// Core algorithmic facilities -*- C++ -*-
// Copyright (C) 2001-2020 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/>.
/*
*
* Copyright (c) 1994
* Hewlett-Packard Company
*
* Permission to use, copy, modify, distribute and sell this software
* and its documentation for any purpose is hereby granted without fee,
* provided that the above copyright notice appear in all copies and
* that both that copyright notice and this permission notice appear
* in supporting documentation. Hewlett-Packard Company makes no
* representations about the suitability of this software for any
* purpose. It is provided "as is" without express or implied warranty.
*
*
* Copyright (c) 1996-1998
* Silicon Graphics Computer Systems, Inc.
*
* Permission to use, copy, modify, distribute and sell this software
* and its documentation for any purpose is hereby granted without fee,
* provided that the above copyright notice appear in all copies and
* that both that copyright notice and this permission notice appear
* in supporting documentation. Silicon Graphics makes no
* representations about the suitability of this software for any
* purpose. It is provided "as is" without express or implied warranty.
*/
/** @file bits/stl_algobase.h
* This is an internal header file, included by other library headers.
* Do not attempt to use it directly. @headername{algorithm}
*/
#ifndef _STL_ALGOBASE_H
#define _STL_ALGOBASE_H 1
#include <bits/c++config.h>
#include <bits/functexcept.h>
#include <bits/cpp_type_traits.h>
#include <ext/type_traits.h>
#include <ext/numeric_traits.h>
#include <bits/stl_pair.h>
#include <bits/stl_iterator_base_types.h>
#include <bits/stl_iterator_base_funcs.h>
#include <bits/stl_iterator.h>
#include <bits/concept_check.h>
#include <debug/debug.h>
#include <bits/move.h> // For std::swap
#include <bits/predefined_ops.h>
#if __cplusplus >= 201103L
# include <type_traits>
#endif
#if __cplusplus > 201703L
# include <compare>
#endif
namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
/*
* A constexpr wrapper for __builtin_memcmp.
* @param __num The number of elements of type _Tp (not bytes).
*/
template<typename _Tp, typename _Up>
_GLIBCXX14_CONSTEXPR
inline int
__memcmp(const _Tp* __first1, const _Up* __first2, size_t __num)
{
#if __cplusplus >= 201103L
static_assert(sizeof(_Tp) == sizeof(_Up), "can be compared with memcmp");
#endif
#ifdef __cpp_lib_is_constant_evaluated
if (std::is_constant_evaluated())
{
for(; __num > 0; ++__first1, ++__first2, --__num)
if (*__first1 != *__first2)
return *__first1 < *__first2 ? -1 : 1;
return 0;
}
else
#endif
return __builtin_memcmp(__first1, __first2, sizeof(_Tp) * __num);
}
#if __cplusplus < 201103L
// See http://gcc.gnu.org/ml/libstdc++/2004-08/msg00167.html: in a
// nutshell, we are partially implementing the resolution of DR 187,
// when it's safe, i.e., the value_types are equal.
template<bool _BoolType>
struct __iter_swap
{
template<typename _ForwardIterator1, typename _ForwardIterator2>
static void
iter_swap(_ForwardIterator1 __a, _ForwardIterator2 __b)
{
typedef typename iterator_traits<_ForwardIterator1>::value_type
_ValueType1;
_ValueType1 __tmp = *__a;
*__a = *__b;
*__b = __tmp;
}
};
template<>
struct __iter_swap<true>
{
template<typename _ForwardIterator1, typename _ForwardIterator2>
static void
iter_swap(_ForwardIterator1 __a, _ForwardIterator2 __b)
{
swap(*__a, *__b);
}
};
#endif // C++03
/**
* @brief Swaps the contents of two iterators.
* @ingroup mutating_algorithms
* @param __a An iterator.
* @param __b Another iterator.
* @return Nothing.
*
* This function swaps the values pointed to by two iterators, not the
* iterators themselves.
*/
template<typename _ForwardIterator1, typename _ForwardIterator2>
_GLIBCXX20_CONSTEXPR
inline void
iter_swap(_ForwardIterator1 __a, _ForwardIterator2 __b)
{
// concept requirements
__glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
_ForwardIterator1>)
__glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
_ForwardIterator2>)
#if __cplusplus < 201103L
typedef typename iterator_traits<_ForwardIterator1>::value_type
_ValueType1;
typedef typename iterator_traits<_ForwardIterator2>::value_type
_ValueType2;
__glibcxx_function_requires(_ConvertibleConcept<_ValueType1,
_ValueType2>)
__glibcxx_function_requires(_ConvertibleConcept<_ValueType2,
_ValueType1>)
typedef typename iterator_traits<_ForwardIterator1>::reference
_ReferenceType1;
typedef typename iterator_traits<_ForwardIterator2>::reference
_ReferenceType2;
std::__iter_swap<__are_same<_ValueType1, _ValueType2>::__value
&& __are_same<_ValueType1&, _ReferenceType1>::__value
&& __are_same<_ValueType2&, _ReferenceType2>::__value>::
iter_swap(__a, __b);
#else
// _GLIBCXX_RESOLVE_LIB_DEFECTS
// 187. iter_swap underspecified
swap(*__a, *__b);
#endif
}
/**
* @brief Swap the elements of two sequences.
* @ingroup mutating_algorithms
* @param __first1 A forward iterator.
* @param __last1 A forward iterator.
* @param __first2 A forward iterator.
* @return An iterator equal to @p first2+(last1-first1).
*
* Swaps each element in the range @p [first1,last1) with the
* corresponding element in the range @p [first2,(last1-first1)).
* The ranges must not overlap.
*/
template<typename _ForwardIterator1, typename _ForwardIterator2>
_GLIBCXX20_CONSTEXPR
_ForwardIterator2
swap_ranges(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
_ForwardIterator2 __first2)
{
// concept requirements
__glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
_ForwardIterator1>)
__glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
_ForwardIterator2>)
__glibcxx_requires_valid_range(__first1, __last1);
for (; __first1 != __last1; ++__first1, (void)++__first2)
std::iter_swap(__first1, __first2);
return __first2;
}
/**
* @brief This does what you think it does.
* @ingroup sorting_algorithms
* @param __a A thing of arbitrary type.
* @param __b Another thing of arbitrary type.
* @return The lesser of the parameters.
*
* This is the simple classic generic implementation. It will work on
* temporary expressions, since they are only evaluated once, unlike a
* preprocessor macro.
*/
template<typename _Tp>
_GLIBCXX14_CONSTEXPR
inline const _Tp&
min(const _Tp& __a, const _Tp& __b)
{
// concept requirements
__glibcxx_function_requires(_LessThanComparableConcept<_Tp>)
//return __b < __a ? __b : __a;
if (__b < __a)
return __b;
return __a;
}
/**
* @brief This does what you think it does.
* @ingroup sorting_algorithms
* @param __a A thing of arbitrary type.
* @param __b Another thing of arbitrary type.
* @return The greater of the parameters.
*
* This is the simple classic generic implementation. It will work on
* temporary expressions, since they are only evaluated once, unlike a
* preprocessor macro.
*/
template<typename _Tp>
_GLIBCXX14_CONSTEXPR
inline const _Tp&
max(const _Tp& __a, const _Tp& __b)
{
// concept requirements
__glibcxx_function_requires(_LessThanComparableConcept<_Tp>)
//return __a < __b ? __b : __a;
if (__a < __b)
return __b;
return __a;
}
/**
* @brief This does what you think it does.
* @ingroup sorting_algorithms
* @param __a A thing of arbitrary type.
* @param __b Another thing of arbitrary type.
* @param __comp A @link comparison_functors comparison functor@endlink.
* @return The lesser of the parameters.
*
* This will work on temporary expressions, since they are only evaluated
* once, unlike a preprocessor macro.
*/
template<typename _Tp, typename _Compare>
_GLIBCXX14_CONSTEXPR
inline const _Tp&
min(const _Tp& __a, const _Tp& __b, _Compare __comp)
{
//return __comp(__b, __a) ? __b : __a;
if (__comp(__b, __a))
return __b;
return __a;
}
/**
* @brief This does what you think it does.
* @ingroup sorting_algorithms
* @param __a A thing of arbitrary type.
* @param __b Another thing of arbitrary type.
* @param __comp A @link comparison_functors comparison functor@endlink.
* @return The greater of the parameters.
*
* This will work on temporary expressions, since they are only evaluated
* once, unlike a preprocessor macro.
*/
template<typename _Tp, typename _Compare>
_GLIBCXX14_CONSTEXPR
inline const _Tp&
max(const _Tp& __a, const _Tp& __b, _Compare __comp)
{
//return __comp(__a, __b) ? __b : __a;
if (__comp(__a, __b))
return __b;
return __a;
}
// Fallback implementation of the function in bits/stl_iterator.h used to
// remove the __normal_iterator wrapper. See copy, fill, ...
template<typename _Iterator>
_GLIBCXX20_CONSTEXPR
inline _Iterator
__niter_base(_Iterator __it)
_GLIBCXX_NOEXCEPT_IF(std::is_nothrow_copy_constructible<_Iterator>::value)
{ return __it; }
// Reverse the __niter_base transformation to get a
// __normal_iterator back again (this assumes that __normal_iterator
// is only used to wrap random access iterators, like pointers).
template<typename _From, typename _To>
_GLIBCXX20_CONSTEXPR
inline _From
__niter_wrap(_From __from, _To __res)
{ return __from + (__res - std::__niter_base(__from)); }
// No need to wrap, iterator already has the right type.
template<typename _Iterator>
_GLIBCXX20_CONSTEXPR
inline _Iterator
__niter_wrap(const _Iterator&, _Iterator __res)
{ return __res; }
// All of these auxiliary structs serve two purposes. (1) Replace
// calls to copy with memmove whenever possible. (Memmove, not memcpy,
// because the input and output ranges are permitted to overlap.)
// (2) If we're using random access iterators, then write the loop as
// a for loop with an explicit count.
template<bool _IsMove, bool _IsSimple, typename _Category>
struct __copy_move
{
template<typename _II, typename _OI>
_GLIBCXX20_CONSTEXPR
static _OI
__copy_m(_II __first, _II __last, _OI __result)
{
for (; __first != __last; ++__result, (void)++__first)
*__result = *__first;
return __result;
}
};
#if __cplusplus >= 201103L
template<typename _Category>
struct __copy_move<true, false, _Category>
{
template<typename _II, typename _OI>
_GLIBCXX20_CONSTEXPR
static _OI
__copy_m(_II __first, _II __last, _OI __result)
{
for (; __first != __last; ++__result, (void)++__first)
*__result = std::move(*__first);
return __result;
}
};
#endif
template<>
struct __copy_move<false, false, random_access_iterator_tag>
{
template<typename _II, typename _OI>
_GLIBCXX20_CONSTEXPR
static _OI
__copy_m(_II __first, _II __last, _OI __result)
{
typedef typename iterator_traits<_II>::difference_type _Distance;
for(_Distance __n = __last - __first; __n > 0; --__n)
{
*__result = *__first;
++__first;
++__result;
}
return __result;
}
};
#if __cplusplus >= 201103L
template<>
struct __copy_move<true, false, random_access_iterator_tag>
{
template<typename _II, typename _OI>
_GLIBCXX20_CONSTEXPR
static _OI
__copy_m(_II __first, _II __last, _OI __result)
{
typedef typename iterator_traits<_II>::difference_type _Distance;
for(_Distance __n = __last - __first; __n > 0; --__n)
{
*__result = std::move(*__first);
++__first;
++__result;
}
return __result;
}
};
#endif
template<bool _IsMove>
struct __copy_move<_IsMove, true, random_access_iterator_tag>
{
template<typename _Tp>
_GLIBCXX20_CONSTEXPR
static _Tp*
__copy_m(const _Tp* __first, const _Tp* __last, _Tp* __result)
{
#if __cplusplus >= 201103L
using __assignable = conditional<_IsMove,
is_move_assignable<_Tp>,
is_copy_assignable<_Tp>>;
// trivial types can have deleted assignment
static_assert( __assignable::type::value, "type is not assignable" );
#endif
const ptrdiff_t _Num = __last - __first;
if (_Num)
__builtin_memmove(__result, __first, sizeof(_Tp) * _Num);
return __result + _Num;
}
};
// Helpers for streambuf iterators (either istream or ostream).
// NB: avoid including <iosfwd>, relatively large.
template<typename _CharT>
struct char_traits;
template<typename _CharT, typename _Traits>
class istreambuf_iterator;
template<typename _CharT, typename _Traits>
class ostreambuf_iterator;
template<bool _IsMove, typename _CharT>
typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
ostreambuf_iterator<_CharT, char_traits<_CharT> > >::__type
__copy_move_a2(_CharT*, _CharT*,
ostreambuf_iterator<_CharT, char_traits<_CharT> >);
template<bool _IsMove, typename _CharT>
typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
ostreambuf_iterator<_CharT, char_traits<_CharT> > >::__type
__copy_move_a2(const _CharT*, const _CharT*,
ostreambuf_iterator<_CharT, char_traits<_CharT> >);
template<bool _IsMove, typename _CharT>
typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
_CharT*>::__type
__copy_move_a2(istreambuf_iterator<_CharT, char_traits<_CharT> >,
istreambuf_iterator<_CharT, char_traits<_CharT> >, _CharT*);
template<bool _IsMove, typename _II, typename _OI>
_GLIBCXX20_CONSTEXPR
inline _OI
__copy_move_a2(_II __first, _II __last, _OI __result)
{
typedef typename iterator_traits<_II>::iterator_category _Category;
#ifdef __cpp_lib_is_constant_evaluated
if (std::is_constant_evaluated())
return std::__copy_move<_IsMove, false, _Category>::
__copy_m(__first, __last, __result);
#endif
return std::__copy_move<_IsMove, __memcpyable<_OI, _II>::__value,
_Category>::__copy_m(__first, __last, __result);
}
_GLIBCXX_BEGIN_NAMESPACE_CONTAINER
template<typename _Tp, typename _Ref, typename _Ptr>
struct _Deque_iterator;
_GLIBCXX_END_NAMESPACE_CONTAINER
template<bool _IsMove,
typename _Tp, typename _Ref, typename _Ptr, typename _OI>
_OI
__copy_move_a1(_GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr>,
_GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr>,
_OI);
template<bool _IsMove,
typename _ITp, typename _IRef, typename _IPtr, typename _OTp>
_GLIBCXX_STD_C::_Deque_iterator<_OTp, _OTp&, _OTp*>
__copy_move_a1(_GLIBCXX_STD_C::_Deque_iterator<_ITp, _IRef, _IPtr>,
_GLIBCXX_STD_C::_Deque_iterator<_ITp, _IRef, _IPtr>,
_GLIBCXX_STD_C::_Deque_iterator<_OTp, _OTp&, _OTp*>);
template<bool _IsMove, typename _II, typename _Tp>
typename __gnu_cxx::__enable_if<
__is_random_access_iter<_II>::__value,
_GLIBCXX_STD_C::_Deque_iterator<_Tp, _Tp&, _Tp*> >::__type
__copy_move_a1(_II, _II, _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Tp&, _Tp*>);
template<bool _IsMove, typename _II, typename _OI>
_GLIBCXX20_CONSTEXPR
inline _OI
__copy_move_a1(_II __first, _II __last, _OI __result)
{ return std::__copy_move_a2<_IsMove>(__first, __last, __result); }
template<bool _IsMove, typename _II, typename _OI>
_GLIBCXX20_CONSTEXPR
inline _OI
__copy_move_a(_II __first, _II __last, _OI __result)
{
return std::__niter_wrap(__result,
std::__copy_move_a1<_IsMove>(std::__niter_base(__first),
std::__niter_base(__last),
std::__niter_base(__result)));
}
template<bool _IsMove,
typename _Ite, typename _Seq, typename _Cat, typename _OI>
_OI
__copy_move_a(const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>&,
const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>&,
_OI);
template<bool _IsMove,
typename _II, typename _Ite, typename _Seq, typename _Cat>
__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>
__copy_move_a(_II, _II,
const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>&);
template<bool _IsMove,
typename _IIte, typename _ISeq, typename _ICat,
typename _OIte, typename _OSeq, typename _OCat>
::__gnu_debug::_Safe_iterator<_OIte, _OSeq, _OCat>
__copy_move_a(const ::__gnu_debug::_Safe_iterator<_IIte, _ISeq, _ICat>&,
const ::__gnu_debug::_Safe_iterator<_IIte, _ISeq, _ICat>&,
const ::__gnu_debug::_Safe_iterator<_OIte, _OSeq, _OCat>&);
/**
* @brief Copies the range [first,last) into result.
* @ingroup mutating_algorithms
* @param __first An input iterator.
* @param __last An input iterator.
* @param __result An output iterator.
* @return result + (last - first)
*
* This inline function will boil down to a call to @c memmove whenever
* possible. Failing that, if random access iterators are passed, then the
* loop count will be known (and therefore a candidate for compiler
* optimizations such as unrolling). Result may not be contained within
* [first,last); the copy_backward function should be used instead.
*
* Note that the end of the output range is permitted to be contained
* within [first,last).
*/
template<typename _II, typename _OI>
_GLIBCXX20_CONSTEXPR
inline _OI
copy(_II __first, _II __last, _OI __result)
{
// concept requirements
__glibcxx_function_requires(_InputIteratorConcept<_II>)
__glibcxx_function_requires(_OutputIteratorConcept<_OI,
typename iterator_traits<_II>::value_type>)
__glibcxx_requires_can_increment_range(__first, __last, __result);
return std::__copy_move_a<__is_move_iterator<_II>::__value>
(std::__miter_base(__first), std::__miter_base(__last), __result);
}
#if __cplusplus >= 201103L
/**
* @brief Moves the range [first,last) into result.
* @ingroup mutating_algorithms
* @param __first An input iterator.
* @param __last An input iterator.
* @param __result An output iterator.
* @return result + (last - first)
*
* This inline function will boil down to a call to @c memmove whenever
* possible. Failing that, if random access iterators are passed, then the
* loop count will be known (and therefore a candidate for compiler
* optimizations such as unrolling). Result may not be contained within
* [first,last); the move_backward function should be used instead.
*
* Note that the end of the output range is permitted to be contained
* within [first,last).
*/
template<typename _II, typename _OI>
_GLIBCXX20_CONSTEXPR
inline _OI
move(_II __first, _II __last, _OI __result)
{
// concept requirements
__glibcxx_function_requires(_InputIteratorConcept<_II>)
__glibcxx_function_requires(_OutputIteratorConcept<_OI,
typename iterator_traits<_II>::value_type>)
__glibcxx_requires_can_increment_range(__first, __last, __result);
return std::__copy_move_a<true>(std::__miter_base(__first),
std::__miter_base(__last), __result);
}
#define _GLIBCXX_MOVE3(_Tp, _Up, _Vp) std::move(_Tp, _Up, _Vp)
#else
#define _GLIBCXX_MOVE3(_Tp, _Up, _Vp) std::copy(_Tp, _Up, _Vp)
#endif
template<bool _IsMove, bool _IsSimple, typename _Category>
struct __copy_move_backward
{
template<typename _BI1, typename _BI2>
_GLIBCXX20_CONSTEXPR
static _BI2
__copy_move_b(_BI1 __first, _BI1 __last, _BI2 __result)
{
while (__first != __last)
*--__result = *--__last;
return __result;
}
};
#if __cplusplus >= 201103L
template<typename _Category>
struct __copy_move_backward<true, false, _Category>
{
template<typename _BI1, typename _BI2>
_GLIBCXX20_CONSTEXPR
static _BI2
__copy_move_b(_BI1 __first, _BI1 __last, _BI2 __result)
{
while (__first != __last)
*--__result = std::move(*--__last);
return __result;
}
};
#endif
template<>
struct __copy_move_backward<false, false, random_access_iterator_tag>
{
template<typename _BI1, typename _BI2>
_GLIBCXX20_CONSTEXPR
static _BI2
__copy_move_b(_BI1 __first, _BI1 __last, _BI2 __result)
{
typename iterator_traits<_BI1>::difference_type
__n = __last - __first;
for (; __n > 0; --__n)
*--__result = *--__last;
return __result;
}
};
#if __cplusplus >= 201103L
template<>
struct __copy_move_backward<true, false, random_access_iterator_tag>
{
template<typename _BI1, typename _BI2>
_GLIBCXX20_CONSTEXPR
static _BI2
__copy_move_b(_BI1 __first, _BI1 __last, _BI2 __result)
{
typename iterator_traits<_BI1>::difference_type
__n = __last - __first;
for (; __n > 0; --__n)
*--__result = std::move(*--__last);
return __result;
}
};
#endif
template<bool _IsMove>
struct __copy_move_backward<_IsMove, true, random_access_iterator_tag>
{
template<typename _Tp>
_GLIBCXX20_CONSTEXPR
static _Tp*
__copy_move_b(const _Tp* __first, const _Tp* __last, _Tp* __result)
{
#if __cplusplus >= 201103L
using __assignable = conditional<_IsMove,
is_move_assignable<_Tp>,
is_copy_assignable<_Tp>>;
// trivial types can have deleted assignment
static_assert( __assignable::type::value, "type is not assignable" );
#endif
const ptrdiff_t _Num = __last - __first;
if (_Num)
__builtin_memmove(__result - _Num, __first, sizeof(_Tp) * _Num);
return __result - _Num;
}
};
template<bool _IsMove, typename _BI1, typename _BI2>
_GLIBCXX20_CONSTEXPR
inline _BI2
__copy_move_backward_a2(_BI1 __first, _BI1 __last, _BI2 __result)
{
typedef typename iterator_traits<_BI1>::iterator_category _Category;
#ifdef __cpp_lib_is_constant_evaluated
if (std::is_constant_evaluated())
return std::__copy_move_backward<_IsMove, false, _Category>::
__copy_move_b(__first, __last, __result);
#endif
return std::__copy_move_backward<_IsMove,
__memcpyable<_BI2, _BI1>::__value,
_Category>::__copy_move_b(__first,
__last,
__result);
}
template<bool _IsMove, typename _BI1, typename _BI2>
_GLIBCXX20_CONSTEXPR
inline _BI2
__copy_move_backward_a1(_BI1 __first, _BI1 __last, _BI2 __result)
{ return std::__copy_move_backward_a2<_IsMove>(__first, __last, __result); }
template<bool _IsMove,
typename _Tp, typename _Ref, typename _Ptr, typename _OI>
_OI
__copy_move_backward_a1(_GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr>,
_GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr>,
_OI);
template<bool _IsMove,
typename _ITp, typename _IRef, typename _IPtr, typename _OTp>
_GLIBCXX_STD_C::_Deque_iterator<_OTp, _OTp&, _OTp*>
__copy_move_backward_a1(
_GLIBCXX_STD_C::_Deque_iterator<_ITp, _IRef, _IPtr>,
_GLIBCXX_STD_C::_Deque_iterator<_ITp, _IRef, _IPtr>,
_GLIBCXX_STD_C::_Deque_iterator<_OTp, _OTp&, _OTp*>);
template<bool _IsMove, typename _II, typename _Tp>
typename __gnu_cxx::__enable_if<
__is_random_access_iter<_II>::__value,
_GLIBCXX_STD_C::_Deque_iterator<_Tp, _Tp&, _Tp*> >::__type
__copy_move_backward_a1(_II, _II,
_GLIBCXX_STD_C::_Deque_iterator<_Tp, _Tp&, _Tp*>);
template<bool _IsMove, typename _II, typename _OI>
_GLIBCXX20_CONSTEXPR
inline _OI
__copy_move_backward_a(_II __first, _II __last, _OI __result)
{
return std::__niter_wrap(__result,
std::__copy_move_backward_a1<_IsMove>
(std::__niter_base(__first), std::__niter_base(__last),
std::__niter_base(__result)));
}
template<bool _IsMove,
typename _Ite, typename _Seq, typename _Cat, typename _OI>
_OI
__copy_move_backward_a(
const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>&,
const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>&,
_OI);
template<bool _IsMove,
typename _II, typename _Ite, typename _Seq, typename _Cat>
__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>
__copy_move_backward_a(_II, _II,
const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>&);
template<bool _IsMove,
typename _IIte, typename _ISeq, typename _ICat,
typename _OIte, typename _OSeq, typename _OCat>
::__gnu_debug::_Safe_iterator<_OIte, _OSeq, _OCat>
__copy_move_backward_a(
const ::__gnu_debug::_Safe_iterator<_IIte, _ISeq, _ICat>&,
const ::__gnu_debug::_Safe_iterator<_IIte, _ISeq, _ICat>&,
const ::__gnu_debug::_Safe_iterator<_OIte, _OSeq, _OCat>&);
/**
* @brief Copies the range [first,last) into result.
* @ingroup mutating_algorithms
* @param __first A bidirectional iterator.
* @param __last A bidirectional iterator.
* @param __result A bidirectional iterator.
* @return result - (last - first)
*
* The function has the same effect as copy, but starts at the end of the
* range and works its way to the start, returning the start of the result.
* This inline function will boil down to a call to @c memmove whenever
* possible. Failing that, if random access iterators are passed, then the
* loop count will be known (and therefore a candidate for compiler
* optimizations such as unrolling).
*
* Result may not be in the range (first,last]. Use copy instead. Note
* that the start of the output range may overlap [first,last).
*/
template<typename _BI1, typename _BI2>
_GLIBCXX20_CONSTEXPR
inline _BI2
copy_backward(_BI1 __first, _BI1 __last, _BI2 __result)
{
// concept requirements
__glibcxx_function_requires(_BidirectionalIteratorConcept<_BI1>)
__glibcxx_function_requires(_Mutable_BidirectionalIteratorConcept<_BI2>)
__glibcxx_function_requires(_ConvertibleConcept<
typename iterator_traits<_BI1>::value_type,
typename iterator_traits<_BI2>::value_type>)
__glibcxx_requires_can_decrement_range(__first, __last, __result);
return std::__copy_move_backward_a<__is_move_iterator<_BI1>::__value>
(std::__miter_base(__first), std::__miter_base(__last), __result);
}
#if __cplusplus >= 201103L
/**
* @brief Moves the range [first,last) into result.
* @ingroup mutating_algorithms
* @param __first A bidirectional iterator.
* @param __last A bidirectional iterator.
* @param __result A bidirectional iterator.
* @return result - (last - first)
*
* The function has the same effect as move, but starts at the end of the
* range and works its way to the start, returning the start of the result.
* This inline function will boil down to a call to @c memmove whenever
* possible. Failing that, if random access iterators are passed, then the
* loop count will be known (and therefore a candidate for compiler
* optimizations such as unrolling).
*
* Result may not be in the range (first,last]. Use move instead. Note
* that the start of the output range may overlap [first,last).
*/
template<typename _BI1, typename _BI2>
_GLIBCXX20_CONSTEXPR
inline _BI2
move_backward(_BI1 __first, _BI1 __last, _BI2 __result)
{
// concept requirements
__glibcxx_function_requires(_BidirectionalIteratorConcept<_BI1>)
__glibcxx_function_requires(_Mutable_BidirectionalIteratorConcept<_BI2>)
__glibcxx_function_requires(_ConvertibleConcept<
typename iterator_traits<_BI1>::value_type,
typename iterator_traits<_BI2>::value_type>)
__glibcxx_requires_can_decrement_range(__first, __last, __result);
return std::__copy_move_backward_a<true>(std::__miter_base(__first),
std::__miter_base(__last),
__result);
}
#define _GLIBCXX_MOVE_BACKWARD3(_Tp, _Up, _Vp) std::move_backward(_Tp, _Up, _Vp)
#else
#define _GLIBCXX_MOVE_BACKWARD3(_Tp, _Up, _Vp) std::copy_backward(_Tp, _Up, _Vp)
#endif
template<typename _ForwardIterator, typename _Tp>
_GLIBCXX20_CONSTEXPR
inline typename
__gnu_cxx::__enable_if<!__is_scalar<_Tp>::__value, void>::__type
__fill_a1(_ForwardIterator __first, _ForwardIterator __last,
const _Tp& __value)
{
for (; __first != __last; ++__first)
*__first = __value;
}
template<typename _ForwardIterator, typename _Tp>
_GLIBCXX20_CONSTEXPR
inline typename
__gnu_cxx::__enable_if<__is_scalar<_Tp>::__value, void>::__type
__fill_a1(_ForwardIterator __first, _ForwardIterator __last,
const _Tp& __value)
{
const _Tp __tmp = __value;
for (; __first != __last; ++__first)
*__first = __tmp;
}
// Specialization: for char types we can use memset.
template<typename _Tp>
_GLIBCXX20_CONSTEXPR
inline typename
__gnu_cxx::__enable_if<__is_byte<_Tp>::__value, void>::__type
__fill_a1(_Tp* __first, _Tp* __last, const _Tp& __c)
{
const _Tp __tmp = __c;
#if __cpp_lib_is_constant_evaluated
if (std::is_constant_evaluated())
{
for (; __first != __last; ++__first)
*__first = __tmp;
return;
}
#endif
if (const size_t __len = __last - __first)
__builtin_memset(__first, static_cast<unsigned char>(__tmp), __len);
}
template<typename _Ite, typename _Cont, typename _Tp>
_GLIBCXX20_CONSTEXPR
inline void
__fill_a1(::__gnu_cxx::__normal_iterator<_Ite, _Cont> __first,
::__gnu_cxx::__normal_iterator<_Ite, _Cont> __last,
const _Tp& __value)
{ std::__fill_a1(__first.base(), __last.base(), __value); }
template<typename _Tp, typename _VTp>
void
__fill_a1(const _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Tp&, _Tp*>&,
const _GLIBCXX_STD_C::_Deque_iterator<_Tp, _Tp&, _Tp*>&,
const _VTp&);
template<typename _FIte, typename _Tp>
_GLIBCXX20_CONSTEXPR
inline void
__fill_a(_FIte __first, _FIte __last, const _Tp& __value)
{ std::__fill_a1(__first, __last, __value); }
template<typename _Ite, typename _Seq, typename _Cat, typename _Tp>
void
__fill_a(const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>&,
const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>&,
const _Tp&);
/**
* @brief Fills the range [first,last) with copies of value.
* @ingroup mutating_algorithms
* @param __first A forward iterator.
* @param __last A forward iterator.
* @param __value A reference-to-const of arbitrary type.
* @return Nothing.
*
* This function fills a range with copies of the same value. For char
* types filling contiguous areas of memory, this becomes an inline call
* to @c memset or @c wmemset.
*/
template<typename _ForwardIterator, typename _Tp>
_GLIBCXX20_CONSTEXPR
inline void
fill(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value)
{
// concept requirements
__glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
_ForwardIterator>)
__glibcxx_requires_valid_range(__first, __last);
std::__fill_a(__first, __last, __value);
}
// Used by fill_n, generate_n, etc. to convert _Size to an integral type:
inline _GLIBCXX_CONSTEXPR int
__size_to_integer(int __n) { return __n; }
inline _GLIBCXX_CONSTEXPR unsigned
__size_to_integer(unsigned __n) { return __n; }
inline _GLIBCXX_CONSTEXPR long
__size_to_integer(long __n) { return __n; }
inline _GLIBCXX_CONSTEXPR unsigned long
__size_to_integer(unsigned long __n) { return __n; }
inline _GLIBCXX_CONSTEXPR long long
__size_to_integer(long long __n) { return __n; }
inline _GLIBCXX_CONSTEXPR unsigned long long
__size_to_integer(unsigned long long __n) { return __n; }
#if defined(__GLIBCXX_TYPE_INT_N_0)
inline _GLIBCXX_CONSTEXPR __GLIBCXX_TYPE_INT_N_0
__size_to_integer(__GLIBCXX_TYPE_INT_N_0 __n) { return __n; }
inline _GLIBCXX_CONSTEXPR unsigned __GLIBCXX_TYPE_INT_N_0
__size_to_integer(unsigned __GLIBCXX_TYPE_INT_N_0 __n) { return __n; }
#endif
#if defined(__GLIBCXX_TYPE_INT_N_1)
inline _GLIBCXX_CONSTEXPR __GLIBCXX_TYPE_INT_N_1
__size_to_integer(__GLIBCXX_TYPE_INT_N_1 __n) { return __n; }
inline _GLIBCXX_CONSTEXPR unsigned __GLIBCXX_TYPE_INT_N_1
__size_to_integer(unsigned __GLIBCXX_TYPE_INT_N_1 __n) { return __n; }
#endif
#if defined(__GLIBCXX_TYPE_INT_N_2)
inline _GLIBCXX_CONSTEXPR __GLIBCXX_TYPE_INT_N_2
__size_to_integer(__GLIBCXX_TYPE_INT_N_2 __n) { return __n; }
inline _GLIBCXX_CONSTEXPR unsigned __GLIBCXX_TYPE_INT_N_2
__size_to_integer(unsigned __GLIBCXX_TYPE_INT_N_2 __n) { return __n; }
#endif
#if defined(__GLIBCXX_TYPE_INT_N_3)
inline _GLIBCXX_CONSTEXPR unsigned __GLIBCXX_TYPE_INT_N_3
__size_to_integer(__GLIBCXX_TYPE_INT_N_3 __n) { return __n; }
inline _GLIBCXX_CONSTEXPR __GLIBCXX_TYPE_INT_N_3
__size_to_integer(unsigned __GLIBCXX_TYPE_INT_N_3 __n) { return __n; }
#endif
inline _GLIBCXX_CONSTEXPR long long
__size_to_integer(float __n) { return (long long)__n; }
inline _GLIBCXX_CONSTEXPR long long
__size_to_integer(double __n) { return (long long)__n; }
inline _GLIBCXX_CONSTEXPR long long
__size_to_integer(long double __n) { return (long long)__n; }
#if !defined(__STRICT_ANSI__) && defined(_GLIBCXX_USE_FLOAT128)
inline _GLIBCXX_CONSTEXPR long long
__size_to_integer(__float128 __n) { return (long long)__n; }
#endif
template<typename _OutputIterator, typename _Size, typename _Tp>
_GLIBCXX20_CONSTEXPR
inline typename
__gnu_cxx::__enable_if<!__is_scalar<_Tp>::__value, _OutputIterator>::__type
__fill_n_a1(_OutputIterator __first, _Size __n, const _Tp& __value)
{
for (; __n > 0; --__n, (void) ++__first)
*__first = __value;
return __first;
}
template<typename _OutputIterator, typename _Size, typename _Tp>
_GLIBCXX20_CONSTEXPR
inline typename
__gnu_cxx::__enable_if<__is_scalar<_Tp>::__value, _OutputIterator>::__type
__fill_n_a1(_OutputIterator __first, _Size __n, const _Tp& __value)
{
const _Tp __tmp = __value;
for (; __n > 0; --__n, (void) ++__first)
*__first = __tmp;
return __first;
}
template<typename _Ite, typename _Seq, typename _Cat, typename _Size,
typename _Tp>
::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>
__fill_n_a(const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>& __first,
_Size __n, const _Tp& __value,
std::input_iterator_tag);
template<typename _OutputIterator, typename _Size, typename _Tp>
_GLIBCXX20_CONSTEXPR
inline _OutputIterator
__fill_n_a(_OutputIterator __first, _Size __n, const _Tp& __value,
std::output_iterator_tag)
{
#if __cplusplus >= 201103L
static_assert(is_integral<_Size>{}, "fill_n must pass integral size");
#endif
return __fill_n_a1(__first, __n, __value);
}
template<typename _OutputIterator, typename _Size, typename _Tp>
_GLIBCXX20_CONSTEXPR
inline _OutputIterator
__fill_n_a(_OutputIterator __first, _Size __n, const _Tp& __value,
std::input_iterator_tag)
{
#if __cplusplus >= 201103L
static_assert(is_integral<_Size>{}, "fill_n must pass integral size");
#endif
return __fill_n_a1(__first, __n, __value);
}
template<typename _OutputIterator, typename _Size, typename _Tp>
_GLIBCXX20_CONSTEXPR
inline _OutputIterator
__fill_n_a(_OutputIterator __first, _Size __n, const _Tp& __value,
std::random_access_iterator_tag)
{
#if __cplusplus >= 201103L
static_assert(is_integral<_Size>{}, "fill_n must pass integral size");
#endif
if (__n <= 0)
return __first;
__glibcxx_requires_can_increment(__first, __n);
std::__fill_a(__first, __first + __n, __value);
return __first + __n;
}
/**
* @brief Fills the range [first,first+n) with copies of value.
* @ingroup mutating_algorithms
* @param __first An output iterator.
* @param __n The count of copies to perform.
* @param __value A reference-to-const of arbitrary type.
* @return The iterator at first+n.
*
* This function fills a range with copies of the same value. For char
* types filling contiguous areas of memory, this becomes an inline call
* to @c memset or @c wmemset.
*
* If @p __n is negative, the function does nothing.
*/
// _GLIBCXX_RESOLVE_LIB_DEFECTS
// DR 865. More algorithms that throw away information
// DR 426. search_n(), fill_n(), and generate_n() with negative n
template<typename _OI, typename _Size, typename _Tp>
_GLIBCXX20_CONSTEXPR
inline _OI
fill_n(_OI __first, _Size __n, const _Tp& __value)
{
// concept requirements
__glibcxx_function_requires(_OutputIteratorConcept<_OI, _Tp>)
return std::__fill_n_a(__first, std::__size_to_integer(__n), __value,
std::__iterator_category(__first));
}
template<bool _BoolType>
struct __equal
{
template<typename _II1, typename _II2>
_GLIBCXX20_CONSTEXPR
static bool
equal(_II1 __first1, _II1 __last1, _II2 __first2)
{
for (; __first1 != __last1; ++__first1, (void) ++__first2)
if (!(*__first1 == *__first2))
return false;
return true;
}
};
template<>
struct __equal<true>
{
template<typename _Tp>
_GLIBCXX20_CONSTEXPR
static bool
equal(const _Tp* __first1, const _Tp* __last1, const _Tp* __first2)
{
if (const size_t __len = (__last1 - __first1))
return !std::__memcmp(__first1, __first2, __len);
return true;
}
};
template<typename _Tp, typename _Ref, typename _Ptr, typename _II>
typename __gnu_cxx::__enable_if<
__is_random_access_iter<_II>::__value, bool>::__type
__equal_aux1(_GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr>,
_GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr>,
_II);
template<typename _Tp1, typename _Ref1, typename _Ptr1,
typename _Tp2, typename _Ref2, typename _Ptr2>
bool
__equal_aux1(_GLIBCXX_STD_C::_Deque_iterator<_Tp1, _Ref1, _Ptr1>,
_GLIBCXX_STD_C::_Deque_iterator<_Tp1, _Ref1, _Ptr1>,
_GLIBCXX_STD_C::_Deque_iterator<_Tp2, _Ref2, _Ptr2>);
template<typename _II, typename _Tp, typename _Ref, typename _Ptr>
typename __gnu_cxx::__enable_if<
__is_random_access_iter<_II>::__value, bool>::__type
__equal_aux1(_II, _II,
_GLIBCXX_STD_C::_Deque_iterator<_Tp, _Ref, _Ptr>);
template<typename _II1, typename _II2>
_GLIBCXX20_CONSTEXPR
inline bool
__equal_aux1(_II1 __first1, _II1 __last1, _II2 __first2)
{
typedef typename iterator_traits<_II1>::value_type _ValueType1;
const bool __simple = ((__is_integer<_ValueType1>::__value
|| __is_pointer<_ValueType1>::__value)
&& __memcmpable<_II1, _II2>::__value);
return std::__equal<__simple>::equal(__first1, __last1, __first2);
}
template<typename _II1, typename _II2>
_GLIBCXX20_CONSTEXPR
inline bool
__equal_aux(_II1 __first1, _II1 __last1, _II2 __first2)
{
return std::__equal_aux1(std::__niter_base(__first1),
std::__niter_base(__last1),
std::__niter_base(__first2));
}
template<typename _II1, typename _Seq1, typename _Cat1, typename _II2>
bool
__equal_aux(const ::__gnu_debug::_Safe_iterator<_II1, _Seq1, _Cat1>&,
const ::__gnu_debug::_Safe_iterator<_II1, _Seq1, _Cat1>&,
_II2);
template<typename _II1, typename _II2, typename _Seq2, typename _Cat2>
bool
__equal_aux(_II1, _II1,
const ::__gnu_debug::_Safe_iterator<_II2, _Seq2, _Cat2>&);
template<typename _II1, typename _Seq1, typename _Cat1,
typename _II2, typename _Seq2, typename _Cat2>
bool
__equal_aux(const ::__gnu_debug::_Safe_iterator<_II1, _Seq1, _Cat1>&,
const ::__gnu_debug::_Safe_iterator<_II1, _Seq1, _Cat1>&,
const ::__gnu_debug::_Safe_iterator<_II2, _Seq2, _Cat2>&);
template<typename, typename>
struct __lc_rai
{
template<typename _II1, typename _II2>
_GLIBCXX20_CONSTEXPR
static _II1
__newlast1(_II1, _II1 __last1, _II2, _II2)
{ return __last1; }
template<typename _II>
_GLIBCXX20_CONSTEXPR
static bool
__cnd2(_II __first, _II __last)
{ return __first != __last; }
};
template<>
struct __lc_rai<random_access_iterator_tag, random_access_iterator_tag>
{
template<typename _RAI1, typename _RAI2>
_GLIBCXX20_CONSTEXPR
static _RAI1
__newlast1(_RAI1 __first1, _RAI1 __last1,
_RAI2 __first2, _RAI2 __last2)
{
const typename iterator_traits<_RAI1>::difference_type
__diff1 = __last1 - __first1;
const typename iterator_traits<_RAI2>::difference_type
__diff2 = __last2 - __first2;
return __diff2 < __diff1 ? __first1 + __diff2 : __last1;
}
template<typename _RAI>
static _GLIBCXX20_CONSTEXPR bool
__cnd2(_RAI, _RAI)
{ return true; }
};
template<typename _II1, typename _II2, typename _Compare>
_GLIBCXX20_CONSTEXPR
bool
__lexicographical_compare_impl(_II1 __first1, _II1 __last1,
_II2 __first2, _II2 __last2,
_Compare __comp)
{
typedef typename iterator_traits<_II1>::iterator_category _Category1;
typedef typename iterator_traits<_II2>::iterator_category _Category2;
typedef std::__lc_rai<_Category1, _Category2> __rai_type;
__last1 = __rai_type::__newlast1(__first1, __last1, __first2, __last2);
for (; __first1 != __last1 && __rai_type::__cnd2(__first2, __last2);
++__first1, (void)++__first2)
{
if (__comp(__first1, __first2))
return true;
if (__comp(__first2, __first1))
return false;
}
return __first1 == __last1 && __first2 != __last2;
}
template<bool _BoolType>
struct __lexicographical_compare
{
template<typename _II1, typename _II2>
_GLIBCXX20_CONSTEXPR
static bool
__lc(_II1 __first1, _II1 __last1, _II2 __first2, _II2 __last2)
{
using __gnu_cxx::__ops::__iter_less_iter;
return std::__lexicographical_compare_impl(__first1, __last1,
__first2, __last2,
__iter_less_iter());
}
};
template<>
struct __lexicographical_compare<true>
{
template<typename _Tp, typename _Up>
_GLIBCXX20_CONSTEXPR
static bool
__lc(const _Tp* __first1, const _Tp* __last1,
const _Up* __first2, const _Up* __last2)
{
const size_t __len1 = __last1 - __first1;
const size_t __len2 = __last2 - __first2;
if (const size_t __len = std::min(__len1, __len2))
if (int __result = std::__memcmp(__first1, __first2, __len))
return __result < 0;
return __len1 < __len2;
}
};
template<typename _II1, typename _II2>
_GLIBCXX20_CONSTEXPR
inline bool
__lexicographical_compare_aux(_II1 __first1, _II1 __last1,
_II2 __first2, _II2 __last2)
{
typedef typename iterator_traits<_II1>::value_type _ValueType1;
typedef typename iterator_traits<_II2>::value_type _ValueType2;
const bool __simple =
(__is_memcmp_ordered_with<_ValueType1, _ValueType2>::__value
&& __is_pointer<_II1>::__value
&& __is_pointer<_II2>::__value
#if __cplusplus > 201703L && __cpp_lib_concepts
// For C++20 iterator_traits<volatile T*>::value_type is non-volatile
// so __is_byte<T> could be true, but we can't use memcmp with
// volatile data.
&& !is_volatile_v<remove_reference_t<iter_reference_t<_II1>>>
&& !is_volatile_v<remove_reference_t<iter_reference_t<_II2>>>
#endif
);
return std::__lexicographical_compare<__simple>::__lc(__first1, __last1,
__first2, __last2);
}
template<typename _ForwardIterator, typename _Tp, typename _Compare>
_GLIBCXX20_CONSTEXPR
_ForwardIterator
__lower_bound(_ForwardIterator __first, _ForwardIterator __last,
const _Tp& __val, _Compare __comp)
{
typedef typename iterator_traits<_ForwardIterator>::difference_type
_DistanceType;
_DistanceType __len = std::distance(__first, __last);
while (__len > 0)
{
_DistanceType __half = __len >> 1;
_ForwardIterator __middle = __first;
std::advance(__middle, __half);
if (__comp(__middle, __val))
{
__first = __middle;
++__first;
__len = __len - __half - 1;
}
else
__len = __half;
}
return __first;
}
/**
* @brief Finds the first position in which @a val could be inserted
* without changing the ordering.
* @param __first An iterator.
* @param __last Another iterator.
* @param __val The search term.
* @return An iterator pointing to the first element <em>not less
* than</em> @a val, or end() if every element is less than
* @a val.
* @ingroup binary_search_algorithms
*/
template<typename _ForwardIterator, typename _Tp>
_GLIBCXX20_CONSTEXPR
inline _ForwardIterator
lower_bound(_ForwardIterator __first, _ForwardIterator __last,
const _Tp& __val)
{
// concept requirements
__glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
__glibcxx_function_requires(_LessThanOpConcept<
typename iterator_traits<_ForwardIterator>::value_type, _Tp>)
__glibcxx_requires_partitioned_lower(__first, __last, __val);
return std::__lower_bound(__first, __last, __val,
__gnu_cxx::__ops::__iter_less_val());
}
/// This is a helper function for the sort routines and for random.tcc.
// Precondition: __n > 0.
inline _GLIBCXX_CONSTEXPR int
__lg(int __n)
{ return (int)sizeof(int) * __CHAR_BIT__ - 1 - __builtin_clz(__n); }
inline _GLIBCXX_CONSTEXPR unsigned
__lg(unsigned __n)
{ return (int)sizeof(int) * __CHAR_BIT__ - 1 - __builtin_clz(__n); }
inline _GLIBCXX_CONSTEXPR long
__lg(long __n)
{ return (int)sizeof(long) * __CHAR_BIT__ - 1 - __builtin_clzl(__n); }
inline _GLIBCXX_CONSTEXPR unsigned long
__lg(unsigned long __n)
{ return (int)sizeof(long) * __CHAR_BIT__ - 1 - __builtin_clzl(__n); }
inline _GLIBCXX_CONSTEXPR long long
__lg(long long __n)
{ return (int)sizeof(long long) * __CHAR_BIT__ - 1 - __builtin_clzll(__n); }
inline _GLIBCXX_CONSTEXPR unsigned long long
__lg(unsigned long long __n)
{ return (int)sizeof(long long) * __CHAR_BIT__ - 1 - __builtin_clzll(__n); }
_GLIBCXX_BEGIN_NAMESPACE_ALGO
/**
* @brief Tests a range for element-wise equality.
* @ingroup non_mutating_algorithms
* @param __first1 An input iterator.
* @param __last1 An input iterator.
* @param __first2 An input iterator.
* @return A boolean true or false.
*
* This compares the elements of two ranges using @c == and returns true or
* false depending on whether all of the corresponding elements of the
* ranges are equal.
*/
template<typename _II1, typename _II2>
_GLIBCXX20_CONSTEXPR
inline bool
equal(_II1 __first1, _II1 __last1, _II2 __first2)
{
// concept requirements
__glibcxx_function_requires(_InputIteratorConcept<_II1>)
__glibcxx_function_requires(_InputIteratorConcept<_II2>)
__glibcxx_function_requires(_EqualOpConcept<
typename iterator_traits<_II1>::value_type,
typename iterator_traits<_II2>::value_type>)
__glibcxx_requires_can_increment_range(__first1, __last1, __first2);
return std::__equal_aux(__first1, __last1, __first2);
}
/**
* @brief Tests a range for element-wise equality.
* @ingroup non_mutating_algorithms
* @param __first1 An input iterator.
* @param __last1 An input iterator.
* @param __first2 An input iterator.
* @param __binary_pred A binary predicate @link functors
* functor@endlink.
* @return A boolean true or false.
*
* This compares the elements of two ranges using the binary_pred
* parameter, and returns true or
* false depending on whether all of the corresponding elements of the
* ranges are equal.
*/
template<typename _IIter1, typename _IIter2, typename _BinaryPredicate>
_GLIBCXX20_CONSTEXPR
inline bool
equal(_IIter1 __first1, _IIter1 __last1,
_IIter2 __first2, _BinaryPredicate __binary_pred)
{
// concept requirements
__glibcxx_function_requires(_InputIteratorConcept<_IIter1>)
__glibcxx_function_requires(_InputIteratorConcept<_IIter2>)
__glibcxx_requires_valid_range(__first1, __last1);
for (; __first1 != __last1; ++__first1, (void)++__first2)
if (!bool(__binary_pred(*__first1, *__first2)))
return false;
return true;
}
#if __cplusplus >= 201103L
// 4-iterator version of std::equal<It1, It2> for use in C++11.
template<typename _II1, typename _II2>
_GLIBCXX20_CONSTEXPR
inline bool
__equal4(_II1 __first1, _II1 __last1, _II2 __first2, _II2 __last2)
{
using _RATag = random_access_iterator_tag;
using _Cat1 = typename iterator_traits<_II1>::iterator_category;
using _Cat2 = typename iterator_traits<_II2>::iterator_category;
using _RAIters = __and_<is_same<_Cat1, _RATag>, is_same<_Cat2, _RATag>>;
if (_RAIters())
{
auto __d1 = std::distance(__first1, __last1);
auto __d2 = std::distance(__first2, __last2);
if (__d1 != __d2)
return false;
return _GLIBCXX_STD_A::equal(__first1, __last1, __first2);
}
for (; __first1 != __last1 && __first2 != __last2;
++__first1, (void)++__first2)
if (!(*__first1 == *__first2))
return false;
return __first1 == __last1 && __first2 == __last2;
}
// 4-iterator version of std::equal<It1, It2, BinaryPred> for use in C++11.
template<typename _II1, typename _II2, typename _BinaryPredicate>
_GLIBCXX20_CONSTEXPR
inline bool
__equal4(_II1 __first1, _II1 __last1, _II2 __first2, _II2 __last2,
_BinaryPredicate __binary_pred)
{
using _RATag = random_access_iterator_tag;
using _Cat1 = typename iterator_traits<_II1>::iterator_category;
using _Cat2 = typename iterator_traits<_II2>::iterator_category;
using _RAIters = __and_<is_same<_Cat1, _RATag>, is_same<_Cat2, _RATag>>;
if (_RAIters())
{
auto __d1 = std::distance(__first1, __last1);
auto __d2 = std::distance(__first2, __last2);
if (__d1 != __d2)
return false;
return _GLIBCXX_STD_A::equal(__first1, __last1, __first2,
__binary_pred);
}
for (; __first1 != __last1 && __first2 != __last2;
++__first1, (void)++__first2)
if (!bool(__binary_pred(*__first1, *__first2)))
return false;
return __first1 == __last1 && __first2 == __last2;
}
#endif // C++11
#if __cplusplus > 201103L
#define __cpp_lib_robust_nonmodifying_seq_ops 201304
/**
* @brief Tests a range for element-wise equality.
* @ingroup non_mutating_algorithms
* @param __first1 An input iterator.
* @param __last1 An input iterator.
* @param __first2 An input iterator.
* @param __last2 An input iterator.
* @return A boolean true or false.
*
* This compares the elements of two ranges using @c == and returns true or
* false depending on whether all of the corresponding elements of the
* ranges are equal.
*/
template<typename _II1, typename _II2>
_GLIBCXX20_CONSTEXPR
inline bool
equal(_II1 __first1, _II1 __last1, _II2 __first2, _II2 __last2)
{
// concept requirements
__glibcxx_function_requires(_InputIteratorConcept<_II1>)
__glibcxx_function_requires(_InputIteratorConcept<_II2>)
__glibcxx_function_requires(_EqualOpConcept<
typename iterator_traits<_II1>::value_type,
typename iterator_traits<_II2>::value_type>)
__glibcxx_requires_valid_range(__first1, __last1);
__glibcxx_requires_valid_range(__first2, __last2);
return _GLIBCXX_STD_A::__equal4(__first1, __last1, __first2, __last2);
}
/**
* @brief Tests a range for element-wise equality.
* @ingroup non_mutating_algorithms
* @param __first1 An input iterator.
* @param __last1 An input iterator.
* @param __first2 An input iterator.
* @param __last2 An input iterator.
* @param __binary_pred A binary predicate @link functors
* functor@endlink.
* @return A boolean true or false.
*
* This compares the elements of two ranges using the binary_pred
* parameter, and returns true or
* false depending on whether all of the corresponding elements of the
* ranges are equal.
*/
template<typename _IIter1, typename _IIter2, typename _BinaryPredicate>
_GLIBCXX20_CONSTEXPR
inline bool
equal(_IIter1 __first1, _IIter1 __last1,
_IIter2 __first2, _IIter2 __last2, _BinaryPredicate __binary_pred)
{
// concept requirements
__glibcxx_function_requires(_InputIteratorConcept<_IIter1>)
__glibcxx_function_requires(_InputIteratorConcept<_IIter2>)
__glibcxx_requires_valid_range(__first1, __last1);
__glibcxx_requires_valid_range(__first2, __last2);
return _GLIBCXX_STD_A::__equal4(__first1, __last1, __first2, __last2,
__binary_pred);
}
#endif // C++14
/**
* @brief Performs @b dictionary comparison on ranges.
* @ingroup sorting_algorithms
* @param __first1 An input iterator.
* @param __last1 An input iterator.
* @param __first2 An input iterator.
* @param __last2 An input iterator.
* @return A boolean true or false.
*
* <em>Returns true if the sequence of elements defined by the range
* [first1,last1) is lexicographically less than the sequence of elements
* defined by the range [first2,last2). Returns false otherwise.</em>
* (Quoted from [25.3.8]/1.) If the iterators are all character pointers,
* then this is an inline call to @c memcmp.
*/
template<typename _II1, typename _II2>
_GLIBCXX20_CONSTEXPR
inline bool
lexicographical_compare(_II1 __first1, _II1 __last1,
_II2 __first2, _II2 __last2)
{
#ifdef _GLIBCXX_CONCEPT_CHECKS
// concept requirements
typedef typename iterator_traits<_II1>::value_type _ValueType1;
typedef typename iterator_traits<_II2>::value_type _ValueType2;
#endif
__glibcxx_function_requires(_InputIteratorConcept<_II1>)
__glibcxx_function_requires(_InputIteratorConcept<_II2>)
__glibcxx_function_requires(_LessThanOpConcept<_ValueType1, _ValueType2>)
__glibcxx_function_requires(_LessThanOpConcept<_ValueType2, _ValueType1>)
__glibcxx_requires_valid_range(__first1, __last1);
__glibcxx_requires_valid_range(__first2, __last2);
return std::__lexicographical_compare_aux(std::__niter_base(__first1),
std::__niter_base(__last1),
std::__niter_base(__first2),
std::__niter_base(__last2));
}
/**
* @brief Performs @b dictionary comparison on ranges.
* @ingroup sorting_algorithms
* @param __first1 An input iterator.
* @param __last1 An input iterator.
* @param __first2 An input iterator.
* @param __last2 An input iterator.
* @param __comp A @link comparison_functors comparison functor@endlink.
* @return A boolean true or false.
*
* The same as the four-parameter @c lexicographical_compare, but uses the
* comp parameter instead of @c <.
*/
template<typename _II1, typename _II2, typename _Compare>
_GLIBCXX20_CONSTEXPR
inline bool
lexicographical_compare(_II1 __first1, _II1 __last1,
_II2 __first2, _II2 __last2, _Compare __comp)
{
// concept requirements
__glibcxx_function_requires(_InputIteratorConcept<_II1>)
__glibcxx_function_requires(_InputIteratorConcept<_II2>)
__glibcxx_requires_valid_range(__first1, __last1);
__glibcxx_requires_valid_range(__first2, __last2);
return std::__lexicographical_compare_impl
(__first1, __last1, __first2, __last2,
__gnu_cxx::__ops::__iter_comp_iter(__comp));
}
#if __cpp_lib_three_way_comparison
// Iter points to a contiguous range of unsigned narrow character type
// or std::byte, suitable for comparison by memcmp.
template<typename _Iter>
concept __is_byte_iter = contiguous_iterator<_Iter>
&& __is_memcmp_ordered<iter_value_t<_Iter>>::__value;
// Return a struct with two members, initialized to the smaller of x and y
// (or x if they compare equal) and the result of the comparison x <=> y.
template<typename _Tp>
constexpr auto
__min_cmp(_Tp __x, _Tp __y)
{
struct _Res {
_Tp _M_min;
decltype(__x <=> __y) _M_cmp;
};
auto __c = __x <=> __y;
if (__c > 0)
return _Res{__y, __c};
return _Res{__x, __c};
}
/**
* @brief Performs dictionary comparison on ranges.
* @ingroup sorting_algorithms
* @param __first1 An input iterator.
* @param __last1 An input iterator.
* @param __first2 An input iterator.
* @param __last2 An input iterator.
* @param __comp A @link comparison_functors comparison functor@endlink.
* @return The comparison category that `__comp(*__first1, *__first2)`
* returns.
*/
template<typename _InputIter1, typename _InputIter2, typename _Comp>
constexpr auto
lexicographical_compare_three_way(_InputIter1 __first1,
_InputIter1 __last1,
_InputIter2 __first2,
_InputIter2 __last2,
_Comp __comp)
-> decltype(__comp(*__first1, *__first2))
{
// concept requirements
__glibcxx_function_requires(_InputIteratorConcept<_InputIter1>)
__glibcxx_function_requires(_InputIteratorConcept<_InputIter2>)
__glibcxx_requires_valid_range(__first1, __last1);
__glibcxx_requires_valid_range(__first2, __last2);
#if __cpp_lib_is_constant_evaluated
using _Cat = decltype(__comp(*__first1, *__first2));
static_assert(same_as<common_comparison_category_t<_Cat>, _Cat>);
if (!std::is_constant_evaluated())
if constexpr (same_as<_Comp, __detail::_Synth3way>
|| same_as<_Comp, compare_three_way>)
if constexpr (__is_byte_iter<_InputIter1>)
if constexpr (__is_byte_iter<_InputIter2>)
{
const auto [__len, __lencmp]
= std::__min_cmp(__last1 - __first1, __last2 - __first2);
if (__len)
{
const auto __c
= __builtin_memcmp(&*__first1, &*__first2, __len) <=> 0;
if (__c != 0)
return __c;
}
return __lencmp;
}
#endif // is_constant_evaluated
while (__first1 != __last1)
{
if (__first2 == __last2)
return strong_ordering::greater;
if (auto __cmp = __comp(*__first1, *__first2); __cmp != 0)
return __cmp;
++__first1;
++__first2;
}
return (__first2 == __last2) <=> true; // See PR 94006
}
template<typename _InputIter1, typename _InputIter2>
constexpr auto
lexicographical_compare_three_way(_InputIter1 __first1,
_InputIter1 __last1,
_InputIter2 __first2,
_InputIter2 __last2)
{
return std::lexicographical_compare_three_way(__first1, __last1,
__first2, __last2,
compare_three_way{});
}
#endif // three_way_comparison
template<typename _InputIterator1, typename _InputIterator2,
typename _BinaryPredicate>
_GLIBCXX20_CONSTEXPR
pair<_InputIterator1, _InputIterator2>
__mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
_InputIterator2 __first2, _BinaryPredicate __binary_pred)
{
while (__first1 != __last1 && __binary_pred(__first1, __first2))
{
++__first1;
++__first2;
}
return pair<_InputIterator1, _InputIterator2>(__first1, __first2);
}
/**
* @brief Finds the places in ranges which don't match.
* @ingroup non_mutating_algorithms
* @param __first1 An input iterator.
* @param __last1 An input iterator.
* @param __first2 An input iterator.
* @return A pair of iterators pointing to the first mismatch.
*
* This compares the elements of two ranges using @c == and returns a pair
* of iterators. The first iterator points into the first range, the
* second iterator points into the second range, and the elements pointed
* to by the iterators are not equal.
*/
template<typename _InputIterator1, typename _InputIterator2>
_GLIBCXX20_CONSTEXPR
inline pair<_InputIterator1, _InputIterator2>
mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
_InputIterator2 __first2)
{
// concept requirements
__glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
__glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
__glibcxx_function_requires(_EqualOpConcept<
typename iterator_traits<_InputIterator1>::value_type,
typename iterator_traits<_InputIterator2>::value_type>)
__glibcxx_requires_valid_range(__first1, __last1);
return _GLIBCXX_STD_A::__mismatch(__first1, __last1, __first2,
__gnu_cxx::__ops::__iter_equal_to_iter());
}
/**
* @brief Finds the places in ranges which don't match.
* @ingroup non_mutating_algorithms
* @param __first1 An input iterator.
* @param __last1 An input iterator.
* @param __first2 An input iterator.
* @param __binary_pred A binary predicate @link functors
* functor@endlink.
* @return A pair of iterators pointing to the first mismatch.
*
* This compares the elements of two ranges using the binary_pred
* parameter, and returns a pair
* of iterators. The first iterator points into the first range, the
* second iterator points into the second range, and the elements pointed
* to by the iterators are not equal.
*/
template<typename _InputIterator1, typename _InputIterator2,
typename _BinaryPredicate>
_GLIBCXX20_CONSTEXPR
inline pair<_InputIterator1, _InputIterator2>
mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
_InputIterator2 __first2, _BinaryPredicate __binary_pred)
{
// concept requirements
__glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
__glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
__glibcxx_requires_valid_range(__first1, __last1);
return _GLIBCXX_STD_A::__mismatch(__first1, __last1, __first2,
__gnu_cxx::__ops::__iter_comp_iter(__binary_pred));
}
#if __cplusplus > 201103L
template<typename _InputIterator1, typename _InputIterator2,
typename _BinaryPredicate>
_GLIBCXX20_CONSTEXPR
pair<_InputIterator1, _InputIterator2>
__mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
_InputIterator2 __first2, _InputIterator2 __last2,
_BinaryPredicate __binary_pred)
{
while (__first1 != __last1 && __first2 != __last2
&& __binary_pred(__first1, __first2))
{
++__first1;
++__first2;
}
return pair<_InputIterator1, _InputIterator2>(__first1, __first2);
}
/**
* @brief Finds the places in ranges which don't match.
* @ingroup non_mutating_algorithms
* @param __first1 An input iterator.
* @param __last1 An input iterator.
* @param __first2 An input iterator.
* @param __last2 An input iterator.
* @return A pair of iterators pointing to the first mismatch.
*
* This compares the elements of two ranges using @c == and returns a pair
* of iterators. The first iterator points into the first range, the
* second iterator points into the second range, and the elements pointed
* to by the iterators are not equal.
*/
template<typename _InputIterator1, typename _InputIterator2>
_GLIBCXX20_CONSTEXPR
inline pair<_InputIterator1, _InputIterator2>
mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
_InputIterator2 __first2, _InputIterator2 __last2)
{
// concept requirements
__glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
__glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
__glibcxx_function_requires(_EqualOpConcept<
typename iterator_traits<_InputIterator1>::value_type,
typename iterator_traits<_InputIterator2>::value_type>)
__glibcxx_requires_valid_range(__first1, __last1);
__glibcxx_requires_valid_range(__first2, __last2);
return _GLIBCXX_STD_A::__mismatch(__first1, __last1, __first2, __last2,
__gnu_cxx::__ops::__iter_equal_to_iter());
}
/**
* @brief Finds the places in ranges which don't match.
* @ingroup non_mutating_algorithms
* @param __first1 An input iterator.
* @param __last1 An input iterator.
* @param __first2 An input iterator.
* @param __last2 An input iterator.
* @param __binary_pred A binary predicate @link functors
* functor@endlink.
* @return A pair of iterators pointing to the first mismatch.
*
* This compares the elements of two ranges using the binary_pred
* parameter, and returns a pair
* of iterators. The first iterator points into the first range, the
* second iterator points into the second range, and the elements pointed
* to by the iterators are not equal.
*/
template<typename _InputIterator1, typename _InputIterator2,
typename _BinaryPredicate>
_GLIBCXX20_CONSTEXPR
inline pair<_InputIterator1, _InputIterator2>
mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
_InputIterator2 __first2, _InputIterator2 __last2,
_BinaryPredicate __binary_pred)
{
// concept requirements
__glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
__glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
__glibcxx_requires_valid_range(__first1, __last1);
__glibcxx_requires_valid_range(__first2, __last2);
return _GLIBCXX_STD_A::__mismatch(__first1, __last1, __first2, __last2,
__gnu_cxx::__ops::__iter_comp_iter(__binary_pred));
}
#endif
_GLIBCXX_END_NAMESPACE_ALGO
/// This is an overload used by find algos for the Input Iterator case.
template<typename _InputIterator, typename _Predicate>
_GLIBCXX20_CONSTEXPR
inline _InputIterator
__find_if(_InputIterator __first, _InputIterator __last,
_Predicate __pred, input_iterator_tag)
{
while (__first != __last && !__pred(__first))
++__first;
return __first;
}
/// This is an overload used by find algos for the RAI case.
template<typename _RandomAccessIterator, typename _Predicate>
_GLIBCXX20_CONSTEXPR
_RandomAccessIterator
__find_if(_RandomAccessIterator __first, _RandomAccessIterator __last,
_Predicate __pred, random_access_iterator_tag)
{
typename iterator_traits<_RandomAccessIterator>::difference_type
__trip_count = (__last - __first) >> 2;
for (; __trip_count > 0; --__trip_count)
{
if (__pred(__first))
return __first;
++__first;
if (__pred(__first))
return __first;
++__first;
if (__pred(__first))
return __first;
++__first;
if (__pred(__first))
return __first;
++__first;
}
switch (__last - __first)
{
case 3:
if (__pred(__first))
return __first;
++__first;
// FALLTHRU
case 2:
if (__pred(__first))
return __first;
++__first;
// FALLTHRU
case 1:
if (__pred(__first))
return __first;
++__first;
// FALLTHRU
case 0:
default:
return __last;
}
}
template<typename _Iterator, typename _Predicate>
_GLIBCXX20_CONSTEXPR
inline _Iterator
__find_if(_Iterator __first, _Iterator __last, _Predicate __pred)
{
return __find_if(__first, __last, __pred,
std::__iterator_category(__first));
}
template<typename _InputIterator, typename _Predicate>
_GLIBCXX20_CONSTEXPR
typename iterator_traits<_InputIterator>::difference_type
__count_if(_InputIterator __first, _InputIterator __last, _Predicate __pred)
{
typename iterator_traits<_InputIterator>::difference_type __n = 0;
for (; __first != __last; ++__first)
if (__pred(__first))
++__n;
return __n;
}
#if __cplusplus >= 201103L
template<typename _ForwardIterator1, typename _ForwardIterator2,
typename _BinaryPredicate>
_GLIBCXX20_CONSTEXPR
bool
__is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
_ForwardIterator2 __first2, _BinaryPredicate __pred)
{
// Efficiently compare identical prefixes: O(N) if sequences
// have the same elements in the same order.
for (; __first1 != __last1; ++__first1, (void)++__first2)
if (!__pred(__first1, __first2))
break;
if (__first1 == __last1)
return true;
// Establish __last2 assuming equal ranges by iterating over the
// rest of the list.
_ForwardIterator2 __last2 = __first2;
std::advance(__last2, std::distance(__first1, __last1));
for (_ForwardIterator1 __scan = __first1; __scan != __last1; ++__scan)
{
if (__scan != std::__find_if(__first1, __scan,
__gnu_cxx::__ops::__iter_comp_iter(__pred, __scan)))
continue; // We've seen this one before.
auto __matches
= std::__count_if(__first2, __last2,
__gnu_cxx::__ops::__iter_comp_iter(__pred, __scan));
if (0 == __matches ||
std::__count_if(__scan, __last1,
__gnu_cxx::__ops::__iter_comp_iter(__pred, __scan))
!= __matches)
return false;
}
return true;
}
/**
* @brief Checks whether a permutation of the second sequence is equal
* to the first sequence.
* @ingroup non_mutating_algorithms
* @param __first1 Start of first range.
* @param __last1 End of first range.
* @param __first2 Start of second range.
* @return true if there exists a permutation of the elements in the range
* [__first2, __first2 + (__last1 - __first1)), beginning with
* ForwardIterator2 begin, such that equal(__first1, __last1, begin)
* returns true; otherwise, returns false.
*/
template<typename _ForwardIterator1, typename _ForwardIterator2>
_GLIBCXX20_CONSTEXPR
inline bool
is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
_ForwardIterator2 __first2)
{
// concept requirements
__glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator1>)
__glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator2>)
__glibcxx_function_requires(_EqualOpConcept<
typename iterator_traits<_ForwardIterator1>::value_type,
typename iterator_traits<_ForwardIterator2>::value_type>)
__glibcxx_requires_valid_range(__first1, __last1);
return std::__is_permutation(__first1, __last1, __first2,
__gnu_cxx::__ops::__iter_equal_to_iter());
}
#endif // C++11
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace std
// NB: This file is included within many other C++ includes, as a way
// of getting the base algorithms. So, make sure that parallel bits
// come in too if requested.
#ifdef _GLIBCXX_PARALLEL
# include <parallel/algobase.h>
#endif
#endif