libstdc++-v3/include/debug/functions.h - gcc - Git at Google

 // Debugging support implementation -*- C++ -*-

 // Copyright (C) 2003-2021 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 debug/functions.h
  *  This file is a GNU debug extension to the Standard C++ Library.
  */

 #ifndef _GLIBCXX_DEBUG_FUNCTIONS_H
 #define _GLIBCXX_DEBUG_FUNCTIONS_H 1

 #include <bits/stl_function.h>	// for less

 #if __cplusplus >= 201103L
 # include <bits/stl_iterator.h>	// for __miter_base
 # include <type_traits>		// for is_lvalue_reference and __conditional_t.
 #endif

 #include <debug/helper_functions.h>
 #include <debug/formatter.h>

 namespace __gnu_debug
 {
   template<typename _Sequence>
     struct _Insert_range_from_self_is_safe
     { enum { __value = 0 }; };

   template<typename _Sequence>
     struct _Is_contiguous_sequence : std::__false_type { };

   /* Checks that [first, last) is a valid range, and then returns
    * __first. This routine is useful when we can't use a separate
    * assertion statement because, e.g., we are in a constructor.
   */
   template<typename _InputIterator>
     inline _InputIterator
     __check_valid_range(const _InputIterator& __first,
 			const _InputIterator& __last,
 			const char* __file,
 			unsigned int __line,
 			const char* __function)
     {
       __glibcxx_check_valid_range_at(__first, __last,
 				     __file, __line, __function);
       return __first;
     }

   /* Handle the case where __other is a pointer to _Sequence::value_type. */
   template<typename _Iterator, typename _Sequence, typename _Category>
     inline bool
     __foreign_iterator_aux4(
 	const _Safe_iterator<_Iterator, _Sequence, _Category>& __it,
 	const typename _Sequence::value_type* __other)
     {
       typedef const typename _Sequence::value_type* _PointerType;
       typedef std::less<_PointerType> _Less;
 #if __cplusplus >= 201103L
       constexpr _Less __l{};
 #else
       const _Less __l = _Less();
 #endif
       const _Sequence* __seq = __it._M_get_sequence();
       const _PointerType __begin = std::__addressof(*__seq->_M_base().begin());
       const _PointerType __end = std::__addressof(*(__seq->_M_base().end()-1));

       // Check whether __other points within the contiguous storage.
       return __l(__other, __begin) || __l(__end, __other);
     }

   /* Fallback overload for when we can't tell, assume it is valid. */
   template<typename _Iterator, typename _Sequence, typename _Category>
     inline bool
     __foreign_iterator_aux4(
 	const _Safe_iterator<_Iterator, _Sequence, _Category>&, ...)
     { return true; }

   /* Handle sequences with contiguous storage */
   template<typename _Iterator, typename _Sequence, typename _Category,
 	   typename _InputIterator>
     inline bool
     __foreign_iterator_aux3(
 	const _Safe_iterator<_Iterator, _Sequence, _Category>& __it,
 	const _InputIterator& __other, const _InputIterator& __other_end,
 	std::__true_type)
     {
       if (__other == __other_end)
 	return true;  // inserting nothing is safe even if not foreign iters
       if (__it._M_get_sequence()->empty())
 	return true;  // can't be self-inserting if self is empty
       return __foreign_iterator_aux4(__it, std::__addressof(*__other));
     }

   /* Handle non-contiguous containers, assume it is valid. */
   template<typename _Iterator, typename _Sequence, typename _Category,
 	   typename _InputIterator>
     inline bool
     __foreign_iterator_aux3(
 	const _Safe_iterator<_Iterator, _Sequence, _Category>&,
 	const _InputIterator&, const _InputIterator&,
 	std::__false_type)
     { return true; }

   /** Handle debug iterators from the same type of container. */
   template<typename _Iterator, typename _Sequence, typename _Category,
 	   typename _OtherIterator>
     inline bool
     __foreign_iterator_aux2(
 	const _Safe_iterator<_Iterator, _Sequence, _Category>& __it,
 	const _Safe_iterator<_OtherIterator, _Sequence, _Category>& __other,
 	const _Safe_iterator<_OtherIterator, _Sequence, _Category>&)
     { return __it._M_get_sequence() != __other._M_get_sequence(); }

   /** Handle debug iterators from different types of container. */
   template<typename _Iterator, typename _Sequence, typename _Category,
 	   typename _OtherIterator, typename _OtherSequence,
 	   typename _OtherCategory>
     inline bool
     __foreign_iterator_aux2(
 	const _Safe_iterator<_Iterator, _Sequence, _Category>&,
 	const _Safe_iterator<_OtherIterator, _OtherSequence,
 			     _OtherCategory>&,
 	const _Safe_iterator<_OtherIterator, _OtherSequence,
 			     _OtherCategory>&)
     { return true; }

   /* Handle non-debug iterators. */
   template<typename _Iterator, typename _Sequence, typename _Category,
 	   typename _InputIterator>
     inline bool
     __foreign_iterator_aux2(
 	const _Safe_iterator<_Iterator, _Sequence, _Category>& __it,
 	const _InputIterator& __other,
 	const _InputIterator& __other_end)
     {
 #if __cplusplus < 201103L
       typedef _Is_contiguous_sequence<_Sequence> __tag;
 #else
       using __lvalref = std::is_lvalue_reference<
 	typename std::iterator_traits<_InputIterator>::reference>;
       using __contiguous = _Is_contiguous_sequence<_Sequence>;
       using __tag = std::__conditional_t<__lvalref::value, __contiguous,
 					 std::__false_type>;
 #endif
       return __foreign_iterator_aux3(__it, __other, __other_end, __tag());
     }

   /* Handle the case where we aren't really inserting a range after all */
   template<typename _Iterator, typename _Sequence, typename _Category,
 	   typename _Integral>
     inline bool
     __foreign_iterator_aux(
 	const _Safe_iterator<_Iterator, _Sequence, _Category>&,
 	_Integral, _Integral, std::__true_type)
     { return true; }

   /* Handle all iterators. */
   template<typename _Iterator, typename _Sequence, typename _Category,
 	   typename _InputIterator>
     inline bool
     __foreign_iterator_aux(
 	const _Safe_iterator<_Iterator, _Sequence, _Category>& __it,
 	_InputIterator __other, _InputIterator __other_end,
 	std::__false_type)
     {
       return _Insert_range_from_self_is_safe<_Sequence>::__value
 	|| __foreign_iterator_aux2(__it, std::__miter_base(__other),
 				   std::__miter_base(__other_end));
     }

   template<typename _Iterator, typename _Sequence, typename _Category,
 	   typename _InputIterator>
     inline bool
     __foreign_iterator(
 	const _Safe_iterator<_Iterator, _Sequence, _Category>& __it,
 	_InputIterator __other, _InputIterator __other_end)
     {
       typedef typename std::__is_integer<_InputIterator>::__type _Integral;
       return __foreign_iterator_aux(__it, __other, __other_end, _Integral());
     }

   // Can't check if an input iterator sequence is sorted, because we
   // can't step through the sequence.
   template<typename _InputIterator>
     _GLIBCXX20_CONSTEXPR
     inline bool
     __check_sorted_aux(const _InputIterator&, const _InputIterator&,
                        std::input_iterator_tag)
     { return true; }

   // Can verify if a forward iterator sequence is in fact sorted using
   // std::__is_sorted
   template<typename _ForwardIterator>
     _GLIBCXX20_CONSTEXPR
     inline bool
     __check_sorted_aux(_ForwardIterator __first, _ForwardIterator __last,
                        std::forward_iterator_tag)
     {
       if (__first == __last)
         return true;

       _ForwardIterator __next = __first;
       for (++__next; __next != __last; __first = __next, (void)++__next)
         if (*__next < *__first)
           return false;

       return true;
     }

   // Can't check if an input iterator sequence is sorted, because we can't step
   // through the sequence.
   template<typename _InputIterator, typename _Predicate>
     _GLIBCXX20_CONSTEXPR
     inline bool
     __check_sorted_aux(const _InputIterator&, const _InputIterator&,
                        _Predicate, std::input_iterator_tag)
     { return true; }

   // Can verify if a forward iterator sequence is in fact sorted using
   // std::__is_sorted
   template<typename _ForwardIterator, typename _Predicate>
     _GLIBCXX20_CONSTEXPR
     inline bool
     __check_sorted_aux(_ForwardIterator __first, _ForwardIterator __last,
                        _Predicate __pred, std::forward_iterator_tag)
     {
       if (__first == __last)
         return true;

       _ForwardIterator __next = __first;
       for (++__next; __next != __last; __first = __next, (void)++__next)
         if (__pred(*__next, *__first))
           return false;

       return true;
     }

   // Determine if a sequence is sorted.
   template<typename _InputIterator>
     _GLIBCXX20_CONSTEXPR
     inline bool
     __check_sorted(const _InputIterator& __first, const _InputIterator& __last)
     {
       return __check_sorted_aux(__first, __last,
 				std::__iterator_category(__first));
     }

   template<typename _InputIterator, typename _Predicate>
     _GLIBCXX20_CONSTEXPR
     inline bool
     __check_sorted(const _InputIterator& __first, const _InputIterator& __last,
                    _Predicate __pred)
     {
       return __check_sorted_aux(__first, __last, __pred,
 				std::__iterator_category(__first));
     }

   template<typename _InputIterator>
     _GLIBCXX20_CONSTEXPR
     inline bool
     __check_sorted_set_aux(const _InputIterator& __first,
 			   const _InputIterator& __last,
 			   std::__true_type)
     { return __check_sorted(__first, __last); }

   template<typename _InputIterator>
     _GLIBCXX20_CONSTEXPR
     inline bool
     __check_sorted_set_aux(const _InputIterator&,
 			   const _InputIterator&,
 			   std::__false_type)
     { return true; }

   template<typename _InputIterator, typename _Predicate>
     _GLIBCXX20_CONSTEXPR
     inline bool
     __check_sorted_set_aux(const _InputIterator& __first,
 			   const _InputIterator& __last,
 			   _Predicate __pred, std::__true_type)
     { return __check_sorted(__first, __last, __pred); }

   template<typename _InputIterator, typename _Predicate>
     _GLIBCXX20_CONSTEXPR
     inline bool
     __check_sorted_set_aux(const _InputIterator&,
 			   const _InputIterator&, _Predicate,
 			   std::__false_type)
     { return true; }

   // ... special variant used in std::merge, std::includes, std::set_*.
   template<typename _InputIterator1, typename _InputIterator2>
     _GLIBCXX20_CONSTEXPR
     inline bool
     __check_sorted_set(const _InputIterator1& __first,
 		       const _InputIterator1& __last,
 		       const _InputIterator2&)
     {
       typedef typename std::iterator_traits<_InputIterator1>::value_type
 	_ValueType1;
       typedef typename std::iterator_traits<_InputIterator2>::value_type
 	_ValueType2;

       typedef typename std::__are_same<_ValueType1, _ValueType2>::__type
 	_SameType;
       return __check_sorted_set_aux(__first, __last, _SameType());
     }

   template<typename _InputIterator1, typename _InputIterator2,
 	   typename _Predicate>
     _GLIBCXX20_CONSTEXPR
     inline bool
     __check_sorted_set(const _InputIterator1& __first,
 		       const _InputIterator1& __last,
 		       const _InputIterator2&, _Predicate __pred)
     {
       typedef typename std::iterator_traits<_InputIterator1>::value_type
 	_ValueType1;
       typedef typename std::iterator_traits<_InputIterator2>::value_type
 	_ValueType2;

       typedef typename std::__are_same<_ValueType1, _ValueType2>::__type
 	_SameType;
       return __check_sorted_set_aux(__first, __last, __pred, _SameType());
    }

   // _GLIBCXX_RESOLVE_LIB_DEFECTS
   // 270. Binary search requirements overly strict
   // Determine if a sequence is partitioned w.r.t. this element.
   template<typename _ForwardIterator, typename _Tp>
     _GLIBCXX20_CONSTEXPR
     inline bool
     __check_partitioned_lower(_ForwardIterator __first,
 			      _ForwardIterator __last, const _Tp& __value)
     {
       while (__first != __last && *__first < __value)
 	++__first;
       if (__first != __last)
 	{
 	  ++__first;
 	  while (__first != __last && !(*__first < __value))
 	    ++__first;
 	}
       return __first == __last;
     }

   template<typename _ForwardIterator, typename _Tp>
     _GLIBCXX20_CONSTEXPR
     inline bool
     __check_partitioned_upper(_ForwardIterator __first,
 			      _ForwardIterator __last, const _Tp& __value)
     {
       while (__first != __last && !(__value < *__first))
 	++__first;
       if (__first != __last)
 	{
 	  ++__first;
 	  while (__first != __last && __value < *__first)
 	    ++__first;
 	}
       return __first == __last;
     }

   // Determine if a sequence is partitioned w.r.t. this element.
   template<typename _ForwardIterator, typename _Tp, typename _Pred>
     _GLIBCXX20_CONSTEXPR
     inline bool
     __check_partitioned_lower(_ForwardIterator __first,
 			      _ForwardIterator __last, const _Tp& __value,
 			      _Pred __pred)
     {
       while (__first != __last && bool(__pred(*__first, __value)))
 	++__first;
       if (__first != __last)
 	{
 	  ++__first;
 	  while (__first != __last && !bool(__pred(*__first, __value)))
 	    ++__first;
 	}
       return __first == __last;
     }

   template<typename _ForwardIterator, typename _Tp, typename _Pred>
     _GLIBCXX20_CONSTEXPR
     inline bool
     __check_partitioned_upper(_ForwardIterator __first,
 			      _ForwardIterator __last, const _Tp& __value,
 			      _Pred __pred)
     {
       while (__first != __last && !bool(__pred(__value, *__first)))
 	++__first;
       if (__first != __last)
 	{
 	  ++__first;
 	  while (__first != __last && bool(__pred(__value, *__first)))
 	    ++__first;
 	}
       return __first == __last;
     }

 #if __cplusplus >= 201103L
   struct _Irreflexive_checker
   {
     template<typename _It>
       static typename std::iterator_traits<_It>::reference
       __ref();

     template<typename _It,
 	     typename = decltype(__ref<_It>() < __ref<_It>())>
       _GLIBCXX20_CONSTEXPR
       static bool
       _S_is_valid(_It __it)
       { return !(*__it < *__it); }

     // Fallback method if operator doesn't exist.
     template<typename... _Args>
       _GLIBCXX20_CONSTEXPR
       static bool
       _S_is_valid(_Args...)
       { return true; }

     template<typename _It, typename _Pred, typename
 	= decltype(std::declval<_Pred>()(__ref<_It>(), __ref<_It>()))>
       _GLIBCXX20_CONSTEXPR
       static bool
       _S_is_valid_pred(_It __it, _Pred __pred)
       { return !__pred(*__it, *__it); }

     // Fallback method if predicate can't be invoked.
     template<typename... _Args>
       _GLIBCXX20_CONSTEXPR
       static bool
       _S_is_valid_pred(_Args...)
       { return true; }
   };

   template<typename _Iterator>
     _GLIBCXX20_CONSTEXPR
     inline bool
     __is_irreflexive(_Iterator __it)
     { return _Irreflexive_checker::_S_is_valid(__it); }

   template<typename _Iterator, typename _Pred>
     _GLIBCXX20_CONSTEXPR
     inline bool
     __is_irreflexive_pred(_Iterator __it, _Pred __pred)
     { return _Irreflexive_checker::_S_is_valid_pred(__it, __pred); }
 #endif

 } // namespace __gnu_debug

 #endif
	// Debugging support implementation -- C++ --

	// Copyright (C) 2003-2021 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 debug/functions.h
	* This file is a GNU debug extension to the Standard C++ Library.
	*/

	#ifndef _GLIBCXX_DEBUG_FUNCTIONS_H
	#define _GLIBCXX_DEBUG_FUNCTIONS_H 1

	#include <bits/stl_function.h> // for less

	#if __cplusplus >= 201103L
	# include <bits/stl_iterator.h> // for __miter_base
	# include <type_traits> // for is_lvalue_reference and __conditional_t.
	#endif

	#include <debug/helper_functions.h>
	#include <debug/formatter.h>

	namespace __gnu_debug
	{
	template<typename _Sequence>
	struct _Insert_range_from_self_is_safe
	{ enum { __value = 0 }; };

	template<typename _Sequence>
	struct _Is_contiguous_sequence : std::__false_type { };

	/* Checks that [first, last) is a valid range, and then returns
	* __first. This routine is useful when we can't use a separate
	* assertion statement because, e.g., we are in a constructor.
	*/
	template<typename _InputIterator>
	inline _InputIterator
	__check_valid_range(const _InputIterator& __first,
	const _InputIterator& __last,
	const char* __file,
	unsigned int __line,
	const char* __function)
	{
	__glibcxx_check_valid_range_at(__first, __last,
	__file, __line, __function);
	return __first;
	}

	/* Handle the case where __other is a pointer to _Sequence::value_type. */
	template<typename _Iterator, typename _Sequence, typename _Category>
	inline bool
	__foreign_iterator_aux4(
	const _Safe_iterator<_Iterator, _Sequence, _Category>& __it,
	const typename _Sequence::value_type* __other)
	{
	typedef const typename _Sequence::value_type* _PointerType;
	typedef std::less<_PointerType> _Less;
	#if __cplusplus >= 201103L
	constexpr _Less __l{};
	#else
	const _Less __l = _Less();
	#endif
	const _Sequence* __seq = __it._M_get_sequence();
	const _PointerType __begin = std::__addressof(*__seq->_M_base().begin());
	const _PointerType __end = std::__addressof(*(__seq->_M_base().end()-1));

	// Check whether __other points within the contiguous storage.
	return __l(__other, __begin) \|\| __l(__end, __other);
	}

	/* Fallback overload for when we can't tell, assume it is valid. */
	template<typename _Iterator, typename _Sequence, typename _Category>
	inline bool
	__foreign_iterator_aux4(
	const _Safe_iterator<_Iterator, _Sequence, _Category>&, ...)
	{ return true; }

	/* Handle sequences with contiguous storage */
	template<typename _Iterator, typename _Sequence, typename _Category,
	typename _InputIterator>
	inline bool
	__foreign_iterator_aux3(
	const _Safe_iterator<_Iterator, _Sequence, _Category>& __it,
	const _InputIterator& __other, const _InputIterator& __other_end,
	std::__true_type)
	{
	if (__other == __other_end)
	return true; // inserting nothing is safe even if not foreign iters
	if (__it._M_get_sequence()->empty())
	return true; // can't be self-inserting if self is empty
	return __foreign_iterator_aux4(__it, std::__addressof(*__other));
	}

	/* Handle non-contiguous containers, assume it is valid. */
	template<typename _Iterator, typename _Sequence, typename _Category,
	typename _InputIterator>
	inline bool
	__foreign_iterator_aux3(
	const _Safe_iterator<_Iterator, _Sequence, _Category>&,
	const _InputIterator&, const _InputIterator&,
	std::__false_type)
	{ return true; }

	/** Handle debug iterators from the same type of container. */
	template<typename _Iterator, typename _Sequence, typename _Category,
	typename _OtherIterator>
	inline bool
	__foreign_iterator_aux2(
	const _Safe_iterator<_Iterator, _Sequence, _Category>& __it,
	const _Safe_iterator<_OtherIterator, _Sequence, _Category>& __other,
	const _Safe_iterator<_OtherIterator, _Sequence, _Category>&)
	{ return __it._M_get_sequence() != __other._M_get_sequence(); }

	/** Handle debug iterators from different types of container. */
	template<typename _Iterator, typename _Sequence, typename _Category,
	typename _OtherIterator, typename _OtherSequence,
	typename _OtherCategory>
	inline bool
	__foreign_iterator_aux2(
	const _Safe_iterator<_Iterator, _Sequence, _Category>&,
	const _Safe_iterator<_OtherIterator, _OtherSequence,
	_OtherCategory>&,
	const _Safe_iterator<_OtherIterator, _OtherSequence,
	_OtherCategory>&)
	{ return true; }

	/* Handle non-debug iterators. */
	template<typename _Iterator, typename _Sequence, typename _Category,
	typename _InputIterator>
	inline bool
	__foreign_iterator_aux2(
	const _Safe_iterator<_Iterator, _Sequence, _Category>& __it,
	const _InputIterator& __other,
	const _InputIterator& __other_end)
	{
	#if __cplusplus < 201103L
	typedef _Is_contiguous_sequence<_Sequence> __tag;
	#else
	using __lvalref = std::is_lvalue_reference<
	typename std::iterator_traits<_InputIterator>::reference>;
	using __contiguous = _Is_contiguous_sequence<_Sequence>;
	using __tag = std::__conditional_t<__lvalref::value, __contiguous,
	std::__false_type>;
	#endif
	return __foreign_iterator_aux3(__it, __other, __other_end, __tag());
	}

	/* Handle the case where we aren't really inserting a range after all */
	template<typename _Iterator, typename _Sequence, typename _Category,
	typename _Integral>
	inline bool
	__foreign_iterator_aux(
	const _Safe_iterator<_Iterator, _Sequence, _Category>&,
	_Integral, _Integral, std::__true_type)
	{ return true; }

	/* Handle all iterators. */
	template<typename _Iterator, typename _Sequence, typename _Category,
	typename _InputIterator>
	inline bool
	__foreign_iterator_aux(
	const _Safe_iterator<_Iterator, _Sequence, _Category>& __it,
	_InputIterator __other, _InputIterator __other_end,
	std::__false_type)
	{
	return _Insert_range_from_self_is_safe<_Sequence>::__value
	\|\| __foreign_iterator_aux2(__it, std::__miter_base(__other),
	std::__miter_base(__other_end));
	}

	template<typename _Iterator, typename _Sequence, typename _Category,
	typename _InputIterator>
	inline bool
	__foreign_iterator(
	const _Safe_iterator<_Iterator, _Sequence, _Category>& __it,
	_InputIterator __other, _InputIterator __other_end)
	{
	typedef typename std::__is_integer<_InputIterator>::__type _Integral;
	return __foreign_iterator_aux(__it, __other, __other_end, _Integral());
	}

	// Can't check if an input iterator sequence is sorted, because we
	// can't step through the sequence.
	template<typename _InputIterator>
	_GLIBCXX20_CONSTEXPR
	inline bool
	__check_sorted_aux(const _InputIterator&, const _InputIterator&,
	std::input_iterator_tag)
	{ return true; }

	// Can verify if a forward iterator sequence is in fact sorted using
	// std::__is_sorted
	template<typename _ForwardIterator>
	_GLIBCXX20_CONSTEXPR
	inline bool
	__check_sorted_aux(_ForwardIterator __first, _ForwardIterator __last,
	std::forward_iterator_tag)
	{
	if (__first == __last)
	return true;

	_ForwardIterator __next = __first;
	for (++__next; __next != __last; __first = __next, (void)++__next)
	if (__next < __first)
	return false;

	return true;
	}

	// Can't check if an input iterator sequence is sorted, because we can't step
	// through the sequence.
	template<typename _InputIterator, typename _Predicate>
	_GLIBCXX20_CONSTEXPR
	inline bool
	__check_sorted_aux(const _InputIterator&, const _InputIterator&,
	_Predicate, std::input_iterator_tag)
	{ return true; }

	// Can verify if a forward iterator sequence is in fact sorted using
	// std::__is_sorted
	template<typename _ForwardIterator, typename _Predicate>
	_GLIBCXX20_CONSTEXPR
	inline bool
	__check_sorted_aux(_ForwardIterator __first, _ForwardIterator __last,
	_Predicate __pred, std::forward_iterator_tag)
	{
	if (__first == __last)
	return true;

	_ForwardIterator __next = __first;
	for (++__next; __next != __last; __first = __next, (void)++__next)
	if (__pred(__next, __first))
	return false;

	return true;
	}

	// Determine if a sequence is sorted.
	template<typename _InputIterator>
	_GLIBCXX20_CONSTEXPR
	inline bool
	__check_sorted(const _InputIterator& __first, const _InputIterator& __last)
	{
	return __check_sorted_aux(__first, __last,
	std::__iterator_category(__first));
	}

	template<typename _InputIterator, typename _Predicate>
	_GLIBCXX20_CONSTEXPR
	inline bool
	__check_sorted(const _InputIterator& __first, const _InputIterator& __last,
	_Predicate __pred)
	{
	return __check_sorted_aux(__first, __last, __pred,
	std::__iterator_category(__first));
	}

	template<typename _InputIterator>
	_GLIBCXX20_CONSTEXPR
	inline bool
	__check_sorted_set_aux(const _InputIterator& __first,
	const _InputIterator& __last,
	std::__true_type)
	{ return __check_sorted(__first, __last); }

	template<typename _InputIterator>
	_GLIBCXX20_CONSTEXPR
	inline bool
	__check_sorted_set_aux(const _InputIterator&,
	const _InputIterator&,
	std::__false_type)
	{ return true; }

	template<typename _InputIterator, typename _Predicate>
	_GLIBCXX20_CONSTEXPR
	inline bool
	__check_sorted_set_aux(const _InputIterator& __first,
	const _InputIterator& __last,
	_Predicate __pred, std::__true_type)
	{ return __check_sorted(__first, __last, __pred); }

	template<typename _InputIterator, typename _Predicate>
	_GLIBCXX20_CONSTEXPR
	inline bool
	__check_sorted_set_aux(const _InputIterator&,
	const _InputIterator&, _Predicate,
	std::__false_type)
	{ return true; }

	// ... special variant used in std::merge, std::includes, std::set_*.
	template<typename _InputIterator1, typename _InputIterator2>
	_GLIBCXX20_CONSTEXPR
	inline bool
	__check_sorted_set(const _InputIterator1& __first,
	const _InputIterator1& __last,
	const _InputIterator2&)
	{
	typedef typename std::iterator_traits<_InputIterator1>::value_type
	_ValueType1;
	typedef typename std::iterator_traits<_InputIterator2>::value_type
	_ValueType2;

	typedef typename std::__are_same<_ValueType1, _ValueType2>::__type
	_SameType;
	return __check_sorted_set_aux(__first, __last, _SameType());
	}

	template<typename _InputIterator1, typename _InputIterator2,
	typename _Predicate>
	_GLIBCXX20_CONSTEXPR
	inline bool
	__check_sorted_set(const _InputIterator1& __first,
	const _InputIterator1& __last,
	const _InputIterator2&, _Predicate __pred)
	{
	typedef typename std::iterator_traits<_InputIterator1>::value_type
	_ValueType1;
	typedef typename std::iterator_traits<_InputIterator2>::value_type
	_ValueType2;

	typedef typename std::__are_same<_ValueType1, _ValueType2>::__type
	_SameType;
	return __check_sorted_set_aux(__first, __last, __pred, _SameType());
	}

	// _GLIBCXX_RESOLVE_LIB_DEFECTS
	// 270. Binary search requirements overly strict
	// Determine if a sequence is partitioned w.r.t. this element.
	template<typename _ForwardIterator, typename _Tp>
	_GLIBCXX20_CONSTEXPR
	inline bool
	__check_partitioned_lower(_ForwardIterator __first,
	_ForwardIterator __last, const _Tp& __value)
	{
	while (__first != __last && *__first < __value)
	++__first;
	if (__first != __last)
	{
	++__first;
	while (__first != __last && !(*__first < __value))
	++__first;
	}
	return __first == __last;
	}

	template<typename _ForwardIterator, typename _Tp>
	_GLIBCXX20_CONSTEXPR
	inline bool
	__check_partitioned_upper(_ForwardIterator __first,
	_ForwardIterator __last, const _Tp& __value)
	{
	while (__first != __last && !(__value < *__first))
	++__first;
	if (__first != __last)
	{
	++__first;
	while (__first != __last && __value < *__first)
	++__first;
	}
	return __first == __last;
	}

	// Determine if a sequence is partitioned w.r.t. this element.
	template<typename _ForwardIterator, typename _Tp, typename _Pred>
	_GLIBCXX20_CONSTEXPR
	inline bool
	__check_partitioned_lower(_ForwardIterator __first,
	_ForwardIterator __last, const _Tp& __value,
	_Pred __pred)
	{
	while (__first != __last && bool(__pred(*__first, __value)))
	++__first;
	if (__first != __last)
	{
	++__first;
	while (__first != __last && !bool(__pred(*__first, __value)))
	++__first;
	}
	return __first == __last;
	}

	template<typename _ForwardIterator, typename _Tp, typename _Pred>
	_GLIBCXX20_CONSTEXPR
	inline bool
	__check_partitioned_upper(_ForwardIterator __first,
	_ForwardIterator __last, const _Tp& __value,
	_Pred __pred)
	{
	while (__first != __last && !bool(__pred(__value, *__first)))
	++__first;
	if (__first != __last)
	{
	++__first;
	while (__first != __last && bool(__pred(__value, *__first)))
	++__first;
	}
	return __first == __last;
	}

	#if __cplusplus >= 201103L
	struct _Irreflexive_checker
	{
	template<typename _It>
	static typename std::iterator_traits<_It>::reference
	__ref();

	template<typename _It,
	typename = decltype(__ref<_It>() < __ref<_It>())>
	_GLIBCXX20_CONSTEXPR
	static bool
	_S_is_valid(_It __it)
	{ return !(__it < __it); }

	// Fallback method if operator doesn't exist.
	template<typename... _Args>
	_GLIBCXX20_CONSTEXPR
	static bool
	_S_is_valid(_Args...)
	{ return true; }

	template<typename _It, typename _Pred, typename
	= decltype(std::declval<_Pred>()(__ref<_It>(), __ref<_It>()))>
	_GLIBCXX20_CONSTEXPR
	static bool
	_S_is_valid_pred(_It __it, _Pred __pred)
	{ return !__pred(__it, __it); }

	// Fallback method if predicate can't be invoked.
	template<typename... _Args>
	_GLIBCXX20_CONSTEXPR
	static bool
	_S_is_valid_pred(_Args...)
	{ return true; }
	};

	template<typename _Iterator>
	_GLIBCXX20_CONSTEXPR
	inline bool
	__is_irreflexive(_Iterator __it)
	{ return _Irreflexive_checker::_S_is_valid(__it); }

	template<typename _Iterator, typename _Pred>
	_GLIBCXX20_CONSTEXPR
	inline bool
	__is_irreflexive_pred(_Iterator __it, _Pred __pred)
	{ return _Irreflexive_checker::_S_is_valid_pred(__it, __pred); }
	#endif

	} // namespace __gnu_debug

	#endif