1 // Safe sequence implementation -*- C++ -*-
2
3 // Copyright (C) 2003-2023 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
37 namespace __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