1// Safe sequence implementation  -*- C++ -*-
2
3// Copyright (C) 2003-2022 Free Software Foundation, Inc.
4//
5// This file is part of the GNU ISO C++ Library.  This library is free
6// software; you can redistribute it and/or modify it under the
7// terms of the GNU General Public License as published by the
8// Free Software Foundation; either version 3, or (at your option)
9// any later version.
10
11// This library is distributed in the hope that it will be useful,
12// but WITHOUT ANY WARRANTY; without even the implied warranty of
13// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14// GNU General Public License for more details.
15
16// Under Section 7 of GPL version 3, you are granted additional
17// permissions described in the GCC Runtime Library Exception, version
18// 3.1, as published by the Free Software Foundation.
19
20// You should have received a copy of the GNU General Public License and
21// a copy of the GCC Runtime Library Exception along with this program;
22// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
23// <http://www.gnu.org/licenses/>.
24
25/** @file debug/safe_sequence.h
26 *  This file is a GNU debug extension to the Standard C++ Library.
27 */
28
29#ifndef _GLIBCXX_DEBUG_SAFE_SEQUENCE_H
30#define _GLIBCXX_DEBUG_SAFE_SEQUENCE_H 1
31
32#include <debug/assertions.h>
33#include <debug/macros.h>
34#include <debug/functions.h>
35#include <debug/safe_base.h>
36
37namespace __gnu_debug
38{
39  /** A simple function object that returns true if the passed-in
40   *  value is not equal to the stored value. It saves typing over
41   *  using both bind1st and not_equal.
42   */
43  template<typename _Type>
44    class _Not_equal_to
45    {
46      _Type __value;
47
48    public:
49      explicit _Not_equal_to(const _Type& __v) : __value(__v) { }
50
51      bool
52      operator()(const _Type& __x) const
53      { return __value != __x; }
54    };
55
56  /** A simple function object that returns true if the passed-in
57   *  value is equal to the stored value. */
58  template <typename _Type>
59    class _Equal_to
60    {
61      _Type __value;
62
63    public:
64      explicit _Equal_to(const _Type& __v) : __value(__v) { }
65
66      bool
67      operator()(const _Type& __x) const
68      { return __value == __x; }
69    };
70
71  /** A function object that returns true when the given random access
72      iterator is at least @c n steps away from the given iterator. */
73  template<typename _Iterator>
74    class _After_nth_from
75    {
76      typedef typename std::iterator_traits<_Iterator>::difference_type
77      difference_type;
78
79      _Iterator _M_base;
80      difference_type _M_n;
81
82    public:
83      _After_nth_from(const difference_type& __n, const _Iterator& __base)
84      : _M_base(__base), _M_n(__n) { }
85
86      bool
87      operator()(const _Iterator& __x) const
88      { return __x - _M_base >= _M_n; }
89    };
90
91  /**
92   * @brief Base class for constructing a @a safe sequence type that
93   * tracks iterators that reference it.
94   *
95   * The class template %_Safe_sequence simplifies the construction of
96   * @a safe sequences that track the iterators that reference the
97   * sequence, so that the iterators are notified of changes in the
98   * sequence that may affect their operation, e.g., if the container
99   * invalidates its iterators or is destructed. This class template
100   * may only be used by deriving from it and passing the name of the
101   * derived class as its template parameter via the curiously
102   * recurring template pattern. The derived class must have @c
103   * iterator and @c const_iterator types that are instantiations of
104   * class template _Safe_iterator for this sequence. Iterators will
105   * then be tracked automatically.
106   */
107  template<typename _Sequence>
108    class _Safe_sequence : public _Safe_sequence_base
109    {
110    public:
111      /** Invalidates all iterators @c x that reference this sequence,
112	  are not singular, and for which @c __pred(x) returns @c
113	  true. @c __pred will be invoked with the normal iterators nested
114	  in the safe ones. */
115      template<typename _Predicate>
116	void
117	_M_invalidate_if(_Predicate __pred);
118
119      /** Transfers all iterators @c x that reference @c from sequence,
120	  are not singular, and for which @c __pred(x) returns @c
121	  true. @c __pred will be invoked with the normal iterators nested
122	  in the safe ones. */
123      template<typename _Predicate>
124	void
125	_M_transfer_from_if(_Safe_sequence& __from, _Predicate __pred);
126    };
127
128  /// Like _Safe_sequence but with a special _M_invalidate_all implementation
129  /// not invalidating past-the-end iterators. Used by node based sequence.
130  template<typename _Sequence>
131    class _Safe_node_sequence
132    : public _Safe_sequence<_Sequence>
133    {
134    protected:
135      void
136      _M_invalidate_all()
137      {
138	typedef typename _Sequence::const_iterator _Const_iterator;
139	typedef typename _Const_iterator::iterator_type _Base_const_iterator;
140	typedef __gnu_debug::_Not_equal_to<_Base_const_iterator> _Not_equal;
141	const _Sequence& __seq = *static_cast<_Sequence*>(this);
142	this->_M_invalidate_if(_Not_equal(__seq._M_base().end()));
143      }
144    };
145
146} // namespace __gnu_debug
147
148#include <debug/safe_sequence.tcc>
149
150#endif
151