for<_Iter1> _Sent1,
input_iterator _Iter2, sentinel_for<_Iter2> _Sent2,
weakly_incrementable _Out, typename _Comp = ranges::less,
typename _Proj1 = identity, typename _Proj2 = identity>
requires mergeable<_Iter1, _Iter2, _Out, _Comp, _Proj1, _Proj2>
constexpr set_union_result<_Iter1, _Iter2, _Out>
operator()(_Iter1 __first1, _Sent1 __last1,
_Iter2 __first2, _Sent2 __last2,
_Out __result, _Comp __comp = {},
_Proj1 __proj1 = {}, _Proj2 __proj2 = {}) const
{
while (__first1 != __last1 && __first2 != __last2)
{
if (std::__invoke(__comp,
std::__invoke(__proj1, *__first1),
std::__invoke(__proj2, *__first2)))
{
*__result = *__first1;
++__first1;
}
else if (std::__invoke(__comp,
std::__invoke(__proj2, *__first2),
std::__invoke(__proj1, *__first1)))
{
*__result = *__first2;
++__first2;
}
else
{
*__result = *__first1;
++__first1;
++__first2;
}
++__result;
}
auto __copy1 = ranges::copy(std::move(__first1), std::move(__last1),
std::move(__result));
auto __copy2 = ranges::copy(std::move(__first2), std::move(__last2),
std::move(__copy1.out));
return {std::move(__copy1.in), std::move(__copy2.in),
std::move(__copy2.out)};
}
template<input_range _Range1, input_range _Range2, weakly_incrementable _Out,
typename _Comp = ranges::less,
typename _Proj1 = identity, typename _Proj2 = identity>
requires mergeable<iterator_t<_Range1>, iterator_t<_Range2>, _Out,
_Comp, _Proj1, _Proj2>
constexpr set_union_result<borrowed_iterator_t<_Range1>,
borrowed_iterator_t<_Range2>, _Out>
operator()(_Range1&& __r1, _Range2&& __r2,
_Out __result, _Comp __comp = {},
_Proj1 __proj1 = {}, _Proj2 __proj2 = {}) const
{
return (*this)(ranges::begin(__r1), ranges::end(__r1),
ranges::begin(__r2), ranges::end(__r2),
std::move(__result), std::move(__comp),
std::move(__proj1), std::move(__proj2));
}
};
inline constexpr __set_union_fn set_union{};
template<typename _Iter1, typename _Iter2, typename _Out>
using set_intersection_result = in_in_out_result<_Iter1, _Iter2, _Out>;
struct __set_intersection_fn
{
template<input_iterator _Iter1, sentinel_for<_Iter1> _Sent1,
input_iterator _Iter2, sentinel_for<_Iter2> _Sent2,
weakly_incrementable _Out, typename _Comp = ranges::less,
typename _Proj1 = identity, typename _Proj2 = identity>
requires mergeable<_Iter1, _Iter2, _Out, _Comp, _Proj1, _Proj2>
constexpr set_intersection_result<_Iter1, _Iter2, _Out>
operator()(_Iter1 __first1, _Sent1 __last1,
_Iter2 __first2, _Sent2 __last2, _Out __result,
_Comp __comp = {},
_Proj1 __proj1 = {}, _Proj2 __proj2 = {}) const
{
while (__first1 != __last1 && __first2 != __last2)
if (std::__invoke(__comp,
std::__invoke(__proj1, *__first1),
std::__invoke(__proj2, *__first2)))
++__first1;
else if (std::__invoke(__comp,
std::__invoke(__proj2, *__first2),
std::__invoke(__proj1, *__first1)))
++__first2;
else
{
*__result = *__first1;
++__first1;
++__first2;
++__result;
}
// TODO: Eliminating these variables triggers an ICE.
auto __last1i = ranges::next(std::move(__first1), std::move(__last1));
auto __last2i = ranges::next(std::move(__first2), std::move(__last2));
return {std::move(__last1i), std::move(__last2i), std::move(__result)};
}
template<input_range _Range1, input_range _Range2, weakly_incrementable _Out,
typename _Comp = ranges::less,
typename _Proj1 = identity, typename _Proj2 = identity>
requires mergeable<iterator_t<_Range1>, iterator_t<_Range2>, _Out,
_Comp, _Proj1, _Proj2>
constexpr set_intersection_result<borrowed_iterator_t<_Range1>,
borrowed_iterator_t<_Range2>, _Out>
operator()(_Range1&& __r1, _Range2&& __r2, _Out __result,
_Comp __comp = {},
_Proj1 __proj1 = {}, _Proj2 __proj2 = {}) const
{
return (*this)(ranges::begin(__r1), ranges::end(__r1),
ranges::begin(__r2), ranges::end(__r2),
std::move(__result), std::move(__comp),
std::move(__proj1), std::move(__proj2));
}
};
inline constexpr __set_intersection_fn set_intersection{};
template<typename _Iter, typename _Out>
using set_difference_result = in_out_result<_Iter, _Out>;
struct __set_difference_fn
{
template<input_iterator _Iter1, sentinel_for<_Iter1> _Sent1,
input_iterator _Iter2, sentinel_for<_Iter2> _Sent2,
weakly_incrementable _Out, typename _Comp = ranges::less,
typename _Proj1 = identity, typename _Proj2 = identity>
requires mergeable<_Iter1, _Iter2, _Out, _Comp, _Proj1, _Proj2>
constexpr set_difference_result<_Iter1, _Out>
operator()(_Iter1 __first1, _Sent1 __last1,
_Iter2 __first2, _Sent2 __last2, _Out __result,
_Comp __comp = {},
_Proj1 __proj1 = {}, _Proj2 __proj2 = {}) const
{
while (__first1 != __last1 && __first2 != __last2)
if (std::__invoke(__comp,
std::__invoke(__proj1, *__first1),
std::__invoke(__proj2, *__first2)))
{
*__result = *__first1;
++__first1;
++__result;
}
else if (std::__invoke(__comp,
std::__invoke(__proj2, *__first2),
std::__invoke(__proj1, *__first1)))
++__first2;
else
{
++__first1;
++__first2;
}
return ranges::copy(std::move(__first1), std::move(__last1),
std::move(__result));
}
template<input_range _Range1, input_range _Range2, weakly_incrementable _Out,
typename _Comp = ranges::less,
typename _Proj1 = identity, typename _Proj2 = identity>
requires mergeable<iterator_t<_Range1>, iterator_t<_Range2>, _Out,
_Comp, _Proj1, _Proj2>
constexpr set_difference_result<borrowed_iterator_t<_Range1>, _Out>
operator()(_Range1&& __r1, _Range2&& __r2, _Out __result,
_Comp __comp = {},
_Proj1 __proj1 = {}, _Proj2 __proj2 = {}) const
{
return (*this)(ranges::begin(__r1), ranges::end(__r1),
ranges::begin(__r2), ranges::end(__r2),
std::move(__result), std::move(__comp),
std::move(__proj1), std::move(__proj2));
}
};
inline constexpr __set_difference_fn set_difference{};
template<typename _Iter1, typename _Iter2, typename _Out>
using set_symmetric_difference_result
= in_in_out_result<_Iter1, _Iter2, _Out>;
struct __set_symmetric_difference_fn
{
template<input_iterator _Iter1, sentinel_for<_Iter1> _Sent1,
input_iterator _Iter2, sentinel_for<_Iter2> _Sent2,
weakly_incrementable _Out, typename _Comp = ranges::less,
typename _Proj1 = identity, typename _Proj2 = identity>
requires mergeable<_Iter1, _Iter2, _Out, _Comp, _Proj1, _Proj2>
constexpr set_symmetric_difference_result<_Iter1, _Iter2, _Out>
operator()(_Iter1 __first1, _Sent1 __last1,
_Iter2 __first2, _Sent2 __last2,
_Out __result, _Comp __comp = {},
_Proj1 __proj1 = {}, _Proj2 __proj2 = {}) const
{
while (__first1 != __last1 && __first2 != __last2)
if (std::__invoke(__comp,
std::__invoke(__proj1, *__first1),
std::__invoke(__proj2, *__first2)))
{
*__result = *__first1;
++__first1;
++__result;
}
else if (std::__invoke(__comp,
std::__invoke(__proj2, *__first2),
std::__invoke(__proj1, *__first1)))
{
*__result = *__first2;
++__first2;
++__result;
}
else
{
++__first1;
++__first2;
}
auto __copy1 = ranges::copy(std::move(__first1), std::move(__last1),
std::move(__result));
auto __copy2 = ranges::copy(std::move(__first2), std::move(__last2),
std::move(__copy1.out));
return {std::move(__copy1.in), std::move(__copy2.in),
std::move(__copy2.out)};
}
template<input_range _Range1, input_range _Range2, weakly_incrementable _Out,
typename _Comp = ranges::less,
typename _Proj1 = identity, typename _Proj2 = identity>
requires mergeable<iterator_t<_Range1>, iterator_t<_Range2>, _Out,
_Comp, _Proj1, _Proj2>
constexpr set_symmetric_difference_result<borrowed_iterator_t<_Range1>,
borrowed_iterator_t<_Range2>,
_Out>
operator()(_Range1&& __r1, _Range2&& __r2, _Out __result,
_Comp __comp = {},
_Proj1 __proj1 = {}, _Proj2 __proj2 = {}) const
{
return (*this)(ranges::begin(__r1), ranges::end(__r1),
ranges::begin(__r2), ranges::end(__r2),
std::move(__result), std::move(__comp),
std::move(__proj1), std::move(__proj2));
}
};
inline constexpr __set_symmetric_difference_fn set_symmetric_difference{};
struct __min_fn
{
template<typename _Tp, typename _Proj = identity,
indirect_strict_weak_order<projected<const _Tp*, _Proj>>
_Comp = ranges::less>
constexpr const _Tp&
operator()(const _Tp& __a, const _Tp& __b,
_Comp __comp = {}, _Proj __proj = {}) const
{
if (std::__invoke(std::move(__comp),
std::__invoke(__proj, __b),
std::__invoke(__proj, __a)))
return __b;
else
return __a;
}
template<input_range _Range, typename _Proj = identity,
indirect_strict_weak_order<projected<iterator_t<_Range>, _Proj>>
_Comp = ranges::less>
requires indirectly_copyable_storable<iterator_t<_Range>,
range_value_t<_Range>*>
constexpr range_value_t<_Range>
operator()(_Range&& __r, _Comp __comp = {}, _Proj __proj = {}) const
{
auto __first = ranges::begin(__r);
auto __last = ranges::end(__r);
__glibcxx_assert(__first != __last);
auto __result = *__first;
while (++__first != __last)
{
auto __tmp = *__first;
if (std::__invoke(__comp,
std::__invoke(__proj, __tmp),
std::__invoke(__proj, __result)))
__result = std::move(__tmp);
}
return __result;
}
template<copyable _Tp, typename _Proj = identity,
indirect_strict_weak_order<projected<const _Tp*, _Proj>>
_Comp = ranges::less>
constexpr _Tp
operator()(initializer_list<_Tp> __r,
_Comp __comp = {}, _Proj __proj = {}) const
{
return (*this)(ranges::subrange(__r),
std::move(__comp), std::move(__proj));
}
};
inline constexpr __min_fn min{};
struct __max_fn
{
template<typename _Tp, typename _Proj = identity,
indirect_strict_weak_order<projected<const _Tp*, _Proj>>
_Comp = ranges::less>
constexpr const _Tp&
operator()(const _Tp& __a, const _Tp& __b,
_Comp __comp = {}, _Proj __proj = {}) const
{
if (std::__invoke(std::move(__comp),
std::__invoke(__proj, __a),
std::__invoke(__proj, __b)))
return __b;
else
return __a;
}
template<input_range _Range, typename _Proj = identity,
indirect_strict_weak_order<projected<iterator_t<_Range>, _Proj>>
_Comp = ranges::less>
requires indirectly_copyable_storable<iterator_t<_Range>,
range_value_t<_Range>*>
constexpr range_value_t<_Range>
operator()(_Range&& __r, _Comp __comp = {}, _Proj __proj = {}) const
{
auto __first = ranges::begin(__r);
auto __last = ranges::end(__r);
__glibcxx_assert(__first != __last);
auto __result = *__first;
while (++__first != __last)
{
auto __tmp = *__first;
if (std::__invoke(__comp,
std::__invoke(__proj, __result),
std::__invoke(__proj, __tmp)))
__result = std::move(__tmp);
}
return __result;
}
template<copyable _Tp, typename _Proj = identity,
indirect_strict_weak_order<projected<const _Tp*, _Proj>>
_Comp = ranges::less>
constexpr _Tp
operator()(initializer_list<_Tp> __r,
_Comp __comp = {}, _Proj __proj = {}) const
{
return (*this)(ranges::subrange(__r),
std::move(__comp), std::move(__proj));
}
};
inline constexpr __max_fn max{};
struct __clamp_fn
{
template<typename _Tp, typename _Proj = identity,
indirect_strict_weak_order<projected<const _Tp*, _Proj>> _Comp
= ranges::less>
constexpr const _Tp&
operator()(const _Tp& __val, const _Tp& __lo, const _Tp& __hi,
_Comp __comp = {}, _Proj __proj = {}) const
{
__glibcxx_assert(!(std::__invoke(__comp,
std::__invoke(__proj, __hi),
std::__invoke(__proj, __lo))));
auto&& __proj_val = std::__invoke(__proj, __val);
if (std::__invoke(__comp, __proj_val, std::__invoke(__proj, __lo)))
return __lo;
else if (std::__invoke(__comp, std::__invoke(__proj, __hi), __proj_val))
return __hi;
else
return __val;
}
};
inline constexpr __clamp_fn clamp{};
template<typename _Tp>
struct min_max_result
{
[[no_unique_address]] _Tp min;
[[no_unique_address]] _Tp max;
template<typename _Tp2>
requires convertible_to<const _Tp&, _Tp2>
constexpr
operator min_max_result<_Tp2>() const &
{ return {min, max}; }
template<typename _Tp2>
requires convertible_to<_Tp, _Tp2>
constexpr
operator min_max_result<_Tp2>() &&
{ return {std::move(min), std::move(max)}; }
};
template<typename _Tp>
using minmax_result = min_max_result<_Tp>;
struct __minmax_fn
{
template<typename _Tp, typename _Proj = identity,
indirect_strict_weak_order<projected<const _Tp*, _Proj>>
_Comp = ranges::less>
constexpr minmax_result<const _Tp&>
operator()(const _Tp& __a, const _Tp& __b,
_Comp __comp = {}, _Proj __proj = {}) const
{
if (std::__invoke(std::move(__comp),
std::__invoke(__proj, __b),
std::__invoke(__proj, __a)))
return {__b, __a};
else
return {__a, __b};
}
template<input_range _Range, typename _Proj = identity,
indirect_strict_weak_order<projected<iterator_t<_Range>, _Proj>>
_Comp = ranges::less>
requires indirectly_copyable_storable<iterator_t<_Range>,
range_value_t<_Range>*>
constexpr minmax_result<range_value_t<_Range>>
operator()(_Range&& __r, _Comp __comp = {}, _Proj __proj = {}) const
{
auto __first = ranges::begin(__r);
auto __last = ranges::end(__r);
__glibcxx_assert(__first != __last);
minmax_result<range_value_t<_Range>> __result = {*__first, *__first};
while (++__first != __last)
{
auto __tmp = *__first;
if (std::__invoke(__comp,
std::__invoke(__proj, __tmp),
std::__invoke(__proj, __result.min)))
__result.min = std::move(__tmp);
if (!(bool)std::__invoke(__comp,
std::__invoke(__proj, __tmp),
std::__invoke(__proj, __result.max)))
__result.max = std::move(__tmp);
}
return __result;
}
template<copyable _Tp, typename _Proj = identity,
indirect_strict_weak_order<projected<const _Tp*, _Proj>>
_Comp = ranges::less>
constexpr minmax_result<_Tp>
operator()(initializer_list<_Tp> __r,
_Comp __comp = {}, _Proj __proj = {}) const
{
return (*this)(ranges::subrange(__r),
std::move(__comp), std::move(__proj));
}
};
inline constexpr __minmax_fn minmax{};
struct __min_element_fn
{
template<forward_iterator _Iter, sentinel_for<_Iter> _Sent,
typename _Proj = identity,
indirect_strict_weak_order<projected<_Iter, _Proj>>
_Comp = ranges::less>
constexpr _Iter
operator()(_Iter __first, _Sent __last,
_Comp __comp = {}, _Proj __proj = {}) const
{
if (__first == __last)
return __first;
auto __i = __first;
while (++__i != __last)
{
if (std::__invoke(__comp,
std::__invoke(__proj, *__i),
std::__invoke(__proj, *__first)))
__first = __i;
}
return __first;
}
template<forward_range _Range, typename _Proj = identity,
indirect_strict_weak_order<projected<iterator_t<_Range>, _Proj>>
_Comp = ranges::less>
constexpr borrowed_iterator_t<_Range>
operator()(_Range&& __r, _Comp __comp = {}, _Proj __proj = {}) const
{
return (*this)(ranges::begin(__r), ranges::end(__r),
std::move(__comp), std::move(__proj));
}
};
inline constexpr __min_element_fn min_element{};
struct __max_element_fn
{
template<forward_iterator _Iter, sentinel_for<_Iter> _Sent,
typename _Proj = identity,
indirect_strict_weak_order<projected<_Iter, _Proj>>
_Comp = ranges::less>
constexpr _Iter
operator()(_Iter __first, _Sent __last,
_Comp __comp = {}, _Proj __proj = {}) const
{
if (__first == __last)
return __first;
auto __i = __first;
while (++__i != __last)
{
if (std::__invoke(__comp,
std::__invoke(__proj, *__first),
std::__invoke(__proj, *__i)))
__first = __i;
}
return __first;
}
template<forward_range _Range, typename _Proj = identity,
indirect_strict_weak_order<projected<iterator_t<_Range>, _Proj>>
_Comp = ranges::less>
constexpr borrowed_iterator_t<_Range>
operator()(_Range&& __r, _Comp __comp = {}, _Proj __proj = {}) const
{
return (*this)(ranges::begin(__r), ranges::end(__r),
std::move(__comp), std::move(__proj));
}
};
inline constexpr __max_element_fn max_element{};
template<typename _Iter>
using minmax_element_result = min_max_result<_Iter>;
struct __minmax_element_fn
{
template<forward_iterator _Iter, sentinel_for<_Iter> _Sent,
typename _Proj = identity,
indirect_strict_weak_order<projected<_Iter, _Proj>>
_Comp = ranges::less>
constexpr minmax_element_result<_Iter>
operator()(_Iter __first, _Sent __last,
_Comp __comp = {}, _Proj __proj = {}) const
{
if (__first == __last)
return {__first, __first};
minmax_element_result<_Iter> __result = {__first, __first};
auto __i = __first;
while (++__i != __last)
{
if (std::__invoke(__comp,
std::__invoke(__proj, *__i),
std::__invoke(__proj, *__result.min)))
__result.min = __i;
if (!(bool)std::__invoke(__comp,
std::__invoke(__proj, *__i),
std::__invoke(__proj, *__result.max)))
__result.max = __i;
}
return __result;
}
template<forward_range _Range, typename _Proj = identity,
indirect_strict_weak_order<projected<iterator_t<_Range>, _Proj>>
_Comp = ranges::less>
constexpr minmax_element_result<borrowed_iterator_t<_Range>>
operator()(_Range&& __r, _Comp __comp = {}, _Proj __proj = {}) const
{
return (*this)(ranges::begin(__r), ranges::end(__r),
std::move(__comp), std::move(__proj));
}
};
inline constexpr __minmax_element_fn minmax_element{};
struct __lexicographical_compare_fn
{
template<input_iterator _Iter1, sentinel_for<_Iter1> _Sent1,
input_iterator _Iter2, sentinel_for<_Iter2> _Sent2,
typename _Proj1 = identity, typename _Proj2 = identity,
indirect_strict_weak_order<projected<_Iter1, _Proj1>,
projected<_Iter2, _Proj2>>
_Comp = ranges::less>
constexpr bool
operator()(_Iter1 __first1, _Sent1 __last1,
_Iter2 __first2, _Sent2 __last2,
_Comp __comp = {},
_Proj1 __proj1 = {}, _Proj2 __proj2 = {}) const
{
if constexpr (__detail::__is_normal_iterator<_Iter1>
&& same_as<_Iter1, _Sent1>)
return (*this)(__first1.base(), __last1.base(),
std::move(__first2), std::move(__last2),
std::move(__comp),
std::move(__proj1), std::move(__proj2));
else if constexpr (__detail::__is_normal_iterator<_Iter2>
&& same_as<_Iter2, _Sent2>)
return (*this)(std::move(__first1), std::move(__last1),
__first2.base(), __last2.base(),
std::move(__comp),
std::move(__proj1), std::move(__proj2));
else
{
constexpr bool __sized_iters
= (sized_sentinel_for<_Sent1, _Iter1>
&& sized_sentinel_for<_Sent2, _Iter2>);
if constexpr (__sized_iters)
{
using _ValueType1 = iter_value_t<_Iter1>;
using _ValueType2 = iter_value_t<_Iter2>;
// This condition is consistent with the one in
// __lexicographical_compare_aux in <bits/stl_algobase.h>.
constexpr bool __use_memcmp
= (__is_memcmp_ordered_with<_ValueType1, _ValueType2>::__value
&& __ptr_to_nonvolatile<_Iter1>
&& __ptr_to_nonvolatile<_Iter2>
&& (is_same_v<_Comp, ranges::less>
|| is_same_v<_Comp, ranges::greater>)
&& is_same_v<_Proj1, identity>
&& is_same_v<_Proj2, identity>);
if constexpr (__use_memcmp)
{
const auto __d1 = __last1 - __first1;
const auto __d2 = __last2 - __first2;
if (const auto __len = std::min(__d1, __d2))
{
const auto __c
= std::__memcmp(__first1, __first2, __len);
if constexpr (is_same_v<_Comp, ranges::less>)
{
if (__c < 0)
return true;
if (__c > 0)
return false;
}
else if constexpr (is_same_v<_Comp, ranges::greater>)
{
if (__c > 0)
return true;
if (__c < 0)
return false;
}
}
return __d1 < __d2;
}
}
for (; __first1 != __last1 && __first2 != __last2;
++__first1, (void) ++__first2)
{
if (std::__invoke(__comp,
std::__invoke(__proj1, *__first1),
std::__invoke(__proj2, *__first2)))
return true;
if (std::__invoke(__comp,
std::__invoke(__proj2, *__first2),
std::__invoke(__proj1, *__first1)))
return false;
}
return __first1 == __last1 && __first2 != __last2;
}
}
template<input_range _Range1, input_range _Range2,
typename _Proj1 = identity, typename _Proj2 = identity,
indirect_strict_weak_order<projected<iterator_t<_Range1>, _Proj1>,
projected<iterator_t<_Range2>, _Proj2>>
_Comp = ranges::less>
constexpr bool
operator()(_Range1&& __r1, _Range2&& __r2, _Comp __comp = {},
_Proj1 __proj1 = {}, _Proj2 __proj2 = {}) const
{
return (*this)(ranges::begin(__r1), ranges::end(__r1),
ranges::begin(__r2), ranges::end(__r2),
std::move(__comp),
std::move(__proj1), std::move(__proj2));
}
private:
template<typename _Iter, typename _Ref = iter_reference_t<_Iter>>
static constexpr bool __ptr_to_nonvolatile
= is_pointer_v<_Iter> && !is_volatile_v<remove_reference_t<_Ref>>;
};
inline constexpr __lexicographical_compare_fn lexicographical_compare;
template<typename _Iter>
struct in_found_result
{
[[no_unique_address]] _Iter in;
bool found;
template<typename _Iter2>
requires convertible_to<const _Iter&, _Iter2>
constexpr
operator in_found_result<_Iter2>() const &
{ return {in, found}; }
template<typename _Iter2>
requires convertible_to<_Iter, _Iter2>
constexpr
operator in_found_result<_Iter2>() &&
{ return {std::move(in), found}; }
};
template<typename _Iter>
using next_permutation_result = in_found_result<_Iter>;
struct __next_permutation_fn
{
template<bidirectional_iterator _Iter, sentinel_for<_Iter> _Sent,
typename _Comp = ranges::less, typename _Proj = identity>
requires sortable<_Iter, _Comp, _Proj>
constexpr next_permutation_result<_Iter>
operator()(_Iter __first, _Sent __last,
_Comp __comp = {}, _Proj __proj = {}) const
{
if (__first == __last)
return {std::move(__first), false};
auto __i = __first;
++__i;
if (__i == __last)
return {std::move(__i), false};
auto __lasti = ranges::next(__first, __last);
__i = __lasti;
--__i;
for (;;)
{
auto __ii = __i;
--__i;
if (std::__invoke(__comp,
std::__invoke(__proj, *__i),
std::__invoke(__proj, *__ii)))
{
auto __j = __lasti;
while (!(bool)std::__invoke(__comp,
std::__invoke(__proj, *__i),
std::__invoke(__proj, *--__j)))
;
ranges::iter_swap(__i, __j);
ranges::reverse(__ii, __last);
return {std::move(__lasti), true};
}
if (__i == __first)
{
ranges::reverse(__first, __last);
return {std::move(__lasti), false};
}
}
}
template<bidirectional_range _Range, typename _Comp = ranges::less,
typename _Proj = identity>
requires sortable<iterator_t<_Range>, _Comp, _Proj>
constexpr next_permutation_result<borrowed_iterator_t<_Range>>
operator()(_Range&& __r, _Comp __comp = {}, _Proj __proj = {}) const
{
return (*this)(ranges::begin(__r), ranges::end(__r),
std::move(__comp), std::move(__proj));
}
};
inline constexpr __next_permutation_fn next_permutation{};
template<typename _Iter>
using prev_permutation_result = in_found_result<_Iter>;
struct __prev_permutation_fn
{
template<bidirectional_iterator _Iter, sentinel_for<_Iter> _Sent,
typename _Comp = ranges::less, typename _Proj = identity>
requires sortable<_Iter, _Comp, _Proj>
constexpr prev_permutation_result<_Iter>
operator()(_Iter __first, _Sent __last,
_Comp __comp = {}, _Proj __proj = {}) const
{
if (__first == __last)
return {std::move(__first), false};
auto __i = __first;
++__i;
if (__i == __last)
return {std::move(__i), false};
auto __lasti = ranges::next(__first, __last);
__i = __lasti;
--__i;
for (;;)
{
auto __ii = __i;
--__i;
if (std::__invoke(__comp,
std::__invoke(__proj, *__ii),
std::__invoke(__proj, *__i)))
{
auto __j = __lasti;
while (!(bool)std::__invoke(__comp,
std::__invoke(__proj, *--__j),
std::__invoke(__proj, *__i)))
;
ranges::iter_swap(__i, __j);
ranges::reverse(__ii, __last);
return {std::move(__lasti), true};
}
if (__i == __first)
{
ranges::reverse(__first, __last);
return {std::move(__lasti), false};
}
}
}
template<bidirectional_range _Range, typename _Comp = ranges::less,
typename _Proj = identity>
requires sortable<iterator_t<_Range>, _Comp, _Proj>
constexpr prev_permutation_result<borrowed_iterator_t<_Range>>
operator()(_Range&& __r, _Comp __comp = {}, _Proj __proj = {}) const
{
return (*this)(ranges::begin(__r), ranges::end(__r),
std::move(__comp), std::move(__proj));
}
};
inline constexpr __prev_permutation_fn prev_permutation{};
} // namespace ranges
#define __cpp_lib_shift 201806L
template<typename _ForwardIterator>
constexpr _ForwardIterator
shift_left(_ForwardIterator __first, _ForwardIterator __last,
typename iterator_traits<_ForwardIterator>::difference_type __n)
{
__glibcxx_assert(__n >= 0);
if (__n == 0)
return __last;
auto __mid = ranges::next(__first, __n, __last);
if (__mid == __last)
return __first;
return std::move(std::move(__mid), std::move(__last), std::move(__first));
}
template<typename _ForwardIterator>
constexpr _ForwardIterator
shift_right(_ForwardIterator __first, _ForwardIterator __last,
typename iterator_traits<_ForwardIterator>::difference_type __n)
{
__glibcxx_assert(__n >= 0);
if (__n == 0)
return __first;
using _Cat
= typename iterator_traits<_ForwardIterator>::iterator_category;
if constexpr (derived_from<_Cat, bidirectional_iterator_tag>)
{
auto __mid = ranges::next(__last, -__n, __first);
if (__mid == __first)
return __last;
return std::move_backward(std::move(__first), std::move(__mid),
std::move(__last));
}
else
{
auto __result = ranges::next(__first, __n, __last);
if (__result == __last)
return __last;
auto __dest_head = __first, __dest_tail = __result;
while (__dest_head != __result)
{
if (__dest_tail == __last)
{
// If we get here, then we must have
// 2*n >= distance(__first, __last)
// i.e. we are shifting out at least half of the range. In
// this case we can safely perform the shift with a single
// move.
std::move(std::move(__first), std::move(__dest_head),
std::move(__result));
return __result;
}
++__dest_head;
++__dest_tail;
}
for (;;)
{
// At the start of each iteration of this outer loop, the range
// [__first, __result) contains those elements that after shifting
// the whole range right by __n, should end up in
// [__dest_head, __dest_tail) in order.
// The below inner loop swaps the elements of [__first, __result)
// and [__dest_head, __dest_tail), while simultaneously shifting
// the latter range by __n.
auto __cursor = __first;
while (__cursor != __result)
{
if (__dest_tail == __last)
{
// At this point the ranges [__first, result) and
// [__dest_head, dest_tail) are disjoint, so we can safely
// move the remaining elements.
__dest_head = std::move(__cursor, __result,
std::move(__dest_head));
std::move(std::move(__first), std::move(__cursor),
std::move(__dest_head));
return __result;
}
std::iter_swap(__cursor, __dest_head);
++__dest_head;
++__dest_tail;
++__cursor;
}
}
}
}
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace std
#endif // concepts
#endif // C++20
#endif // _RANGES_ALGO_H
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