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08036331 | 1 | /* A safe iterator for GDB, the GNU debugger. |
42a4f53d | 2 | Copyright (C) 2018-2019 Free Software Foundation, Inc. |
08036331 PA |
3 | |
4 | This file is part of GDB. | |
5 | ||
6 | This program is free software; you can redistribute it and/or modify | |
7 | it under the terms of the GNU General Public License as published by | |
8 | the Free Software Foundation; either version 3 of the License, or | |
9 | (at your option) any later version. | |
10 | ||
11 | This program 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 | You should have received a copy of the GNU General Public License | |
17 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ | |
18 | ||
1a5c2598 TT |
19 | #ifndef COMMON_SAFE_ITERATOR_H |
20 | #define COMMON_SAFE_ITERATOR_H | |
08036331 PA |
21 | |
22 | /* A forward iterator that wraps Iterator, such that when iterating | |
23 | with iterator IT, it is possible to delete *IT without invalidating | |
24 | IT. Suitably wrapped in a range type and used with range-for, this | |
25 | allow convenient patterns like this: | |
26 | ||
27 | // range_safe() returns a range type whose begin()/end() methods | |
28 | // return safe iterators. | |
29 | for (foo *f : range_safe ()) | |
30 | { | |
31 | if (f->should_delete ()) | |
32 | { | |
33 | // The ++it operation implicitly done by the range-for is | |
34 | // still OK after this. | |
35 | delete f; | |
36 | } | |
37 | } | |
38 | */ | |
39 | ||
40 | template<typename Iterator> | |
41 | class basic_safe_iterator | |
42 | { | |
43 | public: | |
44 | typedef basic_safe_iterator self_type; | |
45 | typedef typename Iterator::value_type value_type; | |
46 | typedef typename Iterator::reference reference; | |
47 | typedef typename Iterator::pointer pointer; | |
48 | typedef typename Iterator::iterator_category iterator_category; | |
49 | typedef typename Iterator::difference_type difference_type; | |
50 | ||
51 | /* Construct by forwarding all arguments to the underlying | |
52 | iterator. */ | |
53 | template<typename... Args> | |
54 | explicit basic_safe_iterator (Args &&...args) | |
55 | : m_it (std::forward<Args> (args)...), | |
56 | m_next (m_it) | |
57 | { | |
58 | if (m_it != m_end) | |
59 | ++m_next; | |
60 | } | |
61 | ||
62 | /* Create a one-past-end iterator. */ | |
63 | basic_safe_iterator () | |
64 | {} | |
65 | ||
66 | value_type operator* () const { return *m_it; } | |
67 | ||
68 | self_type &operator++ () | |
69 | { | |
70 | m_it = m_next; | |
71 | if (m_it != m_end) | |
72 | ++m_next; | |
73 | return *this; | |
74 | } | |
75 | ||
76 | bool operator== (const self_type &other) const | |
77 | { return m_it == other.m_it; } | |
78 | ||
79 | bool operator!= (const self_type &other) const | |
80 | { return m_it != other.m_it; } | |
81 | ||
82 | private: | |
83 | /* The current element. */ | |
84 | Iterator m_it {}; | |
85 | ||
86 | /* The next element. Always one element ahead of M_IT. */ | |
87 | Iterator m_next {}; | |
88 | ||
89 | /* A one-past-end iterator. */ | |
90 | Iterator m_end {}; | |
91 | }; | |
92 | ||
1a5c2598 | 93 | #endif /* COMMON_SAFE_ITERATOR_H */ |