libstdc++

safe_iterator.tcc
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1 // Debugging iterator implementation (out of line) -*- C++ -*-
2
3 // Copyright (C) 2003-2013 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_iterator.tcc
26 * This file is a GNU debug extension to the Standard C++ Library.
27 */
28
29 #ifndef _GLIBCXX_DEBUG_SAFE_ITERATOR_TCC
30 #define _GLIBCXX_DEBUG_SAFE_ITERATOR_TCC 1
31
32 namespace __gnu_debug
33 {
34 template<typename _Iterator, typename _Sequence>
35 bool
36 _Safe_iterator<_Iterator, _Sequence>::
37 _M_can_advance(const difference_type& __n) const
38 {
39 typedef typename _Sequence::const_iterator const_debug_iterator;
40 typedef typename const_debug_iterator::iterator_type const_iterator;
41
42 if (this->_M_singular())
43 return false;
44 if (__n == 0)
45 return true;
46 if (__n < 0)
47 {
48 const_iterator __begin = _M_get_sequence()->_M_base().begin();
49 std::pair<difference_type, _Distance_precision> __dist =
50 __get_distance(__begin, base());
51 bool __ok = ((__dist.second == __dp_exact && __dist.first >= -__n)
52 || (__dist.second != __dp_exact && __dist.first > 0));
53 return __ok;
54 }
55 else
56 {
57 const_iterator __end = _M_get_sequence()->_M_base().end();
58 std::pair<difference_type, _Distance_precision> __dist =
59 __get_distance(base(), __end);
60 bool __ok = ((__dist.second == __dp_exact && __dist.first >= __n)
61 || (__dist.second != __dp_exact && __dist.first > 0));
62 return __ok;
63 }
64 }
65
66 template<typename _Iterator, typename _Sequence>
67 template<typename _Other>
68 bool
69 _Safe_iterator<_Iterator, _Sequence>::
70 _M_valid_range(const _Safe_iterator<_Other, _Sequence>& __rhs) const
71 {
72 if (!_M_can_compare(__rhs))
73 return false;
74
75 /* Determine if we can order the iterators without the help of
76 the container */
77 std::pair<difference_type, _Distance_precision> __dist =
78 __get_distance(base(), __rhs.base());
79 switch (__dist.second) {
80 case __dp_equality:
81 if (__dist.first == 0)
82 return true;
83 break;
84
85 case __dp_sign:
86 case __dp_exact:
87 return __dist.first >= 0;
88 }
89
90 /* We can only test for equality, but check if one of the
91 iterators is at an extreme. */
92 /* Optim for classic [begin, it) or [it, end) ranges, limit checks
93 * when code is valid. Note, for the special case of forward_list,
94 * before_begin replaces the role of begin. */
95 if (_M_is_beginnest() || __rhs._M_is_end())
96 return true;
97 if (_M_is_end() || __rhs._M_is_beginnest())
98 return false;
99
100 // Assume that this is a valid range; we can't check anything else
101 return true;
102 }
103 } // namespace __gnu_debug
104
105 #endif
106