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// Core algorithmic facilities -*- C++ -*-
// Copyright (C) 2020-2022 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_algobase.h
* This is an internal header file, included by other library headers.
* Do not attempt to use it directly. @headername{algorithm}
*/
#ifndef _RANGES_ALGOBASE_H
#define _RANGES_ALGOBASE_H 1
#if __cplusplus > 201703L
#include <compare>
#include <bits/stl_iterator_base_types.h>
#include <bits/stl_iterator_base_funcs.h>
#include <bits/stl_iterator.h>
#include <bits/ranges_base.h> // ranges::begin, ranges::range etc.
#include <bits/invoke.h> // __invoke
#include <bits/cpp_type_traits.h> // __is_byte
#if __cpp_lib_concepts
namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
namespace ranges
{
namespace __detail
{
template<typename _Tp>
constexpr inline bool __is_normal_iterator = false;
template<typename _Iterator, typename _Container>
constexpr inline bool
__is_normal_iterator<__gnu_cxx::__normal_iterator<_Iterator,
_Container>> = true;
template<typename _Tp>
constexpr inline bool __is_reverse_iterator = false;
template<typename _Iterator>
constexpr inline bool
__is_reverse_iterator<reverse_iterator<_Iterator>> = true;
template<typename _Tp>
constexpr inline bool __is_move_iterator = false;
template<typename _Iterator>
constexpr inline bool
__is_move_iterator<move_iterator<_Iterator>> = true;
} // namespace __detail
struct __equal_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 bool
operator()(_Iter1 __first1, _Sent1 __last1,
_Iter2 __first2, _Sent2 __last2, _Pred __pred = {},
_Proj1 __proj1 = {}, _Proj2 __proj2 = {}) const
{
// TODO: implement more specializations to at least have parity with
// std::equal.
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(__pred),
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(__pred),
std::move(__proj1), std::move(__proj2));
else if constexpr (sized_sentinel_for<_Sent1, _Iter1>
&& sized_sentinel_for<_Sent2, _Iter2>)
{
auto __d1 = ranges::distance(__first1, __last1);
auto __d2 = ranges::distance(__first2, __last2);
if (__d1 != __d2)
return false;
using _ValueType1 = iter_value_t<_Iter1>;
constexpr bool __use_memcmp
= ((is_integral_v<_ValueType1> || is_pointer_v<_ValueType1>)
&& __memcmpable<_Iter1, _Iter2>::__value
&& is_same_v<_Pred, ranges::equal_to>
&& is_same_v<_Proj1, identity>
&& is_same_v<_Proj2, identity>);
if constexpr (__use_memcmp)
{
if (const size_t __len = (__last1 - __first1))
return !std::__memcmp(__first1, __first2, __len);
return true;
}
else
{
for (; __first1 != __last1; ++__first1, (void)++__first2)
if (!(bool)std::__invoke(__pred,
std::__invoke(__proj1, *__first1),
std::__invoke(__proj2, *__first2)))
return false;
return true;
}
}
else
{
for (; __first1 != __last1 && __first2 != __last2;
++__first1, (void)++__first2)
if (!(bool)std::__invoke(__pred,
std::__invoke(__proj1, *__first1),
std::__invoke(__proj2, *__first2)))
return false;
return __first1 == __last1 && __first2 == __last2;
}
}
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 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 __equal_fn equal{};
template<typename _Iter, typename _Out>
struct in_out_result
{
[[no_unique_address]] _Iter in;
[[no_unique_address]] _Out out;
template<typename _Iter2, typename _Out2>
requires convertible_to<const _Iter&, _Iter2>
&& convertible_to<const _Out&, _Out2>
constexpr
operator in_out_result<_Iter2, _Out2>() const &
{ return {in, out}; }
template<typename _Iter2, typename _Out2>
requires convertible_to<_Iter, _Iter2>
&& convertible_to<_Out, _Out2>
constexpr
operator in_out_result<_Iter2, _Out2>() &&
{ return {std::move(in), std::move(out)}; }
};
template<typename _Iter, typename _Out>
using copy_result = in_out_result<_Iter, _Out>;
template<typename _Iter, typename _Out>
using move_result = in_out_result<_Iter, _Out>;
template<typename _Iter1, typename _Iter2>
using move_backward_result = in_out_result<_Iter1, _Iter2>;
template<typename _Iter1, typename _Iter2>
using copy_backward_result = in_out_result<_Iter1, _Iter2>;
template<bool _IsMove,
bidirectional_iterator _Iter, sentinel_for<_Iter> _Sent,
bidirectional_iterator _Out>
requires (_IsMove
? indirectly_movable<_Iter, _Out>
: indirectly_copyable<_Iter, _Out>)
constexpr __conditional_t<_IsMove,
move_backward_result<_Iter, _Out>,
copy_backward_result<_Iter, _Out>>
__copy_or_move_backward(_Iter __first, _Sent __last, _Out __result);
template<bool _IsMove,
input_iterator _Iter, sentinel_for<_Iter> _Sent,
weakly_incrementable _Out>
requires (_IsMove
? indirectly_movable<_Iter, _Out>
: indirectly_copyable<_Iter, _Out>)
constexpr __conditional_t<_IsMove,
move_result<_Iter, _Out>,
copy_result<_Iter, _Out>>
__copy_or_move(_Iter __first, _Sent __last, _Out __result)
{
// TODO: implement more specializations to be at least on par with
// std::copy/std::move.
using __detail::__is_move_iterator;
using __detail::__is_reverse_iterator;
using __detail::__is_normal_iterator;
if constexpr (__is_move_iterator<_Iter> && same_as<_Iter, _Sent>)
{
auto [__in, __out]
= ranges::__copy_or_move<true>(std::move(__first).base(),
std::move(__last).base(),
std::move(__result));
return {move_iterator{std::move(__in)}, std::move(__out)};
}
else if constexpr (__is_reverse_iterator<_Iter> && same_as<_Iter, _Sent>
&& __is_reverse_iterator<_Out>)
{
auto [__in,__out]
= ranges::__copy_or_move_backward<_IsMove>(std::move(__last).base(),
std::move(__first).base(),
std::move(__result).base());
return {reverse_iterator{std::move(__in)},
reverse_iterator{std::move(__out)}};
}
else if constexpr (__is_normal_iterator<_Iter> && same_as<_Iter, _Sent>)
{
auto [__in,__out]
= ranges::__copy_or_move<_IsMove>(__first.base(), __last.base(),
std::move(__result));
return {decltype(__first){__in}, std::move(__out)};
}
else if constexpr (__is_normal_iterator<_Out>)
{
auto [__in,__out]
= ranges::__copy_or_move<_IsMove>(std::move(__first), __last, __result.base());
return {std::move(__in), decltype(__result){__out}};
}
else if constexpr (sized_sentinel_for<_Sent, _Iter>)
{
if (!std::__is_constant_evaluated())
{
if constexpr (__memcpyable<_Iter, _Out>::__value)
{
using _ValueTypeI = iter_value_t<_Iter>;
static_assert(_IsMove
? is_move_assignable_v<_ValueTypeI>
: is_copy_assignable_v<_ValueTypeI>);
auto __num = __last - __first;
if (__num)
__builtin_memmove(__result, __first,
sizeof(_ValueTypeI) * __num);
return {__first + __num, __result + __num};
}
}
for (auto __n = __last - __first; __n > 0; --__n)
{
if constexpr (_IsMove)
*__result = std::move(*__first);
else
*__result = *__first;
++__first;
++__result;
}
return {std::move(__first), std::move(__result)};
}
else
{
while (__first != __last)
{
if constexpr (_IsMove)
*__result = std::move(*__first);
else
*__result = *__first;
++__first;
++__result;
}
return {std::move(__first), std::move(__result)};
}
}
struct __copy_fn
{
template<input_iterator _Iter, sentinel_for<_Iter> _Sent,
weakly_incrementable _Out>
requires indirectly_copyable<_Iter, _Out>
constexpr copy_result<_Iter, _Out>
operator()(_Iter __first, _Sent __last, _Out __result) const
{
return ranges::__copy_or_move<false>(std::move(__first),
std::move(__last),
std::move(__result));
}
template<input_range _Range, weakly_incrementable _Out>
requires indirectly_copyable<iterator_t<_Range>, _Out>
constexpr 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 __copy_fn copy{};
struct __move_fn
{
template<input_iterator _Iter, sentinel_for<_Iter> _Sent,
weakly_incrementable _Out>
requires indirectly_movable<_Iter, _Out>
constexpr move_result<_Iter, _Out>
operator()(_Iter __first, _Sent __last, _Out __result) const
{
return ranges::__copy_or_move<true>(std::move(__first),
std::move(__last),
std::move(__result));
}
template<input_range _Range, weakly_incrementable _Out>
requires indirectly_movable<iterator_t<_Range>, _Out>
constexpr move_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 __move_fn move{};
template<bool _IsMove,
bidirectional_iterator _Iter, sentinel_for<_Iter> _Sent,
bidirectional_iterator _Out>
requires (_IsMove
? indirectly_movable<_Iter, _Out>
: indirectly_copyable<_Iter, _Out>)
constexpr __conditional_t<_IsMove,
move_backward_result<_Iter, _Out>,
copy_backward_result<_Iter, _Out>>
__copy_or_move_backward(_Iter __first, _Sent __last, _Out __result)
{
// TODO: implement more specializations to be at least on par with
// std::copy_backward/std::move_backward.
using __detail::__is_reverse_iterator;
using __detail::__is_normal_iterator;
if constexpr (__is_reverse_iterator<_Iter> && same_as<_Iter, _Sent>
&& __is_reverse_iterator<_Out>)
{
auto [__in,__out]
= ranges::__copy_or_move<_IsMove>(std::move(__last).base(),
std::move(__first).base(),
std::move(__result).base());
return {reverse_iterator{std::move(__in)},
reverse_iterator{std::move(__out)}};
}
else if constexpr (__is_normal_iterator<_Iter> && same_as<_Iter, _Sent>)
{
auto [__in,__out]
= ranges::__copy_or_move_backward<_IsMove>(__first.base(),
__last.base(),
std::move(__result));
return {decltype(__first){__in}, std::move(__out)};
}
else if constexpr (__is_normal_iterator<_Out>)
{
auto [__in,__out]
= ranges::__copy_or_move_backward<_IsMove>(std::move(__first),
std::move(__last),
__result.base());
return {std::move(__in), decltype(__result){__out}};
}
else if constexpr (sized_sentinel_for<_Sent, _Iter>)
{
if (!std::__is_constant_evaluated())
{
if constexpr (__memcpyable<_Out, _Iter>::__value)
{
using _ValueTypeI = iter_value_t<_Iter>;
static_assert(_IsMove
? is_move_assignable_v<_ValueTypeI>
: is_copy_assignable_v<_ValueTypeI>);
auto __num = __last - __first;
if (__num)
__builtin_memmove(__result - __num, __first,
sizeof(_ValueTypeI) * __num);
return {__first + __num, __result - __num};
}
}
auto __lasti = ranges::next(__first, __last);
auto __tail = __lasti;
for (auto __n = __last - __first; __n > 0; --__n)
{
--__tail;
--__result;
if constexpr (_IsMove)
*__result = std::move(*__tail);
else
*__result = *__tail;
}
return {std::move(__lasti), std::move(__result)};
}
else
{
auto __lasti = ranges::next(__first, __last);
auto __tail = __lasti;
while (__first != __tail)
{
--__tail;
--__result;
if constexpr (_IsMove)
*__result = std::move(*__tail);
else
*__result = *__tail;
}
return {std::move(__lasti), std::move(__result)};
}
}
struct __copy_backward_fn
{
template<bidirectional_iterator _Iter1, sentinel_for<_Iter1> _Sent1,
bidirectional_iterator _Iter2>
requires indirectly_copyable<_Iter1, _Iter2>
constexpr copy_backward_result<_Iter1, _Iter2>
operator()(_Iter1 __first, _Sent1 __last, _Iter2 __result) const
{
return ranges::__copy_or_move_backward<false>(std::move(__first),
std::move(__last),
std::move(__result));
}
template<bidirectional_range _Range, bidirectional_iterator _Iter>
requires indirectly_copyable<iterator_t<_Range>, _Iter>
constexpr copy_backward_result<borrowed_iterator_t<_Range>, _Iter>
operator()(_Range&& __r, _Iter __result) const
{
return (*this)(ranges::begin(__r), ranges::end(__r),
std::move(__result));
}
};
inline constexpr __copy_backward_fn copy_backward{};
struct __move_backward_fn
{
template<bidirectional_iterator _Iter1, sentinel_for<_Iter1> _Sent1,
bidirectional_iterator _Iter2>
requires indirectly_movable<_Iter1, _Iter2>
constexpr move_backward_result<_Iter1, _Iter2>
operator()(_Iter1 __first, _Sent1 __last, _Iter2 __result) const
{
return ranges::__copy_or_move_backward<true>(std::move(__first),
std::move(__last),
std::move(__result));
}
template<bidirectional_range _Range, bidirectional_iterator _Iter>
requires indirectly_movable<iterator_t<_Range>, _Iter>
constexpr move_backward_result<borrowed_iterator_t<_Range>, _Iter>
operator()(_Range&& __r, _Iter __result) const
{
return (*this)(ranges::begin(__r), ranges::end(__r),
std::move(__result));
}
};
inline constexpr __move_backward_fn move_backward{};
template<typename _Iter, typename _Out>
using copy_n_result = in_out_result<_Iter, _Out>;
struct __copy_n_fn
{
template<input_iterator _Iter, weakly_incrementable _Out>
requires indirectly_copyable<_Iter, _Out>
constexpr copy_n_result<_Iter, _Out>
operator()(_Iter __first, iter_difference_t<_Iter> __n,
_Out __result) const
{
if constexpr (random_access_iterator<_Iter>)
{
if (__n > 0)
return ranges::copy(__first, __first + __n, std::move(__result));
}
else
{
for (; __n > 0; --__n, (void)++__result, (void)++__first)
*__result = *__first;
}
return {std::move(__first), std::move(__result)};
}
};
inline constexpr __copy_n_fn copy_n{};
struct __fill_n_fn
{
template<typename _Tp, output_iterator<const _Tp&> _Out>
constexpr _Out
operator()(_Out __first, iter_difference_t<_Out> __n,
const _Tp& __value) const
{
// TODO: implement more specializations to be at least on par with
// std::fill_n
if (__n <= 0)
return __first;
if constexpr (is_scalar_v<_Tp>)
{
// TODO: Generalize this optimization to contiguous iterators.
if constexpr (is_pointer_v<_Out>
// Note that __is_byte already implies !is_volatile.
&& __is_byte<remove_pointer_t<_Out>>::__value
&& integral<_Tp>)
{
if (!std::__is_constant_evaluated())
{
__builtin_memset(__first,
static_cast<unsigned char>(__value),
__n);
return __first + __n;
}
}
const auto __tmp = __value;
for (; __n > 0; --__n, (void)++__first)
*__first = __tmp;
return __first;
}
else
{
for (; __n > 0; --__n, (void)++__first)
*__first = __value;
return __first;
}
}
};
inline constexpr __fill_n_fn fill_n{};
struct __fill_fn
{
template<typename _Tp,
output_iterator<const _Tp&> _Out, sentinel_for<_Out> _Sent>
constexpr _Out
operator()(_Out __first, _Sent __last, const _Tp& __value) const
{
// TODO: implement more specializations to be at least on par with
// std::fill
if constexpr (sized_sentinel_for<_Sent, _Out>)
{
const auto __len = __last - __first;
return ranges::fill_n(__first, __len, __value);
}
else if constexpr (is_scalar_v<_Tp>)
{
const auto __tmp = __value;
for (; __first != __last; ++__first)
*__first = __tmp;
return __first;
}
else
{
for (; __first != __last; ++__first)
*__first = __value;
return __first;
}
}
template<typename _Tp, output_range<const _Tp&> _Range>
constexpr borrowed_iterator_t<_Range>
operator()(_Range&& __r, const _Tp& __value) const
{
return (*this)(ranges::begin(__r), ranges::end(__r), __value);
}
};
inline constexpr __fill_fn fill{};
}
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace std
#endif // concepts
#endif // C++20
#endif // _RANGES_ALGOBASE_H
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