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d9ba0dd6 | 1 | // Debugging support implementation -*- C++ -*- |
2 | ||
f1717362 | 3 | // Copyright (C) 2003-2016 Free Software Foundation, Inc. |
d9ba0dd6 | 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/helper_functions.h | |
26 | * This file is a GNU debug extension to the Standard C++ Library. | |
27 | */ | |
28 | ||
29 | #ifndef _GLIBCXX_DEBUG_HELPER_FUNCTIONS_H | |
30 | #define _GLIBCXX_DEBUG_HELPER_FUNCTIONS_H 1 | |
31 | ||
32 | #include <bits/stl_iterator_base_types.h> // for iterator_traits, | |
33 | // categories and _Iter_base | |
34 | #include <bits/cpp_type_traits.h> // for __is_integer | |
35 | ||
36 | #include <bits/stl_pair.h> // for pair | |
37 | ||
38 | namespace __gnu_debug | |
39 | { | |
40 | /** The precision to which we can calculate the distance between | |
41 | * two iterators. | |
42 | */ | |
43 | enum _Distance_precision | |
44 | { | |
45 | __dp_none, // Not even an iterator type | |
46 | __dp_equality, //< Can compare iterator equality, only | |
47 | __dp_sign, //< Can determine equality and ordering | |
48 | __dp_exact //< Can determine distance precisely | |
49 | }; | |
50 | ||
51 | template<typename _Iterator, | |
52 | typename = typename std::__is_integer<_Iterator>::__type> | |
53 | struct _Distance_traits | |
54 | { | |
55 | private: | |
56 | typedef | |
57 | typename std::iterator_traits<_Iterator>::difference_type _ItDiffType; | |
58 | ||
59 | template<typename _DiffType, | |
60 | typename = typename std::__is_void<_DiffType>::__type> | |
61 | struct _DiffTraits | |
62 | { typedef _DiffType __type; }; | |
63 | ||
64 | template<typename _DiffType> | |
65 | struct _DiffTraits<_DiffType, std::__true_type> | |
66 | { typedef std::ptrdiff_t __type; }; | |
67 | ||
68 | typedef typename _DiffTraits<_ItDiffType>::__type _DiffType; | |
69 | ||
70 | public: | |
71 | typedef std::pair<_DiffType, _Distance_precision> __type; | |
72 | }; | |
73 | ||
74 | template<typename _Integral> | |
75 | struct _Distance_traits<_Integral, std::__true_type> | |
76 | { typedef std::pair<std::ptrdiff_t, _Distance_precision> __type; }; | |
77 | ||
78 | /** Determine the distance between two iterators with some known | |
79 | * precision. | |
80 | */ | |
81 | template<typename _Iterator> | |
82 | inline typename _Distance_traits<_Iterator>::__type | |
83 | __get_distance(const _Iterator& __lhs, const _Iterator& __rhs, | |
84 | std::random_access_iterator_tag) | |
85 | { return std::make_pair(__rhs - __lhs, __dp_exact); } | |
86 | ||
87 | template<typename _Iterator> | |
88 | inline typename _Distance_traits<_Iterator>::__type | |
89 | __get_distance(const _Iterator& __lhs, const _Iterator& __rhs, | |
90 | std::input_iterator_tag) | |
91 | { | |
92 | if (__lhs == __rhs) | |
93 | return std::make_pair(0, __dp_exact); | |
94 | ||
95 | return std::make_pair(1, __dp_equality); | |
96 | } | |
97 | ||
98 | template<typename _Iterator> | |
99 | inline typename _Distance_traits<_Iterator>::__type | |
100 | __get_distance(const _Iterator& __lhs, const _Iterator& __rhs) | |
101 | { return __get_distance(__lhs, __rhs, std::__iterator_category(__lhs)); } | |
102 | ||
103 | /** We say that integral types for a valid range, and defer to other | |
104 | * routines to realize what to do with integral types instead of | |
105 | * iterators. | |
106 | */ | |
107 | template<typename _Integral> | |
108 | inline bool | |
109 | __valid_range_aux(const _Integral&, const _Integral&, | |
110 | typename _Distance_traits<_Integral>::__type& __dist, | |
111 | std::__true_type) | |
112 | { | |
113 | __dist = std::make_pair(0, __dp_none); | |
114 | return true; | |
115 | } | |
116 | ||
117 | /** We have iterators, so figure out what kind of iterators that are | |
118 | * to see if we can check the range ahead of time. | |
119 | */ | |
120 | template<typename _InputIterator> | |
121 | inline bool | |
122 | __valid_range_aux(const _InputIterator& __first, | |
123 | const _InputIterator& __last, | |
124 | typename _Distance_traits<_InputIterator>::__type& __dist, | |
125 | std::__false_type) | |
126 | { | |
127 | __dist = __get_distance(__first, __last); | |
128 | switch (__dist.second) | |
129 | { | |
130 | case __dp_none: | |
131 | break; | |
132 | case __dp_equality: | |
133 | if (__dist.first == 0) | |
134 | return true; | |
135 | break; | |
136 | case __dp_sign: | |
137 | case __dp_exact: | |
138 | return __dist.first >= 0; | |
139 | } | |
140 | ||
141 | return true; | |
142 | } | |
143 | ||
144 | /** Don't know what these iterators are, or if they are even | |
145 | * iterators (we may get an integral type for InputIterator), so | |
146 | * see if they are integral and pass them on to the next phase | |
147 | * otherwise. | |
148 | */ | |
149 | template<typename _InputIterator> | |
150 | inline bool | |
151 | __valid_range(const _InputIterator& __first, const _InputIterator& __last, | |
152 | typename _Distance_traits<_InputIterator>::__type& __dist) | |
153 | { | |
154 | typedef typename std::__is_integer<_InputIterator>::__type _Integral; | |
155 | return __valid_range_aux(__first, __last, __dist, _Integral()); | |
156 | } | |
157 | ||
158 | template<typename _InputIterator> | |
159 | inline bool | |
160 | __valid_range(const _InputIterator& __first, const _InputIterator& __last) | |
161 | { | |
162 | typename _Distance_traits<_InputIterator>::__type __dist; | |
163 | return __valid_range(__first, __last, __dist); | |
164 | } | |
165 | ||
166 | #if __cplusplus < 201103L | |
167 | // Helper struct to detect random access safe iterators. | |
168 | template<typename _Iterator> | |
169 | struct __is_safe_random_iterator | |
170 | { | |
171 | enum { __value = 0 }; | |
172 | typedef std::__false_type __type; | |
173 | }; | |
174 | ||
175 | template<typename _Iterator> | |
176 | struct _Siter_base | |
177 | : std::_Iter_base<_Iterator, __is_safe_random_iterator<_Iterator>::__value> | |
178 | { }; | |
179 | ||
180 | /** Helper function to extract base iterator of random access safe iterator | |
181 | in order to reduce performance impact of debug mode. Limited to random | |
182 | access iterator because it is the only category for which it is possible | |
183 | to check for correct iterators order in the __valid_range function | |
184 | thanks to the < operator. | |
185 | */ | |
186 | template<typename _Iterator> | |
187 | inline typename _Siter_base<_Iterator>::iterator_type | |
188 | __base(_Iterator __it) | |
189 | { return _Siter_base<_Iterator>::_S_base(__it); } | |
190 | #else | |
191 | template<typename _Iterator> | |
192 | inline _Iterator | |
193 | __base(_Iterator __it) | |
194 | { return __it; } | |
195 | #endif | |
196 | ||
197 | #if __cplusplus < 201103L | |
198 | template<typename _Iterator> | |
199 | struct _Unsafe_type | |
200 | { typedef _Iterator _Type; }; | |
201 | #endif | |
202 | ||
203 | /* Remove debug mode safe iterator layer, if any. */ | |
204 | template<typename _Iterator> | |
205 | inline _Iterator | |
206 | __unsafe(_Iterator __it) | |
207 | { return __it; } | |
208 | } | |
209 | ||
210 | #endif |