safe_iterator.tcc
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// Debugging iterator implementation (out of line) -*- C++ -*-
// Copyright (C) 2003-2026 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/safe_iterator.tcc
* This file is a GNU debug extension to the Standard C++ Library.
*/
#ifndef _GLIBCXX_DEBUG_SAFE_ITERATOR_TCC
#define _GLIBCXX_DEBUG_SAFE_ITERATOR_TCC 1
#include <bits/stl_algobase.h>
namespace __gnu_debug
{
template<typename _Iterator, typename _Sequence, typename _Category>
typename _Distance_traits<_Iterator>::__type
_Safe_iterator<_Iterator, _Sequence, _Category>::
_M_get_distance_from_begin() const
{
typedef _Sequence_traits<_Sequence> _SeqTraits;
// No need to consider before_begin as this function is only used in
// _M_can_advance which won't be used for forward_list iterators.
if (_M_is_begin())
return std::make_pair(0, __dp_exact);
if (_M_is_end())
return _SeqTraits::_S_size(*_M_get_sequence());
typename _Distance_traits<_Iterator>::__type __res
= __get_distance(_M_get_sequence()->_M_base().begin(), base());
if (__res.second == __dp_equality)
return std::make_pair(1, __dp_sign);
return __res;
}
template<typename _Iterator, typename _Sequence, typename _Category>
typename _Distance_traits<_Iterator>::__type
_Safe_iterator<_Iterator, _Sequence, _Category>::
_M_get_distance_to_end() const
{
typedef _Sequence_traits<_Sequence> _SeqTraits;
// No need to consider before_begin as this function is only used in
// _M_can_advance which won't be used for forward_list iterators.
if (_M_is_begin())
return _SeqTraits::_S_size(*_M_get_sequence());
if (_M_is_end())
return std::make_pair(0, __dp_exact);
typename _Distance_traits<_Iterator>::__type __res
= __get_distance(base(), _M_get_sequence()->_M_base().end());
if (__res.second == __dp_equality)
return std::make_pair(1, __dp_sign);
return __res;
}
template<typename _Iterator, typename _Sequence, typename _Category>
bool
_Safe_iterator<_Iterator, _Sequence, _Category>::
_M_can_advance(difference_type __n, bool __strict) const
{
if (this->_M_value_initialized() && __n == 0)
return true;
if (this->_M_singular())
return false;
if (__n == 0)
return true;
std::pair<difference_type, _Distance_precision> __dist = __n < 0
? _M_get_distance_from_begin()
: _M_get_distance_to_end();
if (__n < 0)
__n = -__n;
return __dist.second > __dp_sign
? __dist.first >= __n
: !__strict && __dist.first > 0;
}
template<typename _Iterator, typename _Sequence, typename _Category>
template<typename _Diff>
bool
_Safe_iterator<_Iterator, _Sequence, _Category>::
_M_can_advance(const std::pair<_Diff, _Distance_precision>& __dist,
int __way) const
{
return __dist.second == __dp_exact
? _M_can_advance(__way * __dist.first)
: _M_can_advance(__way * (__dist.first == 0
? 0
: __dist.first < 0 ? -1 : 1));
}
template<typename _Iterator, typename _Sequence, typename _Category>
typename _Distance_traits<_Iterator>::__type
_Safe_iterator<_Iterator, _Sequence, _Category>::
_M_get_distance_to(const _Safe_iterator& __rhs) const
{
typedef typename _Distance_traits<_Iterator>::__type _Dist;
typedef _Sequence_traits<_Sequence> _SeqTraits;
_Dist __base_dist = __get_distance(this->base(), __rhs.base());
if (__base_dist.second == __dp_exact)
return __base_dist;
_Dist __seq_dist = _SeqTraits::_S_size(*this->_M_get_sequence());
if (this->_M_is_before_begin())
{
if (__rhs._M_is_begin())
return std::make_pair(1, __dp_exact);
return __seq_dist.second == __dp_exact
? std::make_pair(__seq_dist.first + 1, __dp_exact)
: __seq_dist;
}
if (this->_M_is_begin())
{
if (__rhs._M_is_before_begin())
return std::make_pair(-1, __dp_exact);
if (__rhs._M_is_end())
return __seq_dist;
return std::make_pair(__seq_dist.first,
__seq_dist.second == __dp_exact
? __dp_sign_max_size : __seq_dist.second);
}
if (this->_M_is_end())
{
if (__rhs._M_is_before_begin())
return __seq_dist.second == __dp_exact
? std::make_pair(-__seq_dist.first - 1, __dp_exact)
: std::make_pair(-__seq_dist.first, __dp_sign);
if (__rhs._M_is_begin())
return std::make_pair(-__seq_dist.first, __seq_dist.second);
return std::make_pair(-__seq_dist.first,
__seq_dist.second == __dp_exact
? __dp_sign_max_size : __seq_dist.second);
}
if (__rhs._M_is_before_begin())
return __seq_dist.second == __dp_exact
? std::make_pair(__seq_dist.first - 1, __dp_exact)
: std::make_pair(-__seq_dist.first, __dp_sign);
if (__rhs._M_is_begin())
return std::make_pair(-__seq_dist.first,
__seq_dist.second == __dp_exact
? __dp_sign_max_size : __seq_dist.second);
if (__rhs._M_is_end())
return std::make_pair(__seq_dist.first,
__seq_dist.second == __dp_exact
? __dp_sign_max_size : __seq_dist.second);
return std::make_pair(1, __dp_equality);
}
template<typename _Iterator, typename _Sequence, typename _Category>
bool
_Safe_iterator<_Iterator, _Sequence, _Category>::
_M_valid_range(const _Safe_iterator& __rhs,
std::pair<difference_type, _Distance_precision>& __dist,
bool __check_dereferenceable) const
{
if (_M_value_initialized() && __rhs._M_value_initialized())
{
__dist = std::make_pair(0, __dp_exact);
return true;
}
if (_M_singular() || __rhs._M_singular() || !_M_can_compare(__rhs))
return false;
/* Determine iterators order */
__dist = _M_get_distance_to(__rhs);
if (__dist.second != __dp_equality)
{
// If range is not empty first iterator must be dereferenceable.
return __dist.first == 0
|| (__dist.first > 0
&& (!__check_dereferenceable || _M_dereferenceable()));
}
// Assume that this is a valid range; we can't check anything else.
return true;
}
template<typename _Iterator, typename _Sequence>
bool
_Safe_iterator<_Iterator, _Sequence, std::random_access_iterator_tag>::
_M_valid_range(const _Safe_iterator& __rhs,
std::pair<difference_type,
_Distance_precision>& __dist) const
{
if (this->_M_value_initialized() && __rhs._M_value_initialized())
{
__dist = std::make_pair(0, __dp_exact);
return true;
}
if (this->_M_singular() || __rhs._M_singular()
|| !this->_M_can_compare(__rhs))
return false;
/* Determine iterators order */
__dist = std::make_pair(__rhs.base() - this->base(), __dp_exact);
// If range is not empty first iterator must be dereferenceable.
return __dist.first == 0
|| (__dist.first > 0 && this->_M_dereferenceable());
}
} // namespace __gnu_debug
namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
#if __cplusplus < 201103L
template<typename _Ite, typename _Seq>
_Ite
__niter_base(const ::__gnu_debug::_Safe_iterator<_Ite, _Seq,
std::random_access_iterator_tag>& __it)
{ return __it.base(); }
template<typename _Ite, typename _Cont, typename _DbgSeq>
_Ite
__niter_base(const ::__gnu_debug::_Safe_iterator<
::__gnu_cxx::__normal_iterator<_Ite, _Cont>, _DbgSeq,
std::random_access_iterator_tag>& __it)
{ return __it.base().base(); }
#else
template<typename _Ite, typename _Seq>
_GLIBCXX20_CONSTEXPR
decltype(std::__niter_base(std::declval<_Ite>()))
__niter_base(const ::__gnu_debug::_Safe_iterator<_Ite, _Seq,
std::random_access_iterator_tag>& __it)
noexcept(std::is_nothrow_copy_constructible<_Ite>::value)
{ return std::__niter_base(__it.base()); }
#endif
template<bool _IsMove,
typename _Ite, typename _Seq, typename _Cat, typename _OI>
_GLIBCXX20_CONSTEXPR
_OI
__copy_move_a(
const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>& __first,
const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>& __last,
_OI __result)
{
typename ::__gnu_debug::_Distance_traits<_Ite>::__type __dist;
__glibcxx_check_valid_range2(__first, __last, __dist);
__glibcxx_check_can_increment_dist(__result, __dist, 1);
if (__dist.second > ::__gnu_debug::__dp_equality)
return std::__copy_move_a<_IsMove>(__first.base(), __last.base(),
__result);
return std::__copy_move_a1<_IsMove>(__first, __last, __result);
}
template<bool _IsMove,
typename _II, typename _Ite, typename _Seq, typename _Cat>
_GLIBCXX20_CONSTEXPR
__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>
__copy_move_a(_II __first, _II __last,
const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>& __result)
{
typename ::__gnu_debug::_Distance_traits<_II>::__type __dist;
__glibcxx_check_valid_range2(__first, __last, __dist);
__glibcxx_check_can_increment_dist(__result, __dist, 1);
if (__dist.second > ::__gnu_debug::__dp_sign
&& __result._M_can_advance(__dist.first, true))
return ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>(
std::__copy_move_a<_IsMove>(__first, __last, __result.base()),
__result._M_sequence);
return std::__copy_move_a1<_IsMove>(__first, __last, __result);
}
template<bool _IsMove,
typename _IIte, typename _ISeq, typename _ICat,
typename _OIte, typename _OSeq, typename _OCat>
_GLIBCXX20_CONSTEXPR
::__gnu_debug::_Safe_iterator<_OIte, _OSeq, _OCat>
__copy_move_a(
const ::__gnu_debug::_Safe_iterator<_IIte, _ISeq, _ICat>& __first,
const ::__gnu_debug::_Safe_iterator<_IIte, _ISeq, _ICat>& __last,
const ::__gnu_debug::_Safe_iterator<_OIte, _OSeq, _OCat>& __result)
{
typename ::__gnu_debug::_Distance_traits<_IIte>::__type __dist;
__glibcxx_check_valid_range2(__first, __last, __dist);
__glibcxx_check_can_increment_dist(__result, __dist, 1);
if (__dist.second > ::__gnu_debug::__dp_equality)
{
if (__dist.second > ::__gnu_debug::__dp_sign
&& __result._M_can_advance(__dist.first, true))
return ::__gnu_debug::_Safe_iterator<_OIte, _OSeq, _OCat>(
std::__copy_move_a<_IsMove>(__first.base(), __last.base(),
__result.base()),
__result._M_sequence);
return std::__copy_move_a<_IsMove>(__first.base(), __last.base(),
__result);
}
return std::__copy_move_a1<_IsMove>(__first, __last, __result);
}
template<bool _IsMove,
typename _Ite, typename _Seq, typename _Cat, typename _OI>
_GLIBCXX20_CONSTEXPR
_OI
__copy_move_backward_a(
const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>& __first,
const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>& __last,
_OI __result)
{
typename ::__gnu_debug::_Distance_traits<_Ite>::__type __dist;
__glibcxx_check_valid_range2(__first, __last, __dist);
__glibcxx_check_can_increment_dist(__result, __dist, -1);
if (__dist.second > ::__gnu_debug::__dp_equality)
return std::__copy_move_backward_a<_IsMove>(
__first.base(), __last.base(), __result);
return std::__copy_move_backward_a1<_IsMove>(__first, __last, __result);
}
template<bool _IsMove,
typename _II, typename _Ite, typename _Seq, typename _Cat>
_GLIBCXX20_CONSTEXPR
__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>
__copy_move_backward_a(_II __first, _II __last,
const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>& __result)
{
typename ::__gnu_debug::_Distance_traits<_II>::__type __dist;
__glibcxx_check_valid_range2(__first, __last, __dist);
__glibcxx_check_can_increment_dist(__result, __dist, -1);
if (__dist.second > ::__gnu_debug::__dp_sign
&& __result._M_can_advance(-__dist.first, true))
return ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>(
std::__copy_move_backward_a<_IsMove>(__first, __last,
__result.base()),
__result._M_sequence);
return std::__copy_move_backward_a1<_IsMove>(__first, __last, __result);
}
template<bool _IsMove,
typename _IIte, typename _ISeq, typename _ICat,
typename _OIte, typename _OSeq, typename _OCat>
_GLIBCXX20_CONSTEXPR
::__gnu_debug::_Safe_iterator<_OIte, _OSeq, _OCat>
__copy_move_backward_a(
const ::__gnu_debug::_Safe_iterator<_IIte, _ISeq, _ICat>& __first,
const ::__gnu_debug::_Safe_iterator<_IIte, _ISeq, _ICat>& __last,
const ::__gnu_debug::_Safe_iterator<_OIte, _OSeq, _OCat>& __result)
{
typename ::__gnu_debug::_Distance_traits<_IIte>::__type __dist;
__glibcxx_check_valid_range2(__first, __last, __dist);
__glibcxx_check_can_increment_dist(__result, __dist, -1);
if (__dist.second > ::__gnu_debug::__dp_equality)
{
if (__dist.second > ::__gnu_debug::__dp_sign
&& __result._M_can_advance(-__dist.first, true))
return ::__gnu_debug::_Safe_iterator<_OIte, _OSeq, _OCat>(
std::__copy_move_backward_a<_IsMove>(__first.base(), __last.base(),
__result.base()),
__result._M_sequence);
return std::__copy_move_backward_a<_IsMove>(
__first.base(), __last.base(), __result);
}
return std::__copy_move_backward_a1<_IsMove>(__first, __last, __result);
}
template<typename _Ite, typename _Seq, typename _Cat, typename _Tp>
_GLIBCXX20_CONSTEXPR
void
__fill_a(const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>& __first,
const ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>& __last,
const _Tp& __value)
{
typename ::__gnu_debug::_Distance_traits<_Ite>::__type __dist;
__glibcxx_check_valid_range2(__first, __last, __dist);
if (__dist.second > ::__gnu_debug::__dp_equality)
std::__fill_a(__first.base(), __last.base(), __value);
std::__fill_a1(__first, __last, __value);
}
template<typename _Ite, typename _Seq, typename _Cat, typename _Size,
typename _Tp>
_GLIBCXX20_CONSTEXPR
::__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)
{
#if __cplusplus >= 201103L
static_assert(is_integral<_Size>{}, "fill_n must pass integral size");
#endif
if (__n <= 0)
return __first;
__glibcxx_check_can_increment(__first, __n);
if (__first._M_can_advance(__n, true))
return ::__gnu_debug::_Safe_iterator<_Ite, _Seq, _Cat>(
std::__fill_n_a(__first.base(), __n, __value, _Cat()),
__first._M_sequence);
return std::__fill_n_a1(__first, __n, __value);
}
template<typename _II1, typename _Seq1, typename _Cat1, typename _II2>
_GLIBCXX20_CONSTEXPR
bool
__equal_aux(
const ::__gnu_debug::_Safe_iterator<_II1, _Seq1, _Cat1>& __first1,
const ::__gnu_debug::_Safe_iterator<_II1, _Seq1, _Cat1>& __last1,
_II2 __first2)
{
typename ::__gnu_debug::_Distance_traits<_II1>::__type __dist;
__glibcxx_check_valid_range2(__first1, __last1, __dist);
__glibcxx_check_can_increment_dist(__first2, __dist, 1);
if (__dist.second > ::__gnu_debug::__dp_equality)
return std::__equal_aux(__first1.base(), __last1.base(), __first2);
return std::__equal_aux1(__first1, __last1, __first2);
}
template<typename _II1, typename _II2, typename _Seq2, typename _Cat2>
_GLIBCXX20_CONSTEXPR
bool
__equal_aux(_II1 __first1, _II1 __last1,
const ::__gnu_debug::_Safe_iterator<_II2, _Seq2, _Cat2>& __first2)
{
typename ::__gnu_debug::_Distance_traits<_II1>::__type __dist;
__glibcxx_check_valid_range2(__first1, __last1, __dist);
__glibcxx_check_can_increment_dist(__first2, __dist, 1);
if (__dist.second > ::__gnu_debug::__dp_sign
&& __first2._M_can_advance(__dist.first, true))
return std::__equal_aux(__first1, __last1, __first2.base());
return std::__equal_aux1(__first1, __last1, __first2);
}
template<typename _II1, typename _Seq1, typename _Cat1,
typename _II2, typename _Seq2, typename _Cat2>
_GLIBCXX20_CONSTEXPR
bool
__equal_aux(
const ::__gnu_debug::_Safe_iterator<_II1, _Seq1, _Cat1>& __first1,
const ::__gnu_debug::_Safe_iterator<_II1, _Seq1, _Cat1>& __last1,
const ::__gnu_debug::_Safe_iterator<_II2, _Seq2, _Cat2>& __first2)
{
typename ::__gnu_debug::_Distance_traits<_II1>::__type __dist;
__glibcxx_check_valid_range2(__first1, __last1, __dist);
__glibcxx_check_can_increment_dist(__first2, __dist, 1);
if (__dist.second > ::__gnu_debug::__dp_equality)
{
if (__dist.second > ::__gnu_debug::__dp_sign &&
__first2._M_can_advance(__dist.first, true))
return std::__equal_aux(__first1.base(), __last1.base(),
__first2.base());
return std::__equal_aux(__first1.base(), __last1.base(), __first2);
}
return __equal_aux1(__first1, __last1, __first2);
}
template<typename _Ite1, typename _Seq1, typename _Cat1,
typename _II2>
_GLIBCXX20_CONSTEXPR
bool
__lexicographical_compare_aux(
const ::__gnu_debug::_Safe_iterator<_Ite1, _Seq1, _Cat1>& __first1,
const ::__gnu_debug::_Safe_iterator<_Ite1, _Seq1, _Cat1>& __last1,
_II2 __first2, _II2 __last2)
{
typename ::__gnu_debug::_Distance_traits<_Ite1>::__type __dist1;
__glibcxx_check_valid_range2(__first1, __last1, __dist1);
__glibcxx_check_valid_range(__first2, __last2);
if (__dist1.second > ::__gnu_debug::__dp_equality)
return std::__lexicographical_compare_aux(__first1.base(),
__last1.base(),
__first2, __last2);
return std::__lexicographical_compare_aux1(__first1, __last1,
__first2, __last2);
}
template<typename _II1,
typename _Ite2, typename _Seq2, typename _Cat2>
_GLIBCXX20_CONSTEXPR
bool
__lexicographical_compare_aux(
_II1 __first1, _II1 __last1,
const ::__gnu_debug::_Safe_iterator<_Ite2, _Seq2, _Cat2>& __first2,
const ::__gnu_debug::_Safe_iterator<_Ite2, _Seq2, _Cat2>& __last2)
{
__glibcxx_check_valid_range(__first1, __last1);
typename ::__gnu_debug::_Distance_traits<_II1>::__type __dist2;
__glibcxx_check_valid_range2(__first2, __last2, __dist2);
if (__dist2.second > ::__gnu_debug::__dp_equality)
return std::__lexicographical_compare_aux(__first1, __last1,
__first2.base(),
__last2.base());
return std::__lexicographical_compare_aux1(__first1, __last1,
__first2, __last2);
}
template<typename _Ite1, typename _Seq1, typename _Cat1,
typename _Ite2, typename _Seq2, typename _Cat2>
_GLIBCXX20_CONSTEXPR
bool
__lexicographical_compare_aux(
const ::__gnu_debug::_Safe_iterator<_Ite1, _Seq1, _Cat1>& __first1,
const ::__gnu_debug::_Safe_iterator<_Ite1, _Seq1, _Cat1>& __last1,
const ::__gnu_debug::_Safe_iterator<_Ite2, _Seq2, _Cat2>& __first2,
const ::__gnu_debug::_Safe_iterator<_Ite2, _Seq2, _Cat2>& __last2)
{
typename ::__gnu_debug::_Distance_traits<_Ite1>::__type __dist1;
__glibcxx_check_valid_range2(__first1, __last1, __dist1);
typename ::__gnu_debug::_Distance_traits<_Ite2>::__type __dist2;
__glibcxx_check_valid_range2(__first2, __last2, __dist2);
if (__dist1.second > ::__gnu_debug::__dp_equality)
{
if (__dist2.second > ::__gnu_debug::__dp_equality)
return std::__lexicographical_compare_aux(__first1.base(),
__last1.base(),
__first2.base(),
__last2.base());
return std::__lexicographical_compare_aux(__first1.base(),
__last1.base(),
__first2, __last2);
}
if (__dist2.second > ::__gnu_debug::__dp_equality)
return std::__lexicographical_compare_aux(__first1, __last1,
__first2.base(),
__last2.base());
return std::__lexicographical_compare_aux1(__first1, __last1,
__first2, __last2);
}
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace std
#endif
stl_algobase.h
std::pair::pair
pair(_T1, _T2) -> pair< _T1, _T2 >
Two pairs are equal iff their members are equal.
std::make_pair
constexpr pair< typename __decay_and_strip< _T1 >::__type, typename __decay_and_strip< _T2 >::__type > make_pair(_T1 &&__x, _T2 &&__y)
A convenience wrapper for creating a pair from two objects.
Definition stl_pair.h:1166
std::declval
auto declval() noexcept -> decltype(__declval< _Tp >(0))
Definition type_traits:2714
std
ISO C++ entities toplevel namespace is std.
__gnu_debug
GNU debug classes for public use.
Definition boost_concept_check.h:60
__gnu_debug::_Distance_precision
_Distance_precision
Definition helper_functions.h:55
__gnu_debug::__get_distance
constexpr _Distance_traits< _Iterator >::__type __get_distance(_Iterator __lhs, _Iterator __rhs, std::random_access_iterator_tag)
Definition helper_functions.h:101
std::is_integral
is_integral
Definition type_traits:541
__gnu_debug::_Safe_iterator
Safe iterator wrapper.
Definition safe_iterator.h:133
std::pair::first
_T1 first
The first member.
Definition stl_pair.h:308
std::pair::second
_T2 second
The second member.
Definition stl_pair.h:309
__gnu_debug::_Sequence_traits
Definition safe_iterator.h:104